WO2018100831A1 - Bougie d'allumage - Google Patents

Bougie d'allumage Download PDF

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Publication number
WO2018100831A1
WO2018100831A1 PCT/JP2017/032600 JP2017032600W WO2018100831A1 WO 2018100831 A1 WO2018100831 A1 WO 2018100831A1 JP 2017032600 W JP2017032600 W JP 2017032600W WO 2018100831 A1 WO2018100831 A1 WO 2018100831A1
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WIPO (PCT)
Prior art keywords
alloy
electrode
ground electrode
spark plug
area
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PCT/JP2017/032600
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English (en)
Japanese (ja)
Inventor
和樹 伊藤
柴田　勉
大典 角力山
健介 藤野
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日本特殊陶業株式会社
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Publication of WO2018100831A1 publication Critical patent/WO2018100831A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T13/00—Sparking plugs
    • H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
    • H01T13/39—Selection of materials for electrodes

Definitions

  • This specification relates to a spark plug for igniting fuel gas in an internal combustion engine or the like.
  • An ignition plug used in an internal combustion engine for example, generates a spark discharge in a gap formed between a center electrode and a ground electrode, and ignites fuel gas in the internal combustion engine or the like.
  • These electrodes preferably have all of strength, oxidation resistance, and spark wear resistance.
  • improvement in strength contributes to improvement in ignition performance of the spark plug by reducing the diameter of the electrode
  • improvement in oxidation resistance and spark wear resistance contributes to improvement in durability of the ignition plug.
  • various electrode materials have been proposed in order to improve these characteristics.
  • Patent Document 1 discloses nickel (Ni) containing, as an electrode material, at least one element of titanium (Ti), vanadium (V), and niobium (Nb), a rare earth element, and manganese (Mn). Alloys have been proposed. According to this alloy, high thermal conductivity and strength can be maintained.
  • Patent Document 2 proposes a Ni alloy containing silicon (Si), aluminum (Al), and rare earth elements (for example, Y, Nd, Sm) as electrode materials. According to this alloy, both high-temperature oxidation resistance and spark wear resistance can be achieved.
  • the spark plug is required to have further improvement in strength, oxidation resistance, and spark consumption resistance.
  • This specification discloses a new technology capable of improving the strength, oxidation resistance, and spark consumption resistance of the electrode of the spark plug.
  • the Ni alloy contains 1% by mass or more in total of one or more elements selected from the group consisting of aluminum (Al), chromium (Cr), silicon (Si), and manganese (Mn).
  • the electrode in a cross section in which the portion formed of the Ni alloy is cut perpendicularly to the longitudinal direction of the electrode in the vicinity of the gap, The ratio of the area occupied by the precipitate containing Ag to the area of the measurement area of 80 ⁇ m ⁇ 80 ⁇ m starting from a point with a distance of 100 ⁇ m in the depth direction from the surface of the electrode and ending with a point of 180 ⁇ m is 0.1% That's it,
  • the spark plug, wherein the Ni alloy has an average particle size of 250 ⁇ m or less.
  • the strength, oxidation resistance, and spark consumption resistance of the spark plug electrode can be improved.
  • the spark wear resistance of the electrode can be further improved.
  • the spark plug according to Application Example 1 or 2 The Ni alloy is a spark plug including 85% by weight or more of Ni.
  • the spark wear resistance of the electrode can be further improved.
  • the electrode strength and spark wear resistance can be further improved.
  • the spark wear resistance of the electrode in a high temperature environment can be improved.
  • the present invention can be realized in various modes.
  • an ignition plug and an ignition device using the ignition plug an internal combustion engine equipped with the ignition plug, and an ignition device using the ignition plug are provided. It can be realized in the form of an internal combustion engine to be mounted, an electrode of a spark plug, an alloy for an electrode of the spark plug, or the like.
  • FIG. 2 is an enlarged cross-sectional view of the vicinity of a tip of a spark plug 100.
  • FIG. FIG. 3 is a diagram showing a cross-section CS that cuts the ground electrode 30 in the vicinity of a gap G perpendicular to the longitudinal direction of the ground electrode 30.
  • FIG. 2 is a Ni—Ag binary phase diagram. It is explanatory drawing of the measuring method of average particle diameter Rave. It is a figure which shows the cross section CS2 which cut
  • FIG. It is a figure which shows the cross section CS of the ground electrode 30b of a modification.
  • FIG. 1 is a sectional view of an example of a spark plug of an embodiment.
  • the dotted line shown in the figure indicates the axis CO of the spark plug 100.
  • the illustrated cross section is a cross section including the axis CO.
  • a direction parallel to the axis CO is also referred to as an “axis direction”.
  • the lower direction in FIG. 1 is referred to as a front end direction LD
  • the upper direction is also referred to as a rear end direction BD.
  • the tip direction LD is a direction from the terminal fitting 40 described later toward the electrodes 20 and 30.
  • radial direction of a circle centered on the axis CO and located on a plane perpendicular to the axis CO is simply referred to as “radial direction”, and the circumferential direction of the circle is also simply referred to as “circumferential direction”.
  • An end in the front end direction LD is also simply referred to as a front end
  • an end in the rear end direction BD is also simply referred to as a rear end.
  • the spark plug 100 includes an insulator 10, a center electrode 20, a ground electrode 30, a terminal fitting 40, a metal shell 50, a first conductive seal layer 60, a resistor 70, and a second conductive material.
  • a seal layer 80, a first packing 8, a talc 9, a second packing 6, and a third packing 7 are provided.
  • the insulator 10 is a substantially cylindrical member having an axial hole 12 extending along the axial direction and penetrating the insulator 10.
  • the insulator 10 is formed by firing alumina (other insulating materials can also be used).
  • the insulator 10 is arranged in order from the front end side toward the rear end direction BD, the leg portion 13, the reduced outer diameter portion 15, the first trunk portion 17, the flange portion 19, the second trunk portion 18, have.
  • the outer diameter of the reduced outer diameter portion 15 is gradually reduced toward the distal direction LD.
  • a reduced inner diameter portion 16 whose inner diameter is gradually reduced toward the distal direction LD is formed. Has been.
  • the center electrode 20 is located on the tip side in the shaft hole 12 of the insulator 10.
  • the center electrode 20 is a rod-shaped member extending along the axial direction.
  • the center electrode 20 has a leg portion 25, a flange portion 24, and a head portion 23 that are arranged in order from the front end side toward the rear end direction BD.
  • a portion on the distal end side of the leg portion 25 is exposed outside the shaft hole 12 on the distal end side of the insulator 10.
  • the other part of the center electrode 20 is held in the shaft hole 12.
  • the front end side surface of the flange portion 24 is supported by the reduced inner diameter portion 16 of the insulator 10.
  • the center electrode 20 is formed using, for example, nickel (Ni) or an alloy containing nickel as a main component (for example, NCF600, NCF601).
  • the terminal fitting 40 is located on the rear end side in the shaft hole 12 of the insulator 10.
  • the terminal fitting 40 is a rod-like body extending along the axial direction, and is formed using a conductive material (for example, a metal such as low carbon steel).
  • the terminal fitting 40 includes a leg portion 43, a flange portion 42, and a cap mounting portion 41 that are arranged in order from the front end side toward the rear end direction BD.
  • the leg portion 43 is inserted into the shaft hole 12 of the insulator 10.
  • the cap mounting portion 41 is exposed outside the shaft hole 12 on the rear end side of the insulator 10.
  • the columnar resistor 70 is disposed between the terminal fitting 40 and the center electrode 20 in the shaft hole 12 of the insulator 10.
  • the resistor 70 has a function of reducing radio noise when a spark is generated.
  • the resistor 70 is formed of, for example, a composition including glass particles that are main components, ceramic particles other than glass, and a conductive material.
  • the first conductive seal layer 60 is disposed between the center electrode 20 and the resistor 70, and the second conductive seal layer 80 is disposed between the terminal fitting 40 and the resistor 70.
  • the center electrode 20 and the terminal fitting 40 are electrically connected via the resistor 70 and the conductive seal layers 60 and 80.
  • the conductive seal layers 60 and 80 are formed of a composition containing glass particles such as B 2 O 3 —SiO 2 and metal particles (Cu, Fe, etc.), for example.
  • the metal shell 50 is a substantially cylindrical member having an insertion hole 59 that extends along the axis CO and passes through the metal shell 50.
  • the metal shell 50 is formed using a low carbon steel material (other conductive materials (for example, metal materials) can also be used).
  • the insulator 10 is inserted into the insertion hole 59 of the metal shell 50.
  • the metal shell 50 holds the insulator 10 in a state of being arranged around the insulator 10 in the radial direction.
  • the end portion on the distal end side of the insulator 10 (in this embodiment, the portion on the distal end side of the leg portion 13) is exposed outside the insertion hole 59.
  • the end portion on the rear end side of the insulator 10 (in this embodiment, the portion on the rear end side of the second body portion 18) is exposed outside the insertion hole 59.
  • the metal shell 50 includes a screw part 52, a seat part 54, a deforming part 58, a tool engaging part 51, and a caulking part 53, which are arranged in order from the front end side toward the rear end direction BD. ing.
  • An annular gasket 5 formed by bending a metal plate is fitted between the seat portion 54 and the screw portion 52.
  • the seat part 54 is a bowl-shaped part.
  • the screw portion 52 is a substantially cylindrical portion in which a screw for screwing into a mounting hole of the internal combustion engine is formed on the outer peripheral surface.
  • the metal shell 50 has a reduced inner diameter portion 56 disposed on the tip side of the deformable portion 58.
  • the inner diameter of the reduced inner diameter portion 56 gradually decreases from the rear end side toward the front end direction LD.
  • the first packing 8 is sandwiched between the reduced inner diameter portion 56 of the metal shell 50 and the reduced outer diameter portion 15 of the insulator 10.
  • the first packing 8 is an iron O-ring (other materials (for example, metal materials such as copper) can also be used).
  • the shape of the tool engaging portion 51 is a shape (for example, a hexagonal column) with which the spark plug wrench is engaged.
  • a caulking portion 53 is provided on the rear end side of the tool engaging portion 51.
  • the caulking portion 53 is disposed on the rear end side of the flange portion 19 of the insulator 10 and forms an end on the rear end side of the metal shell 50.
  • the caulking portion 53 is bent toward the inner side in the radial direction.
  • an annular space SP is formed between the inner peripheral surface of the metal shell 50 and the outer peripheral surface of the insulator 10.
  • the space SP is a space surrounded by the crimping portion 53 and the tool engagement portion 51 of the metal shell 50, the rear end portion of the flange portion 19 of the insulator 10, and the second body portion 18. It is.
  • a second packing 6 is disposed on the rear end side in the space SP.
  • a third packing 7 is disposed on the front end side in the space SP. In this embodiment, these packings 6 and 7 are iron C-rings (other materials are also employable). Between the two packings 6 and 7 in the space SP, powder of talc (talc) 9 is filled.
  • the crimping portion 53 is crimped so as to be bent inward. And the crimping part 53 is pressed to the front end side. Thereby, the deformation
  • the first packing 8 is pressed between the reduced outer diameter portion 15 and the reduced inner diameter portion 56, and seals between the metal shell 50 and the insulator 10. As a result, the gas in the combustion chamber of the internal combustion engine is prevented from leaking outside through the metal shell 50 and the insulator 10. In addition, the metal shell 50 is fixed to the insulator 10.
  • the ground electrode 30 is a rod-shaped member that is electrically connected to the metal shell 50.
  • the ground electrode 30 is formed using, for example, an alloy containing nickel (Ni) as a main component. Details of the nickel alloy forming the ground electrode 30 will be described later.
  • FIG. 2 is an enlarged cross-sectional view of the vicinity of the tip of the spark plug 100.
  • the distal end of the insulator 10 (that is, the distal end of the leg portion 13) is located closer to the distal end side than the distal end of the metal shell 50.
  • the tip of the center electrode 20 is located on the tip side of the insulator 10.
  • connection end 31 connected to the tip of the metal shell 50 by, for example, resistance welding so that the ground electrode 30 and the metal shell 50 are electrically connected.
  • the other end of the ground electrode 30 is a free end 32.
  • connection portion 33 which is a portion on the connection end 31 side connected to the metal shell 50, extends in parallel with the axis CO.
  • a free end portion 34 that is a portion on the free end 32 side extends perpendicular to the axis CO.
  • a curved portion 35 which is a portion between the connecting portion 33 and the free end portion 34, is bent by about 90 degrees.
  • the side surface 341 on the rear end side includes a second discharge surface 39 that faces the first discharge surface 29 that is the front end surface of the center electrode 20 in the axial direction.
  • the first discharge surface 29 of the center electrode 20 and the second discharge surface 39 of the ground electrode 30 form a gap G (also referred to as a spark gap) where spark discharge occurs.
  • the spark plug 100 of the present embodiment does not include a noble metal tip made of a noble metal such as iridium or palladium or an alloy containing the noble metal in a portion where the gap G of the ground electrode 30 is formed.
  • a noble metal tip made of a noble metal such as iridium or palladium or an alloy containing the noble metal in a portion where the gap G of the ground electrode 30 is formed.
  • FIG. 3 is a view showing a cross-section CS of the ground electrode 30 cut in the vicinity of the gap G in a direction perpendicular to the longitudinal direction of the ground electrode 30.
  • This cross section CS is a cross section passing through the second discharge surface 39, and is an AA cross section including the axis CO in the example of FIG.
  • the cross section CS has a substantially rectangular shape.
  • 3 is an enlarged view of the area SA in the vicinity of the surface in the upper cross section of FIG.
  • a material for forming ground electrode 30 will be described.
  • the cross-sectional area perpendicular to the longitudinal direction of the ground electrode 30 is smaller, the energy loss due to the action (extinguishing action) of absorbing the thermal energy of the spark or the combustion gas flame by the ground electrode 30 becomes smaller.
  • the ground electrode 30 is the most protruding portion in the combustion chamber, it is exposed to high-temperature combustion gas. For this reason, the material forming the ground electrode 30 is required to have high oxidation resistance from the viewpoint of ensuring the life of the spark plug 100. If the oxidation resistance is low, the oxidation consumption increases, and it becomes difficult to reduce the cross-sectional area perpendicular to the longitudinal direction of the ground electrode 30, so that the oxidation resistance is preferably high from the viewpoint of ignition performance.
  • the spark plug 100 of the present embodiment does not use a noble metal tip in the portion where the gap G is formed.
  • the material for forming the ground electrode 30 is required to have resistance to consumption due to the energy of spark discharge (spark wear resistance) from the viewpoint of ensuring the life of the spark plug 100. If the spark wear resistance is low, the wear due to the spark is increased, and it is difficult to reduce the cross-sectional area perpendicular to the longitudinal direction of the ground electrode 30, so that the spark wear resistance is also high from the viewpoint of ignition performance. Is preferred.
  • the temperature in the combustion chamber of the internal combustion engine has been further increased, and the spark plug 100 has been reduced in size.
  • the material forming 30 is required to have higher levels of oxidation resistance, spark wear resistance, and strength. For this reason, in this embodiment, in order to improve the oxidation resistance, spark wear resistance, and strength of the ground electrode 30, the material forming the ground electrode 30 is devised. This will be described in detail below.
  • the material of the ground electrode 30 is an alloy containing nickel (Ni) as a main component (hereinafter also simply referred to as Ni alloy). This Ni alloy (that is, the ground electrode 30 of the present embodiment) satisfies the following (1) to (5).
  • the Ni alloy contains 50% by weight or more of Ni.
  • the Ni alloy is a total of at least one element selected from the group consisting of aluminum (Al), chromium (Cr), silicon (Si), and manganese (Mn) as an additive. 1% by mass or more.
  • the Ni alloy further contains silver (Ag), and the ratio of the area occupied by the silver precipitate OP to the area of the measurement region MA (FIG. 2) in the cross-section CS (hereinafter also referred to as the surface vicinity area ratio SR) is , 0.1% or more.
  • the average particle diameter Rave (average particle diameter of the base material MP) of the Ni alloy is 250 ⁇ m or less.
  • the ratio of the area where Ni is exposed hereinafter also referred to as Ni exposure rate NR) is 50% or more.
  • a Ni alloy containing 50% by weight or more of Ni has a higher melting point and superior oxidation resistance compared to, for example, an alloy containing 50% by weight or more of iron (Fe).
  • Fe iron
  • the oxidation resistance of the base alloy is insufficient, so even if the additives described later are controlled, sufficient oxidation resistance cannot be obtained.
  • the Ni alloy when the proportion of Ni is reduced, the proportion of other elements is relatively increased and the thermal conductivity is lowered, so that the ground electrode 30 is likely to become high temperature. As a result, in the Ni alloy, when the Ni content is reduced, the spark wear resistance of the ground electrode 30 is reduced.
  • the Ni alloy of the present embodiment satisfies the above (1), the oxidation resistance and the spark wear resistance of the ground electrode 30 can be improved.
  • One or more additional elements selected from the group consisting of Al, Cr, Si, and Mn are oxides (for example, Al 2 O 3 , Cr 2 O 3 , SiO 2 , MnO 2 ) and Ni alloys. Therefore, the oxidation resistance of the Ni alloy can be improved.
  • the Ni alloy of the present embodiment satisfies the above (2), the oxidation resistance of the ground electrode 30 can be improved.
  • the Ni alloy (ground electrode 30) of the present embodiment includes a base material MP and silver precipitates OP that are dispersed and arranged inside the base material MP.
  • the silver precipitate OP is a precipitate containing silver (Ag) as a main component (for example, containing 98% by weight or more of Ag).
  • the silver precipitate OP is precipitated at the grain boundaries of the crystal grains of the base material MP (not shown).
  • the measurement area MA is a rectangular area of 80 ⁇ m ⁇ 80 ⁇ m starting from a point where the distance in the depth direction from the surface of the ground electrode 30 is 100 ⁇ m and ending at a point of 180 ⁇ m.
  • FIG. 3 the measurement area MA is a rectangular area of 80 ⁇ m ⁇ 80 ⁇ m starting from a point where the distance in the depth direction from the surface of the ground electrode 30 is 100 ⁇ m and ending at a point of 180 ⁇ m.
  • the measurement area MA is a rectangular area whose width in the direction parallel to the nearest surface SF is 80 ⁇ m and whose width in the direction perpendicular to the surface SF is 80 ⁇ m.
  • the distance between the side NE close to the surface SF and the surface SF among the two sides parallel to the surface SF of the measurement region MA is 100 ⁇ m.
  • the distance between the side FE far from the surface SF and the surface SF is 180 ⁇ m.
  • FIG. 4 is a Ni-Ag binary system phase diagram. As can be seen from this phase diagram, the solid solution amount of Ag in Ni is very small. Therefore, when a certain amount (for example, 0.1 wt% or more) of Ag is added to the Ni alloy, silver is contained in the base material MP. A precipitate OP is deposited.
  • the Ag content (solid solution amount) of the base material MP is very small. Therefore, the decrease in the thermal conductivity of the base material MP due to the addition of Ag is a solid solution in Ni. It is smaller than the case of adding an element that is easy to do. Similarly, the lowering of the melting point of the base material MP due to the addition of Ag is smaller than that in the case of adding an element that easily dissolves in Ni. Therefore, the decrease in the spark wear resistance of the base material MP due to the addition of Ag is very small.
  • Ag has higher thermal conductivity than Ni. Further, as can be seen from the phase diagram of FIG. 4, since the solid solution amount of Ni with respect to Ag is extremely small, it is considered that the purity of Ag in the silver precipitate OP is high. From this, it is considered that the thermal conductivity of the silver precipitate OP is very good. For this reason, since the silver precipitate OP improves the overall thermal conductivity of the Ni alloy, it is possible to suppress an increase in the temperature of the Ni alloy and to improve the spark wear resistance of the Ni alloy.
  • the presence of the silver precipitate OP improves the thermal conductivity in the vicinity of the surface of the ground electrode 30, and in turn, the spark wear resistance of the ground electrode 30. Can be improved.
  • precipitation strengthening by precipitates is significantly greater in the degree to which the material is strengthened than solid solution strengthening by solid additives.
  • the silver precipitate OP significantly improves the strength of the Ni alloy.
  • Most of the breakage of the ground electrode 30 caused by insufficient strength is due to fatigue failure due to the impact received in the combustion chamber of the internal combustion engine. Fatigue failure occurs when cracks generated on the surface of the ground electrode 30 propagate inside. For this reason, it is important to improve the strength in the vicinity of the surface of the ground electrode 30 (that is, the surface of the Ni alloy).
  • the strength in the vicinity of the surface of the ground electrode 30 can be improved by the presence of the silver precipitate OP.
  • the spark wear resistance of the ground electrode 30 can be improved.
  • the strength, oxidation resistance, and spark consumption resistance of the ground electrode 30 of the spark plug 100 are improved. be able to.
  • the oxidation resistance can be improved by increasing the additive elements (for example, Al, Cr, Si, and Mn described above) that form the oxide film. It is difficult to improve.
  • the oxide film and the Ni alloy main body are bonded with an intermolecular force having a weaker binding force than an intermetallic bond or a covalent bond.
  • the oxide film is relatively easily separated from the Ni alloy body by the impact of spark discharge. Therefore, in order to improve the spark wear resistance, it is effective to suppress the decrease in the melting point and the decrease in the thermal conductivity by suppressing the amount of the additive element and increasing the Ni content.
  • the Ni alloy of the present embodiment preferably contains 85% by weight or more of Ni. By so doing, the spark wear resistance of the ground electrode 30 can be further improved.
  • the temperature increase of the ground electrode 30 can be suppressed when the thermal conductivity is higher not only in the vicinity of the surface of the ground electrode 30 but also inside the ground electrode 30, the spark wear resistance of the ground electrode 30 is improved.
  • the strength of the entire ground electrode 30 can be improved when the strength of the interior of the ground electrode 30 is higher.
  • the ratio of the area occupied by the silver precipitate OP to the entire area of the cross-section CS (hereinafter also referred to as the overall area ratio AR) is preferably 0.1% or more. . In this way, the strength and spark wear resistance of the ground electrode 30 can be improved.
  • the temperature in the combustion chamber becomes a high temperature of 900 degrees Celsius or higher at a high rotation speed, so that if the structure in the ground electrode 30 changes at a high temperature, the strength and spark wear resistance of the ground electrode 30 may be reduced.
  • the strength and spark wear resistance of the ground electrode 30 may decrease.
  • the entire area of the silver precipitate OP in a state after a treatment hereinafter also referred to as a high-temperature holding treatment
  • the rate AR is preferably 0.1% or more
  • the average particle size Rave of the Ni alloy is preferably 250 ⁇ m or less. In this way, the spark wear resistance of the ground electrode 30 in a high temperature environment can be improved.
  • the ground electrode 30 is manufactured through a melting process, a cooling process, and a processing process.
  • a molten alloy having a desired component composition is prepared using a normal vacuum melting furnace.
  • an ingot is obtained by cooling the molten metal in a vacuum melting furnace.
  • the processing step the ingot is processed into a bar having a predetermined diameter (for example, 1.6 mm) by, for example, hot forging.
  • a wire having a predetermined cross-sectional dimension for example, a rectangle of 1.5 mm ⁇ 2.8 mm
  • the ground electrode 30 is obtained by cutting the wire into a predetermined length (for example, 10 mm).
  • the obtained ground electrode 30 is joined at one end to the tip of the metal shell 50 and then bent. Thereby, the ground electrode 30 is completed.
  • the amount of the silver precipitate OP and the adjustment of the average particle diameter Rave of the Ni alloy are adjusted by, for example, the composition of the Ni alloy prepared in the melting step, the conditions of the heat treatment in the melting step and the cooling step (retention temperature and This is realized by devising the processing conditions (processing rate, processing temperature, etc.) in the processing process.
  • the amount of the silver precipitate OP can be increased. Therefore, the surface area ratio SR and the overall area ratio AR of the silver precipitate OP are increased. Can be made. Further, under the heat treatment conditions, the amount of silver precipitate OP can be increased as the cooling rate is increased and the heat treatment time is increased.
  • the average particle size Rave of the Ni alloy can be reduced as the amount of impurities that do not affect the performance is increased. In addition, the average particle size Rave of the Ni alloy can be reduced as the heat treatment temperature is lowered under the heat treatment conditions. Further, in the processing conditions, the average particle size Rave of the Ni alloy can be reduced as the processing rate is increased.
  • suppressing an excessive decrease in the amount of the silver precipitate OP is realized by, for example, increasing the Ag content in advance in the composition of the Ni alloy, for example. be able to. For example, if the Ag content in the entire Ni alloy is 1% by weight or more, the overall area ratio AR of the silver precipitate OP can be maintained at 0.1% or more even after the high temperature holding treatment.
  • suppressing an excessive increase in the average particle size Rave of the Ni alloy in the state after the high temperature holding treatment is realized by, for example, reducing the average particle size Rave of the Ni alloy before the high temperature holding treatment. can do.
  • Screw diameter of metal shell 50 M14 Length from the metal shell 50 tip to the insulator 10 tip: 2 mm Length from the metal shell 50 tip to the center electrode 20 tip: 3 mm Diameter of center electrode 20 tip (diameter of first discharge surface 29): 0.6 mm
  • Dimension of cross section of ground electrode 30 before bending 1.5 mm ⁇ 2.8 mm Length in the longitudinal direction of the ground electrode 30 before bending: 10 mm Length of gap G (distance between first discharge surface 29 and second discharge surface 39): 0.85 mm
  • the materials forming the ground electrode 30 are different from each other.
  • the Ni alloy used for the ground electrode 30 of these samples has a composition and an area ratio of the silver precipitate OP before the high temperature holding treatment (surface area ratio SR and total area ratio AR). ), The overall area ratio AR of the silver precipitate OP after the high temperature holding treatment, the Ni exposure rate NR, and the average particle size Rave of the Ni alloy are different.
  • the alloy used for the ground electrode 30 of each type of sample is composed of the elements shown in Table 1 (Ni, Ag, Si, Cr, Al, Mn, etc.) and the contents shown in Table 1 (unit: wt%). Contains only. In the sample 16, “other” elements are 4% by weight of Fe, the remaining B, Mo, V, W, Co, Ti, C, and inevitable impurities. In Samples 6 to 10 and 17 to 23, 8 wt% Fe and the remaining B, Mo, V, W, Co, Ti, C, and unavoidable impurities. In Samples 5, 11 to 13, and 15, 16% by weight of Fe and the remaining B, Mo, V, W, Co, Ti, C, and unavoidable impurities.
  • sample 14 40 wt% Fe and the remaining B, Mo, V, W, Co, Ti, C, and inevitable impurities. In samples 1 to 4, 45% by weight of Fe and the remaining B, Mo, V, W, Co, Ti, C, and unavoidable impurities.
  • the content rate of the component of the ground electrode 30 of each sample is the high frequency inductively coupled plasma (ICP) emission spectroscopic analysis method for the portion of the ground electrode 30 that is 3 mm away from the metal shell 50 and the tip surface. was measured.
  • ICP inductively coupled plasma
  • the total content of Si, Cr, Al, and Mn in each sample is 0%, 0.9%, 1%, 2%, 3%, 4%, 9%, 28%, 29%, 30% , 32%, or 33%.
  • Table 2 shows, for each sample, the surface vicinity area ratio SR and the total area ratio AR before the high-temperature holding treatment, and the total area ratio AR after the high-temperature holding treatment.
  • the surface vicinity area ratio SR was measured as follows. First, a silver deposit OP in the measurement area MA is detected by taking a mapping image of the Ag component in the measurement area MA (FIG. 3) of the cross section CS of FIG. 3 of the ground electrode 30 of each sample. It was. The mapping image is captured using FE-EPMA (Field Emission-Electron Probe Micro-Analysis), specifically, WDS (Wavelength Dispersive X-ray Spectrometer) attached to JXA-8500F manufactured by JEOL Ltd. It was.
  • FE-EPMA Field Emission-Electron Probe Micro-Analysis
  • WDS Widelength Dispersive X-ray Spectrometer
  • the mapping image was taken at an acceleration voltage of 20 KV and a count of 150,000 or more. Then, using the mapping image of the Ag component, the area of the silver precipitate OP with respect to the area of the measurement region MA was calculated as the surface vicinity area ratio SR.
  • the total area ratio AR was measured by performing the same analysis using a 80 ⁇ m ⁇ 80 ⁇ m rectangular region (not shown) in the vicinity of the center of the cross section CS in FIG. 3 as a measurement region.
  • the surface area ratio SR before high temperature treatment of each sample is any of 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.20%. It was.
  • the total area ratio AR of each sample before high temperature treatment is 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%,. It was either 12%, 0.13%, or 0.15%.
  • the total area ratio AR of each sample after high temperature treatment is either 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, or 0.12% Met.
  • Table 2 shows the Ni exposure rate NR of the second discharge surface 39 of each sample.
  • the Ni exposure rate NR was measured as follows. Using the 200 ⁇ m ⁇ 200 ⁇ m rectangular area (not shown) in the vicinity of the center of the second discharge surface 39 of the ground electrode 30 as a measurement area, the above-described Ni component mapping image using the FE-EPMA was taken. The mapping image was taken at an acceleration voltage of 20 KV and a count of 150,000 or more. Then, using the Ni component mapping image, the area of the portion where Ni was detected relative to the area of the measurement region was calculated as the Ni exposure rate NR.
  • the Ni exposure rate NR of each sample was 40%, 45%, 50%, 55%, or 80%.
  • FIG. 5 is an explanatory diagram of a method for measuring the average particle size Rave.
  • a cross section having the same shape as the cross section CS of FIG. 3
  • a cross section cut perpendicularly to the longitudinal direction is polished at a position 2 mm away from the free end 32 of the ground electrode 30 of each sample to obtain a mirror surface.
  • an enlarged photograph of the mirror surface is taken using a metal microscope.
  • a rectangular area SMA FIG.
  • a vertical line L1 and a horizontal line L2 that divide the rectangular area SMA into a grid of 0.2 mm ⁇ 0.2 mm are set (FIG. 5).
  • the vertical lines L1 are arranged at intervals of 0.2 mm.
  • the number of vertical lines L1 is 6, including the lines forming the outer frame of the rectangular area SMA.
  • the horizontal line L2 is six lines arranged at intervals of 0.2 mm. For each of these 12 lines L1 and L2, the number of intersections between the line and the grain boundary of the crystal grain of the base material MP of the Ni alloy is counted. The total number of intersections of each line is Mc.
  • the average particle size Rave before the high temperature holding treatment of each sample was any of 200 ⁇ m, 250 ⁇ m, and 260 ⁇ m.
  • the average particle size Rave after the high temperature holding treatment of each sample was either 250 ⁇ m or 260 ⁇ m.
  • These samples 1 to 23 were produced by the above-described manufacturing method, and were produced by changing at least one of the above-described Ni alloy composition, heat treatment conditions, and processing conditions for each sample.
  • a test in a low temperature range (a temperature range of about 700 degrees Celsius) and a test in a high temperature range (a temperature range of about 900 degrees Celsius) were performed.
  • the actual machine operation was performed for 200 hours, and the amount of increase in the gap G (spark gap) of each sample after the actual machine operation was measured.
  • the actual operation was carried out under the conditions of 4 cylinders, a displacement of 1.3 L, each sample attached to a naturally aspirated gasoline engine, full throttle (WOT (Wide-Open Throttle)), and a rotational speed of 3000 rpm.
  • WOT Wide-Open Throttle
  • the rotation speed was set to 5000 rpm, and the other conditions were the same as the low temperature region test.
  • the evaluation of the sample having an increase in the gap G of 0.3 mm or more is “D”, and the evaluation of the sample of 0.2 mm or more and less than 0.3 mm is “C”, and the evaluation is 0.1 mm or more and less than 0.2 mm.
  • the evaluation of the sample was “B”, and the evaluation of the sample that was less than 0.1 mm was “A”.
  • test temperature was set to 900 degrees Celsius, and the other conditions were the same as the low temperature range test.
  • the evaluation of the sample fractured in the test with a stress amplitude of 100 MP is “C”
  • the evaluation of the sample that is not broken in the test with the stress amplitude of 100 MP and the fracture with the test of the stress amplitude of 150 MP is “B”
  • the stress amplitude is The evaluation of the sample that did not break in the 150 MP test was designated as “A”.
  • Samples 1 to 12 are samples for comparison, and do not satisfy at least one of the above (1) to (5) that the above embodiment satisfies. Samples 13 to 23 satisfy at least all of the above (1) to (5).
  • Samples 1 to 10 do not satisfy at least one of the above (1), (3), and (5).
  • Samples 1 to 4 do not satisfy any of (1), (3), and (5).
  • Samples 5 and 6 satisfy (1) but do not satisfy (3) and (5).
  • Samples 7 and 8 satisfy (1) and (3), but do not satisfy (5).
  • Samples 9 and 10 satisfy (1) and (5), but do not satisfy (3).
  • samples 13 to 23 that satisfy all of the above (1) to (5) will be further described.
  • the evaluation of the spark wear resistance of samples 13 to 15 having a Ni content of less than 85% by weight was “C” in both the high temperature range and the low temperature range.
  • the evaluation of the spark wear resistance of Samples 16 to 23 having a Ni content of 85% by weight or more was “B” or more in both the high temperature range and the low temperature range. From this result, it was confirmed that the Ni alloy forming the ground electrode 30 can further improve the spark wear resistance of the ground electrode 30 by containing 85 wt% or more of Ni.
  • the low area of the samples 16 and 17 in which the total area ratio AR of the silver precipitate OP before the high temperature holding treatment is less than 0.10% The evaluation of the spark wear resistance and strength was “B”.
  • the average particle diameter Rave of the Ni alloy after the high temperature holding treatment exceeds 250 ⁇ m, or the total area ratio AR of the silver precipitate OP after the high temperature holding treatment is 0.10.
  • the average particle size Rave of the Ni alloy after the high temperature holding treatment is 250 ⁇ m or less, and the total area ratio AR of the silver precipitate OP after the high temperature holding treatment is 0.
  • the evaluation of the strength of the samples 22 and 23 at 10% or higher in the high temperature range was “A”.
  • the average particle size Rave of the Ni alloy after the high temperature holding treatment is 250 ⁇ m or less, and the total area ratio AR of the silver precipitate OP after the high temperature holding treatment is 0.10%.
  • the strength of the ground electrode 30 in the high temperature range could be further improved.
  • the material of the ground electrode 30 of the first embodiment can also be used as the material of the center electrode 20.
  • This example will be described as a second embodiment.
  • the configuration excluding the material of the center electrode 20 of the second embodiment is the same as the configuration of the spark plug 100 of the first example shown in FIGS.
  • FIG. 6 is a view showing a cross-section CS2 that cuts the center electrode 20 of the second embodiment in the vicinity of the gap G in a direction perpendicular to the longitudinal direction of the center electrode 20.
  • This section CS2 is a section taken along line BB in FIG.
  • the cross section CS2 is a cross section parallel to the first discharge surface 29 and having a distance ⁇ H with respect to the first discharge surface 29 of 0.3 mm or less.
  • the cross section CS has a circular shape. 6 shows an enlarged view of the area SAb in the vicinity of the surface in the upper cross section of FIG.
  • the material of the center electrode 20 satisfies the above (1) to (5) that the ground electrode 30 of the first embodiment satisfies.
  • the strength, oxidation resistance, and spark consumption resistance of the center electrode 20 of the spark plug can be improved.
  • the Ni alloy forming the center electrode 20 preferably contains 85% by weight or more of Ni.
  • the total area ratio AR of the silver precipitate OP is preferably 0.1% or more.
  • the total area ratio AR of the silver precipitate OP is preferably 0.1% or more, and the average particle size Rave of the Ni alloy is preferably 250 ⁇ m or less.
  • the surface vicinity area ratio SR and the overall area ratio AR measured in the cross section CS of FIG. 3 in the first embodiment are measured in the cross section CS2 of FIG.
  • the measurement area MAb of the near-surface area ratio SR of the second embodiment has a point (100 in FIG. 6) having a distance in the depth direction from the surface (side surface) of the center electrode 20 as shown in FIG. This is a rectangular region of 80 ⁇ m ⁇ 80 ⁇ m starting from a point P2) and ending at a point of 180 ⁇ m (point P1 in FIG. 6).
  • the start point P2 is a point on the straight line L1 passing through the center of the cross section CS2 (the position of the axis CO in FIG. 6), and the intersection point P3 of the line L1 and the surface of the central electrode 20 The distance is 100 ⁇ m.
  • the end point P1 is a point on the line L1, and is a point whose distance from the point P2 is 80 ⁇ m and whose distance from the point P3 is 180 ⁇ m.
  • Two of the four sides of the measurement region MAb are parallel to the line L1, and the other two sides are perpendicular to the line L1.
  • the overall area ratio AR is the ratio of the area occupied by the silver precipitate OP to the entire area of the cross section CS2 in FIG.
  • FIG. 7 is a diagram illustrating a cross-section CS of the ground electrode 30b according to the modification.
  • the ground electrode 30b of the modified example has a two-layer structure including an outer portion 301 formed of a Ni alloy and a core portion 302 formed of a material having higher thermal conductivity than a Ni alloy such as copper. .
  • the center electrode 20 of the second embodiment may also have a two-layer structure including an outer portion formed of a Ni alloy and a core portion formed of a material having high thermal conductivity. Also in this case, it is only necessary that the outer portion made of the Ni alloy satisfies the above (1) to (5).
  • the ground electrode 30 of the first embodiment satisfies the above (1) to (5) as described above.
  • the Ni exposure rate NR of the second discharge surface 39 in (5) satisfies that it is 50% or more, for example, when actual operation or the like is performed before the ignition plug is shipped. Is heated in the actual operation, thereby forming an oxide film of Al, Cr, Si, Mn or the like on the surface of the ground electrode 30.
  • the above (5) is not satisfied, but the strength, spark wear resistance, and strength of the ground electrode 30 are equivalent to those of the spark plug of the first embodiment.
  • the above (5) may not be satisfied.
  • the specific configuration of the spark plug 100 of FIGS. 1 and 2 is an example, and other configurations may be employed.
  • various configurations can be adopted as the configuration of the ignition portion of the spark plug.
  • the spark plug may be a spark plug of a type in which the ground electrode 30 and the center electrode 20 face each other in a direction perpendicular to the axis to form a gap.
  • a spark plug of a type that includes a plurality of ground electrodes 30 and one center electrode 20 and that has a plurality of gaps may be used.
  • the material of the insulator 10 and the material of the terminal fitting 40 are not limited to the above-described materials.
  • the insulator 10 is composed of other compounds (for example, AlN, ZrO 2 , SiC, TiO 2 , Y 2 O 3, etc.) as the main component instead of ceramics whose main component is alumina (Al 2 O 3 ). It may be formed using ceramics.
  • Metal fitting 51 ... Tool engagement part, 52 ... Screw part, 53 ... Clamping part, 54 ... Seat part, 56 ... Reduced inner diameter portion, 58 ... Deformed portion, 59 ... Insertion hole, 60 ... First conductive seal layer, 70 ... Resistor, 80 ... Second conductivity Seal layer, 100 ... Spark plug, MP ... Base material, OP ... Silver deposit, R ... total area ratio, SR ... near the surface area ratio

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Spark Plugs (AREA)

Abstract

L'invention permet d'améliorer la solidité, la résistance à l'oxydation, et la résistance à l'usure d'allumage d'une électrode de cette bougie d'allumage. Une électrode centrale et/ou une électrode de masse de la bougie d'allumage sont formées au moyen d'un alliage de nickel (Ni) contenant 50 % en poids ou plus de nickel. L'alliage de Ni contient 1 % en masse ou plus, au total, d'un ou plusieurs éléments sélectionnés parmi le groupe constitué d'Al, de Cr, de Si et de Mn, et contient de l'Ag. Dans une section transversale obtenue en coupant, près d'une lacune, une partie de l'électrode constituée d'alliage de Ni dans une direction perpendiculaire à la direction longitudinale de l'électrode : le pourcentage d'une aire occupée par un précipité contenant de l'Ag est d'au moins 0,1 % par rapport à l'air d'une zone de mesure de 80 µm × 80 µm ayant un point de départ à 100 µm et un point d'arrivée à 180 µm dans la direction de la profondeur depuis une surface de l'électrode ; et le diamètre moyen de grains de l'alliage de Ni est inférieur ou égal à 250 µm.
PCT/JP2017/032600 2016-11-30 2017-09-11 Bougie d'allumage WO2018100831A1 (fr)

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JP2016-233693 2016-11-30
JP2016233693A JP6456343B2 (ja) 2016-11-30 2016-11-30 点火プラグ

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WO2018100831A1 true WO2018100831A1 (fr) 2018-06-07

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JP7206983B2 (ja) * 2019-02-08 2023-01-18 株式会社Ihi Ｎｉ合金のクリープ寿命評価方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03111534A (ja) * 1989-09-26 1991-05-13 Mitsubishi Materials Corp スパークプラグ用電極材料
JPH09291327A (ja) * 1996-04-26 1997-11-11 Sumitomo Electric Ind Ltd 点火プラグ用電極材料

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Publication number Priority date Publication date Assignee Title
DE4203250A1 (de) * 1992-02-05 1993-08-12 Beru Werk Ruprecht Gmbh Co A Silber-nickel-verbundwerkstoff fuer elektrische kontakte und elektroden
JPH06314587A (ja) * 1993-04-30 1994-11-08 Tanaka Kikinzoku Kogyo Kk 放電を伴う電極用複合材料

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03111534A (ja) * 1989-09-26 1991-05-13 Mitsubishi Materials Corp スパークプラグ用電極材料
JPH09291327A (ja) * 1996-04-26 1997-11-11 Sumitomo Electric Ind Ltd 点火プラグ用電極材料

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