WO2021166309A1 - Electrically heated carrier and exhaust gas purification device - Google Patents
Electrically heated carrier and exhaust gas purification device Download PDFInfo
- Publication number
- WO2021166309A1 WO2021166309A1 PCT/JP2020/035865 JP2020035865W WO2021166309A1 WO 2021166309 A1 WO2021166309 A1 WO 2021166309A1 JP 2020035865 W JP2020035865 W JP 2020035865W WO 2021166309 A1 WO2021166309 A1 WO 2021166309A1
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- WIPO (PCT)
- Prior art keywords
- metal
- honeycomb structure
- electrode
- columnar honeycomb
- electrically heated
- Prior art date
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Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J33/00—Protection of catalysts, e.g. by coating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
- B01J35/56—Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/81—Coating or impregnation
- C04B41/85—Coating or impregnation with inorganic materials
- C04B41/87—Ceramics
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/02—Details
- H05B3/03—Electrodes
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
- H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
Definitions
- the present invention relates to an electrically heated carrier and an exhaust gas purifying device.
- EHC electric heating catalyst
- Patent Document 1 a pair of metal terminals are joined to a pair of electrode layers arranged on the outer surface of the outer peripheral side wall of the honeycomb structure portion via one or two or more welded portions.
- Honeycomb structures are disclosed.
- a base layer is arranged in a spot shape on a pair of electrode layers arranged on the outer peripheral wall of the honeycomb structure, and the electrode portions are electrically joined via the base layer.
- a carrier for an electrically heated catalyst is disclosed.
- the conductive honeycomb structure described in Patent Document 1 is welded by applying thermal energy to a part between the ceramics and the conductive connecting member (metal electrode), but in order to obtain a large connection area, the metal electrode is used. Must be pressed against the ceramics to fix it.
- the metal electrode if a metal having high hardness is used as the metal electrode, the ceramics may be broken at the time of fixing.
- there is a correlation between hardness and tensile strength and if a metal with low hardness is used as the metal electrode, the tensile strength will be low, and vibration stress applied during driving of the automobile cannot be interfered with, resulting in disconnection. there were.
- the pressing of the metal electrode is weakened in order to suppress the destruction of the ceramics at the time of fixing, there is a problem that the contact points with the ceramics are reduced and the strength of the joint portion is lowered.
- the present invention has been created in view of the above circumstances, and the honeycomb structure is destroyed when the metal electrode is fixed to the honeycomb structure, the metal electrode is broken due to vibration, and the metal electrode and the honeycomb structure are joined to each other.
- An object of the present invention is to provide an electrically heated carrier and an exhaust gas purifying device capable of satisfactorily suppressing a decrease in the strength of each part.
- the electrically heated carrier according to (1) and A metal can body holding the electrically heated carrier and Exhaust gas purification device with.
- the destruction of the honeycomb structure when fixing the metal electrode to the honeycomb structure, the disconnection of the metal electrode due to vibration, and the decrease in the strength of the joint portion between the metal electrode and the honeycomb structure are all satisfactorily satisfied. It is possible to provide an electrically heated carrier and an exhaust gas purifying device that can be suppressed.
- FIG. 5 is a schematic cross-sectional view perpendicular to the stretching direction of the cell of the electroheated carrier according to the embodiment of the present invention. It is a schematic appearance figure of the columnar honeycomb structure and the electrode layer in embodiment of this invention.
- FIG. 5 is a schematic cross-sectional view of a columnar honeycomb structure, an electrode layer, a mixed layer, a metal material, and a metal electrode according to an embodiment of the present invention.
- FIG. 5 is a schematic cross-sectional view of a columnar honeycomb structure, an electrode layer, an intermediate layer, a mixed layer, a metal material, and a metal electrode according to an embodiment of the present invention. It is a top view which shows the arrangement example of the metal material of the electric heating type carrier in embodiment of this invention.
- FIG. 1 is a schematic cross-sectional view of the electroheated carrier 10 according to the embodiment of the present invention, which is perpendicular to the stretching direction of the cell.
- the electrically heated carrier 10 includes a columnar honeycomb structure 11, electrode layers 13a and 13b arranged on the surface of the outer peripheral wall 12 of the columnar honeycomb structure 11, and a mixed layer 20a provided on the electrode layers 13a and 13b. , 20b, metal materials 16a and 16b provided on the mixed layers 20a and 20b, and metal electrodes 14a and 14b provided on the metal materials 16a and 16b.
- FIG. 2 shows a schematic external view of the columnar honeycomb structure 11 and the electrode layers 13a and 13b according to the embodiment of the present invention.
- the columnar honeycomb structure 11 includes an outer peripheral wall 12 and a partition wall 19 which is arranged inside the outer peripheral wall 12 and which partitions a plurality of cells 18 which penetrate from one end face to the other end face to form a flow path. Have.
- the outer shape of the columnar honeycomb structure 11 is not particularly limited as long as it is columnar. , Octagon, etc.) can be shaped like a columnar shape. Further, the size of the columnar honeycomb structure 11 is preferably 2000 to 20000 mm 2 and preferably 5000 to 15000 mm for the reason of improving heat resistance (suppressing cracks entering the circumferential direction of the outer peripheral wall). it is more preferably 2.
- the columnar honeycomb structure 11 is made of ceramics and has conductivity. As long as the conductive columnar honeycomb structure 11 is energized and can generate heat by Joule heat, the electrical resistivity of the ceramic is not particularly limited, but is preferably 0.1 to 200 ⁇ cm, preferably 1 to 200 ⁇ cm. More preferably, it is 10 to 100 ⁇ cm. In the present invention, the electrical resistivity of the columnar honeycomb structure 11 is a value measured at 25 ° C. by the four-terminal method.
- the material of the columnar honeycomb structure 11 is not limited, but includes a group consisting of oxide-based ceramics such as alumina, mullite, zirconia and cordierite, and non-oxide ceramics such as silicon carbide, silicon nitride and aluminum nitride. You can choose. Further, a silicon carbide-metal silicon composite material, a silicon carbide / graphite composite material, or the like can also be used. Among these, from the viewpoint of achieving both heat resistance and conductivity, the material of the columnar honeycomb structure 11 preferably contains a silicon-silicon carbide composite material or ceramics containing silicon carbide as a main component.
- the columnar honeycomb structure 11 When the material of the columnar honeycomb structure 11 is mainly composed of a silicon-silicon carbide composite material, the columnar honeycomb structure 11 contains the silicon-silicon carbide composite material (total mass) as a total of 90 masses. It means that it contains% or more.
- the silicon-silicon carbide composite material contains silicon carbide particles as an aggregate and silicon as a binder for binding the silicon carbide particles, and a plurality of silicon carbide particles are formed between the silicon carbide particles. It is preferably bonded by silicon so as to form pores.
- the material of the columnar honeycomb structure 11 is mainly composed of silicon carbide, it means that the columnar honeycomb structure 11 contains silicon carbide (total mass) in an amount of 90% by mass or more of the whole. means.
- the “mass of silicon carbide particles as aggregate” contained in the columnar honeycomb structure 11 and the columnar honeycomb structure 11 are contained.
- the ratio of the "mass of silicon as a binder" contained in the columnar honeycomb structure 11 to the total of the "mass of silicon as a composite” is preferably 10 to 40% by mass, preferably 15 to 35. It is more preferably mass%.
- the shape of the cell in the cross section perpendicular to the extending direction of the cell 18 is not limited, but it is preferably a quadrangle, a hexagon, an octagon, or a combination thereof. Among these, a quadrangle and a hexagon are preferable. A quadrangle is particularly preferable from the viewpoint of easily achieving both structural strength and heating uniformity.
- the thickness of the partition wall 19 for partitioning the cell 18 is preferably 0.1 to 0.3 mm, more preferably 0.15 to 0.25 mm.
- the thickness of the partition wall 19 is defined as the length of a portion of a line segment connecting the centers of gravity of adjacent cells 18 that passes through the partition wall 19 in a cross section perpendicular to the extending direction of the cell 18.
- the columnar honeycomb structure 11 preferably has a cell density of 40 to 150 cells / cm 2 , and more preferably 70 to 100 cells / cm 2 in a cross section perpendicular to the flow path direction of the cells 18.
- the cell density is a value obtained by dividing the number of cells by the area of one bottom surface portion of the columnar honeycomb structure 11 excluding the outer peripheral wall 12 portion.
- the thickness of the outer peripheral wall 12 is preferably 0.1 mm or more, more preferably 0.15 mm or more, and even more preferably 0.2 mm or more.
- the thickness of the outer peripheral wall 12 is preferably 1.0 mm or less. , More preferably 0.7 mm or less, and even more preferably 0.5 mm or less.
- the thickness of the outer peripheral wall 12 is the normal direction with respect to the tangent line of the outer peripheral wall 12 at the measurement location when the portion of the outer peripheral wall 12 whose thickness is to be measured is observed in a cross section perpendicular to the extending direction of the cell. Defined as thickness.
- the partition wall 19 can be made porous.
- the porosity of the partition wall 19 is preferably 35 to 60%, more preferably 35 to 45%. Porosity is a value measured by a mercury porosimeter.
- the average pore diameter of the partition wall 19 of the columnar honeycomb structure 11 is preferably 2 to 15 ⁇ m, more preferably 4 to 8 ⁇ m.
- the average pore diameter is a value measured by a mercury porosimeter.
- Electrode layers 13a and 13b are arranged on the surface of the outer peripheral wall 12 of the columnar honeycomb structure 11.
- the electrode layers 13a and 13b may be a pair of electrode layers 13a and 13b arranged so as to face each other with the central axis of the columnar honeycomb structure 11 interposed therebetween. Further, the electrode layers 13a and 13b may not be provided.
- each of the electrode layers 13a and 13b is formed on the outer surface of the outer peripheral wall 12 of the outer peripheral wall 12. It is preferable to extend the cells in a strip shape in the circumferential direction and the extending direction of the cell. Specifically, each of the electrode layers 13a and 13b has a length of 80% or more, preferably a length of 90% or more, and more preferably a total length between both bottom surfaces of the columnar honeycomb structure 11. It is desirable that the current extends over the electrode layers 13a and 13b from the viewpoint that the current easily spreads in the axial direction.
- the thickness of each of the electrode layers 13a and 13b is preferably 0.01 to 5 mm, more preferably 0.01 to 3 mm. By setting it in such a range, uniform heat generation can be enhanced.
- the thickness of each of the electrode layers 13a and 13b is relative to the tangent line of the outer surface of each of the electrode layers 13a and 13b at the measurement point when the portion of the electrode layer for which the thickness is to be measured is observed in a cross section perpendicular to the stretching direction of the cell. It is defined as the thickness in the normal direction.
- the electrical resistivity of the electrode layers 13a and 13b is preferably 1/10 or less, more preferably 1/20 or less, and preferably 1/30 or less of the electrical resistivity of the columnar honeycomb structure 11. Even more preferable. However, if the difference in electrical resistivity between the two becomes too large, the current is concentrated between the ends of the opposing electrode layers and the heat generation of the columnar honeycomb structure 11 is biased. Therefore, the electrical resistivity of the electrode layers 13a and 13b is increased.
- the electrical resistivity of the columnar honeycomb structure 11 is preferably 1/200 or more, more preferably 1/150 or more, and even more preferably 1/100 or more.
- the electrical resistivity of the electrode layers 13a and 13b is a value measured at 25 ° C. by the four-terminal method.
- a composite material (cermet) of metal and conductive ceramics can be used as the material of each of the electrode layers 13a and 13b.
- the metal include elemental metals of Cr, Fe, Co, Ni, Si and Ti, and alloys containing at least one metal selected from the group consisting of these metals.
- the conductive ceramics include, but are not limited to, silicon carbide (SiC), and examples thereof include metal compounds such as metal siliceates such as tantalum silicate (TaSi 2 ) and chromium silicate (CrSi 2).
- the composite material (cermet) of metal and conductive ceramics include a composite material of metallic silicon and silicon carbide, a composite material of metal siliceous material such as tantalum silicate and chromium silicate, and a composite material of metallic silicon and silicon carbide, and further described above. From the viewpoint of reducing thermal expansion, a composite material obtained by adding one or more kinds of insulating ceramics such as alumina, mulite, zirconia, cordierite, silicon nitride and aluminum nitride to one or more kinds of metals can be mentioned.
- the electrode layers 13a and 13b may be made of a columnar honeycomb by combining a metal silice such as tantalum silicate or chromium silicate and a composite material of metallic silicon and silicon carbide. It is preferable because it can be fired at the same time as the structural part, which contributes to simplification of the manufacturing process.
- mixed layers 20a and 20b are provided on the electrode layers 13a and 13b. Due to the presence of the mixed layers 20a and 20b, the metal materials 16a and 16b described later can be satisfactorily bonded to the columnar honeycomb structure 11.
- the mixed layers 20a and 20b may be conductive base layers.
- an intermediate layer 21 made of glass or the like may be further provided between the electrode layers 13a and 13b and the mixed layers 20a and 20b. According to such a configuration, the thermal stress due to the difference in the coefficient of thermal expansion between the electrode layers 13a and 13b and the mixed layers 20a and 20b is relaxed and generated at the interface between the electrode layers 13a and 13b and the mixed layers 20a and 20b. Cracks can be suppressed better.
- the mixed layers 20a and 20b contain metal and ceramics.
- the mixed layers 20a and 20b are preferably composed of metal and ceramics.
- the same material as the composite material (cermet) of the metal and the conductive ceramics shown as the material of the electrode layers 13a and 13b described above can be used.
- the mixed layers 20a and 20b preferably contain 20 to 85% by volume of metal.
- the mixed layers 20a and 20b contain 20% by volume or more of metal, the bondability with the metal materials 16a and 16b is further improved.
- the mixed layers 20a and 20b contain 85% by volume or less of metal, the occurrence of cracks due to the difference in thermal expansion between the metal and the ceramics is reduced.
- the mixed layers 20a and 20b more preferably contain 35 to 70% by volume of metal, and even more preferably 40 to 60% by volume of metal.
- the mixed layers 20a and 20b may be provided directly on the outer peripheral wall 12 of the columnar honeycomb structure 11. Further, the mixed layers 20a and 20b may be the above-mentioned electrode layers 13a and 13b.
- the thickness of the mixed layers 20a and 20b is preferably 50 to 800 ⁇ m.
- the thickness of the mixed layers 20a and 20b is 50 ⁇ m or more, the metal materials 16a and 16b can be satisfactorily joined by the columnar honeycomb structure 11.
- the thicknesses of the mixed layers 20a and 20b are 800 ⁇ m or less, the occurrence of cracks during firing due to strain caused by the difference in thermal expansion between the mixed layer and the electrode layer is reduced.
- the thickness of the mixed layers 20a and 20b is more preferably 150 to 500 ⁇ m, and even more preferably 200 to 300 ⁇ m.
- the number and arrangement of the mixed layers 20a and 20b are not limited, and can be appropriately set within the range necessary for fixing the metal electrodes 14a and 14b. Further, the shapes of the mixed layers 20a and 20b can be formed into any shape such as a circular shape, an elliptical shape, and a polygonal shape in a plan view. The shapes of the mixed layers 20a and 20b are preferably circular or rectangular from the viewpoint of productivity and practicality.
- Metal materials 16a and 16b are provided between the mixed layers 20a and 20b and the metal electrodes 14a and 14b.
- the Brinell hardness of the metal materials 16a and 16b is smaller than that of the metal electrodes 14a and 14b. According to such a configuration, when the metal electrodes 14a and 14b are pressed against the columnar honeycomb structure 11 and fixed at the time of manufacturing the electroheating carrier 10, even if a metal having high hardness is used as the metal electrodes 14a and 14b. It is presumed that the metal materials 16a and 16b having a brinel hardness smaller than that of the metal electrodes 14a and 14b can relieve the stress caused by pressing the metal electrodes 14a and 14b.
- the destruction of the columnar honeycomb structure 11 is suppressed. Further, since the destruction of the columnar honeycomb structure 11 due to the pressing of the metal electrodes 14a and 14b is suppressed in this way, the metal electrodes 14a and 14b can be sufficiently pressed at the time of joining. Therefore, the number of contacts with the columnar honeycomb structure 11 is increased, and it is possible to suppress a decrease in the allowable current and a decrease in the strength of the joint. Further, it is not necessary to use a metal having a low hardness as the metal electrodes 14a and 14b, and it is possible to suppress disconnection of the metal electrodes 14a and 14b due to vibration.
- the Brinell hardness of the metal materials 16a and 16b can be measured by a Brinell hardness tester according to the test method of JIS Z 2243.
- the Brinell hardness of the metal materials 16a and 16b is preferably HB200 or less.
- the brinell hardness of the metal materials 16a and 16b is HB200 or less, the columnar honeycomb structures 11 are broken when the metal electrodes 14a and 14b are fixed to the columnar honeycomb structure 11, the metal electrodes 14a and 14b are disconnected due to vibration, and the metal electrodes 14a and 14b are disconnected.
- the decrease in strength of the joint portion between the metal electrodes 14a and 14b and the columnar honeycomb structure 11 can be suppressed more satisfactorily.
- the Brinell hardness of the metal materials 16a and 16b is more preferably HB100 or less, and even more preferably HB50 or less.
- the metal materials 16a and 16b can be composed of a metal or alloy containing at least one selected from the group consisting of Al, Pt, Pd, Ni, Au, Cu, Ag, Zn, Sn and Cr.
- the metal materials 16a and 16b are composed of Pt, Pd, Au, or an alloy thereof, these metals or alloys have a property of being difficult to oxidize. Therefore, the effect that the joint strength can be maintained even in a high temperature atmosphere can be obtained.
- a part of the metal materials 16a and 16b may react with the surfaces of the metal electrodes 14a and 14b. Further, a part of the metal materials 16a and 16b may react with the surfaces of the mixed layers 20a and 20b. According to such a configuration, the metal materials 16a and 16b are made stronger than those in which the metal materials 16a and 16b are not reacted with the metal electrodes 14a and 14b or the mixed layers 20a and 20b. It can be provided between the 20b and the metal electrodes 14a and 14b.
- a part of the metal materials 16a and 16b that reacts with the surfaces of the metal electrodes 14a and 14b or the surfaces of the mixed layers 20a and 20b is not particularly limited, but is 1 to 20% of the thickness of the metal materials 16a and 16b.
- the metal materials 16a and 16b are more firmly combined with the mixed layers 20a and 20b. It can be provided between the metal electrodes 14a and 14b.
- 20% or less of the thickness of the metal materials 16a and 16b reacts with the surface of the metal electrodes 14a and 14b or the surface of the mixed layers 20a and 20b, the heat resistance or corrosion resistance of the metal materials 16a and 16b deteriorates. Can be suppressed.
- a part of the metal materials 16a and 16b that reacts with the surfaces of the metal electrodes 14a and 14b or the surfaces of the mixed layers 20a and 20b is more preferably 1 to 10% of the thickness of the metal materials 16a and 16b. Even more preferably, it is ⁇ 5%.
- the above-mentioned reaction between the metal materials 16a and 16b and the surfaces of the metal electrodes 14a and 14b and the reaction between the metal materials 16a and 16b and the surfaces of the mixed layers 20a and 20b are EDS (energy dispersive X-ray analysis) or It can be confirmed by EPMA (electron probe microanalyzer) or the like.
- the thickness of the metal materials 16a and 16b is preferably 5 to 500 ⁇ m. When the thicknesses of the metal materials 16a and 16b are 5 ⁇ m or more, the effect can be obtained more remarkably. When the thickness of the metal materials 16a and 16b is 500 ⁇ m or less, damage to the metal materials 16a and 16b can be further suppressed.
- the thickness of the metal materials 16a and 16b is more preferably 10 to 100 ⁇ m, and even more preferably 50 to 100 ⁇ m.
- the number and arrangement of the metal materials 16a and 16b are not limited, and can be appropriately set within the range necessary for fixing the metal electrodes 14a and 14b. Further, the shapes of the metal materials 16a and 16b can be formed into any shape such as a circular shape, an elliptical shape, and a polygonal shape in a plan view. The shapes of the metal materials 16a and 16b are preferably circular or rectangular from the viewpoint of productivity and practicality.
- the metal electrodes 14a and 14b are provided on the metal materials 16a and 16b.
- the metal electrodes 14a and 14b may be a pair of metal electrodes in which one metal electrode 14a is arranged so as to face the other metal electrode 14b with the central axis of the columnar honeycomb structure 11 interposed therebetween. good.
- a voltage is applied to the metal electrodes 14a and 14b via the electrode layers 13a and 13b, the metal electrodes 14a and 14b are energized and the columnar honeycomb structure 11 can be heated by Joule heat. Therefore, the electrically heated carrier 10 can be suitably used as a heater.
- the applied voltage is preferably 12 to 900 V, more preferably 64 to 600 V, but the applied voltage can be changed as appropriate.
- the material of the metal electrodes 14a and 14b there are no particular restrictions as long as it is a metal, and a single metal, an alloy, or the like can be adopted. However, from the viewpoint of corrosion resistance, electrical resistance, and linear expansion rate, for example, Cr and Fe , Co, Ni and Ti are preferably used as alloys containing at least one selected from the group, and stainless steel and Fe—Ni alloys are more preferable.
- the shapes and sizes of the metal electrodes 14a and 14b are not particularly limited, and can be appropriately designed according to the size of the electrically heated carrier 10 and the energization performance.
- the Brinell hardness of the metal electrodes 14a and 14b is preferably HB170 or higher, more preferably HB170 to 300, even more preferably HB170 to 270, and even more preferably HB170 to 220.
- the metal electrodes 14a and 14b may have two or more electrode portions 15. Each electrode portion 15 may be fixed to the outer surface of the metal materials 16a and 16b. Here, the electrode portion 15 may be fixed to the metal materials 16a and 16b by welding, or may be fixed to the metal materials 16a and 16b by a fixing layer formed by thermal spraying.
- the metal electrodes 14a and 14b each have three comb-shaped electrode portions 15, and the respective electrode portions 15 are fixed to the two metal materials 16a and 16b.
- the electrical connection between the comb-shaped electrode portion 15 and the electrode layers 13a and 13b may be realized by two or more metal materials 16a and 16b that are separated from each other.
- the electrode portion 15 is formed in a comb shape in FIG. 5, it is fixed to the metal materials 16a and 16b and can be electrically connected to the electrode layers 13a and 13b, or the electrode layers 13a and 13b are sprayed. Any shape can be adopted as long as it can be fixed to.
- the electrically heated carrier 10 By supporting the catalyst on the electrically heated carrier 10, the electrically heated carrier 10 can be used as a catalyst.
- a fluid such as automobile exhaust gas can flow through the flow paths of the plurality of cells 18.
- the catalyst include noble metal-based catalysts and catalysts other than these.
- a noble metal such as platinum (Pt), palladium (Pd), or rhodium (Rh) is supported on the surface of the alumina pores, and a three-way catalyst containing a co-catalyst such as ceria or zirconia, an oxidation catalyst, or an alkali.
- An example is a NO x storage reduction catalyst (LNT catalyst) containing earth metal and platinum as storage components of nitrogen oxide (NO x).
- LNT catalyst NO x storage reduction catalyst
- catalysts that do not use noble metals include NO x selective reduction catalysts (SCR catalysts) containing copper-substituted or iron-substituted zeolites. Further, two or more kinds of catalysts selected from the group consisting of these catalysts may be used.
- the method of supporting the catalyst is also not particularly limited, and can be carried out according to the conventional method of supporting the catalyst on the honeycomb structure.
- the method for producing the electroheating carrier 10 of the present invention includes a step A1 for obtaining an unfired honeycomb structure portion with an electrode layer forming paste and a columnar honeycomb structure by firing the unfired honeycomb structure portion with an electrode layer forming paste.
- Step A2 for obtaining a body for obtaining a body
- step A3 for obtaining a columnar honeycomb structure with a mixed layer after providing a mixed layer forming paste on the electrode layer of the columnar honeycomb structure, and firing to obtain a columnar honeycomb structure with a mixed layer, and on the mixed layer of the columnar honeycomb structure.
- Step A1 is a step of producing a honeycomb molded body which is a precursor of the honeycomb structure portion, applying an electrode layer forming paste to the side surface of the honeycomb molded portion, and obtaining an unfired honeycomb structure portion with the electrode layer forming paste.
- the honeycomb molded body can be produced according to the method for producing a honeycomb molded body in the known method for producing a honeycomb structure portion. For example, first, a metal silicon powder (metal silicon), a binder, a surfactant, a pore-forming material, water, or the like is added to silicon carbide powder (silicon carbide) to prepare a molding raw material.
- the mass of the metallic silicon is 10 to 40% by mass with respect to the total of the mass of the silicon carbide powder and the mass of the metallic silicon.
- the average particle size of the silicon carbide particles in the silicon carbide powder is preferably 3 to 50 ⁇ m, more preferably 3 to 40 ⁇ m.
- the average particle size of metallic silicon (metallic silicon powder) is preferably 2 to 35 ⁇ m.
- the average particle size of silicon carbide particles and metallic silicon (metal silicon particles) refers to the arithmetic mean diameter based on the volume when the frequency distribution of particle size is measured by the laser diffraction method.
- the silicon carbide particles are fine particles of silicon carbide constituting the silicon carbide powder, and the metallic silicon particles are fine particles of metallic silicon constituting the metallic silicon powder. This is a blending of molding raw materials when the material of the honeycomb structure is silicon-silicon carbide-based composite material, and when the material of the honeycomb structure is silicon carbide, metallic silicon is not added.
- binder examples include methyl cellulose, hydroxypropyl methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol and the like. Among these, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination.
- the binder content is preferably 2.0 to 10.0 parts by mass when the total mass of the silicon carbide powder and the metallic silicon powder is 100 parts by mass.
- the water content is preferably 20 to 60 parts by mass when the total mass of the silicon carbide powder and the metallic silicon powder is 100 parts by mass.
- ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used as the surfactant. These may be used individually by 1 type, or may be used in combination of 2 or more type.
- the content of the surfactant is preferably 0.1 to 2.0 parts by mass when the total mass of the silicon carbide powder and the metal silicon powder is 100 parts by mass.
- the pore-forming material is not particularly limited as long as it becomes pores after firing, and examples thereof include graphite, starch, foamed resin, water-absorbent resin, and silica gel.
- the content of the pore-forming material is preferably 0.5 to 10.0 parts by mass when the total mass of the silicon carbide powder and the metallic silicon powder is 100 parts by mass.
- the average particle size of the pore-forming material is preferably 10 to 30 ⁇ m.
- the average particle size of the pore-forming material refers to the arithmetic mean diameter based on the volume when the frequency distribution of the particle size is measured by the laser diffraction method.
- the average particle size of the pore-forming material is the average particle size after water absorption.
- the clay is extruded to produce a honeycomb molded body.
- a mouthpiece having a desired overall shape, cell shape, partition wall thickness, cell density and the like can be used.
- both bottom portions of the honeycomb molded body can be cut to obtain the desired length.
- the dried honeycomb molded body is called a honeycomb dried body.
- the electrode layer forming paste for forming the electrode layer is prepared.
- the electrode layer forming paste can be formed by appropriately adding various additives to the raw material powder (metal powder, ceramic powder, etc.) blended according to the required characteristics of the electrode layer and kneading.
- the average particle size of the metal powder in the paste for the second electrode layer is made larger than the average particle size of the metal powder in the paste for the first electrode layer.
- the bonding strength between the metal terminal and the electrode layer tends to improve.
- the average particle size of the metal powder refers to the arithmetic mean diameter based on the volume when the frequency distribution of the particle size is measured by the laser diffraction method.
- the obtained electrode layer forming paste is applied to the side surface of the honeycomb molded body (typically, the dried honeycomb body) to obtain an unfired honeycomb structure portion with the electrode layer forming paste.
- the method of preparing the electrode layer forming paste and the method of applying the electrode layer forming paste to the honeycomb molded body can be performed according to a known method for producing a honeycomb structure, but the electrode layer is compared with the honeycomb structure portion. In order to obtain a low electrical resistance, the metal content ratio can be increased or the particle size of the metal particles can be reduced as compared with the honeycomb structure portion.
- the honeycomb molded body may be fired once before applying the electrode layer forming paste. That is, in this modified example, the honeycomb molded body is fired to produce a honeycomb fired body, and the electrode layer forming paste is applied to the honeycomb fired body.
- the unfired honeycomb structure portion with the electrode layer forming paste is fired to obtain a columnar honeycomb structure.
- the unfired honeycomb structure with the electrode layer forming paste may be dried.
- degreasing may be performed in order to remove the binder and the like.
- the firing conditions it is preferable to heat at 1400 to 1500 ° C. for 1 to 20 hours in an inert atmosphere such as nitrogen or argon.
- an oxidation treatment at 1200 to 1350 ° C. for 1 to 10 hours in order to improve durability.
- the method of degreasing and firing is not particularly limited, and firing can be performed using an electric furnace, a gas furnace, or the like.
- a paste containing metal and ceramics for forming a mixed layer is applied to the surface of the electrode layer on the columnar honeycomb structure.
- the paste containing the metal and ceramics prepared in this way is applied by a curved surface printing machine or the like so as to have a predetermined arrangement, dried, and then fired to form a mixed layer.
- the paste containing metal and ceramics for forming the mixed layer for example, metal powder (NiCr-based material, metal powder such as stainless steel) is mixed with the glass material.
- a ceramic raw material can be prepared by mixing a metal ratio of 20 to 85% by volume and a glass material at a volume ratio of 15 to 80% by volume.
- a mixed layer-forming paste can be prepared by adding 1% by mass of a binder, 1% by mass of a surfactant, and 20 to 40% by mass of water to the ceramic raw material.
- the mixed layer may be formed by spraying a conductive material so as to have a predetermined arrangement and shape.
- step A4 a metal material is provided on the mixed layer of the columnar honeycomb structure with a mixed layer obtained in step A3 by plating or crimping a metal foil. As a result, a columnar honeycomb structure with a metal material can be obtained.
- step A5 the metal electrode is fixed on the metal material of the columnar honeycomb structure with metal material obtained in step A4 by laser welding or ultrasonic welding. In this way, the electroheated carrier according to the embodiment of the present invention is obtained.
- the electrically heated carrier according to the embodiment of the present invention described above can be used in an exhaust gas purification device.
- the exhaust gas purifying device has an electrically heated carrier and a metal can body that holds the electrically heated carrier.
- the electrically heated carrier is installed in the middle of the exhaust gas flow path for flowing the exhaust gas from the engine.
- a metal tubular member or the like accommodating an electrically heated carrier can be used.
- Example 1 (1. Preparation of columnar clay) Silicon carbide (SiC) powder and metallic silicon (Si) powder were mixed at a mass ratio of 80:20 to prepare a ceramic raw material. Then, hydroxypropyl methylcellulose as a binder and a water-absorbent resin as a pore-forming material were added to the ceramic raw material, and water was added to prepare a molding raw material. Then, the molding raw material was kneaded with a vacuum clay kneader to prepare a columnar clay. The binder content was 7 parts by mass when the total of the silicon carbide (SiC) powder and the metallic silicon (Si) powder was 100 parts by mass.
- the content of the pore-forming material was 3 parts by mass when the total of the silicon carbide (SiC) powder and the metallic silicon (Si) powder was 100 parts by mass.
- the water content was 42 parts by mass when the total of the silicon carbide (SiC) powder and the metallic silicon (Si) powder was 100 parts by mass.
- the average particle size of the silicon carbide powder was 20 ⁇ m, and the average particle size of the metallic silicon powder was 6 ⁇ m.
- the average particle size of the pore-forming material was 20 ⁇ m.
- the average particle size of the silicon carbide powder, the metallic silicon powder, and the pore-forming material refers to the arithmetic mean diameter based on the volume when the frequency distribution of the particle size is measured by the laser diffraction method.
- Electrode layer forming paste Metallic silicon (Si) powder, silicon carbide (SiC) powder, methyl cellulose, glycerin, and water were mixed with a rotating and revolving stirrer to prepare an electrode layer forming paste.
- the average particle size of the metallic silicon powder was 6 ⁇ m.
- the average particle size of the silicon carbide powder was 35 ⁇ m.
- this electrode layer forming paste is applied to the honeycomb dried body with an appropriate area and film thickness by a curved surface printing machine, further dried at 120 ° C. for 30 minutes with a hot air dryer, and then Ar atmosphere together with the honeycomb dried body. Was fired at 1400 ° C. for 3 hours to obtain a columnar honeycomb structure.
- the above mixed layer forming paste was applied to the electrode layer of the columnar honeycomb structure by a curved surface printing machine. Subsequently, it was dried at 120 ° C. for 30 minutes in a hot air dryer, and then fired at 1100 ° C. for 1 hour in an Ar atmosphere.
- the bottom surface of the honeycomb structure was circular with a diameter of 100 mm, and the height (length in the flow path direction of the cell) was 100 mm.
- the cell density was 93 cells / cm 2
- the thickness of the partition was 101.6 ⁇ m
- the porosity of the partition was 45%
- the average pore diameter of the partition was 8.6 ⁇ m.
- the thickness of the electrode layer was 0.3 mm
- the thickness of the mixed layer was 0.2 mm.
- a plate material (Brinell hardness 130) made of Ti and having a thickness of 0.05 mm was prepared, and the metal material was placed on the mixed layer.
- a metal electrode (Brinell hardness 180) made of SUS430 and having a thickness of 0.2 mm and a width of 0.5 mm is placed on the metal material, and while pressing from above, each metal electrode and the mixed layer overlap each other. Laser welding was performed at four points with a laser output of 200 W / mm 2.
- Example 2 A sample was prepared in the same manner as in Example 1 except that the metal material was made of Cu (Brinell hardness 90).
- Example 3 A sample was prepared in the same manner as in Example 1 except that the metal material was made of Pt (Brinell hardness 49). In the samples of Examples 1 to 3, a part of the metal material was reacting with the surface of the metal electrode and the mixed layer.
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Abstract
An electrically heated carrier, provided with: a columnar honeycomb structure made of a ceramic, the columnar honeycomb structure having an outer peripheral wall and partition walls provided on the inner side of the outer peripheral wall, the partition walls defining and forming a plurality of cells which penetrate from one end surface to the other end surface and form channels; a mixture layer containing a metal and a ceramic and provided on the outer peripheral wall of the columnar honeycomb structure; a metal electrode; and a metal material provided between the mixture layer and the metal electrode, wherein the Brinell hardness of the metal material being less than the Brinell hardness of the metal electrode.
Description
本発明は、電気加熱式担体及び排気ガス浄化装置に関する。
The present invention relates to an electrically heated carrier and an exhaust gas purifying device.
近年、エンジン始動直後の排気ガス浄化性能の低下を改善するため、電気加熱触媒（ＥＨＣ）が提案されている。ＥＨＣは、例えば、導電性セラミックスからなる柱状のハニカム構造体に金属電極を接続し、通電によりハニカム構造体自体を発熱させることで、エンジン始動前に触媒の活性温度まで昇温できるようにしたものである。ＥＨＣに電流を流すためには、外部配線に接続された金属電極をＥＨＣに接合させる必要がある。
In recent years, an electric heating catalyst (EHC) has been proposed in order to improve the deterioration of exhaust gas purification performance immediately after starting the engine. In EHC, for example, a metal electrode is connected to a columnar honeycomb structure made of conductive ceramics, and the honeycomb structure itself is heated by energization so that the temperature can be raised to the active temperature of the catalyst before starting the engine. Is. In order to pass a current through the EHC, it is necessary to join the metal electrode connected to the external wiring to the EHC.
特許文献１には、ハニカム構造部の外周側壁の外面上に配設された一対の電極層に、一対の金属端子が、一箇所又は二箇所以上の溶接部位を介して接合されている導電性ハニカム構造体が開示されている。
In Patent Document 1, a pair of metal terminals are joined to a pair of electrode layers arranged on the outer surface of the outer peripheral side wall of the honeycomb structure portion via one or two or more welded portions. Honeycomb structures are disclosed.
特許文献２には、ハニカム構造体の外周壁に配設された一対の電極層上に、スポット状に下地層が配置されており、電極部が当該下地層を介して電気的に接合された電気加熱型触媒用担体が開示されている。
In Patent Document 2, a base layer is arranged in a spot shape on a pair of electrode layers arranged on the outer peripheral wall of the honeycomb structure, and the electrode portions are electrically joined via the base layer. A carrier for an electrically heated catalyst is disclosed.
特許文献１に記載の導電性ハニカム構造体は、セラミックス－導電性接続部材（金属電極）間の一部に熱エネルギーを加えて溶接されているが、接続面積を多く得るためには、金属電極をセラミックスに押し付けて固定する必要がある。ここで、金属電極として硬度が高い金属を用いると、固定時にセラミックスを破壊する可能性があった。一方で、硬度と引っ張り強さには相関があり、金属電極として硬度が低い金属を用いると、引っ張り強さが低くなり、自動車の運転中に加わる振動応力等を干渉しきれず、断線する問題があった。また、固定時のセラミックスの破壊を抑制するために、金属電極の押し付けを弱くすると、セラミックスとの接点が減少し、接合部の強度が低下する問題があった。
The conductive honeycomb structure described in Patent Document 1 is welded by applying thermal energy to a part between the ceramics and the conductive connecting member (metal electrode), but in order to obtain a large connection area, the metal electrode is used. Must be pressed against the ceramics to fix it. Here, if a metal having high hardness is used as the metal electrode, the ceramics may be broken at the time of fixing. On the other hand, there is a correlation between hardness and tensile strength, and if a metal with low hardness is used as the metal electrode, the tensile strength will be low, and vibration stress applied during driving of the automobile cannot be interfered with, resulting in disconnection. there were. Further, if the pressing of the metal electrode is weakened in order to suppress the destruction of the ceramics at the time of fixing, there is a problem that the contact points with the ceramics are reduced and the strength of the joint portion is lowered.
特許文献２に記載の電気加熱型触媒用担体では、熱膨張差による影響を緩和するため、セラミックス担体と金属電極との間に下地層を設けている。しかしながら、特許文献１における上述と同様の問題があり、改善の余地がある。
In the electrically heated catalyst carrier described in Patent Document 2, an underlayer is provided between the ceramic carrier and the metal electrode in order to mitigate the influence of the difference in thermal expansion. However, there is a problem similar to the above in Patent Document 1, and there is room for improvement.
本発明は上記事情に鑑みて創作されたものであり、ハニカム構造体へ金属電極を固定する際のハニカム構造体の破壊、振動による金属電極の断線、及び、金属電極とハニカム構造体との接合部の強度低下を、それぞれ良好に抑制することが可能な電気加熱式担体及び排気ガス浄化装置を提供することを課題とする。
The present invention has been created in view of the above circumstances, and the honeycomb structure is destroyed when the metal electrode is fixed to the honeycomb structure, the metal electrode is broken due to vibration, and the metal electrode and the honeycomb structure are joined to each other. An object of the present invention is to provide an electrically heated carrier and an exhaust gas purifying device capable of satisfactorily suppressing a decrease in the strength of each part.
上記課題は、以下の本発明によって解決されるものであり、本発明は以下のように特定される。
（１）外周壁と、前記外周壁の内側に配設され、一方の端面から他方の端面まで貫通して流路を形成する複数のセルを区画形成する隔壁と、を有するセラミックス製の柱状ハニカム構造体と、
前記柱状ハニカム構造体の外周壁上に設けられている、金属とセラミックスとを含む混合層と、
金属電極と、
前記混合層と前記金属電極との間に設けられている金属材と、
を備え、
前記金属材のブリネル硬度が、前記金属電極のブリネル硬度より小さい、電気加熱式担体。
（２）（１）に記載の電気加熱式担体と、
前記電気加熱式担体を保持する金属製の缶体と、
を有する排気ガス浄化装置。 The above problem is solved by the following invention, and the present invention is specified as follows.
(1) A columnar honeycomb made of ceramics having an outer peripheral wall and a partition wall which is disposed inside the outer peripheral wall and forms a plurality of cells which form a flow path from one end face to the other end face. Structure and
A mixed layer containing metal and ceramics provided on the outer peripheral wall of the columnar honeycomb structure, and
With metal electrodes
A metal material provided between the mixed layer and the metal electrode,
With
An electrically heated carrier in which the Brinell hardness of the metal material is smaller than the Brinell hardness of the metal electrode.
(2) The electrically heated carrier according to (1) and
A metal can body holding the electrically heated carrier and
Exhaust gas purification device with.
（１）外周壁と、前記外周壁の内側に配設され、一方の端面から他方の端面まで貫通して流路を形成する複数のセルを区画形成する隔壁と、を有するセラミックス製の柱状ハニカム構造体と、
前記柱状ハニカム構造体の外周壁上に設けられている、金属とセラミックスとを含む混合層と、
金属電極と、
前記混合層と前記金属電極との間に設けられている金属材と、
を備え、
前記金属材のブリネル硬度が、前記金属電極のブリネル硬度より小さい、電気加熱式担体。
（２）（１）に記載の電気加熱式担体と、
前記電気加熱式担体を保持する金属製の缶体と、
を有する排気ガス浄化装置。 The above problem is solved by the following invention, and the present invention is specified as follows.
(1) A columnar honeycomb made of ceramics having an outer peripheral wall and a partition wall which is disposed inside the outer peripheral wall and forms a plurality of cells which form a flow path from one end face to the other end face. Structure and
A mixed layer containing metal and ceramics provided on the outer peripheral wall of the columnar honeycomb structure, and
With metal electrodes
A metal material provided between the mixed layer and the metal electrode,
With
An electrically heated carrier in which the Brinell hardness of the metal material is smaller than the Brinell hardness of the metal electrode.
(2) The electrically heated carrier according to (1) and
A metal can body holding the electrically heated carrier and
Exhaust gas purification device with.
本発明によれば、ハニカム構造体へ金属電極を固定する際のハニカム構造体の破壊、振動による金属電極の断線、及び、金属電極とハニカム構造体との接合部の強度低下を、それぞれ良好に抑制することが可能な電気加熱式担体及び排気ガス浄化装置を提供することができる。
According to the present invention, the destruction of the honeycomb structure when fixing the metal electrode to the honeycomb structure, the disconnection of the metal electrode due to vibration, and the decrease in the strength of the joint portion between the metal electrode and the honeycomb structure are all satisfactorily satisfied. It is possible to provide an electrically heated carrier and an exhaust gas purifying device that can be suppressed.
次に本発明を実施するための形態を、図面を参照しながら詳細に説明する。本発明は以下の実施形態に限定されるものではなく、本発明の趣旨を逸脱しない範囲で、当業者の通常の知識に基づいて、適宜設計の変更、改良等が加えられることが理解されるべきである。
Next, a mode for carrying out the present invention will be described in detail with reference to the drawings. It is understood that the present invention is not limited to the following embodiments, and design changes, improvements, etc. may be appropriately made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.
（１．電気加熱式担体）
図１は、本発明の実施形態における電気加熱式担体１０のセルの延伸方向に垂直な断面模式図である。電気加熱式担体１０は、柱状ハニカム構造体１１と、柱状ハニカム構造体１１の外周壁１２の表面に配設された電極層１３ａ、１３ｂと、電極層１３ａ、１３ｂ上に設けられた混合層２０ａ、２０ｂと、混合層２０ａ、２０ｂ上に設けられた金属材１６ａ、１６ｂと、金属材１６ａ、１６ｂ上に設けられた金属電極１４ａ、１４ｂとを備えている。 (1. Electric heating type carrier)
FIG. 1 is a schematic cross-sectional view of theelectroheated carrier 10 according to the embodiment of the present invention, which is perpendicular to the stretching direction of the cell. The electrically heated carrier 10 includes a columnar honeycomb structure 11, electrode layers 13a and 13b arranged on the surface of the outer peripheral wall 12 of the columnar honeycomb structure 11, and a mixed layer 20a provided on the electrode layers 13a and 13b. , 20b, metal materials 16a and 16b provided on the mixed layers 20a and 20b, and metal electrodes 14a and 14b provided on the metal materials 16a and 16b.
図１は、本発明の実施形態における電気加熱式担体１０のセルの延伸方向に垂直な断面模式図である。電気加熱式担体１０は、柱状ハニカム構造体１１と、柱状ハニカム構造体１１の外周壁１２の表面に配設された電極層１３ａ、１３ｂと、電極層１３ａ、１３ｂ上に設けられた混合層２０ａ、２０ｂと、混合層２０ａ、２０ｂ上に設けられた金属材１６ａ、１６ｂと、金属材１６ａ、１６ｂ上に設けられた金属電極１４ａ、１４ｂとを備えている。 (1. Electric heating type carrier)
FIG. 1 is a schematic cross-sectional view of the
（１－１．柱状ハニカム構造体）
図２は本発明の実施形態における柱状ハニカム構造体１１及び電極層１３ａ、１３ｂの外観模式図を示すものである。柱状ハニカム構造体１１は、外周壁１２と、外周壁１２の内側に配設され、一方の端面から他方の端面まで貫通して流路を形成する複数のセル１８を区画形成する隔壁１９とを有する。 (1-1. Columnar honeycomb structure)
FIG. 2 shows a schematic external view of thecolumnar honeycomb structure 11 and the electrode layers 13a and 13b according to the embodiment of the present invention. The columnar honeycomb structure 11 includes an outer peripheral wall 12 and a partition wall 19 which is arranged inside the outer peripheral wall 12 and which partitions a plurality of cells 18 which penetrate from one end face to the other end face to form a flow path. Have.
図２は本発明の実施形態における柱状ハニカム構造体１１及び電極層１３ａ、１３ｂの外観模式図を示すものである。柱状ハニカム構造体１１は、外周壁１２と、外周壁１２の内側に配設され、一方の端面から他方の端面まで貫通して流路を形成する複数のセル１８を区画形成する隔壁１９とを有する。 (1-1. Columnar honeycomb structure)
FIG. 2 shows a schematic external view of the
柱状ハニカム構造体１１の外形は柱状である限り特に限定されず、例えば、底面が円形の柱状（円柱形状）、底面がオーバル形状の柱状、底面が多角形（四角形、五角形、六角形、七角形、八角形等）の柱状等の形状とすることができる。また、柱状ハニカム構造体１１の大きさは、耐熱性を高める（外周壁の周方向に入るクラックを抑制する）という理由により、底面の面積が２０００～２００００ｍｍ2であることが好ましく、５０００～１５０００ｍｍ2であることが更に好ましい。
The outer shape of the columnar honeycomb structure 11 is not particularly limited as long as it is columnar. , Octagon, etc.) can be shaped like a columnar shape. Further, the size of the columnar honeycomb structure 11 is preferably 2000 to 20000 mm 2 and preferably 5000 to 15000 mm for the reason of improving heat resistance (suppressing cracks entering the circumferential direction of the outer peripheral wall). it is more preferably 2.
柱状ハニカム構造体１１は、セラミックス製であり、導電性を有する。導電性の柱状ハニカム構造体１１が通電してジュール熱により発熱可能である限り、当該セラミックスの電気抵抗率については特に制限はないが、０．１～２００Ωｃｍであることが好ましく、１～２００Ωｃｍがより好ましく、１０～１００Ωｃｍであることが更に好ましい。本発明において、柱状ハニカム構造体１１の電気抵抗率は、四端子法により２５℃で測定した値とする。
The columnar honeycomb structure 11 is made of ceramics and has conductivity. As long as the conductive columnar honeycomb structure 11 is energized and can generate heat by Joule heat, the electrical resistivity of the ceramic is not particularly limited, but is preferably 0.1 to 200 Ωcm, preferably 1 to 200 Ωcm. More preferably, it is 10 to 100 Ωcm. In the present invention, the electrical resistivity of the columnar honeycomb structure 11 is a value measured at 25 ° C. by the four-terminal method.
柱状ハニカム構造体１１の材質としては、限定的ではないが、アルミナ、ムライト、ジルコニア及びコージェライト等の酸化物系セラミックス、炭化珪素、窒化珪素及び窒化アルミ等の非酸化物系セラミックスからなる群から選択することができる。また、炭化珪素－金属珪素複合材や炭化珪素／グラファイト複合材等を用いることもできる。これらの中でも、耐熱性と導電性の両立の観点から、柱状ハニカム構造体１１の材質は、珪素－炭化珪素複合材又は炭化珪素を主成分とするセラミックスを含有していることが好ましい。柱状ハニカム構造体１１の材質が、珪素－炭化珪素複合材を主成分とするものであるというときは、柱状ハニカム構造体１１が、珪素－炭化珪素複合材（合計質量）を、全体の９０質量％以上含有していることを意味する。ここで、珪素－炭化珪素複合材は、骨材としての炭化珪素粒子、及び炭化珪素粒子を結合させる結合材としての珪素を含有するものであり、複数の炭化珪素粒子が、炭化珪素粒子間に細孔を形成するようにして、珪素によって結合されていることが好ましい。柱状ハニカム構造体１１の材質が、炭化珪素を主成分とするものであるというときは、柱状ハニカム構造体１１が、炭化珪素（合計質量）を、全体の９０質量％以上含有していることを意味する。
The material of the columnar honeycomb structure 11 is not limited, but includes a group consisting of oxide-based ceramics such as alumina, mullite, zirconia and cordierite, and non-oxide ceramics such as silicon carbide, silicon nitride and aluminum nitride. You can choose. Further, a silicon carbide-metal silicon composite material, a silicon carbide / graphite composite material, or the like can also be used. Among these, from the viewpoint of achieving both heat resistance and conductivity, the material of the columnar honeycomb structure 11 preferably contains a silicon-silicon carbide composite material or ceramics containing silicon carbide as a main component. When the material of the columnar honeycomb structure 11 is mainly composed of a silicon-silicon carbide composite material, the columnar honeycomb structure 11 contains the silicon-silicon carbide composite material (total mass) as a total of 90 masses. It means that it contains% or more. Here, the silicon-silicon carbide composite material contains silicon carbide particles as an aggregate and silicon as a binder for binding the silicon carbide particles, and a plurality of silicon carbide particles are formed between the silicon carbide particles. It is preferably bonded by silicon so as to form pores. When the material of the columnar honeycomb structure 11 is mainly composed of silicon carbide, it means that the columnar honeycomb structure 11 contains silicon carbide (total mass) in an amount of 90% by mass or more of the whole. means.
柱状ハニカム構造体１１が、珪素－炭化珪素複合材を含んでいる場合、柱状ハニカム構造体１１に含有される「骨材としての炭化珪素粒子の質量」と、柱状ハニカム構造体１１に含有される「結合材としての珪素の質量」との合計に対する、柱状ハニカム構造体１１に含有される「結合材としての珪素の質量」の比率が、１０～４０質量％であることが好ましく、１５～３５質量％であることが更に好ましい。
When the columnar honeycomb structure 11 contains a silicon-silicon carbide composite material, the “mass of silicon carbide particles as aggregate” contained in the columnar honeycomb structure 11 and the columnar honeycomb structure 11 are contained. The ratio of the "mass of silicon as a binder" contained in the columnar honeycomb structure 11 to the total of the "mass of silicon as a composite" is preferably 10 to 40% by mass, preferably 15 to 35. It is more preferably mass%.
セル１８の延伸方向に垂直な断面におけるセルの形状に制限はないが、四角形、六角形、八角形、又はこれらの組み合わせであることが好ましい。これ等のなかでも、四角形及び六角形が好ましい。構造強度及び加熱均一性を両立させやすいという観点からは、四角形が特に好ましい。
The shape of the cell in the cross section perpendicular to the extending direction of the cell 18 is not limited, but it is preferably a quadrangle, a hexagon, an octagon, or a combination thereof. Among these, a quadrangle and a hexagon are preferable. A quadrangle is particularly preferable from the viewpoint of easily achieving both structural strength and heating uniformity.
セル１８を区画形成する隔壁１９の厚みは、０．１～０．３ｍｍであることが好ましく、０．１５～０．２５ｍｍであることがより好ましい。本発明において、隔壁１９の厚みは、セル１８の延伸方向に垂直な断面において、隣接するセル１８の重心同士を結ぶ線分のうち、隔壁１９を通過する部分の長さとして定義される。
The thickness of the partition wall 19 for partitioning the cell 18 is preferably 0.1 to 0.3 mm, more preferably 0.15 to 0.25 mm. In the present invention, the thickness of the partition wall 19 is defined as the length of a portion of a line segment connecting the centers of gravity of adjacent cells 18 that passes through the partition wall 19 in a cross section perpendicular to the extending direction of the cell 18.
柱状ハニカム構造体１１は、セル１８の流路方向に垂直な断面において、セル密度が４０～１５０セル／ｃｍ2であることが好ましく、７０～１００セル／ｃｍ2であることが更に好ましい。セル密度をこのような範囲にすることにより、排気ガスを流したときの圧力損失を小さくした状態で、触媒の浄化性能を高くすることができる。セル密度は、外周壁１２部分を除く柱状ハニカム構造体１１の一つの底面部分の面積でセル数を除して得られる値である。
The columnar honeycomb structure 11 preferably has a cell density of 40 to 150 cells / cm 2 , and more preferably 70 to 100 cells / cm 2 in a cross section perpendicular to the flow path direction of the cells 18. By setting the cell density in such a range, the purification performance of the catalyst can be improved while the pressure loss when the exhaust gas is passed is reduced. The cell density is a value obtained by dividing the number of cells by the area of one bottom surface portion of the columnar honeycomb structure 11 excluding the outer peripheral wall 12 portion.
柱状ハニカム構造体１１の外周壁１２を設けることは、柱状ハニカム構造体１１の構造強度を確保し、また、セル１８を流れる流体が外周壁１２から漏洩するのを抑制する観点で有用である。具体的には、外周壁１２の厚みは好ましくは０．１ｍｍ以上であり、より好ましくは０．１５ｍｍ以上、更により好ましくは０．２ｍｍ以上である。但し、外周壁１２を厚くしすぎると高強度になりすぎてしまい、隔壁１９との強度バランスが崩れて耐熱衝撃性が低下することから、外周壁１２の厚みは好ましくは１．０ｍｍ以下であり、より好ましくは０．７ｍｍ以下であり、更により好ましくは０．５ｍｍ以下である。ここで、外周壁１２の厚みは、厚みを測定しようとする外周壁１２の箇所をセルの延伸方向に垂直な断面で観察したときに、当該測定箇所における外周壁１２の接線に対する法線方向の厚みとして定義される。
Providing the outer peripheral wall 12 of the columnar honeycomb structure 11 is useful from the viewpoint of ensuring the structural strength of the columnar honeycomb structure 11 and suppressing the fluid flowing through the cell 18 from leaking from the outer peripheral wall 12. Specifically, the thickness of the outer peripheral wall 12 is preferably 0.1 mm or more, more preferably 0.15 mm or more, and even more preferably 0.2 mm or more. However, if the outer peripheral wall 12 is made too thick, the strength becomes too high, the strength balance with the partition wall 19 is lost, and the heat impact resistance is lowered. Therefore, the thickness of the outer peripheral wall 12 is preferably 1.0 mm or less. , More preferably 0.7 mm or less, and even more preferably 0.5 mm or less. Here, the thickness of the outer peripheral wall 12 is the normal direction with respect to the tangent line of the outer peripheral wall 12 at the measurement location when the portion of the outer peripheral wall 12 whose thickness is to be measured is observed in a cross section perpendicular to the extending direction of the cell. Defined as thickness.
隔壁１９は多孔質とすることができる。隔壁１９の気孔率は、３５～６０％であることが好ましく、３５～４５％であることが更に好ましい。気孔率は、水銀ポロシメータにより測定した値である。
The partition wall 19 can be made porous. The porosity of the partition wall 19 is preferably 35 to 60%, more preferably 35 to 45%. Porosity is a value measured by a mercury porosimeter.
柱状ハニカム構造体１１の隔壁１９の平均細孔径は、２～１５μｍであることが好ましく、４～８μｍであることが更に好ましい。平均細孔径は、水銀ポロシメータにより測定した値である。
The average pore diameter of the partition wall 19 of the columnar honeycomb structure 11 is preferably 2 to 15 μm, more preferably 4 to 8 μm. The average pore diameter is a value measured by a mercury porosimeter.
（１－２．電極層）
柱状ハニカム構造体１１の外周壁１２の表面に、電極層１３ａ、１３ｂが配設されている。電極層１３ａ、１３ｂは、柱状ハニカム構造体１１の中心軸を挟んで対向するように配設された一対の電極層１３ａ、１３ｂであってもよい。また、電極層１３ａ、１３ｂは設けなくてもよい。 (1-2. Electrode layer)
Electrode layers 13a and 13b are arranged on the surface of the outerperipheral wall 12 of the columnar honeycomb structure 11. The electrode layers 13a and 13b may be a pair of electrode layers 13a and 13b arranged so as to face each other with the central axis of the columnar honeycomb structure 11 interposed therebetween. Further, the electrode layers 13a and 13b may not be provided.
柱状ハニカム構造体１１の外周壁１２の表面に、電極層１３ａ、１３ｂが配設されている。電極層１３ａ、１３ｂは、柱状ハニカム構造体１１の中心軸を挟んで対向するように配設された一対の電極層１３ａ、１３ｂであってもよい。また、電極層１３ａ、１３ｂは設けなくてもよい。 (1-2. Electrode layer)
Electrode layers 13a and 13b are arranged on the surface of the outer
電極層１３ａ、１３ｂの形成領域に特段の制約はないが、柱状ハニカム構造体１１の均一発熱性を高めるという観点からは、各電極層１３ａ、１３ｂは外周壁１２の外面上で外周壁１２の周方向及びセルの延伸方向に帯状に延設することが好ましい。具体的には、各電極層１３ａ、１３ｂは、柱状ハニカム構造体１１の両底面間の８０％以上の長さに亘って、好ましくは９０％以上の長さに亘って、より好ましくは全長に亘って延びていることが、電極層１３ａ、１３ｂの軸方向へ電流が広がりやすいという観点から望ましい。
There are no particular restrictions on the formation regions of the electrode layers 13a and 13b, but from the viewpoint of enhancing the uniform heat generation of the columnar honeycomb structure 11, each of the electrode layers 13a and 13b is formed on the outer surface of the outer peripheral wall 12 of the outer peripheral wall 12. It is preferable to extend the cells in a strip shape in the circumferential direction and the extending direction of the cell. Specifically, each of the electrode layers 13a and 13b has a length of 80% or more, preferably a length of 90% or more, and more preferably a total length between both bottom surfaces of the columnar honeycomb structure 11. It is desirable that the current extends over the electrode layers 13a and 13b from the viewpoint that the current easily spreads in the axial direction.
各電極層１３ａ、１３ｂの厚みは、０．０１～５ｍｍであることが好ましく、０．０１～３ｍｍであることが更に好ましい。このような範囲とすることにより均一発熱性を高めることができる。各電極層１３ａ、１３ｂの厚みは、厚みを測定しようとする電極層の箇所をセルの延伸方向に垂直な断面で観察したときに、各電極層１３ａ、１３ｂの外面の当該測定箇所における接線に対する法線方向の厚みとして定義される。
The thickness of each of the electrode layers 13a and 13b is preferably 0.01 to 5 mm, more preferably 0.01 to 3 mm. By setting it in such a range, uniform heat generation can be enhanced. The thickness of each of the electrode layers 13a and 13b is relative to the tangent line of the outer surface of each of the electrode layers 13a and 13b at the measurement point when the portion of the electrode layer for which the thickness is to be measured is observed in a cross section perpendicular to the stretching direction of the cell. It is defined as the thickness in the normal direction.
各電極層１３ａ、１３ｂの電気抵抗率を柱状ハニカム構造体１１の電気抵抗率より低くすることにより、電極層に優先的に電気が流れやすくなり、通電時に電気がセルの流路方向及び周方向に広がりやすくなる。電極層１３ａ、１３ｂの電気抵抗率は、柱状ハニカム構造体１１の電気抵抗率の１／１０以下であることが好ましく、１／２０以下であることがより好ましく、１／３０以下であることが更により好ましい。但し、両者の電気抵抗率の差が大きくなりすぎると対向する電極層の端部間に電流が集中して柱状ハニカム構造体１１の発熱が偏ることから、電極層１３ａ、１３ｂの電気抵抗率は、柱状ハニカム構造体１１の電気抵抗率の１／２００以上であることが好ましく、１／１５０以上であることがより好ましく、１／１００以上であることが更により好ましい。本発明において、電極層１３ａ、１３ｂの電気抵抗率は、四端子法により２５℃で測定した値とする。
By making the electrical resistivity of each of the electrode layers 13a and 13b lower than the electrical resistivity of the columnar honeycomb structure 11, electricity can easily flow to the electrode layer preferentially, and electricity flows in the flow path direction and the circumferential direction of the cell when energized. It becomes easy to spread to. The electrical resistivity of the electrode layers 13a and 13b is preferably 1/10 or less, more preferably 1/20 or less, and preferably 1/30 or less of the electrical resistivity of the columnar honeycomb structure 11. Even more preferable. However, if the difference in electrical resistivity between the two becomes too large, the current is concentrated between the ends of the opposing electrode layers and the heat generation of the columnar honeycomb structure 11 is biased. Therefore, the electrical resistivity of the electrode layers 13a and 13b is increased. , The electrical resistivity of the columnar honeycomb structure 11 is preferably 1/200 or more, more preferably 1/150 or more, and even more preferably 1/100 or more. In the present invention, the electrical resistivity of the electrode layers 13a and 13b is a value measured at 25 ° C. by the four-terminal method.
各電極層１３ａ、１３ｂの材質は、金属及び導電性セラミックスとの複合材（サーメット）を使用することができる。金属としては、例えばＣｒ、Ｆｅ、Ｃｏ、Ｎｉ、Ｓｉ又はＴｉの単体金属又はこれらの金属よりなる群から選択される少なくとも一種の金属を含有する合金が挙げられる。導電性セラミックスとしては、限定的ではないが、炭化珪素（ＳｉＣ）が挙げられ、珪化タンタル（ＴａＳｉ2）及び珪化クロム（ＣｒＳｉ2）等の金属珪化物等の金属化合物が挙げられる。金属及び導電性セラミックスとの複合材（サーメット）の具体例としては、金属珪素と炭化珪素の複合材、珪化タンタルや珪化クロム等の金属珪化物と金属珪素と炭化珪素の複合材、更には上記の一種又は二種以上の金属に熱膨張低減の観点から、アルミナ、ムライト、ジルコニア、コージェライト、窒化珪素及び窒化アルミ等の絶縁性セラミックスを一種又は二種以上添加した複合材が挙げられる。電極層１３ａ、１３ｂの材質としては、上記の各種金属及び導電性セラミックスの中でも、珪化タンタルや珪化クロム等の金属珪化物と金属珪素と炭化珪素の複合材との組合せとすることが、柱状ハニカム構造部と同時に焼成できるので製造工程の簡素化に資するという理由により好ましい。
As the material of each of the electrode layers 13a and 13b, a composite material (cermet) of metal and conductive ceramics can be used. Examples of the metal include elemental metals of Cr, Fe, Co, Ni, Si and Ti, and alloys containing at least one metal selected from the group consisting of these metals. Examples of the conductive ceramics include, but are not limited to, silicon carbide (SiC), and examples thereof include metal compounds such as metal siliceates such as tantalum silicate (TaSi 2 ) and chromium silicate (CrSi 2). Specific examples of the composite material (cermet) of metal and conductive ceramics include a composite material of metallic silicon and silicon carbide, a composite material of metal siliceous material such as tantalum silicate and chromium silicate, and a composite material of metallic silicon and silicon carbide, and further described above. From the viewpoint of reducing thermal expansion, a composite material obtained by adding one or more kinds of insulating ceramics such as alumina, mulite, zirconia, cordierite, silicon nitride and aluminum nitride to one or more kinds of metals can be mentioned. Among the various metals and conductive ceramics described above, the electrode layers 13a and 13b may be made of a columnar honeycomb by combining a metal silice such as tantalum silicate or chromium silicate and a composite material of metallic silicon and silicon carbide. It is preferable because it can be fired at the same time as the structural part, which contributes to simplification of the manufacturing process.
（１－３．混合層）
図３に示すように、電極層１３ａ、１３ｂ上には、混合層２０ａ、２０ｂが設けられている。混合層２０ａ、２０ｂの存在により、後述の金属材１６ａ、１６ｂを柱状ハニカム構造体１１に良好に接合させることができる。混合層２０ａ、２０ｂは、導電性の下地層であってもよい。電極層１３ａ、１３ｂと、混合層２０ａ、２０ｂとの間には、図４に示すように、ガラス等で構成された中間層２１を更に設けてもよい。このような構成によれば、電極層１３ａ、１３ｂと、混合層２０ａ、２０ｂとの熱膨張率差に伴う熱応力を緩和し、電極層１３ａ、１３ｂと混合層２０ａ、２０ｂとの界面に発生するクラックをより良好に抑制することができる。 (1-3. Mixed layer)
As shown in FIG. 3, mixed layers 20a and 20b are provided on the electrode layers 13a and 13b. Due to the presence of the mixed layers 20a and 20b, the metal materials 16a and 16b described later can be satisfactorily bonded to the columnar honeycomb structure 11. The mixed layers 20a and 20b may be conductive base layers. As shown in FIG. 4, an intermediate layer 21 made of glass or the like may be further provided between the electrode layers 13a and 13b and the mixed layers 20a and 20b. According to such a configuration, the thermal stress due to the difference in the coefficient of thermal expansion between the electrode layers 13a and 13b and the mixed layers 20a and 20b is relaxed and generated at the interface between the electrode layers 13a and 13b and the mixed layers 20a and 20b. Cracks can be suppressed better.
図３に示すように、電極層１３ａ、１３ｂ上には、混合層２０ａ、２０ｂが設けられている。混合層２０ａ、２０ｂの存在により、後述の金属材１６ａ、１６ｂを柱状ハニカム構造体１１に良好に接合させることができる。混合層２０ａ、２０ｂは、導電性の下地層であってもよい。電極層１３ａ、１３ｂと、混合層２０ａ、２０ｂとの間には、図４に示すように、ガラス等で構成された中間層２１を更に設けてもよい。このような構成によれば、電極層１３ａ、１３ｂと、混合層２０ａ、２０ｂとの熱膨張率差に伴う熱応力を緩和し、電極層１３ａ、１３ｂと混合層２０ａ、２０ｂとの界面に発生するクラックをより良好に抑制することができる。 (1-3. Mixed layer)
As shown in FIG. 3,
混合層２０ａ、２０ｂは、金属とセラミックスとを含む。混合層２０ａ、２０ｂは、金属とセラミックスとで構成されていることが好ましい。混合層２０ａ、２０ｂの具体的な材質としては、上述の電極層１３ａ、１３ｂの材質として示した、金属及び導電性セラミックスとの複合材（サーメット）と同様の材料を用いることができる。混合層２０ａ、２０ｂは、金属を２０～８５体積％含有するのが好ましい。混合層２０ａ、２０ｂが、金属を２０体積％以上含有すると、金属材１６ａ、１６ｂとの接合性がより向上する。混合層２０ａ、２０ｂが、金属を８５体積％以下含有すると、金属とセラミックスとの熱膨張差によるクラック発生が低減される。混合層２０ａ、２０ｂは、金属を３５～７０体積％含有するのがより好ましく、金属を４０～６０体積％含有するのが更により好ましい。
The mixed layers 20a and 20b contain metal and ceramics. The mixed layers 20a and 20b are preferably composed of metal and ceramics. As a specific material of the mixed layers 20a and 20b, the same material as the composite material (cermet) of the metal and the conductive ceramics shown as the material of the electrode layers 13a and 13b described above can be used. The mixed layers 20a and 20b preferably contain 20 to 85% by volume of metal. When the mixed layers 20a and 20b contain 20% by volume or more of metal, the bondability with the metal materials 16a and 16b is further improved. When the mixed layers 20a and 20b contain 85% by volume or less of metal, the occurrence of cracks due to the difference in thermal expansion between the metal and the ceramics is reduced. The mixed layers 20a and 20b more preferably contain 35 to 70% by volume of metal, and even more preferably 40 to 60% by volume of metal.
電気加熱式担体１０が電極層１３ａ、１３ｂを有さない場合は、混合層２０ａ、２０ｂは、柱状ハニカム構造体１１の外周壁１２上に直接設けられていてもよい。また、混合層２０ａ、２０ｂが、上述の電極層１３ａ、１３ｂであってもよい。
When the electrically heated carrier 10 does not have the electrode layers 13a and 13b, the mixed layers 20a and 20b may be provided directly on the outer peripheral wall 12 of the columnar honeycomb structure 11. Further, the mixed layers 20a and 20b may be the above-mentioned electrode layers 13a and 13b.
混合層２０ａ、２０ｂの厚みは、５０～８００μｍであるのが好ましい。混合層２０ａ、２０ｂの厚みが５０μｍ以上であると、金属材１６ａ、１６ｂを柱状ハニカム構造体１１により良好に接合させることができる。混合層２０ａ、２０ｂの厚みが８００μｍ以下であると、混合層と電極層の熱膨張差に起因する歪みによる焼成時のクラックの発生が低減される。混合層２０ａ、２０ｂの厚みは、１５０～５００μｍであるのがより好ましく、２００～３００μｍであるのが更により好ましい。
The thickness of the mixed layers 20a and 20b is preferably 50 to 800 μm. When the thickness of the mixed layers 20a and 20b is 50 μm or more, the metal materials 16a and 16b can be satisfactorily joined by the columnar honeycomb structure 11. When the thicknesses of the mixed layers 20a and 20b are 800 μm or less, the occurrence of cracks during firing due to strain caused by the difference in thermal expansion between the mixed layer and the electrode layer is reduced. The thickness of the mixed layers 20a and 20b is more preferably 150 to 500 μm, and even more preferably 200 to 300 μm.
混合層２０ａ、２０ｂの数及び配置の仕方は制限されず、金属電極１４ａ、１４ｂを固定するのに必要な範囲内で適宜設定できる。また、混合層２０ａ、２０ｂの形状は、平面視で円形状、楕円形状、多角形状など、任意の形状に形成することができる。なお、混合層２０ａ、２０ｂの形状は、生産性及び実用性の観点から、円形又は矩形であることが好ましい。
The number and arrangement of the mixed layers 20a and 20b are not limited, and can be appropriately set within the range necessary for fixing the metal electrodes 14a and 14b. Further, the shapes of the mixed layers 20a and 20b can be formed into any shape such as a circular shape, an elliptical shape, and a polygonal shape in a plan view. The shapes of the mixed layers 20a and 20b are preferably circular or rectangular from the viewpoint of productivity and practicality.
（１－４．金属材）
混合層２０ａ、２０ｂと金属電極１４ａ、１４ｂとの間には金属材１６ａ、１６ｂが設けられている。金属材１６ａ、１６ｂのブリネル硬度は、金属電極１４ａ、１４ｂより小さい。このような構成によれば、電気加熱式担体１０の製造時において、金属電極１４ａ、１４ｂを柱状ハニカム構造体１１に押し付けて固定するとき、金属電極１４ａ、１４ｂとして硬度が高い金属を用いても、ブリネル硬度が金属電極１４ａ、１４ｂより小さい金属材１６ａ、１６ｂが、金属電極１４ａ、１４ｂの押し付けによる応力を緩和することができると推測している。このため、柱状ハニカム構造体１１の破壊が抑制される。また、このように、金属電極１４ａ、１４ｂの押し付けによる柱状ハニカム構造体１１の破壊が抑制されるため、接合時に、金属電極１４ａ、１４ｂを十分に押し付けることができる。従って、柱状ハニカム構造体１１との接点が増加し、許容電流の減少や接合部の強度の低下を抑制することができる。さらに、金属電極１４ａ、１４ｂとして硬度が低い金属を用いる必要もなくなり、振動による金属電極１４ａ、１４ｂの断線も抑制することができる。金属材１６ａ、１６ｂのブリネル硬度は、ＪＩＳ Ｚ ２２４３の試験方法に従い、ブリネル硬さ試験機によって測定することができる。 (1-4. Metallic material)
Metal materials 16a and 16b are provided between the mixed layers 20a and 20b and the metal electrodes 14a and 14b. The Brinell hardness of the metal materials 16a and 16b is smaller than that of the metal electrodes 14a and 14b. According to such a configuration, when the metal electrodes 14a and 14b are pressed against the columnar honeycomb structure 11 and fixed at the time of manufacturing the electroheating carrier 10, even if a metal having high hardness is used as the metal electrodes 14a and 14b. It is presumed that the metal materials 16a and 16b having a brinel hardness smaller than that of the metal electrodes 14a and 14b can relieve the stress caused by pressing the metal electrodes 14a and 14b. Therefore, the destruction of the columnar honeycomb structure 11 is suppressed. Further, since the destruction of the columnar honeycomb structure 11 due to the pressing of the metal electrodes 14a and 14b is suppressed in this way, the metal electrodes 14a and 14b can be sufficiently pressed at the time of joining. Therefore, the number of contacts with the columnar honeycomb structure 11 is increased, and it is possible to suppress a decrease in the allowable current and a decrease in the strength of the joint. Further, it is not necessary to use a metal having a low hardness as the metal electrodes 14a and 14b, and it is possible to suppress disconnection of the metal electrodes 14a and 14b due to vibration. The Brinell hardness of the metal materials 16a and 16b can be measured by a Brinell hardness tester according to the test method of JIS Z 2243.
混合層２０ａ、２０ｂと金属電極１４ａ、１４ｂとの間には金属材１６ａ、１６ｂが設けられている。金属材１６ａ、１６ｂのブリネル硬度は、金属電極１４ａ、１４ｂより小さい。このような構成によれば、電気加熱式担体１０の製造時において、金属電極１４ａ、１４ｂを柱状ハニカム構造体１１に押し付けて固定するとき、金属電極１４ａ、１４ｂとして硬度が高い金属を用いても、ブリネル硬度が金属電極１４ａ、１４ｂより小さい金属材１６ａ、１６ｂが、金属電極１４ａ、１４ｂの押し付けによる応力を緩和することができると推測している。このため、柱状ハニカム構造体１１の破壊が抑制される。また、このように、金属電極１４ａ、１４ｂの押し付けによる柱状ハニカム構造体１１の破壊が抑制されるため、接合時に、金属電極１４ａ、１４ｂを十分に押し付けることができる。従って、柱状ハニカム構造体１１との接点が増加し、許容電流の減少や接合部の強度の低下を抑制することができる。さらに、金属電極１４ａ、１４ｂとして硬度が低い金属を用いる必要もなくなり、振動による金属電極１４ａ、１４ｂの断線も抑制することができる。金属材１６ａ、１６ｂのブリネル硬度は、ＪＩＳ Ｚ ２２４３の試験方法に従い、ブリネル硬さ試験機によって測定することができる。 (1-4. Metallic material)
金属材１６ａ、１６ｂのブリネル硬度は、ＨＢ２００以下であるのが好ましい。金属材１６ａ、１６ｂのブリネル硬度がＨＢ２００以下であると、柱状ハニカム構造体１１へ金属電極１４ａ、１４ｂを固定する際の柱状ハニカム構造体１１の破壊、振動による金属電極１４ａ、１４ｂの断線、及び、金属電極１４ａ、１４ｂと柱状ハニカム構造体１１との接合部の強度低下を、より良好に抑制することができる。金属材１６ａ、１６ｂのブリネル硬度は、ＨＢ１００以下であるのがより好ましく、ＨＢ５０以下であるのが更により好ましい。
The Brinell hardness of the metal materials 16a and 16b is preferably HB200 or less. When the brinell hardness of the metal materials 16a and 16b is HB200 or less, the columnar honeycomb structures 11 are broken when the metal electrodes 14a and 14b are fixed to the columnar honeycomb structure 11, the metal electrodes 14a and 14b are disconnected due to vibration, and the metal electrodes 14a and 14b are disconnected. , The decrease in strength of the joint portion between the metal electrodes 14a and 14b and the columnar honeycomb structure 11 can be suppressed more satisfactorily. The Brinell hardness of the metal materials 16a and 16b is more preferably HB100 or less, and even more preferably HB50 or less.
金属材１６ａ、１６ｂは、Ａｌ、Ｐｔ、Ｐｄ、Ｎｉ、Ａｕ、Ｃｕ、Ａｇ、Ｚｎ、Ｓｎ及びＣｒからなる群から選択された少なくとも１種を含む金属または合金で構成することができる。金属材１６ａ、１６ｂが、Ｐｔ、Ｐｄ、Ａｕ、またはこれらの合金で構成されていると、これらの金属または合金が酸化しにくい性質を有する。そのため、高温雰囲気においても接合強度維持ができるという効果が得られる。
The metal materials 16a and 16b can be composed of a metal or alloy containing at least one selected from the group consisting of Al, Pt, Pd, Ni, Au, Cu, Ag, Zn, Sn and Cr. When the metal materials 16a and 16b are composed of Pt, Pd, Au, or an alloy thereof, these metals or alloys have a property of being difficult to oxidize. Therefore, the effect that the joint strength can be maintained even in a high temperature atmosphere can be obtained.
金属材１６ａ、１６ｂの一部が、金属電極１４ａ、１４ｂの表面と反応していてもよい。また、金属材１６ａ、１６ｂの一部が、混合層２０ａ、２０ｂの表面と反応していてもよい。このような構成によれば、金属材１６ａ、１６ｂを金属電極１４ａ、１４ｂまたは混合層２０ａ、２０ｂと反応させていない構成のものに比べて、金属材１６ａ、１６ｂをより強固に混合層２０ａ、２０ｂと金属電極１４ａ、１４ｂとの間に設けることができる。上記金属電極１４ａ、１４ｂの表面または混合層２０ａ、２０ｂの表面と反応する、金属材１６ａ、１６ｂの一部は、特に限定されないが、金属材１６ａ、１６ｂの厚みの１～２０％であるのが好ましい。金属材１６ａ、１６ｂの厚みの１％以上が、金属電極１４ａ、１４ｂの表面または混合層２０ａ、２０ｂの表面と反応していると、金属材１６ａ、１６ｂをより強固に混合層２０ａ、２０ｂと金属電極１４ａ、１４ｂとの間に設けることができる。一方、金属材１６ａ、１６ｂの厚みの２０％以下が、金属電極１４ａ、１４ｂの表面または混合層２０ａ、２０ｂの表面と反応していると、金属材１６ａ、１６ｂが有する耐熱性または耐食性の劣化を抑制することができる。上記金属電極１４ａ、１４ｂの表面または混合層２０ａ、２０ｂの表面と反応する、金属材１６ａ、１６ｂの一部は、金属材１６ａ、１６ｂの厚みの１～１０％であるのがより好ましく、１～５％であるのが更により好ましい。
A part of the metal materials 16a and 16b may react with the surfaces of the metal electrodes 14a and 14b. Further, a part of the metal materials 16a and 16b may react with the surfaces of the mixed layers 20a and 20b. According to such a configuration, the metal materials 16a and 16b are made stronger than those in which the metal materials 16a and 16b are not reacted with the metal electrodes 14a and 14b or the mixed layers 20a and 20b. It can be provided between the 20b and the metal electrodes 14a and 14b. A part of the metal materials 16a and 16b that reacts with the surfaces of the metal electrodes 14a and 14b or the surfaces of the mixed layers 20a and 20b is not particularly limited, but is 1 to 20% of the thickness of the metal materials 16a and 16b. Is preferable. When 1% or more of the thicknesses of the metal materials 16a and 16b react with the surfaces of the metal electrodes 14a and 14b or the surfaces of the mixed layers 20a and 20b, the metal materials 16a and 16b are more firmly combined with the mixed layers 20a and 20b. It can be provided between the metal electrodes 14a and 14b. On the other hand, when 20% or less of the thickness of the metal materials 16a and 16b reacts with the surface of the metal electrodes 14a and 14b or the surface of the mixed layers 20a and 20b, the heat resistance or corrosion resistance of the metal materials 16a and 16b deteriorates. Can be suppressed. A part of the metal materials 16a and 16b that reacts with the surfaces of the metal electrodes 14a and 14b or the surfaces of the mixed layers 20a and 20b is more preferably 1 to 10% of the thickness of the metal materials 16a and 16b. Even more preferably, it is ~ 5%.
従来、金属電極を下地層にロウ付けによって接合する形態のものがある。このような構成では、ロウが金属電極から外へはみ出てしまう問題が生じる。また、ロウの量を少なくして、ロウを外にはみ出さないようにすると、大きく引け（不足部分）が発生する問題が生じる。これに対し、本発明の実施形態に係る電気加熱式担体１０において、上述のように、金属材１６ａ、１６ｂの一部が、金属電極１４ａ、１４ｂの表面と反応している、または、金属材１６ａ、１６ｂの一部が、混合層２０ａ、２０ｂの表面と反応している構成であると、金属材１６ａ、１６ｂを、金属電極１４ａ、１４ｂから外へはみ出さないように、且つ、引け（不足部分）の発生がないように設けることが容易である。
Conventionally, there is a form in which a metal electrode is joined to the base layer by brazing. In such a configuration, there arises a problem that the wax protrudes from the metal electrode. Further, if the amount of wax is reduced so that the wax does not protrude to the outside, there arises a problem that a large shrinkage (insufficient portion) occurs. On the other hand, in the electrically heated carrier 10 according to the embodiment of the present invention, as described above, a part of the metal materials 16a and 16b reacts with the surfaces of the metal electrodes 14a and 14b, or the metal material. When a part of 16a and 16b is configured to react with the surfaces of the mixed layers 20a and 20b, the metal materials 16a and 16b are prevented from protruding from the metal electrodes 14a and 14b and are closed ( It is easy to provide so that there is no shortage).
上述の、金属材１６ａ、１６ｂと金属電極１４ａ、１４ｂの表面との反応、及び、金属材１６ａ、１６ｂと混合層２０ａ、２０ｂの表面との反応は、ＥＤＳ（エネルギー分散型Ｘ線分析）またはＥＰＭＡ（電子線マイクロアナライザ）等で確認することができる。
The above-mentioned reaction between the metal materials 16a and 16b and the surfaces of the metal electrodes 14a and 14b and the reaction between the metal materials 16a and 16b and the surfaces of the mixed layers 20a and 20b are EDS (energy dispersive X-ray analysis) or It can be confirmed by EPMA (electron probe microanalyzer) or the like.
金属材１６ａ、１６ｂの厚みは、５～５００μｍであるのが好ましい。金属材１６ａ、１６ｂの厚みが５μｍ以上であると、その効果をより顕著に得ることができる。金属材１６ａ、１６ｂの厚みが５００μｍ以下であると、金属材１６ａ、１６ｂの破損をより抑制することができる。金属材１６ａ、１６ｂの厚みは、１０～１００μｍであるのがより好ましく、５０～１００μｍであるのが更により好ましい。
The thickness of the metal materials 16a and 16b is preferably 5 to 500 μm. When the thicknesses of the metal materials 16a and 16b are 5 μm or more, the effect can be obtained more remarkably. When the thickness of the metal materials 16a and 16b is 500 μm or less, damage to the metal materials 16a and 16b can be further suppressed. The thickness of the metal materials 16a and 16b is more preferably 10 to 100 μm, and even more preferably 50 to 100 μm.
金属材１６ａ、１６ｂの数及び配置の仕方は制限されず、金属電極１４ａ、１４ｂを固定するのに必要な範囲内で適宜設定できる。また、金属材１６ａ、１６ｂの形状は、平面視で円形状、楕円形状、多角形状など、任意の形状に形成することができる。なお、金属材１６ａ、１６ｂの形状は、生産性及び実用性の観点から、円形又は矩形であることが好ましい。
The number and arrangement of the metal materials 16a and 16b are not limited, and can be appropriately set within the range necessary for fixing the metal electrodes 14a and 14b. Further, the shapes of the metal materials 16a and 16b can be formed into any shape such as a circular shape, an elliptical shape, and a polygonal shape in a plan view. The shapes of the metal materials 16a and 16b are preferably circular or rectangular from the viewpoint of productivity and practicality.
（１－５．金属電極）
金属電極１４ａ、１４ｂは、金属材１６ａ、１６ｂ上に設けられている。金属電極１４ａ、１４ｂは、一方の金属電極１４ａが、他方の金属電極１４ｂに対して、柱状ハニカム構造体１１の中心軸を挟んで対向するように配設される一対の金属電極であってもよい。金属電極１４ａ、１４ｂは、電極層１３ａ、１３ｂを介して電圧を印加すると通電してジュール熱により柱状ハニカム構造体１１を発熱させることが可能である。このため、電気加熱式担体１０はヒーターとしても好適に用いることができる。印加する電圧は１２～９００Ｖが好ましく、６４～６００Ｖが更に好ましいが、印加する電圧は適宜変更可能である。 (1-5. Metal electrode)
The metal electrodes 14a and 14b are provided on the metal materials 16a and 16b. The metal electrodes 14a and 14b may be a pair of metal electrodes in which one metal electrode 14a is arranged so as to face the other metal electrode 14b with the central axis of the columnar honeycomb structure 11 interposed therebetween. good. When a voltage is applied to the metal electrodes 14a and 14b via the electrode layers 13a and 13b, the metal electrodes 14a and 14b are energized and the columnar honeycomb structure 11 can be heated by Joule heat. Therefore, the electrically heated carrier 10 can be suitably used as a heater. The applied voltage is preferably 12 to 900 V, more preferably 64 to 600 V, but the applied voltage can be changed as appropriate.
金属電極１４ａ、１４ｂは、金属材１６ａ、１６ｂ上に設けられている。金属電極１４ａ、１４ｂは、一方の金属電極１４ａが、他方の金属電極１４ｂに対して、柱状ハニカム構造体１１の中心軸を挟んで対向するように配設される一対の金属電極であってもよい。金属電極１４ａ、１４ｂは、電極層１３ａ、１３ｂを介して電圧を印加すると通電してジュール熱により柱状ハニカム構造体１１を発熱させることが可能である。このため、電気加熱式担体１０はヒーターとしても好適に用いることができる。印加する電圧は１２～９００Ｖが好ましく、６４～６００Ｖが更に好ましいが、印加する電圧は適宜変更可能である。 (1-5. Metal electrode)
The
金属電極１４ａ、１４ｂの材質としては、金属であれば特段の制約はなく、単体金属及び合金等を採用することもできるが、耐食性、電気抵抗率及び線膨張率の観点から例えば、Ｃｒ、Ｆｅ、Ｃｏ、Ｎｉ及びＴｉよりなる群から選択される少なくとも一種を含む合金とすることが好ましく、ステンレス鋼及びＦｅ－Ｎｉ合金がより好ましい。金属電極１４ａ、１４ｂの形状及び大きさは、特に限定されず、電気加熱式担体１０の大きさや通電性能等に応じて、適宜設計することができる。金属電極１４ａ、１４ｂのブリネル硬度は、ＨＢ１７０以上であるのが好ましく、ＨＢ１７０～３００であることがより好ましく、ＨＢ１７０～２７０であることが更により好ましく、ＨＢ１７０～２２０であることが更により好ましい。
As the material of the metal electrodes 14a and 14b, there are no particular restrictions as long as it is a metal, and a single metal, an alloy, or the like can be adopted. However, from the viewpoint of corrosion resistance, electrical resistance, and linear expansion rate, for example, Cr and Fe , Co, Ni and Ti are preferably used as alloys containing at least one selected from the group, and stainless steel and Fe—Ni alloys are more preferable. The shapes and sizes of the metal electrodes 14a and 14b are not particularly limited, and can be appropriately designed according to the size of the electrically heated carrier 10 and the energization performance. The Brinell hardness of the metal electrodes 14a and 14b is preferably HB170 or higher, more preferably HB170 to 300, even more preferably HB170 to 270, and even more preferably HB170 to 220.
金属電極１４ａ、１４ｂは２つ以上の電極部１５を有していてもよい。各電極部１５は、金属材１６ａ、１６ｂの外表面に固定されてもよい。ここで、電極部１５は、溶接により金属材１６ａ、１６ｂに固定されてもよく、溶射により形成される固定層で金属材１６ａ、１６ｂに固定されてもよい。
The metal electrodes 14a and 14b may have two or more electrode portions 15. Each electrode portion 15 may be fixed to the outer surface of the metal materials 16a and 16b. Here, the electrode portion 15 may be fixed to the metal materials 16a and 16b by welding, or may be fixed to the metal materials 16a and 16b by a fixing layer formed by thermal spraying.
図５に示される実施形態では、金属電極１４ａ、１４ｂはそれぞれ３つの櫛状電極部１５を有し、それぞれの電極部１５は２つの金属材１６ａ、１６ｂに固定されている。このように、櫛状電極部１５と電極層１３ａ、１３ｂとの電気的接続は、互いに離間した２つ以上の金属材１６ａ、１６ｂにより実現されていてもよい。
In the embodiment shown in FIG. 5, the metal electrodes 14a and 14b each have three comb-shaped electrode portions 15, and the respective electrode portions 15 are fixed to the two metal materials 16a and 16b. As described above, the electrical connection between the comb-shaped electrode portion 15 and the electrode layers 13a and 13b may be realized by two or more metal materials 16a and 16b that are separated from each other.
なお、電極部１５は、図５では櫛状に成形されているが、金属材１６ａ、１６ｂに固定され電極層１３ａ、１３ｂと電気的に接続し得る限り、または、溶射により電極層１３ａ、１３ｂに固定され得る限り、いかなる形状も採用できる。
Although the electrode portion 15 is formed in a comb shape in FIG. 5, it is fixed to the metal materials 16a and 16b and can be electrically connected to the electrode layers 13a and 13b, or the electrode layers 13a and 13b are sprayed. Any shape can be adopted as long as it can be fixed to.
（１－６．触媒体）
電気加熱式担体１０に触媒を担持することにより、電気加熱式担体１０を触媒体として使用することができる。複数のセル１８の流路には、例えば、自動車排気ガス等の流体を流すことができる。触媒としては、例えば、貴金属系触媒又はこれら以外の触媒が挙げられる。貴金属系触媒としては、白金（Ｐｔ）、パラジウム（Ｐｄ）、ロジウム（Ｒｈ）といった貴金属をアルミナ細孔表面に担持し、セリア、ジルコニア等の助触媒を含む三元触媒や酸化触媒、又は、アルカリ土類金属と白金を窒素酸化物（ＮＯx）の吸蔵成分として含むＮＯx吸蔵還元触媒（ＬＮＴ触媒）が例示される。貴金属を用いない触媒として、銅置換又は鉄置換ゼオライトを含むＮＯx選択還元触媒（ＳＣＲ触媒）等が例示される。また、これらの触媒からなる群から選択される２種以上の触媒を用いてもよい。なお、触媒の担持方法についても特に制限はなく、従来、ハニカム構造体に触媒を担持する担持方法に準じて行うことができる。 (1-6. Catalyst)
By supporting the catalyst on the electricallyheated carrier 10, the electrically heated carrier 10 can be used as a catalyst. For example, a fluid such as automobile exhaust gas can flow through the flow paths of the plurality of cells 18. Examples of the catalyst include noble metal-based catalysts and catalysts other than these. As the noble metal catalyst, a noble metal such as platinum (Pt), palladium (Pd), or rhodium (Rh) is supported on the surface of the alumina pores, and a three-way catalyst containing a co-catalyst such as ceria or zirconia, an oxidation catalyst, or an alkali. An example is a NO x storage reduction catalyst (LNT catalyst) containing earth metal and platinum as storage components of nitrogen oxide (NO x). Examples of catalysts that do not use noble metals include NO x selective reduction catalysts (SCR catalysts) containing copper-substituted or iron-substituted zeolites. Further, two or more kinds of catalysts selected from the group consisting of these catalysts may be used. The method of supporting the catalyst is also not particularly limited, and can be carried out according to the conventional method of supporting the catalyst on the honeycomb structure.
電気加熱式担体１０に触媒を担持することにより、電気加熱式担体１０を触媒体として使用することができる。複数のセル１８の流路には、例えば、自動車排気ガス等の流体を流すことができる。触媒としては、例えば、貴金属系触媒又はこれら以外の触媒が挙げられる。貴金属系触媒としては、白金（Ｐｔ）、パラジウム（Ｐｄ）、ロジウム（Ｒｈ）といった貴金属をアルミナ細孔表面に担持し、セリア、ジルコニア等の助触媒を含む三元触媒や酸化触媒、又は、アルカリ土類金属と白金を窒素酸化物（ＮＯx）の吸蔵成分として含むＮＯx吸蔵還元触媒（ＬＮＴ触媒）が例示される。貴金属を用いない触媒として、銅置換又は鉄置換ゼオライトを含むＮＯx選択還元触媒（ＳＣＲ触媒）等が例示される。また、これらの触媒からなる群から選択される２種以上の触媒を用いてもよい。なお、触媒の担持方法についても特に制限はなく、従来、ハニカム構造体に触媒を担持する担持方法に準じて行うことができる。 (1-6. Catalyst)
By supporting the catalyst on the electrically
（２．電気加熱式担体の製造方法）
次に、本発明の実施形態に係る電気加熱式担体１０を製造する方法について例示的に説明する。本発明の電気加熱式担体１０の製造方法は一実施形態において、電極層形成ペースト付き未焼成ハニカム構造部を得る工程Ａ１と、電極層形成ペースト付き未焼成ハニカム構造部を焼成して柱状ハニカム構造体を得る工程Ａ２と、柱状ハニカム構造体の電極層上に、混合層形成ペーストを設けた後、焼成して混合層付き柱状ハニカム構造体を得る工程Ａ３と、柱状ハニカム構造体の混合層上に、金属材を形成する工程Ａ４と、金属材上に金属電極を溶接する工程Ａ５とを含む。 (2. Method for manufacturing electrically heated carrier)
Next, a method for producing the electricallyheated carrier 10 according to the embodiment of the present invention will be exemplified. In one embodiment, the method for producing the electroheating carrier 10 of the present invention includes a step A1 for obtaining an unfired honeycomb structure portion with an electrode layer forming paste and a columnar honeycomb structure by firing the unfired honeycomb structure portion with an electrode layer forming paste. Step A2 for obtaining a body, step A3 for obtaining a columnar honeycomb structure with a mixed layer after providing a mixed layer forming paste on the electrode layer of the columnar honeycomb structure, and firing to obtain a columnar honeycomb structure with a mixed layer, and on the mixed layer of the columnar honeycomb structure. Including a step A4 for forming a metal material and a step A5 for welding a metal electrode onto the metal material.
次に、本発明の実施形態に係る電気加熱式担体１０を製造する方法について例示的に説明する。本発明の電気加熱式担体１０の製造方法は一実施形態において、電極層形成ペースト付き未焼成ハニカム構造部を得る工程Ａ１と、電極層形成ペースト付き未焼成ハニカム構造部を焼成して柱状ハニカム構造体を得る工程Ａ２と、柱状ハニカム構造体の電極層上に、混合層形成ペーストを設けた後、焼成して混合層付き柱状ハニカム構造体を得る工程Ａ３と、柱状ハニカム構造体の混合層上に、金属材を形成する工程Ａ４と、金属材上に金属電極を溶接する工程Ａ５とを含む。 (2. Method for manufacturing electrically heated carrier)
Next, a method for producing the electrically
工程Ａ１は、ハニカム構造部の前駆体であるハニカム成形体を作製し、ハニカム成形部の側面に電極層形成ペーストを塗布して、電極層形成ペースト付き未焼成ハニカム構造部を得る工程である。ハニカム成形体の作製は、公知のハニカム構造部の製造方法におけるハニカム成形体の作製方法に準じて行うことができる。例えば、まず、炭化珪素粉末（炭化珪素）に、金属珪素粉末（金属珪素）、バインダ、界面活性剤、造孔材、水等を添加して成形原料を作製する。炭化珪素粉末の質量と金属珪素の質量との合計に対して、金属珪素の質量が１０～４０質量％となるようにすることが好ましい。炭化珪素粉末における炭化珪素粒子の平均粒子径は、３～５０μｍが好ましく、３～４０μｍが更に好ましい。金属珪素（金属珪素粉末）の平均粒子径は、２～３５μｍであることが好ましい。炭化珪素粒子及び金属珪素（金属珪素粒子）の平均粒子径はレーザー回折法で粒度の頻度分布を測定したときの、体積基準による算術平均径を指す。炭化珪素粒子は、炭化珪素粉末を構成する炭化珪素の微粒子であり、金属珪素粒子は、金属珪素粉末を構成する金属珪素の微粒子である。なお、これは、ハニカム構造部の材質を、珪素－炭化珪素系複合材とする場合の成形原料の配合であり、ハニカム構造部の材質を炭化珪素とする場合には、金属珪素は添加しない。
Step A1 is a step of producing a honeycomb molded body which is a precursor of the honeycomb structure portion, applying an electrode layer forming paste to the side surface of the honeycomb molded portion, and obtaining an unfired honeycomb structure portion with the electrode layer forming paste. The honeycomb molded body can be produced according to the method for producing a honeycomb molded body in the known method for producing a honeycomb structure portion. For example, first, a metal silicon powder (metal silicon), a binder, a surfactant, a pore-forming material, water, or the like is added to silicon carbide powder (silicon carbide) to prepare a molding raw material. It is preferable that the mass of the metallic silicon is 10 to 40% by mass with respect to the total of the mass of the silicon carbide powder and the mass of the metallic silicon. The average particle size of the silicon carbide particles in the silicon carbide powder is preferably 3 to 50 μm, more preferably 3 to 40 μm. The average particle size of metallic silicon (metallic silicon powder) is preferably 2 to 35 μm. The average particle size of silicon carbide particles and metallic silicon (metal silicon particles) refers to the arithmetic mean diameter based on the volume when the frequency distribution of particle size is measured by the laser diffraction method. The silicon carbide particles are fine particles of silicon carbide constituting the silicon carbide powder, and the metallic silicon particles are fine particles of metallic silicon constituting the metallic silicon powder. This is a blending of molding raw materials when the material of the honeycomb structure is silicon-silicon carbide-based composite material, and when the material of the honeycomb structure is silicon carbide, metallic silicon is not added.
バインダとしては、メチルセルロース、ヒドロキシプロピルメチルセルロース、ヒドロキシプロポキシルセルロース、ヒドロキシエチルセルロース、カルボキシメチルセルロース、ポリビニルアルコール等を挙げることができる。これらの中でも、メチルセルロースとヒドロキシプロポキシルセルロースとを併用することが好ましい。バインダの含有量は、炭化珪素粉末及び金属珪素粉末の合計質量を１００質量部としたときに、２．０～１０．０質量部であることが好ましい。
Examples of the binder include methyl cellulose, hydroxypropyl methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol and the like. Among these, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. The binder content is preferably 2.0 to 10.0 parts by mass when the total mass of the silicon carbide powder and the metallic silicon powder is 100 parts by mass.
水の含有量は、炭化珪素粉末及び金属珪素粉末の合計質量を１００質量部としたときに、２０～６０質量部であることが好ましい。
The water content is preferably 20 to 60 parts by mass when the total mass of the silicon carbide powder and the metallic silicon powder is 100 parts by mass.
界面活性剤としては、エチレングリコール、デキストリン、脂肪酸石鹸、ポリアルコール等を用いることができる。これらは、１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。界面活性剤の含有量は、炭化珪素粉末及び金属珪素粉末の合計質量を１００質量部としたときに、０．１～２．０質量部であることが好ましい。
As the surfactant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used individually by 1 type, or may be used in combination of 2 or more type. The content of the surfactant is preferably 0.1 to 2.0 parts by mass when the total mass of the silicon carbide powder and the metal silicon powder is 100 parts by mass.
造孔材としては、焼成後に気孔となるものであれば特に限定されるものではなく、例えば、グラファイト、澱粉、発泡樹脂、吸水性樹脂、シリカゲル等を挙げることができる。造孔材の含有量は、炭化珪素粉末及び金属珪素粉末の合計質量を１００質量部としたときに、０．５～１０．０質量部であることが好ましい。造孔材の平均粒子径は、１０～３０μｍであることが好ましい。造孔材の平均粒子径はレーザー回折法で粒度の頻度分布を測定したときの、体積基準による算術平均径を指す。造孔材が吸水性樹脂の場合には、造孔材の平均粒子径は吸水後の平均粒子径のことである。
The pore-forming material is not particularly limited as long as it becomes pores after firing, and examples thereof include graphite, starch, foamed resin, water-absorbent resin, and silica gel. The content of the pore-forming material is preferably 0.5 to 10.0 parts by mass when the total mass of the silicon carbide powder and the metallic silicon powder is 100 parts by mass. The average particle size of the pore-forming material is preferably 10 to 30 μm. The average particle size of the pore-forming material refers to the arithmetic mean diameter based on the volume when the frequency distribution of the particle size is measured by the laser diffraction method. When the pore-forming material is a water-absorbent resin, the average particle size of the pore-forming material is the average particle size after water absorption.
次に、得られた成形原料を混練して坏土を形成した後、坏土を押出成形してハニカム成形体を作製する。押出成形に際しては、所望の全体形状、セル形状、隔壁厚み、セル密度等を有する口金を用いることができる。次に、得られたハニカム成形体について、乾燥を行うことが好ましい。ハニカム成形体の中心軸方向長さが、所望の長さではない場合は、ハニカム成形体の両底部を切断して所望の長さとすることができる。乾燥後のハニカム成形体をハニカム乾燥体と呼ぶ。
Next, after kneading the obtained molding raw materials to form a clay, the clay is extruded to produce a honeycomb molded body. In extrusion molding, a mouthpiece having a desired overall shape, cell shape, partition wall thickness, cell density and the like can be used. Next, it is preferable to dry the obtained honeycomb molded product. When the length in the central axis direction of the honeycomb molded body is not the desired length, both bottom portions of the honeycomb molded body can be cut to obtain the desired length. The dried honeycomb molded body is called a honeycomb dried body.
次に、電極層を形成するための電極層形成ペーストを調合する。電極層形成ペーストは、電極層の要求特性に応じて配合した原料粉（金属粉末、及び、セラミックス粉末等）に各種添加剤を適宜添加して混練することで形成することができる。電極層を積層構造とする場合、第一の電極層用のペースト中の金属粉末の平均粒子径に比べて、第二の電極層用のペースト中の金属粉末の平均粒子径を大きくすることにより、金属端子と電極層の接合強度が向上する傾向にある。金属粉末の平均粒子径はレーザー回折法で粒度の頻度分布を測定したときの、体積基準による算術平均径を指す。
Next, the electrode layer forming paste for forming the electrode layer is prepared. The electrode layer forming paste can be formed by appropriately adding various additives to the raw material powder (metal powder, ceramic powder, etc.) blended according to the required characteristics of the electrode layer and kneading. When the electrode layer has a laminated structure, the average particle size of the metal powder in the paste for the second electrode layer is made larger than the average particle size of the metal powder in the paste for the first electrode layer. , The bonding strength between the metal terminal and the electrode layer tends to improve. The average particle size of the metal powder refers to the arithmetic mean diameter based on the volume when the frequency distribution of the particle size is measured by the laser diffraction method.
次に、得られた電極層形成ペーストを、ハニカム成形体（典型的にはハニカム乾燥体）の側面に塗布し、電極層形成ペースト付き未焼成ハニカム構造部を得る。電極層形成ペーストを調合する方法、及び電極層形成ペーストをハニカム成形体に塗布する方法については、公知のハニカム構造体の製造方法に準じて行うことができるが、電極層をハニカム構造部に比べて低い電気抵抗率にするために、ハニカム構造部よりも金属の含有比率を高めたり、金属粒子の粒径を小さくしたりすることができる。
Next, the obtained electrode layer forming paste is applied to the side surface of the honeycomb molded body (typically, the dried honeycomb body) to obtain an unfired honeycomb structure portion with the electrode layer forming paste. The method of preparing the electrode layer forming paste and the method of applying the electrode layer forming paste to the honeycomb molded body can be performed according to a known method for producing a honeycomb structure, but the electrode layer is compared with the honeycomb structure portion. In order to obtain a low electrical resistance, the metal content ratio can be increased or the particle size of the metal particles can be reduced as compared with the honeycomb structure portion.
柱状ハニカム構造体の製造方法の変更例として、工程Ａ１において、電極層形成ペーストを塗布する前に、ハニカム成形体を一旦焼成してもよい。すなわち、この変更例では、ハニカム成形体を焼成してハニカム焼成体を作製し、当該ハニカム焼成体に、電極層形成ペーストを塗布する。
As an example of changing the manufacturing method of the columnar honeycomb structure, in step A1, the honeycomb molded body may be fired once before applying the electrode layer forming paste. That is, in this modified example, the honeycomb molded body is fired to produce a honeycomb fired body, and the electrode layer forming paste is applied to the honeycomb fired body.
工程Ａ２では、電極層形成ペースト付き未焼成ハニカム構造部を焼成して、柱状ハニカム構造体を得る。焼成を行う前に、電極層形成ペースト付き未焼成ハニカム構造部を乾燥してもよい。また、焼成の前に、バインダ等を除去するため、脱脂を行ってもよい。焼成条件としては、窒素、アルゴン等の不活性雰囲気において、１４００～１５００℃で、１～２０時間加熱することが好ましい。また、焼成後、耐久性向上のために、１２００～１３５０℃で、１～１０時間、酸化処理を行うことが好ましい。脱脂及び焼成の方法は特に限定されず、電気炉、ガス炉等を用いて焼成することができる。
In step A2, the unfired honeycomb structure portion with the electrode layer forming paste is fired to obtain a columnar honeycomb structure. Before firing, the unfired honeycomb structure with the electrode layer forming paste may be dried. Further, before firing, degreasing may be performed in order to remove the binder and the like. As the firing conditions, it is preferable to heat at 1400 to 1500 ° C. for 1 to 20 hours in an inert atmosphere such as nitrogen or argon. Further, after firing, it is preferable to carry out an oxidation treatment at 1200 to 1350 ° C. for 1 to 10 hours in order to improve durability. The method of degreasing and firing is not particularly limited, and firing can be performed using an electric furnace, a gas furnace, or the like.
工程Ａ３では、柱状ハニカム構造体上の電極層の表面に、混合層を形成するための金属およびセラミックスを含むペーストを塗布する。このように調製した金属およびセラミックスを含むペーストを曲面印刷機などで所定の配置となるように塗布し、これを乾燥した後、焼成することで、混合層を形成する。
In step A3, a paste containing metal and ceramics for forming a mixed layer is applied to the surface of the electrode layer on the columnar honeycomb structure. The paste containing the metal and ceramics prepared in this way is applied by a curved surface printing machine or the like so as to have a predetermined arrangement, dried, and then fired to form a mixed layer.
混合層を形成するための金属およびセラミックスを含むペーストとしては、例えば、金属粉（ＮｉＣｒ系材料、ステンレス等の金属粉）をガラス材料に混合する。このとき、体積割合で金属比率２０～８５体積％、ガラス材料を１５～８０体積％で混合し、セラミック原料を調製することができる。次いで、このセラミック原料に対してバインダを１質量％、界面活性剤を１質量％、水を２０～４０質量％加えることにより、混合層形成ペーストを調製することができる。また、混合層は、導電性材料を溶射によって、所定の配置、形状となるように形成してもよい。
As the paste containing metal and ceramics for forming the mixed layer, for example, metal powder (NiCr-based material, metal powder such as stainless steel) is mixed with the glass material. At this time, a ceramic raw material can be prepared by mixing a metal ratio of 20 to 85% by volume and a glass material at a volume ratio of 15 to 80% by volume. Next, a mixed layer-forming paste can be prepared by adding 1% by mass of a binder, 1% by mass of a surfactant, and 20 to 40% by mass of water to the ceramic raw material. Further, the mixed layer may be formed by spraying a conductive material so as to have a predetermined arrangement and shape.
工程Ａ４では、工程Ａ３によって得られた混合層付き柱状ハニカム構造体の混合層上に、メッキまたは金属箔の圧着等により、金属材を設ける。これにより、金属材付き柱状ハニカム構造体が得られる。
In step A4, a metal material is provided on the mixed layer of the columnar honeycomb structure with a mixed layer obtained in step A3 by plating or crimping a metal foil. As a result, a columnar honeycomb structure with a metal material can be obtained.
工程Ａ５では、工程Ａ４によって得られた金属材付き柱状ハニカム構造体の金属材上に、金属電極をレーザー溶接または超音波溶接により固定する。このようにして、本発明の実施形態に係る電気加熱式担体が得られる。
In step A5, the metal electrode is fixed on the metal material of the columnar honeycomb structure with metal material obtained in step A4 by laser welding or ultrasonic welding. In this way, the electroheated carrier according to the embodiment of the present invention is obtained.
（３．排気ガス浄化装置）
上述した本発明の実施形態に係る電気加熱式担体は、排気ガス浄化装置に用いることができる。当該排気ガス浄化装置は、電気加熱式担体と、当該電気加熱式担体を保持する金属製の缶体とを有する。排気ガス浄化装置において、電気加熱式担体は、エンジンからの排気ガスを流すための排気ガス流路の途中に設置される。缶体としては、電気加熱式担体を収容する金属製の筒状部材等を用いることができる。 (3. Exhaust gas purification device)
The electrically heated carrier according to the embodiment of the present invention described above can be used in an exhaust gas purification device. The exhaust gas purifying device has an electrically heated carrier and a metal can body that holds the electrically heated carrier. In the exhaust gas purification device, the electrically heated carrier is installed in the middle of the exhaust gas flow path for flowing the exhaust gas from the engine. As the can body, a metal tubular member or the like accommodating an electrically heated carrier can be used.
上述した本発明の実施形態に係る電気加熱式担体は、排気ガス浄化装置に用いることができる。当該排気ガス浄化装置は、電気加熱式担体と、当該電気加熱式担体を保持する金属製の缶体とを有する。排気ガス浄化装置において、電気加熱式担体は、エンジンからの排気ガスを流すための排気ガス流路の途中に設置される。缶体としては、電気加熱式担体を収容する金属製の筒状部材等を用いることができる。 (3. Exhaust gas purification device)
The electrically heated carrier according to the embodiment of the present invention described above can be used in an exhaust gas purification device. The exhaust gas purifying device has an electrically heated carrier and a metal can body that holds the electrically heated carrier. In the exhaust gas purification device, the electrically heated carrier is installed in the middle of the exhaust gas flow path for flowing the exhaust gas from the engine. As the can body, a metal tubular member or the like accommodating an electrically heated carrier can be used.
以下、本発明及びその利点をより良く理解するための実施例を例示するが、本発明は実施例に限定されるものではない。
Hereinafter, examples for better understanding the present invention and its advantages will be illustrated, but the present invention is not limited to the examples.
＜実施例１＞
（１．円柱状の坏土の作製）
炭化珪素（ＳｉＣ）粉末と金属珪素（Ｓｉ）粉末とを８０：２０の質量割合で混合してセラミックス原料を調製した。そして、セラミックス原料に、バインダとしてヒドロキシプロピルメチルセルロース、造孔材として吸水性樹脂を添加すると共に、水を添加して成形原料とした。そして、成形原料を真空土練機により混練し、円柱状の坏土を作製した。バインダの含有量は炭化珪素（ＳｉＣ）粉末と金属珪素（Ｓｉ）粉末の合計を１００質量部としたときに７質量部とした。造孔材の含有量は炭化珪素（ＳｉＣ）粉末と金属珪素（Ｓｉ）粉末の合計を１００質量部としたときに３質量部とした。水の含有量は炭化珪素（ＳｉＣ）粉末と金属珪素（Ｓｉ）粉末の合計を１００質量部としたときに４２質量部とした。炭化珪素粉末の平均粒子径は２０μｍであり、金属珪素粉末の平均粒子径は６μｍであった。また、造孔材の平均粒子径は２０μｍであった。炭化珪素粉末、金属珪素粉末及び造孔材の平均粒子径は、レーザー回折法で粒度の頻度分布を測定したときの、体積基準による算術平均径を指す。 <Example 1>
(1. Preparation of columnar clay)
Silicon carbide (SiC) powder and metallic silicon (Si) powder were mixed at a mass ratio of 80:20 to prepare a ceramic raw material. Then, hydroxypropyl methylcellulose as a binder and a water-absorbent resin as a pore-forming material were added to the ceramic raw material, and water was added to prepare a molding raw material. Then, the molding raw material was kneaded with a vacuum clay kneader to prepare a columnar clay. The binder content was 7 parts by mass when the total of the silicon carbide (SiC) powder and the metallic silicon (Si) powder was 100 parts by mass. The content of the pore-forming material was 3 parts by mass when the total of the silicon carbide (SiC) powder and the metallic silicon (Si) powder was 100 parts by mass. The water content was 42 parts by mass when the total of the silicon carbide (SiC) powder and the metallic silicon (Si) powder was 100 parts by mass. The average particle size of the silicon carbide powder was 20 μm, and the average particle size of the metallic silicon powder was 6 μm. The average particle size of the pore-forming material was 20 μm. The average particle size of the silicon carbide powder, the metallic silicon powder, and the pore-forming material refers to the arithmetic mean diameter based on the volume when the frequency distribution of the particle size is measured by the laser diffraction method.
（１．円柱状の坏土の作製）
炭化珪素（ＳｉＣ）粉末と金属珪素（Ｓｉ）粉末とを８０：２０の質量割合で混合してセラミックス原料を調製した。そして、セラミックス原料に、バインダとしてヒドロキシプロピルメチルセルロース、造孔材として吸水性樹脂を添加すると共に、水を添加して成形原料とした。そして、成形原料を真空土練機により混練し、円柱状の坏土を作製した。バインダの含有量は炭化珪素（ＳｉＣ）粉末と金属珪素（Ｓｉ）粉末の合計を１００質量部としたときに７質量部とした。造孔材の含有量は炭化珪素（ＳｉＣ）粉末と金属珪素（Ｓｉ）粉末の合計を１００質量部としたときに３質量部とした。水の含有量は炭化珪素（ＳｉＣ）粉末と金属珪素（Ｓｉ）粉末の合計を１００質量部としたときに４２質量部とした。炭化珪素粉末の平均粒子径は２０μｍであり、金属珪素粉末の平均粒子径は６μｍであった。また、造孔材の平均粒子径は２０μｍであった。炭化珪素粉末、金属珪素粉末及び造孔材の平均粒子径は、レーザー回折法で粒度の頻度分布を測定したときの、体積基準による算術平均径を指す。 <Example 1>
(1. Preparation of columnar clay)
Silicon carbide (SiC) powder and metallic silicon (Si) powder were mixed at a mass ratio of 80:20 to prepare a ceramic raw material. Then, hydroxypropyl methylcellulose as a binder and a water-absorbent resin as a pore-forming material were added to the ceramic raw material, and water was added to prepare a molding raw material. Then, the molding raw material was kneaded with a vacuum clay kneader to prepare a columnar clay. The binder content was 7 parts by mass when the total of the silicon carbide (SiC) powder and the metallic silicon (Si) powder was 100 parts by mass. The content of the pore-forming material was 3 parts by mass when the total of the silicon carbide (SiC) powder and the metallic silicon (Si) powder was 100 parts by mass. The water content was 42 parts by mass when the total of the silicon carbide (SiC) powder and the metallic silicon (Si) powder was 100 parts by mass. The average particle size of the silicon carbide powder was 20 μm, and the average particle size of the metallic silicon powder was 6 μm. The average particle size of the pore-forming material was 20 μm. The average particle size of the silicon carbide powder, the metallic silicon powder, and the pore-forming material refers to the arithmetic mean diameter based on the volume when the frequency distribution of the particle size is measured by the laser diffraction method.
（２．ハニカム乾燥体の作製）
得られた円柱状の坏土を碁盤目状の口金構造を有する押出成形機を用いて成形し、セルの流路方向に垂直な断面における各セル形状が正方形である円柱状ハニカム成形体を得た。このハニカム成形体を高周波誘電加熱乾燥した後、熱風乾燥機を用いて１２０℃で２時間乾燥し、両底面を所定量切断して、ハニカム乾燥体を作製した。 (2. Preparation of dried honeycomb)
The obtained columnar clay was molded using an extrusion molding machine having a grid-like base structure to obtain a columnar honeycomb molded body in which each cell shape is square in a cross section perpendicular to the cell flow path direction. rice field. This honeycomb molded body was dried by high frequency dielectric heating and then dried at 120 ° C. for 2 hours using a hot air dryer, and both bottom surfaces were cut by a predetermined amount to prepare a honeycomb dried body.
得られた円柱状の坏土を碁盤目状の口金構造を有する押出成形機を用いて成形し、セルの流路方向に垂直な断面における各セル形状が正方形である円柱状ハニカム成形体を得た。このハニカム成形体を高周波誘電加熱乾燥した後、熱風乾燥機を用いて１２０℃で２時間乾燥し、両底面を所定量切断して、ハニカム乾燥体を作製した。 (2. Preparation of dried honeycomb)
The obtained columnar clay was molded using an extrusion molding machine having a grid-like base structure to obtain a columnar honeycomb molded body in which each cell shape is square in a cross section perpendicular to the cell flow path direction. rice field. This honeycomb molded body was dried by high frequency dielectric heating and then dried at 120 ° C. for 2 hours using a hot air dryer, and both bottom surfaces were cut by a predetermined amount to prepare a honeycomb dried body.
（３．電極層形成ペーストの調製）
金属珪素（Ｓｉ）粉末、炭化珪素（ＳｉＣ）粉末、メチルセルロース、グリセリン、及び水を、自転公転攪拌機で混合して、電極層形成ペーストを調製した。Ｓｉ粉末、及びＳｉＣ粉末は体積比で、Ｓｉ粉末：ＳｉＣ粉末＝４０：６０となるように配合した。また、ＴａＳｉ2粉末、Ｓｉ粉末、及びＳｉＣ粉末の合計を１００質量部としたときに、メチルセルロースは０．５質量部であり、グリセリンは１０質量部であり、水は３８質量部であった。金属珪素粉末の平均粒子径は６μｍであった。炭化珪素粉末の平均粒子径は３５μｍであった。これらの平均粒子径はレーザー回折法で粒度の頻度分布を測定したときの、体積基準による算術平均径を指す。 (3. Preparation of electrode layer forming paste)
Metallic silicon (Si) powder, silicon carbide (SiC) powder, methyl cellulose, glycerin, and water were mixed with a rotating and revolving stirrer to prepare an electrode layer forming paste. The Si powder and the SiC powder were blended so that the volume ratio was Si powder: SiC powder = 40:60. Further, when the total of TaSi 2 powder, Si powder, and SiC powder was 100 parts by mass, methyl cellulose was 0.5 parts by mass, glycerin was 10 parts by mass, and water was 38 parts by mass. The average particle size of the metallic silicon powder was 6 μm. The average particle size of the silicon carbide powder was 35 μm. These average particle diameters refer to the arithmetic mean diameters based on the volume when the frequency distribution of particle size is measured by the laser diffraction method.
金属珪素（Ｓｉ）粉末、炭化珪素（ＳｉＣ）粉末、メチルセルロース、グリセリン、及び水を、自転公転攪拌機で混合して、電極層形成ペーストを調製した。Ｓｉ粉末、及びＳｉＣ粉末は体積比で、Ｓｉ粉末：ＳｉＣ粉末＝４０：６０となるように配合した。また、ＴａＳｉ2粉末、Ｓｉ粉末、及びＳｉＣ粉末の合計を１００質量部としたときに、メチルセルロースは０．５質量部であり、グリセリンは１０質量部であり、水は３８質量部であった。金属珪素粉末の平均粒子径は６μｍであった。炭化珪素粉末の平均粒子径は３５μｍであった。これらの平均粒子径はレーザー回折法で粒度の頻度分布を測定したときの、体積基準による算術平均径を指す。 (3. Preparation of electrode layer forming paste)
Metallic silicon (Si) powder, silicon carbide (SiC) powder, methyl cellulose, glycerin, and water were mixed with a rotating and revolving stirrer to prepare an electrode layer forming paste. The Si powder and the SiC powder were blended so that the volume ratio was Si powder: SiC powder = 40:60. Further, when the total of TaSi 2 powder, Si powder, and SiC powder was 100 parts by mass, methyl cellulose was 0.5 parts by mass, glycerin was 10 parts by mass, and water was 38 parts by mass. The average particle size of the metallic silicon powder was 6 μm. The average particle size of the silicon carbide powder was 35 μm. These average particle diameters refer to the arithmetic mean diameters based on the volume when the frequency distribution of particle size is measured by the laser diffraction method.
（４．電極層形成ペーストの塗布及び焼成）
次に、この電極層形成ペーストを曲面印刷機によって、ハニカム乾燥体に対して適切な面積及び膜厚で塗布し、さらに熱風乾燥機で１２０℃、３０分乾燥した後、ハニカム乾燥体と共にＡｒ雰囲気にて１４００℃で３時間焼成し、柱状ハニカム構造体とした。 (4. Application and firing of electrode layer forming paste)
Next, this electrode layer forming paste is applied to the honeycomb dried body with an appropriate area and film thickness by a curved surface printing machine, further dried at 120 ° C. for 30 minutes with a hot air dryer, and then Ar atmosphere together with the honeycomb dried body. Was fired at 1400 ° C. for 3 hours to obtain a columnar honeycomb structure.
次に、この電極層形成ペーストを曲面印刷機によって、ハニカム乾燥体に対して適切な面積及び膜厚で塗布し、さらに熱風乾燥機で１２０℃、３０分乾燥した後、ハニカム乾燥体と共にＡｒ雰囲気にて１４００℃で３時間焼成し、柱状ハニカム構造体とした。 (4. Application and firing of electrode layer forming paste)
Next, this electrode layer forming paste is applied to the honeycomb dried body with an appropriate area and film thickness by a curved surface printing machine, further dried at 120 ° C. for 30 minutes with a hot air dryer, and then Ar atmosphere together with the honeycomb dried body. Was fired at 1400 ° C. for 3 hours to obtain a columnar honeycomb structure.
（５．混合層形成ペーストの調製）
金属粉（ＮｉＣｒ）とガラス粉とを、５０％：５０％の体積割合で混合し、セラミック原料を作製した。このセラミック原料に対してバインダを１質量％、界面活性剤を１質量％、水を２０～４０質量％加えてペースト原料を作製した。レーザー回折法で測定した金属粉の平均粒子径は１０μｍであり、ガラス粉の平均粒子径は５μｍであった。 (5. Preparation of mixed layer forming paste)
Metal powder (NiCr) and glass powder were mixed in a volume ratio of 50%: 50% to prepare a ceramic raw material. A binder was added in an amount of 1% by mass, a surfactant was added in an amount of 1% by mass, and water was added in an amount of 20 to 40% by mass with respect to the ceramic raw material to prepare a paste raw material. The average particle size of the metal powder measured by the laser diffraction method was 10 μm, and the average particle size of the glass powder was 5 μm.
金属粉（ＮｉＣｒ）とガラス粉とを、５０％：５０％の体積割合で混合し、セラミック原料を作製した。このセラミック原料に対してバインダを１質量％、界面活性剤を１質量％、水を２０～４０質量％加えてペースト原料を作製した。レーザー回折法で測定した金属粉の平均粒子径は１０μｍであり、ガラス粉の平均粒子径は５μｍであった。 (5. Preparation of mixed layer forming paste)
Metal powder (NiCr) and glass powder were mixed in a volume ratio of 50%: 50% to prepare a ceramic raw material. A binder was added in an amount of 1% by mass, a surfactant was added in an amount of 1% by mass, and water was added in an amount of 20 to 40% by mass with respect to the ceramic raw material to prepare a paste raw material. The average particle size of the metal powder measured by the laser diffraction method was 10 μm, and the average particle size of the glass powder was 5 μm.
（６．混合層形成ペーストの塗布及び焼成）
上記の混合層形成ペーストを、曲面印刷機によって、柱状ハニカム構造体の電極層に対して塗布した。続いて、熱風乾燥機で１２０℃、３０分乾燥した後、Ａｒ雰囲気にて１１００℃で１時間焼成した。 (6. Application and firing of mixed layer forming paste)
The above mixed layer forming paste was applied to the electrode layer of the columnar honeycomb structure by a curved surface printing machine. Subsequently, it was dried at 120 ° C. for 30 minutes in a hot air dryer, and then fired at 1100 ° C. for 1 hour in an Ar atmosphere.
上記の混合層形成ペーストを、曲面印刷機によって、柱状ハニカム構造体の電極層に対して塗布した。続いて、熱風乾燥機で１２０℃、３０分乾燥した後、Ａｒ雰囲気にて１１００℃で１時間焼成した。 (6. Application and firing of mixed layer forming paste)
The above mixed layer forming paste was applied to the electrode layer of the columnar honeycomb structure by a curved surface printing machine. Subsequently, it was dried at 120 ° C. for 30 minutes in a hot air dryer, and then fired at 1100 ° C. for 1 hour in an Ar atmosphere.
ハニカム構造体は、底面が直径１００ｍｍの円形であり、高さ（セルの流路方向における長さ）が１００ｍｍであった。セル密度は９３セル／ｃｍ2であり、隔壁の厚みは１０１．６μｍであり、隔壁の気孔率は４５％であり、隔壁の平均細孔径は８．６μｍであった。電極層の厚みは０．３ｍｍであり、混合層の厚みは０．２ｍｍであった。
The bottom surface of the honeycomb structure was circular with a diameter of 100 mm, and the height (length in the flow path direction of the cell) was 100 mm. The cell density was 93 cells / cm 2 , the thickness of the partition was 101.6 μm, the porosity of the partition was 45%, and the average pore diameter of the partition was 8.6 μm. The thickness of the electrode layer was 0.3 mm, and the thickness of the mixed layer was 0.2 mm.
（７．金属材及び電極の固定）
金属材として、Ｔｉ製で厚み０．０５ｍｍの板材（ブリネル硬度１３０）を準備し、当該金属材を、混合層上に載せた。
次に、金属材上に、ＳＵＳ４３０製で厚み０．２ｍｍ、幅０．５ｍｍの金属電極（ブリネル硬度１８０）を配置して、上から押し付けながら、各金属電極と混合層が重なった部分について、レーザー出力２００Ｗ／ｍｍ2で４点のレーザー溶接を実施した。 (7. Fixing metal material and electrodes)
As a metal material, a plate material (Brinell hardness 130) made of Ti and having a thickness of 0.05 mm was prepared, and the metal material was placed on the mixed layer.
Next, a metal electrode (Brinell hardness 180) made of SUS430 and having a thickness of 0.2 mm and a width of 0.5 mm is placed on the metal material, and while pressing from above, each metal electrode and the mixed layer overlap each other. Laser welding was performed at four points with a laser output of 200 W / mm 2.
金属材として、Ｔｉ製で厚み０．０５ｍｍの板材（ブリネル硬度１３０）を準備し、当該金属材を、混合層上に載せた。
次に、金属材上に、ＳＵＳ４３０製で厚み０．２ｍｍ、幅０．５ｍｍの金属電極（ブリネル硬度１８０）を配置して、上から押し付けながら、各金属電極と混合層が重なった部分について、レーザー出力２００Ｗ／ｍｍ2で４点のレーザー溶接を実施した。 (7. Fixing metal material and electrodes)
As a metal material, a plate material (Brinell hardness 130) made of Ti and having a thickness of 0.05 mm was prepared, and the metal material was placed on the mixed layer.
Next, a metal electrode (Brinell hardness 180) made of SUS430 and having a thickness of 0.2 mm and a width of 0.5 mm is placed on the metal material, and while pressing from above, each metal electrode and the mixed layer overlap each other. Laser welding was performed at four points with a laser output of 200 W / mm 2.
＜実施例２＞
金属材の材質を、Ｃｕ製（ブリネル硬度９０）とした以外は、実施例１と同様にサンプルを作製した。 <Example 2>
A sample was prepared in the same manner as in Example 1 except that the metal material was made of Cu (Brinell hardness 90).
金属材の材質を、Ｃｕ製（ブリネル硬度９０）とした以外は、実施例１と同様にサンプルを作製した。 <Example 2>
A sample was prepared in the same manner as in Example 1 except that the metal material was made of Cu (Brinell hardness 90).
＜実施例３＞
金属材の材質を、Ｐｔ製（ブリネル硬度４９）とした以外は、実施例１と同様にサンプルを作製した。
実施例１～３のサンプルにおいて、金属材の一部は、金属電極及び混合層の表面と反応しているものであった。 <Example 3>
A sample was prepared in the same manner as in Example 1 except that the metal material was made of Pt (Brinell hardness 49).
In the samples of Examples 1 to 3, a part of the metal material was reacting with the surface of the metal electrode and the mixed layer.
金属材の材質を、Ｐｔ製（ブリネル硬度４９）とした以外は、実施例１と同様にサンプルを作製した。
実施例１～３のサンプルにおいて、金属材の一部は、金属電極及び混合層の表面と反応しているものであった。 <Example 3>
A sample was prepared in the same manner as in Example 1 except that the metal material was made of Pt (Brinell hardness 49).
In the samples of Examples 1 to 3, a part of the metal material was reacting with the surface of the metal electrode and the mixed layer.
＜比較例１＞
金属材を設けず、混合層上に直接金属電極を接合した以外は、実施例１と同様にサンプルを作製した。 <Comparative example 1>
A sample was prepared in the same manner as in Example 1 except that the metal electrode was not provided and the metal electrode was directly bonded onto the mixed layer.
金属材を設けず、混合層上に直接金属電極を接合した以外は、実施例１と同様にサンプルを作製した。 <Comparative example 1>
A sample was prepared in the same manner as in Example 1 except that the metal electrode was not provided and the metal electrode was directly bonded onto the mixed layer.
＜比較例２＞
金属電極の材質を、Ｐｔ製（ブリネル硬度４９）とした以外は、実施例１と同様にサンプルを作製した。 <Comparative example 2>
A sample was prepared in the same manner as in Example 1 except that the metal electrode was made of Pt (Brinell hardness 49).
金属電極の材質を、Ｐｔ製（ブリネル硬度４９）とした以外は、実施例１と同様にサンプルを作製した。 <Comparative example 2>
A sample was prepared in the same manner as in Example 1 except that the metal electrode was made of Pt (Brinell hardness 49).
（８．破壊強度評価試験）
実施例１～３及び比較例１～２の各サンプルに対し、それぞれ、ハニカム構造体を固定した状態で、金属電極を横方向へ（ハニカム構造体の表面と平行な方向へ）引っ張り、いずれかの場所に破壊が生じるまでの剪断強度を測定した。また、ｎ＝２０で当該試験を行い、剪断強度の平均値を算出した。
試験条件及び評価結果を表１に示す。 (8. Break strength evaluation test)
For each of the samples of Examples 1 to 3 and Comparative Examples 1 and 2, the metal electrode was pulled laterally (in the direction parallel to the surface of the honeycomb structure) with the honeycomb structure fixed, and either of them was used. The shear strength until the fracture occurred at the site was measured. Further, the test was carried out at n = 20, and the average value of the shear strength was calculated.
Table 1 shows the test conditions and evaluation results.
実施例１～３及び比較例１～２の各サンプルに対し、それぞれ、ハニカム構造体を固定した状態で、金属電極を横方向へ（ハニカム構造体の表面と平行な方向へ）引っ張り、いずれかの場所に破壊が生じるまでの剪断強度を測定した。また、ｎ＝２０で当該試験を行い、剪断強度の平均値を算出した。
試験条件及び評価結果を表１に示す。 (8. Break strength evaluation test)
For each of the samples of Examples 1 to 3 and Comparative Examples 1 and 2, the metal electrode was pulled laterally (in the direction parallel to the surface of the honeycomb structure) with the honeycomb structure fixed, and either of them was used. The shear strength until the fracture occurred at the site was measured. Further, the test was carried out at n = 20, and the average value of the shear strength was calculated.
Table 1 shows the test conditions and evaluation results.
（９．考察）
比較例１は、金属材を設けておらず、且つ、金属電極のブリネル硬度が高かったため、レーザー接合時の押し付けによって混合層にクラックが入り、試験時に混合層で破壊が発生した。
比較例２は、金属電極のブリネル強度が低かったため、剪断応力を加えると、低応力にて金属電極が断線した。
これらに対し、実施例１～３は、レーザー接合での押し付け時には、金属材で応力を緩和することで、平均剪断強度が大幅に上昇していた。このため、実施例１～３では、試験時に混合層で破壊が発生せず、金属電極自体はブリネル硬度が高い材料を使用することができ、金属電極の破壊に至る剪断強度が高かった。また、破壊が金属電極で生じており、金属電極とハニカム構造体との接合部の強度も良好であった。 (9. Consideration)
In Comparative Example 1, since no metal material was provided and the Brinell hardness of the metal electrode was high, the mixed layer was cracked by pressing during laser bonding, and the mixed layer was broken during the test.
In Comparative Example 2, since the Brinell strength of the metal electrode was low, when shear stress was applied, the metal electrode was broken due to the low stress.
On the other hand, in Examples 1 to 3, the average shear strength was significantly increased by relaxing the stress with a metal material at the time of pressing by laser bonding. Therefore, in Examples 1 to 3, fracture did not occur in the mixed layer during the test, a material having a high Brinell hardness could be used for the metal electrode itself, and the shear strength leading to fracture of the metal electrode was high. Further, the fracture occurred at the metal electrode, and the strength of the joint between the metal electrode and the honeycomb structure was also good.
比較例１は、金属材を設けておらず、且つ、金属電極のブリネル硬度が高かったため、レーザー接合時の押し付けによって混合層にクラックが入り、試験時に混合層で破壊が発生した。
比較例２は、金属電極のブリネル強度が低かったため、剪断応力を加えると、低応力にて金属電極が断線した。
これらに対し、実施例１～３は、レーザー接合での押し付け時には、金属材で応力を緩和することで、平均剪断強度が大幅に上昇していた。このため、実施例１～３では、試験時に混合層で破壊が発生せず、金属電極自体はブリネル硬度が高い材料を使用することができ、金属電極の破壊に至る剪断強度が高かった。また、破壊が金属電極で生じており、金属電極とハニカム構造体との接合部の強度も良好であった。 (9. Consideration)
In Comparative Example 1, since no metal material was provided and the Brinell hardness of the metal electrode was high, the mixed layer was cracked by pressing during laser bonding, and the mixed layer was broken during the test.
In Comparative Example 2, since the Brinell strength of the metal electrode was low, when shear stress was applied, the metal electrode was broken due to the low stress.
On the other hand, in Examples 1 to 3, the average shear strength was significantly increased by relaxing the stress with a metal material at the time of pressing by laser bonding. Therefore, in Examples 1 to 3, fracture did not occur in the mixed layer during the test, a material having a high Brinell hardness could be used for the metal electrode itself, and the shear strength leading to fracture of the metal electrode was high. Further, the fracture occurred at the metal electrode, and the strength of the joint between the metal electrode and the honeycomb structure was also good.
１０ 電気加熱式担体
１１ 柱状ハニカム構造体
１２ 外周壁
１３ａ、１３ｂ 電極層
１４ａ、１４ｂ 金属電極
１５ 電極部
１６ａ、１６ｂ 金属材
１８ セル
１９ 隔壁
２０ａ、２０ｂ 混合層
２１ 中間層 10 Electricheating type carrier 11 Columnar honeycomb structure 12 Outer wall 13a, 13b Electrode layer 14a, 14b Metal electrode 15 Electrode part 16a, 16b Metal material 18 Cell 19 Partition wall 20a, 20b Mixed layer 21 Intermediate layer
１１ 柱状ハニカム構造体
１２ 外周壁
１３ａ、１３ｂ 電極層
１４ａ、１４ｂ 金属電極
１５ 電極部
１６ａ、１６ｂ 金属材
１８ セル
１９ 隔壁
２０ａ、２０ｂ 混合層
２１ 中間層 10 Electric
Claims (10)
- 外周壁と、前記外周壁の内側に配設され、一方の端面から他方の端面まで貫通して流路を形成する複数のセルを区画形成する隔壁と、を有するセラミックス製の柱状ハニカム構造体と、
前記柱状ハニカム構造体の外周壁上に設けられている、金属とセラミックスとを含む混合層と、
金属電極と、
前記混合層と前記金属電極との間に設けられている金属材と、
を備え、
前記金属材のブリネル硬度が、前記金属電極のブリネル硬度より小さい、電気加熱式担体。 A ceramic columnar honeycomb structure having an outer peripheral wall and a partition wall that is disposed inside the outer peripheral wall and partitions a plurality of cells that form a flow path from one end face to the other end face. ,
A mixed layer containing metal and ceramics provided on the outer peripheral wall of the columnar honeycomb structure, and
With metal electrodes
A metal material provided between the mixed layer and the metal electrode,
With
An electrically heated carrier in which the Brinell hardness of the metal material is smaller than the Brinell hardness of the metal electrode. - 前記金属材のブリネル硬度がＨＢ２００以下である請求項１に記載の電気加熱式担体。 The electrically heated carrier according to claim 1, wherein the Brinell hardness of the metal material is HB200 or less.
- 前記金属材が、Ａｌ、Ｐｔ、Ｐｄ、Ｎｉ、Ａｕ、Ｃｕ、Ａｇ、Ｚｎ、Ｓｎ及びＣｒからなる群から選択された少なくとも１種を含む金属または合金で構成されている請求項１または２に記載の電気加熱式担体。 Claim 1 or 2 wherein the metal material is made of a metal or alloy containing at least one selected from the group consisting of Al, Pt, Pd, Ni, Au, Cu, Ag, Zn, Sn and Cr. The electroheated carrier according to the description.
- 前記金属材の一部が、前記金属電極の表面と反応している請求項１～３のいずれか一項に記載の電気加熱式担体。 The electroheated carrier according to any one of claims 1 to 3, wherein a part of the metal material reacts with the surface of the metal electrode.
- 前記金属材の一部が、前記混合層の表面と反応している請求項１～４のいずれか一項に記載の電気加熱式担体。 The electroheated carrier according to any one of claims 1 to 4, wherein a part of the metal material reacts with the surface of the mixed layer.
- 前記混合層が、前記柱状ハニカム構造体の外周壁の表面に配設されている電極層である請求項１～５のいずれか一項に記載の電気加熱式担体。 The electroheated carrier according to any one of claims 1 to 5, wherein the mixed layer is an electrode layer arranged on the surface of the outer peripheral wall of the columnar honeycomb structure.
- 前記柱状ハニカム構造体の外周壁の表面に配設されている電極層を更に備え、
前記混合層が、前記電極層上に設けられている導電性の下地層である請求項１～５のいずれか一項に記載の電気加熱式担体。 An electrode layer disposed on the surface of the outer peripheral wall of the columnar honeycomb structure is further provided.
The electrically heated carrier according to any one of claims 1 to 5, wherein the mixed layer is a conductive base layer provided on the electrode layer. - 前記電極層が、前記柱状ハニカム構造体の外周壁の表面に、前記柱状ハニカム構造体の中心軸を挟んで対向するように配設されている一対の電極層である請求項６または７に記載の電気加熱式担体。 6. Electric heating type carrier.
- 前記混合層が、金属を２０～８５体積％含有する請求項１～８のいずれか一項に記載の電気加熱式担体。 The electroheated carrier according to any one of claims 1 to 8, wherein the mixed layer contains 20 to 85% by volume of metal.
- 請求項１～９のいずれか一項に記載の電気加熱式担体と、
前記電気加熱式担体を保持する金属製の缶体と、
を有する排気ガス浄化装置。 The electrically heated carrier according to any one of claims 1 to 9, and the electric heating type carrier.
A metal can body holding the electrically heated carrier and
Exhaust gas purification device with.
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|---|---|---|---|---|
| JPH11343180A (en) * | 1998-05-29 | 1999-12-14 | Kyocera Corp | Ceramic-member/metallic-member joined body and ceramic heater using the same |
| JP2000106266A (en) * | 1998-07-27 | 2000-04-11 | Denso Corp | Ceramic heater |
| JP2018172258A (en) * | 2017-03-31 | 2018-11-08 | 日本碍子株式会社 | Conductive honeycomb structure |
| JP2019171345A (en) * | 2018-03-29 | 2019-10-10 | 日本碍子株式会社 | Electric heating-type catalyst carrier |
-
2020
- 2020-09-23 WO PCT/JP2020/035865 patent/WO2021166309A1/en active Application Filing
- 2020-09-23 JP JP2022501617A patent/JP7225470B2/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11343180A (en) * | 1998-05-29 | 1999-12-14 | Kyocera Corp | Ceramic-member/metallic-member joined body and ceramic heater using the same |
| JP2000106266A (en) * | 1998-07-27 | 2000-04-11 | Denso Corp | Ceramic heater |
| JP2018172258A (en) * | 2017-03-31 | 2018-11-08 | 日本碍子株式会社 | Conductive honeycomb structure |
| JP2019171345A (en) * | 2018-03-29 | 2019-10-10 | 日本碍子株式会社 | Electric heating-type catalyst carrier |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115151715A (en) * | 2020-03-05 | 2022-10-04 | 日本碍子株式会社 | Electric heating type converter and electric heating type carrier |
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