WO2010095615A1 - Method for manufacturing aluminum titanate-based sintered bodies - Google Patents

Method for manufacturing aluminum titanate-based sintered bodies Download PDF

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Publication number
WO2010095615A1
WO2010095615A1 PCT/JP2010/052280 JP2010052280W WO2010095615A1 WO 2010095615 A1 WO2010095615 A1 WO 2010095615A1 JP 2010052280 W JP2010052280 W JP 2010052280W WO 2010095615 A1 WO2010095615 A1 WO 2010095615A1
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WIPO (PCT)
Prior art keywords
source powder
aluminum
magnesium
powder
titanium
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PCT/JP2010/052280
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French (fr)
Japanese (ja)
Inventor
健太郎 岩崎
明欣 根本
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住友化学株式会社
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Publication of WO2010095615A1 publication Critical patent/WO2010095615A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
    • B01D39/2068—Other inorganic materials, e.g. ceramics
    • B01D39/2072—Other inorganic materials, e.g. ceramics the material being particulate or granular
    • B01D39/2075—Other inorganic materials, e.g. ceramics the material being particulate or granular sintered or bonded by inorganic agents
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    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
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    • C04B35/462—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates
    • C04B35/478—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on aluminium titanates
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Definitions

  • the present invention relates to a method for producing a fired body made of an aluminum titanate ceramic, and more specifically, from an aluminum titanate ceramic by firing a molded body of a raw material mixture containing an aluminum source powder, a titanium source powder, and a magnesium source powder. It relates to a method for producing a fired body.
  • Aluminum titanate-based ceramics are known as ceramics that contain titanium and aluminum as constituent elements and have a crystal pattern of aluminum titanate in the X-ray diffraction spectrum, and have excellent heat resistance.
  • Aluminum titanate-based ceramics have been used as a sintering tool such as a crucible, but in recent years, fine carbon particles contained in exhaust gas discharged from internal combustion engines such as diesel engines are collected. As a material constituting a ceramic filter for industrial use, industrial utility value is increasing.
  • an aluminum magnesium titanate fired body is prepared by firing a raw material mixture containing Ti-containing compounds such as titania ceramics, Al-containing compounds such as alumina ceramics, or Mg-containing compounds such as magnesia ceramics, or a molded body thereof. Is disclosed.
  • the organic binder that is usually used is a compound containing a large amount of carbon, and has a problem that a large amount of carbide is generated by vaporization and decomposition during firing of the molded body.
  • Such carbides can be removed or reduced by adding a large amount of heat energy in the firing process, for example, but excessive heat energy is required during firing, carbon dioxide is generated, and ash and This causes problems such as carbon residue.
  • an object of the present invention is to provide a method capable of producing an aluminum magnesium titanate fired body having good mechanical properties without using a binder or even when the amount of binder used is small. is there.
  • the present invention includes a step of firing a molded body of a raw material mixture containing an aluminum source powder, a titanium source powder, and a magnesium source powder, and the magnesium source powder is an aluminum titanate-based fired body containing a hydrotalcite-based compound.
  • a manufacturing method is provided.
  • the raw material mixture may not contain a binder. According to the present invention, an aluminum titanate-based fired body having high mechanical strength can be obtained without using a binder.
  • the raw material mixture may contain a binder, but according to the present invention, an aluminum titanate-based fired body having excellent mechanical strength can be obtained even when the amount used is sufficiently low. Obtainable.
  • the usage-amount of a binder can be 0.3 mass part or less with respect to 100 mass parts of total amounts of an aluminum source powder, a titanium source powder, and a magnesium source powder.
  • the content of the magnesium source other than the hydrotalcite compound in the magnesium source powder is preferably 40% by mass or less in terms of MgO.
  • the amount of magnesium source powder converted to MgO is 0.1 to 15 with respect to 100 parts by mass of the total amount of the amount of titanium source powder converted to TiO 2 and the amount of aluminum source powder converted to Al 2 O 3. It is preferable that it is a mass part.
  • the particle size (D50) equivalent to 50% of the cumulative percentage by volume of the magnesium source powder is preferably 0.1 to 10 ⁇ m.
  • the amount of the titanium source powder in terms of TiO 2 is 30 to 70 parts by weight of the total amount of 100 parts by mass of the amount of the aluminum source powder consumption and in terms of Al 2 O 3 of the titanium source powder in terms of TiO 2 It is preferable that
  • the volume-based cumulative particle size equivalent to 50% of the aluminum source powder (D50) is preferably 0.1 to 50 ⁇ m, and the volume-based cumulative particle size equivalent to 50% of the titanium source powder (D50) is 0.00. It is preferably 1 to 50 ⁇ m.
  • the raw material mixture may further contain a silicon source powder.
  • the amount of the silicon source powder converted to SiO 2 is 0.1 to 10 with respect to 100 parts by mass of the total amount of the amount of titanium source powder converted to TiO 2 and the amount of aluminum source powder converted to Al 2 O 3. It is preferable that it is a mass part.
  • the production method of the present invention it becomes possible to produce a fired aluminum magnesium titanate having good mechanical properties.
  • a binder particularly an organic binder
  • the thermal energy applied during firing can be reduced, and the generation of carbon dioxide during firing and the ash content in the fired body, Residues such as carbon can be prevented or suppressed.
  • the aluminum titanate-based fired body of the present invention is produced by firing a molded body of a raw material mixture containing one or more aluminum source powders, one or more titanium source powders, and one or more magnesium source powders.
  • the aluminum titanate-based fired body obtained using such a raw material mixture is a fired body made of aluminum magnesium titanate crystals.
  • the aluminum source powder contained in the raw material mixture used in the present invention is a powder of a substance that becomes an aluminum component constituting the aluminum titanate-based fired body, and refers to a powder of a substance that contains only aluminum as a metal component.
  • the aluminum source powder include alumina (aluminum oxide) powder.
  • Alumina may be crystalline or amorphous (amorphous).
  • the crystal type include ⁇ -type, ⁇ -type, ⁇ -type, and ⁇ -type, and ⁇ -type, and ⁇ -type alumina is preferably used.
  • the aluminum source powder used in the present invention may be a powder of a substance led to alumina by firing in air.
  • examples of such substances include aluminum salts, aluminum alkoxides, aluminum hydroxide, and aluminum.
  • the aluminum salt may be an inorganic salt or an organic salt.
  • the aluminum inorganic salt include nitrates such as aluminum nitrate and ammonium aluminum nitrate; carbonates such as ammonium aluminum carbonate and the like.
  • the aluminum organic salt include aluminum oxalate, aluminum acetate, aluminum stearate, aluminum lactate, and aluminum laurate.
  • aluminum alkoxide examples include aluminum isopropoxide, aluminum ethoxide, aluminum sec-butoxide, aluminum tert-butoxide, and the like.
  • Aluminum hydroxide may be crystalline or amorphous (amorphous).
  • the crystal type include a gibbsite type, a bayerite type, a norosotrandite type, a boehmite type, and a pseudoboehmite type.
  • the amorphous aluminum hydroxide include an aluminum hydrolyzate obtained by hydrolyzing an aqueous solution of a water-soluble aluminum compound such as an aluminum salt or an aluminum alkoxide.
  • alumina powder and aluminum hydroxide powder are preferably used as the aluminum source powder, more preferably ⁇ -type alumina powder.
  • the aluminum source powder may contain trace components that are inevitably included in the production process.
  • the particle diameter of the aluminum source powder is not particularly limited, but a powder having a volume-based cumulative percentage 50% equivalent particle diameter (D50) of 0.1 to 50 ⁇ m as measured by a laser diffraction method can be preferably used. From the viewpoint of efficiently producing aluminum magnesium titanate, D50 of the aluminum source powder is more preferably 0.3 to 30 ⁇ m.
  • the titanium source powder contained in the raw material mixture is a powder of a substance that becomes a titanium component constituting the aluminum titanate-based fired body, and refers to a substance containing titanium as a metal element.
  • An example of such a substance is titanium oxide powder.
  • titanium oxide include titanium (IV) oxide, titanium (III) oxide, and titanium (II) oxide, and titanium (IV) oxide is preferably used.
  • Titanium (IV) oxide may be crystalline or amorphous (amorphous). When the titanium (IV) oxide is crystalline, examples of the crystal form include anatase type, rutile type, brookite type, and the like. More preferred is anatase type or rutile type titanium (IV) oxide.
  • the titanium source powder used in the present invention may be a powder of a substance that is led to titania (titanium oxide) by firing in air.
  • titania titanium oxide
  • examples of such substances include titanium salts, titanium alkoxides, titanium hydroxide, titanium nitride, titanium sulfide, and titanium.
  • titanium salt examples include titanium trichloride, titanium tetrachloride, titanium sulfide (IV), titanium sulfide (VI), and titanium sulfate (IV).
  • titanium alkoxide examples include titanium (IV) ethoxide, titanium (IV) methoxide, titanium (IV) t-butoxide, titanium (IV) isobutoxide, titanium (IV) n-propoxide, titanium (IV) tetraiso Examples thereof include propoxide and chelates thereof.
  • the titanium source powder a titanium oxide powder is preferably used, and a titanium (IV) oxide powder is more preferable.
  • the titanium source powder may contain a trace component that is inevitably included in the production process.
  • a powder whose surface is coated with a thin surface layer made of alumina, silica, zirconia, aluminum hydroxide or the like can be used as the titanium source powder.
  • a composite oxide containing titanium such as aluminum titanate or aluminum magnesium titanate can be used as the titanium source powder.
  • the particle size of the titanium source powder is not particularly limited, but those having a volume-based cumulative particle size equivalent to 50% (D50) of 0.1 to 50 ⁇ m as measured by a laser diffraction method can be preferably used. From the viewpoint of efficiently producing aluminum magnesium titanate, the D50 of the titanium source powder is more preferably 0.1 to 30 ⁇ m.
  • titanium source powder converted into titania is usually 100 parts by mass of the total amount of titanium source powder converted into titania [TiO 2 ] and aluminum source powder converted into alumina [Al 2 O 3 ]
  • the amount used is 30 to 70 parts by weight and the amount of aluminum source powder converted to alumina is 70 to 30 parts by weight, preferably the amount of titanium source powder converted to titania is 40 to 60 parts by weight,
  • the amount of the aluminum source powder in terms of alumina used is 60 to 40 parts by mass.
  • the mass x 1 of the aluminum source powder in terms of alumina [Al 2 O 3 ] is obtained by the following formula (A).
  • x 1 N 10 ⁇ x 10 (A)
  • N 10 represents the formula amount of Al 2 O 3
  • x 10 represents the molar amount of the aluminum source powder in terms of alumina [Al 2 O 3 ].
  • the molar amount x 10 of the aluminum source powder in terms of alumina [Al 2 O 3 ] is obtained by the following formula (A-1).
  • w 1 represents the amount of aluminum source powder used (g)
  • M 1 represents the number of moles of aluminum in 1 mole of aluminum source powder
  • N 1 represents the formula of the aluminum source powder used. Represents an amount.
  • the molar amount of each aluminum source powder in terms of alumina [Al 2 O 3 ] is determined by the formula (A-1), and the respective molar amounts are totaled. The molar amount in terms of alumina [Al 2 O 3 ] of the aluminum source powder to be used can be determined.
  • the mass x 2 of the titanium source powder in terms of titania [TiO 2 ] is determined by the following formula (B).
  • x 2 N 20 ⁇ x 20 (B)
  • N 20 represents the formula amount of TiO 2
  • x 20 represents the molar amount of the titanium source powder in terms of titania [TiO 2 ].
  • the molar amount x 20 of the titanium source powder in terms of titania [TiO 2 ] is obtained by the following formula (B-1).
  • x 20 (w 2 ⁇ M 2 ) / N 2 (B-1)
  • w 2 represents the amount (g) of titanium source powder used
  • M 2 represents the number of moles of titanium in 1 mole of titanium source powder
  • N 2 represents the formula of the titanium source powder used. Represents an amount.
  • the molar amount of each titanium source powder in terms of titania [TiO 2 ] is obtained by the formula (B-1), and the total molar amounts are used.
  • the molar amount of the titanium source powder in terms of titania [TiO 2 ] can be determined.
  • the magnesium source powder used in the present invention contains one or more hydrotalcite compounds.
  • the “hydrotalcite compound” includes hydrotalcite and hydrotalcite compounds.
  • “Hydrotalcite” is a layered crystal structure represented by the formula: Mg 6 Al 2 (OH) 16 CO 3 .4H 2 O (Mg and Al are divalent and trivalent, respectively). It is a double hydroxide.
  • the “hydrotalcite compound” is defined as a compound having a layered crystal structure similar to that of hydrotalcite, including divalent Mg and trivalent Al.
  • an aluminum titanate-based fired body having high mechanical strength can be obtained without using a binder or even when the amount of binder added is small. Can do.
  • the binder particularly the organic binder, it is possible to reduce the thermal energy given during firing, the generation of carbon dioxide during firing, and the ash and carbon content in the fired body. And the like can be prevented or suppressed.
  • the hydrotalcite compound because the availability is relatively easy, the general formula: Mg x Al y (OH) z CO 3 ⁇ wH can be preferably used a compound represented by the 2 O.
  • x is about 3 to 7
  • y is about 1 to 3
  • z is about 10 to 18, and
  • w is about 2 to 6.
  • Examples of the hydrotalcite compounds represented by the above general formula include “DHT-4A” (Mg 4.5 Al 2 (OH) 13 CO 3 .3.5H 2 O) manufactured by Kyowa Chemical Industry Co., Ltd., “ DHT-6 ”(Mg 6 Al 2 (OH) 16 CO 3 .4H 2 O).
  • the magnesium source powder may be composed only of a hydrotalcite compound or a mixture of a hydrotalcite compound and a magnesium source other than the hydrotalcite compound. However, in order to reduce the amount of binder used as much as possible (preferably zero), it is preferable to increase the content of the hydrotalcite compound in the magnesium source powder as much as possible. More preferably, it consists only of a compound. When a magnesium source other than the hydrotalcite compound is used in combination, the content can be, for example, 40% by mass or less in terms of magnesia (MgO) in the magnesium source powder.
  • MgO magnesia
  • the content of the magnesium source other than the hydrotalcite compound is preferably 30% by mass or less in terms of magnesia (MgO), more preferably 20% by mass or less in terms of magnesia (MgO), and more preferably in terms of magnesia (MgO). It is 10 mass% or less, Most preferably, it is 5 mass% or less in magnesia (MgO) conversion.
  • the mass x 3 of the magnesium source powder in terms of magnesia [MgO] is determined by the following formula (C).
  • x 3 N 30 ⁇ x 30 (C)
  • N 30 represents the formula amount of MgO
  • x 30 represents the molar amount of the magnesium source powder in terms of magnesia [MgO].
  • Molar amount x 30 of the magnesium source powder magnesia [MgO] conversion is obtained by the following equation (C-1).
  • x 30 (w 3 ⁇ M 3 ) / N 3 (C-1)
  • w 3 represents the amount (g) of magnesium source powder used
  • M 3 represents the number of moles of magnesium in 1 mole of magnesium source powder
  • N 3 represents the formula of the magnesium source powder used. Represents an amount.
  • the magnesium amount to be used is determined by calculating the molar amount of each magnesium source powder in terms of magnesia [MgO] according to the formula (C-1), The molar amount of the source powder in terms of magnesia [MgO] can be determined.
  • magnesium sources other than hydrotalcite-based compounds include magnesia (magnesium oxide) powder and powders of substances introduced to magnesia by firing in air.
  • magnesia magnesium oxide
  • examples of the latter include magnesium salt, magnesium alkoxide, magnesium hydroxide, magnesium nitride, magnesium and the like.
  • magnesium salts include magnesium chloride, magnesium perchlorate, magnesium phosphate, magnesium pyrophosphate, magnesium oxalate, magnesium nitrate, magnesium carbonate, magnesium acetate, magnesium sulfate, magnesium citrate, magnesium lactate, magnesium stearate, Examples include magnesium salicylate, magnesium myristate, magnesium gluconate, magnesium dimethacrylate, and magnesium benzoate.
  • magnesium alkoxide examples include magnesium methoxide and magnesium ethoxide.
  • the magnesium source powder can contain trace components that are inevitably included in the production process.
  • a magnesium source other than the hydrotalcite compound a powder of a compound serving as both a magnesium source and an aluminum source can be used.
  • examples of such a compound include magnesia spinel (MgAl 2 O 4 ) and aluminum magnesium titanate.
  • the magnesium source powder other than the hydrotalcite compound only one kind may be used, or two or more kinds may be used in combination.
  • the particle size of the magnesium source powder is not particularly limited, but is measured by a laser diffraction method. Those having (D50) of 0.1 to 10 ⁇ m can be preferably used. From the viewpoint of efficiently producing aluminum magnesium titanate, the D50 of the magnesium source powder is more preferably 0.1 to 2.0 ⁇ m.
  • the content of the magnesium source powder in terms of magnesia [MgO] in the raw material mixture is determined by the amount of titanium source powder in terms of titania [TiO 2 ] and the amount of aluminum source powder in terms of alumina [Al 2 O 3 ].
  • the amount is preferably 0.1 to 15 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass in total.
  • the raw material mixture may further contain one or more silicon source powders.
  • the silicon source powder is a powder of a substance contained in the aluminum titanate-based fired body as a silicon component. By using the silicon source powder in combination, it is possible to obtain an aluminum titanate-based fired body with improved heat resistance. It becomes.
  • Examples of the silicon source powder include powders of silicon oxide (silica) such as silicon dioxide and silicon monoxide.
  • the silicon source powder may be a powder of a substance that is guided to silica by firing in air.
  • examples of such substances include silicic acid, silicon carbide, silicon nitride, silicon sulfide, silicon tetrachloride, silicon acetate, sodium silicate, sodium orthosilicate, feldspar, composite oxide containing silicon and aluminum, glass frit, and the like. It is done.
  • feldspar and glass frit are preferably used because they are easily available industrially, and glass frit and the like are more preferably used because they are easily available industrially and have a stable composition.
  • Glass frit means flakes or powdery glass obtained by pulverizing glass.
  • the yield point of the glass frit is measured using a thermomechanical analyzer (TMA: Thermo Mechanical Analysis).
  • TMA thermomechanical analyzer
  • the yield point of the glass frit is defined as the temperature (° C.) at which the expansion stops and the subsequent contraction starts in the process of raising the glass frit.
  • a general silicate glass containing silicate [SiO 2 ] as a main component can be used as the glass constituting the glass frit.
  • the glass constituting the glass frit includes, as other components, alumina [Al 2 O 3 ], sodium oxide [Na 2 O], potassium oxide [K 2 O], calcium oxide [ CaO], magnesia [MgO] and the like may be included.
  • the glass constituting the glass frit may contain ZrO 2 in order to improve the hot water resistance of the glass itself.
  • the particle size of the silicon source powder is not particularly limited, but those having a volume-based cumulative particle size equivalent to 50% (D50) of 1 to 20 ⁇ m as measured by a laser diffraction method can be preferably used. From the viewpoint of efficiently producing aluminum magnesium titanate, D50 of the silicon source powder is more preferably 5 to 20 ⁇ m.
  • the content of the silicon source powder in terms of SiO 2 (silica) in the raw material mixture is expressed in terms of Al 2 O 3 (alumina) in terms of aluminum source powder and TiO 2 (titania).
  • the total amount with respect to 100 parts by weight of the titanium source powder is usually 0.1 to 10 parts by weight, preferably 5 parts by weight or less.
  • the silicon source powder may contain a trace component inevitably included in the manufacturing process.
  • the silica mass x 4 of the silicon source powder of [SiO 2] terms can be determined by the following formula (D).
  • x 4 N 40 ⁇ x 40 (D)
  • N 40 represents the formula amount of SiO 2
  • x 40 represents the molar amount of the silicon source powder in terms of silica [SiO 2 ].
  • the molar amount x 40 of the silicon source powder in terms of silica [SiO 2 ] is obtained by the following formula (D-1).
  • x 40 (w 4 ⁇ M 4 ) / N 4 (D-1)
  • w 4 represents the amount (g) of silicon source powder used
  • M 4 represents the number of moles of silicon in 1 mole of silicon source powder
  • N 4 represents the formula of the silicon source powder used. Represents an amount.
  • the molar amount of each silicon source powder in terms of silica [SiO 2 ] is obtained by the formula (D-1) and used by summing the respective molar amounts.
  • the molar amount of silicon source powder in terms of silica [SiO 2 ] can be determined.
  • two or more of titanium, aluminum, magnesium, and silicon are used, such as composite oxides such as magnesia spinel (MgAl 2 O 4 ), aluminum titanate, and aluminum magnesium titanate.
  • a compound containing a metal element as a component can be used as a raw material powder.
  • the use of such a compound can be considered to be the same as mixing each metal source compound powder, and based on such an idea, an aluminum source powder, a titanium source powder in the raw material mixture, Content of magnesium source powder and silicon source powder is adjusted in the said range.
  • the raw material mixture can be obtained, for example, by mixing a titanium source powder, an aluminum source powder, a magnesium source powder and an optional silicon source powder.
  • a commonly used mixer can be used.
  • a stirring mixer such as a Nauter mixer or a Laedige mixer mixer
  • an air mixer such as a flash blender
  • a ball mill, a vibration mill, or the like can be used. it can.
  • the mixing method may be either dry mixing or wet mixing.
  • a titanium source powder, an aluminum source powder, a magnesium source powder and an optional silicon source powder may be mixed and stirred in a pulverization container without being dispersed in a liquid medium.
  • stirring is performed in a grinding container in the presence of grinding media.
  • a container made of a metal material such as stainless steel is usually used, and the inner surface may be coated with a fluorine resin, a silicon resin, a urethane resin, or the like.
  • the internal volume of the grinding container is usually 1 to 4 times the total volume of the raw powder (titanium source powder, aluminum source powder, magnesium source powder and optionally used silicon source powder) and the grinding media. Preferably, it is 1.2 to 3 volume times.
  • the grinding media include alumina beads and zirconia beads having a particle diameter of 1 to 100 mm, preferably 5 to 50 mm.
  • the amount of grinding media used is usually 1 to 1000 times, preferably 5 to 100 times, the total amount of raw material powder.
  • the mixing and pulverization of the raw material powder can be performed, for example, by putting the raw material powder and the pulverizing medium into the pulverizing container and then vibrating or rotating the pulverizing container or both.
  • the raw material powder is agitated and mixed with the pulverization media and pulverized.
  • a normal pulverizer such as a vibration mill, a ball mill, a planetary mill, etc. can be used, and the vibration mill is easy to implement on an industrial scale.
  • the amplitude is usually 2 mm to 20 mm, preferably 12 mm or less.
  • Mixing and pulverization may be performed continuously or batchwise. However, it is preferable to perform the mixing and pulverization continuously because they can be easily carried out on an industrial scale.
  • the time required for mixing and grinding is usually 1 minute to 6 hours, preferably 1.5 minutes to 2 hours.
  • additives such as a pulverization aid and a deflocculant may be added.
  • the grinding aid include alcohols such as monools (such as methanol, ethanol and propanol) and glycols (such as propylene glycol, polypropylene glycol and ethylene glycol); amines such as triethanolamine; palmitic acid and stearin And higher fatty acids such as acid and oleic acid; and carbon materials such as carbon black and graphite. These may be used alone or in combination of two or more.
  • the total use amount thereof is usually 0.00 with respect to the total use amount of the raw material powder, that is, 100 parts by mass of the total use amount of the titanium source powder, the aluminum source powder, the magnesium source powder and the silicon source powder. 1 to 10 parts by mass, preferably 0.5 to 5 parts by mass, and more preferably 0.75 to 2 parts by mass.
  • a titanium source powder, an aluminum source powder, a magnesium source powder and an optional silicon source powder may be mixed in a solvent.
  • stirring in a liquid solvent may be performed, or stirring may be performed in a pulverization container in the presence of a pulverization medium.
  • the grinding media, the grinding container, and the grinding machine those described above can be used.
  • additives such as pulverization aids may be used in combination as in the case of dry mixing.
  • the solvent examples include alcohols such as monools (such as methanol, ethanol, propanol, and butanol), glycols (such as propylene glycol, polypropylene glycol, and ethylene glycol); and water. Of these, water is preferable, and ion-exchanged water is more preferably used from the viewpoint of few impurities.
  • the amount of the solvent used is usually 20 parts by mass to 1000 parts by mass, preferably 30 parts by mass to 300 parts by mass with respect to 100 parts by mass of the total amount of the titanium source powder, aluminum source powder, magnesium source powder and silicon source powder. It is.
  • a dispersant When mixing in a wet process, a dispersant may be added to the solvent.
  • the dispersant include inorganic acids such as nitric acid, hydrochloric acid and sulfuric acid; organic acids such as oxalic acid, citric acid, acetic acid, malic acid and lactic acid; alcohols such as methanol, ethanol and propanol; ammonium polycarboxylate Surfactant etc. are mentioned.
  • the amount used is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight per 100 parts by weight of the solvent.
  • a raw material mixture can be obtained by removing the solvent after mixing. Removal of the solvent is usually performed by distilling off the solvent.
  • the method for distilling off the solvent is not particularly limited, and may be air-dried at room temperature, vacuum-dried, or heat-dried.
  • the drying method may be stationary drying or fluidized drying.
  • the temperature at the time of heat-drying is not specifically limited, Usually, it is 50 degreeC or more and 250 degrees C or less. Examples of the equipment used for the heat drying include a shelf dryer, a slurry dryer, and a spray dryer.
  • the molded body is fired.
  • An aluminum titanate-based fired body is obtained.
  • the shape of the formed body is not particularly limited, and examples thereof include a honeycomb shape, a rod shape, a tube shape, a plate shape, and a crucible shape.
  • Examples of the molding machine used for molding the raw material mixture include a uniaxial press, an extrusion molding machine, a tableting machine, and a granulator.
  • additives such as a pore former, a lubricant and a plasticizer, a dispersant, and a solvent can be added to the raw material mixture.
  • a binder may be added to the raw material mixture, but in the present invention, even if no binder is added or the amount of binder added is small, An aluminum titanate-based fired body having good mechanical properties can be produced.
  • Some substances may serve as both a pore-forming agent and a binder. Such a substance is capable of adhering particles at the time of molding to maintain the shape of the molded body, and can burn itself to form pores at the time of subsequent firing, specifically, Polyethylene and the like may be applicable.
  • Examples of the pore former include carbon materials such as graphite; resins such as polyethylene, polypropylene and polymethyl methacrylate; plant materials such as starch, nut shells, walnut shells and corn; ice; and dry ice. It is done.
  • the amount of pore-forming agent added is usually 0 to 40 parts by mass, preferably 0 to 25 parts by mass with respect to 100 parts by mass of the total amount of aluminum source powder, titanium source powder, magnesium source powder and silicon source powder. It is.
  • the lubricant and plasticizer examples include alcohols such as glycerin; higher fatty acids such as caprylic acid, lauric acid, palmitic acid, alginic acid, oleic acid, and stearic acid; and stearic acid metal salts such as aluminum stearate.
  • the addition amount of the lubricant and the plasticizer is usually 0 to 10 parts by mass, preferably 1 to 5 parts per 100 parts by mass of the total amount of the aluminum source powder, the titanium source powder, the magnesium source powder and the silicon source powder. Part by mass.
  • the dispersant examples include inorganic acids such as nitric acid, hydrochloric acid and sulfuric acid; organic acids such as oxalic acid, citric acid, acetic acid, malic acid and lactic acid; alcohols such as methanol, ethanol and propanol; ammonium polycarboxylate; Surfactants such as polyoxyalkylene alkyl ethers may be mentioned.
  • the addition amount of the dispersant is usually 0 to 20 parts by mass, preferably 2 to 8 parts by mass with respect to 100 parts by mass of the total amount of the aluminum source powder, titanium source powder, magnesium source powder and silicon source powder. is there.
  • the solvent for example, alcohols such as monools (methanol, ethanol, butanol, propanol, etc.), glycols (propylene glycol, polypropylene glycol, ethylene glycol, etc.); and water can be used. Of these, water is preferable, and ion-exchanged water is more preferably used from the viewpoint of few impurities.
  • the amount of the solvent used is usually 10 parts by mass to 100 parts by mass, preferably 20 parts by mass to 80 parts by mass with respect to 100 parts by mass of the total amount of the aluminum source powder, titanium source powder, magnesium source powder and silicon source powder. It is.
  • binder examples include celluloses such as methyl cellulose, carboxymethyl cellulose, and sodium carboxymethyl cellulose; alcohols such as polyvinyl alcohol; salts such as lignin sulfonate; waxes such as paraffin wax and microcrystalline wax; EVA, polyethylene, polystyrene, liquid crystal Examples thereof include thermoplastic resins such as polymers and engineering plastics. It is preferable that the addition amount of a binder is 0.3 mass part or less with respect to 100 mass parts of total amounts of aluminum source powder, titanium source powder, magnesium source powder, and silicon source powder.
  • the binder When the binder is added, the binder becomes a gas component of CO 2 or H 2 O by being fired and scattered out of the fired body, but after the binder is fired and removed, there are voids, and the fired body. May adversely affect the mechanical strength. From this viewpoint, it is more preferable not to add a binder.
  • the firing temperature in firing the molded body is usually 1300 ° C. or higher, preferably 1400 ° C. or higher. Moreover, in order to make the produced aluminum titanate-based fired body easy to process, the firing temperature is usually 1650 ° C. or lower, preferably 1600 ° C. or lower, more preferably 1550 ° C. or lower.
  • the rate of temperature increase up to the firing temperature is not particularly limited, but is usually 2 ° C./hour to 500 ° C./hour.
  • the firing process includes a degreasing process for removing the binder.
  • Degreasing is typically performed in a temperature rising stage (for example, a temperature range of 150 to 400 ° C.) up to the firing temperature. In the degreasing step, it is preferable to suppress the temperature rising rate as much as possible.
  • Firing is usually performed in the atmosphere, but depending on the type of raw material powder used (ie, aluminum source powder, titanium source powder, magnesium source powder and silicon source powder) and the ratio of the amount used, inert gases such as nitrogen gas and argon gas are used. It may be fired in a gas, or may be fired in a reducing gas such as carbon monoxide gas or hydrogen gas. Further, the firing may be performed in an atmosphere in which the water vapor partial pressure is lowered.
  • inert gases such as nitrogen gas and argon gas are used. It may be fired in a gas, or may be fired in a reducing gas such as carbon monoxide gas or hydrogen gas. Further, the firing may be performed in an atmosphere in which the water vapor partial pressure is lowered.
  • Calcination is usually performed using a normal firing furnace such as a tubular electric furnace, a box-type electric furnace, a tunnel furnace, a far-infrared furnace, a microwave heating furnace, a shaft furnace, a reflection furnace, a rotary furnace, or a roller hearth furnace. Firing may be performed batchwise or continuously. Moreover, you may carry out by a stationary type and may carry out by a fluid type.
  • a normal firing furnace such as a tubular electric furnace, a box-type electric furnace, a tunnel furnace, a far-infrared furnace, a microwave heating furnace, a shaft furnace, a reflection furnace, a rotary furnace, or a roller hearth furnace.
  • Firing may be performed batchwise or continuously.
  • you may carry out by a stationary type and may carry out by a fluid type.
  • the time required for firing may be sufficient time for the raw material mixture compact to transition to aluminum magnesium titanate crystals, and varies depending on the amount of the raw material mixture, the type of firing furnace, firing temperature, firing atmosphere, etc. Usually, it is 10 minutes to 72 hours.
  • an aluminum titanate-based fired body can be obtained.
  • Such an aluminum titanate-based fired body has a shape that substantially maintains the shape of the molded body immediately after molding.
  • the obtained aluminum titanate-based fired body can be processed into a desired shape by grinding or the like.
  • the aluminum titanate-based fired body obtained by the present invention includes a crystal pattern of aluminum magnesium titanate in the X-ray diffraction spectrum, but may further include a crystal pattern of, for example, silica, alumina, titania, etc. .
  • the aluminum titanate-based fired body of the present invention can be represented by a composition formula: Al 2 (1-x) Mg x Ti (1 + x) O 5 .
  • the value of x is 0.01 or more, preferably 0.01 or more and 0.7 or less, more preferably 0.02 or more and 0.5 or less.
  • Example 1 The following were used as raw material powders and additives.
  • the “part by mass” shown below is a value when the total amount of raw material powder (aluminum source powder, titanium source powder, magnesium source powder and silicon source powder), additive, and water is 100 parts by mass.
  • the obtained fired body was crushed in a mortar, and the diffraction spectrum of the obtained powder was measured by a powder X-ray diffraction method.
  • the powder showed a crystal peak of aluminum magnesium titanate.
  • the AT conversion rate of this powder was determined to be 100%.
  • the three-point bending strength of the fired body was 10 MPa, which showed good mechanical strength.
  • Example 2 A calcined aluminum magnesium titanate was obtained in the same manner as in Example 1 except that no binder (polyvinyl alcohol) was added.
  • the obtained fired body was crushed in a mortar, and the diffraction spectrum of the obtained powder was measured by a powder X-ray diffraction method.
  • the powder showed a crystal peak of aluminum magnesium titanate.
  • the AT conversion rate of this powder was determined to be 100%.
  • the three-point bending strength of the fired body was 12 MPa, which showed good mechanical strength.
  • ⁇ Comparative Example 1> The following were used as the raw material powder.
  • the “part by mass” shown below is a value when the total amount of raw material powder (aluminum source powder, titanium source powder, magnesium source powder and silicon source powder) and water is 100 parts by mass.
  • Aluminum source powder Aluminum oxide powder ( ⁇ -type crystal, D50: 0.5 ⁇ m) 14.6 parts by mass (2) Titanium source powder Titanium oxide powder (rutile crystal, D50: 0.5 ⁇ m) 25.1 parts by mass (3) Magnesium source powder Magnesia spinel powder (D50: 5.5 ⁇ m) 9.3 parts by mass (4) Silicon source powder Glass frit (“CK0832” manufactured by Takara Standard Co., D50: 6.0 ⁇ m) 2.0 parts by mass (5) water 49.0 parts by mass The above aluminum source powder, titanium source powder, magnesium source powder, silicon source powder and water (total amount 204 g) together with 500 g of alumina beads (diameter 15 mm) and a plastic container [Internal volume 1 L] was charged.
  • the container was rotated at a frequency of 30 Hz for 4 hours by a ball mill to mix the raw materials in the container and obtain a precursor mixture.
  • the obtained precursor mixture was dried at 120 ° C. for 4 hours, and then crushed using a mortar to obtain a raw material mixture.
  • 2 g of the obtained raw material mixture was molded under a pressure of 0.3 t / cm 2 with a uniaxial press to produce a molded body having a length of about 50 mm, a width of about 5 mm, and a thickness of about 4 mm. Next, this molded body was heated to 1450 ° C.
  • the obtained fired body was crushed in a mortar, and the diffraction spectrum of the obtained powder was measured by a powder X-ray diffraction method.
  • the powder showed a crystal peak of aluminum magnesium titanate.
  • the AT conversion rate of this powder was determined to be 100%.
  • the three-point bending strength of the fired body was 7.5 MPa, and it was confirmed that the mechanical strength was low.
  • the aluminum titanate-based fired body obtained by the present invention includes, for example, firing furnace jigs such as crucibles, setters, mortars, and furnace materials; exhaust gas filters used for exhaust gas purification of internal combustion engines such as diesel engines and gasoline engines Ceramic filters such as selective permeation filters for selectively permeating gas components generated during petroleum refining, such as carbon monoxide, carbon dioxide, nitrogen, oxygen, etc. It can be suitably applied to electronic parts such as substrates and capacitors.

Abstract

Disclosed is a method for manufacturing aluminum magnesium titanate sintered bodies with excellent mechanical properties, even in cases where a binder is not used or the quantity of binder used is small. The method comprises a step in which a molded body of a base mixture containing an aluminum source powder, a titanium source powder, and a magnesium source powder is sintered, and is a method for manufacturing aluminum titanate-based sintered bodies in which said magnesium source powder contains a hydrotalcite-based compound. The base mixture may also contain a silicon source powder.

Description

チタン酸アルミニウム系焼成体の製造方法Method for producing aluminum titanate-based fired body
　本発明は、チタン酸アルミニウム系セラミックスからなる焼成体の製造方法に関し、より詳しくは、アルミニウム源粉末、チタニウム源粉末およびマグネシクム源粉末を含む原料混合物の成形体を焼成してチタン酸アルミニウム系セラミックスからなる焼成体を製造する方法に関する。 The present invention relates to a method for producing a fired body made of an aluminum titanate ceramic, and more specifically, from an aluminum titanate ceramic by firing a molded body of a raw material mixture containing an aluminum source powder, a titanium source powder, and a magnesium source powder. It relates to a method for producing a fired body.
　チタン酸アルミニウム系セラミックスは、構成元素としてチタンおよびアルミニウムを含み、Ｘ線回折スペクトルにおいて、チタン酸アルミニウムの結晶パターンを有するセラミックスであって、耐熱性に優れたセラミックスとして知られている。チタン酸アルミニウム系セラミックスは、従来からルツボのような焼結用の冶具などとして用いられてきたが、近年では、ディーゼルエンジンなどの内燃機関から排出される排ガスに含まれる微細なカーボン粒子を捕集するためのセラミックスフィルターを構成する材料として、産業上の利用価値が高まっている。 Aluminum titanate-based ceramics are known as ceramics that contain titanium and aluminum as constituent elements and have a crystal pattern of aluminum titanate in the X-ray diffraction spectrum, and have excellent heat resistance. Aluminum titanate-based ceramics have been used as a sintering tool such as a crucible, but in recent years, fine carbon particles contained in exhaust gas discharged from internal combustion engines such as diesel engines are collected. As a material constituting a ceramic filter for industrial use, industrial utility value is increasing.
　チタン酸アルミニウム系セラミックスとしては、たとえばチタン酸アルミニウムマグネシウム結晶からなるセラミックスが知られている。特許文献１には、チタニアセラミックス等のＴｉ含有化合物、アルミナセラミックス等のＡｌ含有化合物、マグネシアセラミックス等のＭｇ含有化合物を含む原料混合物またはその成形体を焼成することによりチタン酸アルミニウムマグネシウム焼成体を調製することが開示されている。 As aluminum titanate ceramics, for example, ceramics made of aluminum magnesium titanate crystals are known. In Patent Document 1, an aluminum magnesium titanate fired body is prepared by firing a raw material mixture containing Ti-containing compounds such as titania ceramics, Al-containing compounds such as alumina ceramics, or Mg-containing compounds such as magnesia ceramics, or a molded body thereof. Is disclosed.
国際公開第０５／１０５７０４号パンフレットWO05 / 105704 pamphlet
　上記のように、各種金属成分を含有するセラミックス粉末混合物を用い、該混合物をあらかじめ成形体に成形してから焼成することによりチタン酸アルミニウムマグネシウム焼成体を得る場合、機械的強度の高い焼成体を得るためには、セラミックス粉末同士を強固に結着させるために、上記混合物にかなり多量のバインダ（結合剤）を添加する必要がある。 As described above, when a ceramic powder mixture containing various metal components is used, and the mixture is formed into a molded body in advance and then fired to obtain an aluminum magnesium titanate fired body, a fired body with high mechanical strength is obtained. In order to obtain it, it is necessary to add a considerably large amount of binder (binder) to the above mixture in order to firmly bond ceramic powders.
　しかしながら、通常用いられる有機系バインダは、炭素を多く含有する化合物であり、成形体の焼成時における気化・分解により、多量の炭化物を発生させるという問題があった。かかる炭化物は、たとえば、焼成過程において多量の熱エネルギーを加えることにより除去または低減可能ではあるが、焼成時に熱エネルギーを過剰に必要とする、二酸化炭素が発生する、および、焼成体中に灰分や炭素分が残留するなどの問題を招来する。 However, the organic binder that is usually used is a compound containing a large amount of carbon, and has a problem that a large amount of carbide is generated by vaporization and decomposition during firing of the molded body. Such carbides can be removed or reduced by adding a large amount of heat energy in the firing process, for example, but excessive heat energy is required during firing, carbon dioxide is generated, and ash and This causes problems such as carbon residue.
　そこで、本発明の目的は、バインダを用いることなく、またはバインダの使用量が少ない場合であっても、良好な機械的特性を有するチタン酸アルミニウムマグネシウム焼成体を製造し得る方法を提供することである。 Accordingly, an object of the present invention is to provide a method capable of producing an aluminum magnesium titanate fired body having good mechanical properties without using a binder or even when the amount of binder used is small. is there.
　本発明は、アルミニウム源粉末、チタニウム源粉末およびマグネシウム源粉末を含む原料混合物の成形体を焼成する工程を備え、該マグネシウム源粉末は、ハイドロタルサイト系化合物を含有するチタン酸アルミニウム系焼成体の製造方法を提供する。 The present invention includes a step of firing a molded body of a raw material mixture containing an aluminum source powder, a titanium source powder, and a magnesium source powder, and the magnesium source powder is an aluminum titanate-based fired body containing a hydrotalcite-based compound. A manufacturing method is provided.
　本発明において、上記原料混合物は、バインダを含まないものとすることができる。本発明によれば、バインダを用いることなく機械的強度が高いチタン酸アルミニウム系焼成体を得ることができる。一方、本発明において、上記原料混合物はバインダを含んでいてもよいが、本発明によれば、その使用量が十分低い場合であっても、機械的強度に優れたチタン酸アルミニウム系焼成体を得ることができる。上記原料混合物がバインダを含有する場合において、バインダの使用量はアルミニウム源粉末、チタニウム源粉末およびマグネシウム源粉末の合計量１００質量部に対して、０．３質量部以下とすることができる。 In the present invention, the raw material mixture may not contain a binder. According to the present invention, an aluminum titanate-based fired body having high mechanical strength can be obtained without using a binder. On the other hand, in the present invention, the raw material mixture may contain a binder, but according to the present invention, an aluminum titanate-based fired body having excellent mechanical strength can be obtained even when the amount used is sufficiently low. Obtainable. When the said raw material mixture contains a binder, the usage-amount of a binder can be 0.3 mass part or less with respect to 100 mass parts of total amounts of an aluminum source powder, a titanium source powder, and a magnesium source powder.
　マグネシウム源粉末中の、ハイドロタルサイト系化合物以外のマグネシウム源の含有量は、ＭｇＯ換算で４０質量％以下であることが好ましい。またＭｇＯ換算のマグネシウム源粉末の使用量は、ＴｉＯ2換算のチタニウム源粉末の使用量とＡｌ2Ｏ3換算のアルミニウム源粉末の使用量との合計量１００質量部に対して０．１～１５質量部であることが好ましい。マグネシウム源粉末の体積基準の累積百分率５０％相当粒子径（Ｄ５０）は０．１～１０μｍであることが好ましい。 The content of the magnesium source other than the hydrotalcite compound in the magnesium source powder is preferably 40% by mass or less in terms of MgO. The amount of magnesium source powder converted to MgO is 0.1 to 15 with respect to 100 parts by mass of the total amount of the amount of titanium source powder converted to TiO 2 and the amount of aluminum source powder converted to Al 2 O 3. It is preferable that it is a mass part. The particle size (D50) equivalent to 50% of the cumulative percentage by volume of the magnesium source powder is preferably 0.1 to 10 μm.
　ＴｉＯ2換算のチタニウム源粉末の使用量は、ＴｉＯ2換算のチタニウム源粉末の使用量とＡｌ2Ｏ3換算のアルミニウム源粉末の使用量との合計量１００質量部に対して３０～７０質量部であることが好ましい。アルミニウム源粉末の体積基準の累積百分率５０％相当粒子径（Ｄ５０）は０．１～５０μｍであることが好ましく、またチタニウム源粉末の体積基準の累積百分率５０％相当粒子径（Ｄ５０）は０．１～５０μｍであることが好ましい。 The amount of the titanium source powder in terms of TiO 2 is 30 to 70 parts by weight of the total amount of 100 parts by mass of the amount of the aluminum source powder consumption and in terms of Al 2 O 3 of the titanium source powder in terms of TiO 2 It is preferable that The volume-based cumulative particle size equivalent to 50% of the aluminum source powder (D50) is preferably 0.1 to 50 μm, and the volume-based cumulative particle size equivalent to 50% of the titanium source powder (D50) is 0.00. It is preferably 1 to 50 μm.
　上記原料混合物は、ケイ素源粉末をさらに含んでいてもよい。ＳｉＯ2換算のケイ素源粉末の使用量は、ＴｉＯ2換算のチタニウム源粉末の使用量とＡｌ2Ｏ3換算のアルミニウム源粉末の使用量との合計量１００質量部に対して０．１～１０質量部であることが好ましい。 The raw material mixture may further contain a silicon source powder. The amount of the silicon source powder converted to SiO 2 is 0.1 to 10 with respect to 100 parts by mass of the total amount of the amount of titanium source powder converted to TiO 2 and the amount of aluminum source powder converted to Al 2 O 3. It is preferable that it is a mass part.
　本発明の製造方法によれば、良好な機械的特性を有するチタン酸アルミニウムマグネシウム焼成体を製造することが可能となる。また、本発明の製造方法によれば、バインダ、特には有機系バインダの低減または不使用により、焼成時に与える熱エネルギーを低減できるとともに、焼成時における二酸化炭素の発生および焼成体中への灰分、炭素分などの残留を防止または抑制することができる。 According to the production method of the present invention, it becomes possible to produce a fired aluminum magnesium titanate having good mechanical properties. In addition, according to the production method of the present invention, by reducing or not using a binder, particularly an organic binder, the thermal energy applied during firing can be reduced, and the generation of carbon dioxide during firing and the ash content in the fired body, Residues such as carbon can be prevented or suppressed.
　本発明のチタン酸アルミニウム系焼成体は、１種以上のアルミニウム源粉末、１種以上のチタニウム源粉末および１種以上のマグネシウム源粉末を含む原料混合物の成形体を焼成することにより製造される。かかる原料混合物を用いて得られるチタン酸アルミニウム系焼成体は、チタン酸アルミニウムマグネシウム結晶からなる焼成体である。 The aluminum titanate-based fired body of the present invention is produced by firing a molded body of a raw material mixture containing one or more aluminum source powders, one or more titanium source powders, and one or more magnesium source powders. The aluminum titanate-based fired body obtained using such a raw material mixture is a fired body made of aluminum magnesium titanate crystals.
　本発明において用いられる原料混合物に含有されるアルミニウム源粉末は、チタン酸アルミニウム系焼成体を構成するアルミニウム成分となる物質の粉末であり、金属成分としてアルミニウムのみを含有する物質の粉末をいう。アルミニウム源粉末としては、たとえば、アルミナ（酸化アルミニウム）の粉末が挙げられる。アルミナは結晶性であってもよく、不定形（アモルファス）であってもよい。アルミナが結晶性である場合、その結晶型としては、γ型、δ型、θ型、α型などが挙げられ、α型のアルミナが好ましく用いられる。 The aluminum source powder contained in the raw material mixture used in the present invention is a powder of a substance that becomes an aluminum component constituting the aluminum titanate-based fired body, and refers to a powder of a substance that contains only aluminum as a metal component. Examples of the aluminum source powder include alumina (aluminum oxide) powder. Alumina may be crystalline or amorphous (amorphous). When the alumina is crystalline, examples of the crystal type include γ-type, δ-type, θ-type, and α-type, and α-type alumina is preferably used.
　本発明で用いられるアルミニウム源粉末は、空気中で焼成することによりアルミナに導かれる物質の粉末であってもよい。かかる物質としては、たとえばアルミニウム塩、アルミニウムアルコキシド、水酸化アルミニウム、アルミニウムなどが挙げられる。 The aluminum source powder used in the present invention may be a powder of a substance led to alumina by firing in air. Examples of such substances include aluminum salts, aluminum alkoxides, aluminum hydroxide, and aluminum.
　アルミニウム塩は、無機塩であってもよいし、有機塩であってもよい。アルミニウム無機塩として具体的には、たとえば、硝酸アルミニウム、硝酸アンモニウムアルミニウムなどの硝酸塩；炭酸アンモニウムアルミニウムなどの炭酸塩などが挙げられる。アルミニウム有機塩としては、たとえば、蓚酸アルミニウム、酢酸アルミニウム、ステアリン酸アルミニウム、乳酸アルミニウム、ラウリン酸アルミニウムなどが挙げられる。 The aluminum salt may be an inorganic salt or an organic salt. Specific examples of the aluminum inorganic salt include nitrates such as aluminum nitrate and ammonium aluminum nitrate; carbonates such as ammonium aluminum carbonate and the like. Examples of the aluminum organic salt include aluminum oxalate, aluminum acetate, aluminum stearate, aluminum lactate, and aluminum laurate.
　また、アルミニウムアルコキシドとして具体的には、たとえば、アルミニウムイソプロポキシド、アルミニウムエトキシド、アルミニウムｓｅｃ－ブトキシド、アルミニウムｔｅｒｔ－ブトキシドなどが挙げられる。 Specific examples of the aluminum alkoxide include aluminum isopropoxide, aluminum ethoxide, aluminum sec-butoxide, aluminum tert-butoxide, and the like.
　水酸化アルミニウムは結晶性であってもよく、不定形（アモルファス）であってもよい。水酸化アルミニウムが結晶性である場合、その結晶型としては、たとえば、ギブサイト型、バイヤライト型、ノロソトランダイト型、ベーマイト型、擬ベーマイト型などが挙げられる。アモルファスの水酸化アルミニウムとしては、たとえば、アルミニウム塩、アルミニウムアルコキシドなどのような水溶性アルミニウム化合物の水溶液を加水分解して得られるアルミニウム加水分解物も挙げられる。 Aluminum hydroxide may be crystalline or amorphous (amorphous). In the case where aluminum hydroxide is crystalline, examples of the crystal type include a gibbsite type, a bayerite type, a norosotrandite type, a boehmite type, and a pseudoboehmite type. Examples of the amorphous aluminum hydroxide include an aluminum hydrolyzate obtained by hydrolyzing an aqueous solution of a water-soluble aluminum compound such as an aluminum salt or an aluminum alkoxide.
　上記のなかでも、アルミニウム源粉末としては、アルミナ粉末および水酸化アルミニウム粉末が好ましく用いられ、より好ましくは、α型のアルミナ粉末である。なお、アルミニウム源粉末は、その製造工程において不可避的に含まれる微量成分を含有し得る。 Among the above, alumina powder and aluminum hydroxide powder are preferably used as the aluminum source powder, more preferably α-type alumina powder. The aluminum source powder may contain trace components that are inevitably included in the production process.
　アルミニウム源粉末の粒径は、特に限定されないが、レーザ回折法により測定される、体積基準の累積百分率５０％相当粒子径（Ｄ５０）が０．１～５０μｍであるものを好ましく用いることができる。チタン酸アルミニウムマグネシウムを効率よく生成させる観点から、アルミニウム源粉末のＤ５０は、より好ましくは０．３～３０μｍである。 The particle diameter of the aluminum source powder is not particularly limited, but a powder having a volume-based cumulative percentage 50% equivalent particle diameter (D50) of 0.1 to 50 μm as measured by a laser diffraction method can be preferably used. From the viewpoint of efficiently producing aluminum magnesium titanate, D50 of the aluminum source powder is more preferably 0.3 to 30 μm.
　上記原料混合物に含有されるチタニウム源粉末は、チタン酸アルミニウム系焼成体を構成するチタン成分となる物質の粉末であり、金属元素としてチタンを含有する物質をいう。かかる物質としては、たとえば酸化チタンの粉末が挙げられる。酸化チタンとしては、たとえば、酸化チタン(ＩＶ)、酸化チタン(ＩＩＩ)、酸化チタン(ＩＩ)などが挙げられ、酸化チタン(ＩＶ)が好ましく用いられる。酸化チタン(ＩＶ)は結晶性であってもよく、不定形（アモルファス）であってもよい。酸化チタン（ＩＶ）が結晶性である場合、その結晶型としては、アナターゼ型、ルチル型、ブルッカイト型などが挙げられる。より好ましくは、アナターゼ型、ルチル型の酸化チタン(ＩＶ)である。 The titanium source powder contained in the raw material mixture is a powder of a substance that becomes a titanium component constituting the aluminum titanate-based fired body, and refers to a substance containing titanium as a metal element. An example of such a substance is titanium oxide powder. Examples of titanium oxide include titanium (IV) oxide, titanium (III) oxide, and titanium (II) oxide, and titanium (IV) oxide is preferably used. Titanium (IV) oxide may be crystalline or amorphous (amorphous). When the titanium (IV) oxide is crystalline, examples of the crystal form include anatase type, rutile type, brookite type, and the like. More preferred is anatase type or rutile type titanium (IV) oxide.
　本発明で用いられるチタニウム源粉末は、空気中で焼成することによりチタニア（酸化チタン）に導かれる物質の粉末であってもよい。かかる物質としては、たとえば、チタニウム塩、チタニウムアルコキシド、水酸化チタニウム、窒化チタン、硫化チタン、チタンなどが挙げられる。 The titanium source powder used in the present invention may be a powder of a substance that is led to titania (titanium oxide) by firing in air. Examples of such substances include titanium salts, titanium alkoxides, titanium hydroxide, titanium nitride, titanium sulfide, and titanium.
　チタニウム塩として具体的には、三塩化チタン、四塩化チタン、硫化チタン(ＩＶ)、硫化チタン(ＶＩ)、硫酸チタン(ＩＶ)などが挙げられる。チタニウムアルコキシドとして具体的には、チタン(ＩＶ)エトキシド、チタン(ＩＶ)メトキシド、チタン(ＩＶ)ｔ－ブトキシド、チタン(ＩＶ)イソブトキシド、チタン(ＩＶ)ｎ－プロポキシド、チタン(ＩＶ)テトライソプロポキシド、および、これらのキレート化物などが挙げられる。 Specific examples of the titanium salt include titanium trichloride, titanium tetrachloride, titanium sulfide (IV), titanium sulfide (VI), and titanium sulfate (IV). Specific examples of titanium alkoxide include titanium (IV) ethoxide, titanium (IV) methoxide, titanium (IV) t-butoxide, titanium (IV) isobutoxide, titanium (IV) n-propoxide, titanium (IV) tetraiso Examples thereof include propoxide and chelates thereof.
　上記のなかでも、チタニウム源粉末としては、酸化チタン粉末が好ましく用いられ、より好ましくは、酸化チタン(ＩＶ)粉末である。なお、チタニウム源粉末は、その製造工程において不可避的に含まれる微量成分を含有し得る。また、チタニウム源粉末として、その表面にアルミナ、シリカ、ジルコニア、水酸化アルミニウムなどからなる薄い表面層がコートされたものを用いることもできる。また、チタニウム源粉末として、チタン酸アルミニウムやチタン酸アルミニウムマグネシウムのようなチタンを含む複合酸化物を用いることもできる。 Among the above, as the titanium source powder, a titanium oxide powder is preferably used, and a titanium (IV) oxide powder is more preferable. The titanium source powder may contain a trace component that is inevitably included in the production process. Further, as the titanium source powder, a powder whose surface is coated with a thin surface layer made of alumina, silica, zirconia, aluminum hydroxide or the like can be used. In addition, a composite oxide containing titanium such as aluminum titanate or aluminum magnesium titanate can be used as the titanium source powder.
　チタニウム源粉末の粒径は、特に限定されないが、レーザ回折法により測定される、体積基準の累積百分率５０％相当粒子径（Ｄ５０）が０．１～５０μｍであるものを好ましく用いることができる。チタン酸アルミニウムマグネシウムを効率よく生成させる観点から、チタニウム源粉末のＤ５０は、より好ましくは０．１～３０μｍである。 The particle size of the titanium source powder is not particularly limited, but those having a volume-based cumulative particle size equivalent to 50% (D50) of 0.1 to 50 μm as measured by a laser diffraction method can be preferably used. From the viewpoint of efficiently producing aluminum magnesium titanate, the D50 of the titanium source powder is more preferably 0.1 to 30 μm.
　チタニア〔ＴｉＯ2〕換算のチタニウム源粉末の使用量とアルミナ〔Ａｌ2Ｏ3〕換算のアルミニウム源粉末の使用量との合計量１００質量部に対して、通常、チタニア換算のチタニウム源粉末の使用量が３０質量部～７０質量部、アルミナ換算のアルミニウム源粉末の使用量が７０質量部～３０質量部であり、好ましくはチタニア換算のチタニウム源粉末の使用量が４０質量部～６０質量部、アルミナ換算のアルミニウム源粉末の使用量が６０質量部～４０質量部である。 Use of titanium source powder converted into titania is usually 100 parts by mass of the total amount of titanium source powder converted into titania [TiO 2 ] and aluminum source powder converted into alumina [Al 2 O 3 ] The amount used is 30 to 70 parts by weight and the amount of aluminum source powder converted to alumina is 70 to 30 parts by weight, preferably the amount of titanium source powder converted to titania is 40 to 60 parts by weight, The amount of the aluminum source powder in terms of alumina used is 60 to 40 parts by mass.
　本発明において、アルミナ〔Ａｌ2Ｏ3〕換算のアルミニウム源粉末の質量ｘ1は、下記式（Ａ）により求められる。
　ｘ1＝Ｎ10×ｘ10　・・・（Ａ）
式（Ａ）中、Ｎ10はＡｌ2Ｏ3の式量を表し、ｘ10はアルミナ〔Ａｌ2Ｏ3〕換算のアルミニウム源粉末のモル量を表す。アルミナ〔Ａｌ2Ｏ3〕換算のアルミニウム源粉末のモル量ｘ10は、下記式（Ａ－１）により求められる。
　ｘ10＝（ｗ1×Ｍ1）／（Ｎ1×２）　・・・（Ａ－１）
式（Ａ－１）中、ｗ1はアルミニウム源粉末の使用量（ｇ）を表し、Ｍ1はアルミニウム源粉末１モル中のアルミニウムのモル数を表し、Ｎ1は使用したアルミニウム源粉末の式量を表す。本発明において２種以上のアルミニウム源粉末を使用する場合、式（Ａ－１）によって各アルミニウム源粉末のアルミナ〔Ａｌ2Ｏ3〕換算のモル量を求め、各モル量を合計することによって、使用するアルミニウム源粉末のアルミナ〔Ａｌ2Ｏ3〕換算のモル量を求めることができる。 In the present invention, the mass x 1 of the aluminum source powder in terms of alumina [Al 2 O 3 ] is obtained by the following formula (A).
x 1 = N 10 × x 10 (A)
In formula (A), N 10 represents the formula amount of Al 2 O 3 , and x 10 represents the molar amount of the aluminum source powder in terms of alumina [Al 2 O 3 ]. The molar amount x 10 of the aluminum source powder in terms of alumina [Al 2 O 3 ] is obtained by the following formula (A-1).
x 10 = (w 1 × M 1 ) / (N 1 × 2) (A-1)
In formula (A-1), w 1 represents the amount of aluminum source powder used (g), M 1 represents the number of moles of aluminum in 1 mole of aluminum source powder, and N 1 represents the formula of the aluminum source powder used. Represents an amount. When two or more kinds of aluminum source powders are used in the present invention, the molar amount of each aluminum source powder in terms of alumina [Al 2 O 3 ] is determined by the formula (A-1), and the respective molar amounts are totaled. The molar amount in terms of alumina [Al 2 O 3 ] of the aluminum source powder to be used can be determined.
　本発明において、チタニア〔ＴｉＯ2〕換算のチタニウム源粉末の質量ｘ2は、下記式（Ｂ）により求められる。
　ｘ2＝Ｎ20×ｘ20　・・・（Ｂ）
式（Ｂ）中、Ｎ20はＴｉＯ2の式量を表し、ｘ20はチタニア〔ＴｉＯ2〕換算のチタニウム源粉末のモル量を表す。チタニア〔ＴｉＯ2〕換算のチタニウム源粉末のモル量ｘ20は、下記式（Ｂ－１）により求められる。
　ｘ20＝（ｗ2×Ｍ2）／Ｎ2　・・・（Ｂ－１）
式（Ｂ－１）中、ｗ2はチタニウム源粉末の使用量（ｇ）を表し、Ｍ2はチタニウム源粉末１モル中のチタニウムのモル数を表し、Ｎ2は使用したチタニウム源粉末の式量を表す。本発明において２種以上のチタニウム源粉末を使用する場合、式（Ｂ－１）によって各チタニウム源粉末のチタニア〔ＴｉＯ2〕換算のモル量を求め、各モル量を合計することによって、使用するチタニウム源粉末のチタニア〔ＴｉＯ2〕換算のモル量を求めることができる。 In the present invention, the mass x 2 of the titanium source powder in terms of titania [TiO 2 ] is determined by the following formula (B).
x 2 = N 20 × x 20 (B)
In the formula (B), N 20 represents the formula amount of TiO 2 , and x 20 represents the molar amount of the titanium source powder in terms of titania [TiO 2 ]. The molar amount x 20 of the titanium source powder in terms of titania [TiO 2 ] is obtained by the following formula (B-1).
x 20 = (w 2 × M 2 ) / N 2 (B-1)
In formula (B-1), w 2 represents the amount (g) of titanium source powder used, M 2 represents the number of moles of titanium in 1 mole of titanium source powder, and N 2 represents the formula of the titanium source powder used. Represents an amount. When two or more kinds of titanium source powders are used in the present invention, the molar amount of each titanium source powder in terms of titania [TiO 2 ] is obtained by the formula (B-1), and the total molar amounts are used. The molar amount of the titanium source powder in terms of titania [TiO 2 ] can be determined.
　次に、マグネシウム源粉末について説明する。本発明で用いられるマグネシウム源粉末は、１種以上のハイドロタルサイト系化合物を含有する。ここで、「ハイドロタルサイト系化合物」とは、ハイドロタルサイトおよびハイドロタルサイト類化合物を包含する。「ハイドロタルサイト」とは、式：Ｍｇ6Ａｌ2（ＯＨ）16ＣＯ3・４Ｈ2Ｏ（Ｍｇ、Ａｌは、それぞれ２価、３価である）で表される層状の結晶構造を有する層状複水酸化物である。また、本発明において、「ハイドロタルサイト類化合物」とは、２価のＭｇおよび３価のＡｌを含む、ハイドロタルサイトと同様の層状結晶構造を有する化合物と定義される。このようなハイドロタルサイト系化合物をマグネシウム源として用いることにより、バインダを使用することなく、あるいはバインダの添加量が少ない場合であっても、機械的強度の高いチタン酸アルミニウム系焼成体を得ることができる。また、バインダ、特には有機バインダの使用量を低減または省略することが可能となるため、焼成時に与える熱エネルギーを低減できるとともに、焼成時における二酸化炭素の発生および焼成体中への灰分、炭素分などの残留を防止または抑制することができる。 Next, the magnesium source powder will be described. The magnesium source powder used in the present invention contains one or more hydrotalcite compounds. Here, the “hydrotalcite compound” includes hydrotalcite and hydrotalcite compounds. “Hydrotalcite” is a layered crystal structure represented by the formula: Mg 6 Al 2 (OH) 16 CO 3 .4H 2 O (Mg and Al are divalent and trivalent, respectively). It is a double hydroxide. In the present invention, the “hydrotalcite compound” is defined as a compound having a layered crystal structure similar to that of hydrotalcite, including divalent Mg and trivalent Al. By using such a hydrotalcite-based compound as a magnesium source, an aluminum titanate-based fired body having high mechanical strength can be obtained without using a binder or even when the amount of binder added is small. Can do. In addition, since it is possible to reduce or omit the use amount of the binder, particularly the organic binder, it is possible to reduce the thermal energy given during firing, the generation of carbon dioxide during firing, and the ash and carbon content in the fired body. And the like can be prevented or suppressed.
　ハイドロタルサイト類化合物としては、入手が比較的容易であることから、一般式：ＭｇxＡｌy（ＯＨ）zＣＯ3・ｗＨ2Ｏで表される化合物を好ましく用いることができる。ここで、上記一般式中におけるｘは３～７程度であり、ｙは１～３程度であり、ｚは１０～１８程度であり、ｗは２～６程度である。上記一般式で表されるハイドロタルサイト類化合物としては、たとえば、協和化学工業（株）製の「ＤＨＴ－４Ａ」（Ｍｇ4.5Ａｌ2（ＯＨ）13ＣＯ3・３．５Ｈ2Ｏ）、「ＤＨＴ－６」（Ｍｇ6Ａｌ2（ＯＨ）16ＣＯ3・４Ｈ2Ｏ）などを挙げることができる。 The hydrotalcite compound, because the availability is relatively easy, the general formula: Mg x Al y (OH) z CO 3 · wH can be preferably used a compound represented by the 2 O. Here, in the above general formula, x is about 3 to 7, y is about 1 to 3, z is about 10 to 18, and w is about 2 to 6. Examples of the hydrotalcite compounds represented by the above general formula include “DHT-4A” (Mg 4.5 Al 2 (OH) 13 CO 3 .3.5H 2 O) manufactured by Kyowa Chemical Industry Co., Ltd., “ DHT-6 ”(Mg 6 Al 2 (OH) 16 CO 3 .4H 2 O).
　マグネシウム源粉末は、ハイドロタルサイト系化合物のみからなっていてもよいし、ハイドロタルサイト系化合物とハイドロタルサイト系化合物以外のマグネシウム源との混合物であってもよい。しかし、バインダの使用量を極力削減する（好ましくはゼロとする）ためには、マグネシウム源粉末中のハイドロタルサイト系化合物の含有率をできるだけ多くすることが好ましく、マグネシウム源粉末がハイドロタルサイト系化合物のみからなることがより好ましい。ハイドロタルサイト系化合物以外のマグネシウム源を併用する場合、その含有率は、マグネシウム源粉末中、マグネシア（ＭｇＯ）換算で、たとえば４０質量％以下とすることができる。ハイドロタルサイト系化合物以外のマグネシウム源の含有率は、好ましくはマグネシア（ＭｇＯ）換算で３０質量％以下、より好ましくはマグネシア（ＭｇＯ）換算で２０質量％以下、さらに好ましくはマグネシア（ＭｇＯ）換算で１０質量％以下、最も好ましくはマグネシア（ＭｇＯ）換算で５質量％以下である。 The magnesium source powder may be composed only of a hydrotalcite compound or a mixture of a hydrotalcite compound and a magnesium source other than the hydrotalcite compound. However, in order to reduce the amount of binder used as much as possible (preferably zero), it is preferable to increase the content of the hydrotalcite compound in the magnesium source powder as much as possible. More preferably, it consists only of a compound. When a magnesium source other than the hydrotalcite compound is used in combination, the content can be, for example, 40% by mass or less in terms of magnesia (MgO) in the magnesium source powder. The content of the magnesium source other than the hydrotalcite compound is preferably 30% by mass or less in terms of magnesia (MgO), more preferably 20% by mass or less in terms of magnesia (MgO), and more preferably in terms of magnesia (MgO). It is 10 mass% or less, Most preferably, it is 5 mass% or less in magnesia (MgO) conversion.
　本発明において、マグネシア〔ＭｇＯ〕換算のマグネシウム源粉末の質量ｘ3は、下記式（Ｃ）により求められる。
　ｘ3＝Ｎ30×ｘ30　・・・（Ｃ）
式（Ｃ）中、Ｎ30はＭｇＯの式量を表し、ｘ30はマグネシア〔ＭｇＯ〕換算のマグネシウム源粉末のモル量を表す。マグネシア〔ＭｇＯ〕換算のマグネシウム源粉末のモル量ｘ30は、下記式（Ｃ－１）により求められる。
　ｘ30＝（ｗ3×Ｍ3）／Ｎ3　・・・（Ｃ－１）
式（Ｃ－１）中、ｗ3はマグネシウム源粉末の使用量（ｇ）を表し、Ｍ3はマグネシウム源粉末１モル中のマグネシウムのモル数を表し、Ｎ3は使用したマグネシウム源粉末の式量を表す。本発明において２種以上のマグネシウム源粉末を使用する場合、式（Ｃ－１）によって各マグネシウム源粉末のマグネシア〔ＭｇＯ〕換算のモル量を求め、各モル量を合計することによって、使用するマグネシウム源粉末のマグネシア〔ＭｇＯ〕換算のモル量を求めることができる。 In the present invention, the mass x 3 of the magnesium source powder in terms of magnesia [MgO] is determined by the following formula (C).
x 3 = N 30 × x 30 (C)
In formula (C), N 30 represents the formula amount of MgO, and x 30 represents the molar amount of the magnesium source powder in terms of magnesia [MgO]. Molar amount x 30 of the magnesium source powder magnesia [MgO] conversion is obtained by the following equation (C-1).
x 30 = (w 3 × M 3 ) / N 3 (C-1)
In formula (C-1), w 3 represents the amount (g) of magnesium source powder used, M 3 represents the number of moles of magnesium in 1 mole of magnesium source powder, and N 3 represents the formula of the magnesium source powder used. Represents an amount. When two or more kinds of magnesium source powders are used in the present invention, the magnesium amount to be used is determined by calculating the molar amount of each magnesium source powder in terms of magnesia [MgO] according to the formula (C-1), The molar amount of the source powder in terms of magnesia [MgO] can be determined.
　ハイドロタルサイト系化合物以外のマグネシウム源としては、マグネシア（酸化マグネシウム）の粉末のほか、空気中で焼成することによりマグネシアに導かれる物質の粉末が挙げられる。後者の例としては、たとえば、マグネシウム塩、マグネシウムアルコキシド、水酸化マグネシウム、窒化マグネシウム、マグネシウムなどが挙げられる。 Examples of magnesium sources other than hydrotalcite-based compounds include magnesia (magnesium oxide) powder and powders of substances introduced to magnesia by firing in air. Examples of the latter include magnesium salt, magnesium alkoxide, magnesium hydroxide, magnesium nitride, magnesium and the like.
　マグネシウム塩として具体的には、塩化マグネシウム、過塩素酸マグネシウム、リン酸マグネシウム、ピロリン酸マグネシウム、蓚酸マグネシウム、硝酸マグネシウム、炭酸マグネシウム、酢酸マグネシウム、硫酸マグネシウム、クエン酸マグネシウム、乳酸マグネシウム、ステアリン酸マグネシウム、サリチル酸マグネシウム、ミリスチン酸マグネシウム、グルコン酸マグネシウム、ジメタクリル酸マグネシウム、安息香酸マグネシウムなどが挙げられる。 Specific examples of magnesium salts include magnesium chloride, magnesium perchlorate, magnesium phosphate, magnesium pyrophosphate, magnesium oxalate, magnesium nitrate, magnesium carbonate, magnesium acetate, magnesium sulfate, magnesium citrate, magnesium lactate, magnesium stearate, Examples include magnesium salicylate, magnesium myristate, magnesium gluconate, magnesium dimethacrylate, and magnesium benzoate.
　マグネシウムアルコキシドとして具体的には、マグネシウムメトキシド、マグネシウムエトキシドなどが挙げられる。なお、マグネシウム源粉末は、その製造工程において不可避的に含まれる微量成分を含有し得る。 Specific examples of the magnesium alkoxide include magnesium methoxide and magnesium ethoxide. The magnesium source powder can contain trace components that are inevitably included in the production process.
　また、ハイドロタルサイト系化合物以外のマグネシウム源として、マグネシウム源とアルミニウム源とを兼ねた化合物の粉末を用いることもできる。このような化合物としては、たとえば、マグネシアスピネル（ＭｇＡｌ2Ｏ4）やチタン酸アルミニウムマグネシウムが挙げられる。ハイドロタルサイト系化合物以外のマグネシウム源粉末としては、１種のみが用いられてもよいし、２種以上を併用してもよい。 In addition, as a magnesium source other than the hydrotalcite compound, a powder of a compound serving as both a magnesium source and an aluminum source can be used. Examples of such a compound include magnesia spinel (MgAl 2 O 4 ) and aluminum magnesium titanate. As the magnesium source powder other than the hydrotalcite compound, only one kind may be used, or two or more kinds may be used in combination.
　マグネシウム源粉末（ハイドロタルサイト系化合物粉末およびハイドロタルサイト系化合物以外のマグネシウム源粉末）の粒径は、特に限定されないが、レーザ回折法により測定される、体積基準の累積百分率５０％相当粒子径（Ｄ５０）が０．１～１０μｍであるものを好ましく用いることができる。チタン酸アルミニウムマグネシウムを効率よく生成させる観点から、マグネシウム源粉末のＤ５０は、より好ましくは０．１～２．０μｍである。 The particle size of the magnesium source powder (hydrotalcite-based compound powder and magnesium source powder other than hydrotalcite-based compound) is not particularly limited, but is measured by a laser diffraction method. Those having (D50) of 0.1 to 10 μm can be preferably used. From the viewpoint of efficiently producing aluminum magnesium titanate, the D50 of the magnesium source powder is more preferably 0.1 to 2.0 μm.
　原料混合物中における、マグネシア〔ＭｇＯ〕換算のマグネシウム源粉末の含有量は、チタニア〔ＴｉＯ2〕換算のチタニウム源粉末の使用量とアルミナ〔Ａｌ2Ｏ3〕換算のアルミニウム源粉末の使用量との合計量１００質量部に対して、０．１質量部～１５質量部であることが好ましく、より好ましくは０．１～１０質量部である。 The content of the magnesium source powder in terms of magnesia [MgO] in the raw material mixture is determined by the amount of titanium source powder in terms of titania [TiO 2 ] and the amount of aluminum source powder in terms of alumina [Al 2 O 3 ]. The amount is preferably 0.1 to 15 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass in total.
　上記原料混合物は、１種以上のケイ素源粉末をさらに含有していてもよい。ケイ素源粉末は、シリコン成分となってチタン酸アルミニウム系焼成体に含まれる物質の粉末であり、ケイ素源粉末の併用により、耐熱性がより向上されたチタン酸アルミニウム系焼成体を得ることが可能となる。ケイ素源粉末としては、たとえば、二酸化ケイ素、一酸化ケイ素などの酸化ケイ素（シリカ）の粉末が挙げられる。 The raw material mixture may further contain one or more silicon source powders. The silicon source powder is a powder of a substance contained in the aluminum titanate-based fired body as a silicon component. By using the silicon source powder in combination, it is possible to obtain an aluminum titanate-based fired body with improved heat resistance. It becomes. Examples of the silicon source powder include powders of silicon oxide (silica) such as silicon dioxide and silicon monoxide.
　また、ケイ素源粉末は、空気中で焼成することによりシリカに導かれる物質の粉末であってもよい。かかる物質としては、たとえば、ケイ酸、炭化ケイ素、窒化ケイ素、硫化ケイ素、四塩化ケイ素、酢酸ケイ素、ケイ酸ナトリウム、オルトケイ酸ナトリウム、長石、ケイ素およびアルミニウムを含む複合酸化物、ガラスフリットなどが挙げられる。なかでも、工業的に入手が容易であることから、長石、ガラスフリットなどが好ましく用いられ、工業的に入手が容易であり、組成が安定している点で、ガラスフリットなどがより好ましく用いられる。なお、ガラスフリットとは、ガラスを粉砕して得られるフレークまたは粉末状のガラスをいう。 Further, the silicon source powder may be a powder of a substance that is guided to silica by firing in air. Examples of such substances include silicic acid, silicon carbide, silicon nitride, silicon sulfide, silicon tetrachloride, silicon acetate, sodium silicate, sodium orthosilicate, feldspar, composite oxide containing silicon and aluminum, glass frit, and the like. It is done. Among them, feldspar and glass frit are preferably used because they are easily available industrially, and glass frit and the like are more preferably used because they are easily available industrially and have a stable composition. . Glass frit means flakes or powdery glass obtained by pulverizing glass.
　ケイ素源粉末としてガラスフリットを用いる場合、得られるチタン酸アルミニウム系焼成体の耐熱分解性をより向上させるという観点から、屈伏点が７００℃以上のものを用いることが好ましい。本発明において、ガラスフリットの屈伏点は、熱機械分析装置（ＴＭＡ：Ｔｈｅｒｍｏ　Ｍｅｃｈａｎｉｃａｌ　Ａｎａｌｙｓｉｓ）を用いて測定される。ガラスフリットの屈伏点は、ガラスフリットの昇温過程において、膨張が止まり、次に収縮が始まる温度（℃）と定義される。 When glass frit is used as the silicon source powder, it is preferable to use one having a yield point of 700 ° C. or higher from the viewpoint of further improving the thermal decomposition resistance of the obtained aluminum titanate-based fired body. In the present invention, the yield point of the glass frit is measured using a thermomechanical analyzer (TMA: Thermo Mechanical Analysis). The yield point of the glass frit is defined as the temperature (° C.) at which the expansion stops and the subsequent contraction starts in the process of raising the glass frit.
　上記ガラスフリットを構成するガラスには、ケイ酸〔ＳｉＯ2〕を主成分（全成分中５０質量％超）とする一般的なケイ酸ガラスを用いることができる。ガラスフリットを構成するガラスは、その他の含有成分として、一般的なケイ酸ガラスと同様、アルミナ〔Ａｌ2Ｏ3〕、酸化ナトリウム〔Ｎａ2Ｏ〕、酸化カリウム〔Ｋ2Ｏ〕、酸化カルシウム〔ＣａＯ〕、マグネシア〔ＭｇＯ〕等を含んでいてもよい。また、ガラスフリットを構成するガラスは、ガラス自体の耐熱水性を向上させるために、ＺｒＯ2を含有していてもよい。 As the glass constituting the glass frit, a general silicate glass containing silicate [SiO 2 ] as a main component (over 50% by mass in all components) can be used. The glass constituting the glass frit includes, as other components, alumina [Al 2 O 3 ], sodium oxide [Na 2 O], potassium oxide [K 2 O], calcium oxide [ CaO], magnesia [MgO] and the like may be included. The glass constituting the glass frit may contain ZrO 2 in order to improve the hot water resistance of the glass itself.
　ケイ素源粉末の粒径は、特に限定されないが、レーザ回折法により測定される、体積基準の累積百分率５０％相当粒子径（Ｄ５０）が１～２０μｍであるものを好ましく用いることができる。チタン酸アルミニウムマグネシウムを効率よく生成させる観点から、ケイ素源粉末のＤ５０は、より好ましくは５～２０μｍである。 The particle size of the silicon source powder is not particularly limited, but those having a volume-based cumulative particle size equivalent to 50% (D50) of 1 to 20 μm as measured by a laser diffraction method can be preferably used. From the viewpoint of efficiently producing aluminum magnesium titanate, D50 of the silicon source powder is more preferably 5 to 20 μm.
　原料混合物がケイ素源粉末を含む場合、原料混合物中におけるＳｉＯ2（シリカ）換算のケイ素源粉末の含有量は、Ａｌ2Ｏ3（アルミナ）換算でのアルミニウム源粉末とＴｉＯ2（チタニア）換算でのチタニウム源粉末との合計量１００質量部に対して、通常０．１質量部～１０質量部であり、好ましくは５質量部以下である。なお、ケイ素源粉末は、その製造工程において不可避的に含まれる微量成分を含有し得る。 When the raw material mixture includes a silicon source powder, the content of the silicon source powder in terms of SiO 2 (silica) in the raw material mixture is expressed in terms of Al 2 O 3 (alumina) in terms of aluminum source powder and TiO 2 (titania). The total amount with respect to 100 parts by weight of the titanium source powder is usually 0.1 to 10 parts by weight, preferably 5 parts by weight or less. In addition, the silicon source powder may contain a trace component inevitably included in the manufacturing process.
　本発明において、シリカ〔ＳｉＯ2〕換算のケイ素源粉末の質量ｘ4は、下記式（Ｄ）により求められる。
　ｘ4＝Ｎ40×ｘ40　・・・（Ｄ）
式（Ｄ）中、Ｎ40はＳｉＯ2の式量を表し、ｘ40はシリカ〔ＳｉＯ2〕換算のケイ素源粉末のモル量を表す。シリカ〔ＳｉＯ2〕換算のケイ素源粉末のモル量ｘ40は、下記式（Ｄ－１）により求められる。
　ｘ40＝（ｗ4×Ｍ4）／Ｎ4　・・・（Ｄ－１）
式（Ｄ－１）中、ｗ4はケイ素源粉末の使用量（ｇ）を表し、Ｍ4はケイ素源粉末１モル中のケイ素のモル数を表し、Ｎ4は使用したケイ素源粉末の式量を表す。本発明において２種以上のケイ素源粉末を使用する場合、式（Ｄ－１）によって各ケイ素源粉末のシリカ〔ＳｉＯ2〕換算のモル量を求め、各モル量を合計することによって、使用するケイ素源粉末のシリカ〔ＳｉＯ2〕換算のモル量を求めることができる。 In the present invention, the silica mass x 4 of the silicon source powder of [SiO 2] terms can be determined by the following formula (D).
x 4 = N 40 × x 40 (D)
In the formula (D), N 40 represents the formula amount of SiO 2 , and x 40 represents the molar amount of the silicon source powder in terms of silica [SiO 2 ]. The molar amount x 40 of the silicon source powder in terms of silica [SiO 2 ] is obtained by the following formula (D-1).
x 40 = (w 4 × M 4 ) / N 4 (D-1)
In formula (D-1), w 4 represents the amount (g) of silicon source powder used, M 4 represents the number of moles of silicon in 1 mole of silicon source powder, and N 4 represents the formula of the silicon source powder used. Represents an amount. When two or more types of silicon source powders are used in the present invention, the molar amount of each silicon source powder in terms of silica [SiO 2 ] is obtained by the formula (D-1) and used by summing the respective molar amounts. The molar amount of silicon source powder in terms of silica [SiO 2 ] can be determined.
　なお、上記のように、本発明では、マグネシアスピネル（ＭｇＡｌ2Ｏ4）、チタン酸アルミニウム、チタン酸アルミニウムマグネシウム等の複合酸化物のように、チタニウム、アルミニウム、マグネシウムおよびケイ素のうち、２つ以上の金属元素を成分とする化合物を原料粉末として用いることができる。この場合、そのような化合物の使用は、それぞれの金属源化合物粉末を混合したことと同じであると考えることができ、このような考えに基づき、原料混合物中におけるアルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末およびケイ素源粉末の含有量が上記範囲内に調整される。 In addition, as described above, in the present invention, two or more of titanium, aluminum, magnesium, and silicon are used, such as composite oxides such as magnesia spinel (MgAl 2 O 4 ), aluminum titanate, and aluminum magnesium titanate. A compound containing a metal element as a component can be used as a raw material powder. In this case, the use of such a compound can be considered to be the same as mixing each metal source compound powder, and based on such an idea, an aluminum source powder, a titanium source powder in the raw material mixture, Content of magnesium source powder and silicon source powder is adjusted in the said range.
　上記原料混合物は、たとえば、チタニウム源粉末、アルミニウム源粉末、マグネシウム源粉末および任意で使用されるケイ素源粉末を混合することにより得ることができる。混合には、通常用いられる混合機を用いることができ、たとえば、ナウター混合機、レーディゲミキサー混合機などの攪拌混合機；フラッシュブレンダーなどのエアー混合機；ボールミル、振動ミルなどを用いることができる。混合方法は、乾式混合、湿式混合のいずれでもよい。 The raw material mixture can be obtained, for example, by mixing a titanium source powder, an aluminum source powder, a magnesium source powder and an optional silicon source powder. For mixing, a commonly used mixer can be used. For example, a stirring mixer such as a Nauter mixer or a Laedige mixer mixer; an air mixer such as a flash blender; a ball mill, a vibration mill, or the like can be used. it can. The mixing method may be either dry mixing or wet mixing.
　乾式混合を行なう場合、たとえば、チタニウム源粉末、アルミニウム源粉末、マグネシウム源粉末および任意で使用されるケイ素源粉末を混合し、液体媒体中に分散させることなく、粉砕容器内で撹拌すればよく、通常、粉砕メディアの共存下に粉砕容器内で撹拌する。 When performing dry mixing, for example, a titanium source powder, an aluminum source powder, a magnesium source powder and an optional silicon source powder may be mixed and stirred in a pulverization container without being dispersed in a liquid medium. Usually, stirring is performed in a grinding container in the presence of grinding media.
　粉砕容器としては、通常、ステンレス鋼などの金属材料で構成されたものが用いられ、内表面がフッ素樹脂、シリコン樹脂、ウレタン樹脂などでコーティングされていてもよい。粉砕容器の内容積は、原料粉末（チタニウム源粉末、アルミニウム源粉末、マグネシウム源粉末および任意で使用されるケイ素源粉末）ならびに粉砕メディアの合計容積に対して、通常、１容量倍～４容量倍、好ましくは１．２容量倍～３容量倍である。 As the pulverization container, a container made of a metal material such as stainless steel is usually used, and the inner surface may be coated with a fluorine resin, a silicon resin, a urethane resin, or the like. The internal volume of the grinding container is usually 1 to 4 times the total volume of the raw powder (titanium source powder, aluminum source powder, magnesium source powder and optionally used silicon source powder) and the grinding media. Preferably, it is 1.2 to 3 volume times.
　粉砕メディアとしては、たとえば、粒子径１ｍｍ～１００ｍｍ、好ましくは５ｍｍ～５０ｍｍのアルミナビーズ、ジルコニアビーズなどが挙げられる。粉砕メディアの使用量は、原料粉末の合計使用量に対して通常、１質量倍～１０００質量倍、好ましくは５質量倍～１００質量倍である。 Examples of the grinding media include alumina beads and zirconia beads having a particle diameter of 1 to 100 mm, preferably 5 to 50 mm. The amount of grinding media used is usually 1 to 1000 times, preferably 5 to 100 times, the total amount of raw material powder.
　原料粉末の混合・粉砕は、たとえば、粉砕容器内に、上記原料粉末および粉砕メディアを投入した後、粉砕容器を振動させたり、回転させたり、あるいはその両方により行なうことができる。粉砕容器を振動または回転させることにより、原料粉末が粉砕メディアと共に撹拌されて混合されると共に、粉砕される。粉砕容器を振動または回転させるためには、たとえば、振動ミル、ボールミル、遊星ミルなどのような通常の粉砕機を用いることができ、工業的規模での実施が容易である点で、振動ミルが好ましく用いられる。粉砕容器を振動させる場合、その振幅は、通常、２ｍｍ～２０ｍｍ、好ましくは１２ｍｍ以下である。混合・粉砕は、連続式で行なってもよいし、回分式で行なってもよいが、工業的規模での実施が容易である点で、連続式で行なうことが好ましい。混合・粉砕に要する時間は、通常、１分～６時間、好ましくは１．５分～２時間である。 The mixing and pulverization of the raw material powder can be performed, for example, by putting the raw material powder and the pulverizing medium into the pulverizing container and then vibrating or rotating the pulverizing container or both. By vibrating or rotating the pulverization container, the raw material powder is agitated and mixed with the pulverization media and pulverized. In order to vibrate or rotate the pulverization vessel, for example, a normal pulverizer such as a vibration mill, a ball mill, a planetary mill, etc. can be used, and the vibration mill is easy to implement on an industrial scale. Preferably used. When the grinding container is vibrated, the amplitude is usually 2 mm to 20 mm, preferably 12 mm or less. Mixing and pulverization may be performed continuously or batchwise. However, it is preferable to perform the mixing and pulverization continuously because they can be easily carried out on an industrial scale. The time required for mixing and grinding is usually 1 minute to 6 hours, preferably 1.5 minutes to 2 hours.
　原料粉末を乾式にて混合および粉砕するにあたっては、粉砕助剤、解膠剤などの添加剤を加えてもよい。粉砕助剤としては、たとえば、モノオール類（メタノール、エタノール、プロパノールなど）、グリコール類（プロピレングリコール、ポリプロピレングリコール、エチレングリコールなど）などのアルコール類；トリエタノールアミンなどのアミン類；パルチミン酸、ステアリン酸、オレイン酸などの高級脂肪酸類；カーボンブラック、グラファイトなどの炭素材料などが挙げられる。これらはそれぞれ単独または２種以上を組み合わせて用いられる。 In mixing and pulverizing the raw material powder in a dry process, additives such as a pulverization aid and a deflocculant may be added. Examples of the grinding aid include alcohols such as monools (such as methanol, ethanol and propanol) and glycols (such as propylene glycol, polypropylene glycol and ethylene glycol); amines such as triethanolamine; palmitic acid and stearin And higher fatty acids such as acid and oleic acid; and carbon materials such as carbon black and graphite. These may be used alone or in combination of two or more.
　添加剤を用いる場合、その合計使用量は、原料粉末の合計使用量、すなわちチタニウム源粉末、アルミニウム源粉末、マグネシウム源粉末およびケイ素源粉末の合計使用量１００質量部に対して、通常、０．１～１０質量部、好ましくは０．５～５質量部、さらに好ましくは０．７５～２質量部である。 When the additive is used, the total use amount thereof is usually 0.00 with respect to the total use amount of the raw material powder, that is, 100 parts by mass of the total use amount of the titanium source powder, the aluminum source powder, the magnesium source powder and the silicon source powder. 1 to 10 parts by mass, preferably 0.5 to 5 parts by mass, and more preferably 0.75 to 2 parts by mass.
　一方、湿式で混合するには、たとえば、チタニウム源粉末、アルミニウム源粉末、マグネシウム源粉末および任意で使用されるケイ素源粉末を溶媒中に分散させた状態で混合すればよい。混合方法としては、液体溶媒中の攪拌処理でもよいし、粉砕メディアの共存下に粉砕容器内で撹拌してもよい。粉砕メディアおよび粉砕容器、ならびに粉砕機としては、上記したものを用いることができる。粉砕メディアの共存下に、粉砕容器内で混合・粉砕する場合、乾式混合の場合と同様、粉砕助剤等の添加剤が併用されてもよい。 On the other hand, for wet mixing, for example, a titanium source powder, an aluminum source powder, a magnesium source powder and an optional silicon source powder may be mixed in a solvent. As a mixing method, stirring in a liquid solvent may be performed, or stirring may be performed in a pulverization container in the presence of a pulverization medium. As the grinding media, the grinding container, and the grinding machine, those described above can be used. When mixing and pulverizing in a pulverization container in the presence of pulverization media, additives such as pulverization aids may be used in combination as in the case of dry mixing.
　上記溶媒としては、たとえば、モノオール類（メタノール、エタノール、プロパノール、ブタノールなど）、グリコール類（プロピレングリコール、ポリプロピレングリコール、エチレングリコールなど）などのアルコール類；および水などを用いることができる。なかでも、水が好ましく、不純物が少ない点で、より好ましくはイオン交換水が用いられる。溶媒の使用量は、チタニウム源粉末、アルミニウム源粉末、マグネシウム源粉末およびケイ素源粉末の合計量１００質量部に対して、通常、２０質量部～１０００質量部、好ましくは３０質量部～３００質量部である。 Examples of the solvent include alcohols such as monools (such as methanol, ethanol, propanol, and butanol), glycols (such as propylene glycol, polypropylene glycol, and ethylene glycol); and water. Of these, water is preferable, and ion-exchanged water is more preferably used from the viewpoint of few impurities. The amount of the solvent used is usually 20 parts by mass to 1000 parts by mass, preferably 30 parts by mass to 300 parts by mass with respect to 100 parts by mass of the total amount of the titanium source powder, aluminum source powder, magnesium source powder and silicon source powder. It is.
　湿式で混合するに際して、溶媒には分散剤を添加してもよい。分散剤としては、たとえば、硝酸、塩酸、硫酸などの無機酸；シュウ酸、クエン酸、酢酸、リンゴ酸、乳酸などの有機酸；メタノール、エタノール、プロパノールなどのアルコール類；ポリカルボン酸アンモニウムなどの界面活性剤などが挙げられる。分散剤を使用する場合、その使用量は溶媒１００質量部あたり、通常、０．１質量部～２０質量部、好ましくは０．２質量部～１０質量部である。 When mixing in a wet process, a dispersant may be added to the solvent. Examples of the dispersant include inorganic acids such as nitric acid, hydrochloric acid and sulfuric acid; organic acids such as oxalic acid, citric acid, acetic acid, malic acid and lactic acid; alcohols such as methanol, ethanol and propanol; ammonium polycarboxylate Surfactant etc. are mentioned. When a dispersant is used, the amount used is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight per 100 parts by weight of the solvent.
　湿式混合においては、混合後、溶媒を除去することにより、原料混合物を得ることができる。溶媒の除去は、通常、溶媒を留去することにより行なわれる。溶媒を留去する方法としては特に限定されず、室温にて風乾してもよいし、真空乾燥してもよいし、加熱乾燥をしてもよい。乾燥方法は静置乾燥でもよいし、流動乾燥でもよい。加熱乾燥をする際の温度は特に限定されないが、通常、５０℃以上２５０℃以下である。加熱乾燥に用いられる機器としては、たとえば、棚段乾燥機、スラリードライヤー、スプレードライヤーなどが挙げられる。 In wet mixing, a raw material mixture can be obtained by removing the solvent after mixing. Removal of the solvent is usually performed by distilling off the solvent. The method for distilling off the solvent is not particularly limited, and may be air-dried at room temperature, vacuum-dried, or heat-dried. The drying method may be stationary drying or fluidized drying. Although the temperature at the time of heat-drying is not specifically limited, Usually, it is 50 degreeC or more and 250 degrees C or less. Examples of the equipment used for the heat drying include a shelf dryer, a slurry dryer, and a spray dryer.
　なお、湿式で混合するにあたり、用いるアルミニウム源粉末等の種類によっては溶媒に溶解することもあるが、溶媒に溶解したアルミニウム源粉末等は、溶媒留去により、再び固形分となって析出する。 In addition, when mixing in a wet manner, depending on the type of aluminum source powder used, etc., it may be dissolved in a solvent, but the aluminum source powder and the like dissolved in the solvent are precipitated again as a solid by evaporation of the solvent.
　本発明においては、上記アルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末および任意で使用されるケイ素源粉末を含む原料混合物を成形して成形体を得た後、当該成形体を焼成することにより、チタン酸アルミニウム系焼成体を得る。成形してから焼成を行なうことにより、原料混合物を直接焼成する場合と比較して、焼成中の収縮を抑えることができることから、得られるチタン酸アルミニウム系焼成体の割れを効果的に抑制でき、また、焼成により生成した多孔質性のチタン酸アルミニウム結晶の細孔形状が維持されたチタン酸アルミニウム系焼成体を得ることができる。成形体の形状は特に制限されないが、たとえば、ハニカム形状、棒状、チューブ状、板状、るつぼ形状等を挙げることができる。 In the present invention, after molding a raw material mixture containing the aluminum source powder, titanium source powder, magnesium source powder and optionally used silicon source powder to obtain a molded body, the molded body is fired. An aluminum titanate-based fired body is obtained. Compared to the case where the raw material mixture is directly fired by performing firing after molding, it is possible to effectively suppress cracking of the resulting aluminum titanate-based fired body, since shrinkage during firing can be suppressed, In addition, an aluminum titanate-based fired body in which the pore shape of the porous aluminum titanate crystal produced by firing is maintained can be obtained. The shape of the formed body is not particularly limited, and examples thereof include a honeycomb shape, a rod shape, a tube shape, a plate shape, and a crucible shape.
　原料混合物の成形に用いる成形機としては、一軸プレス、押出成形機、打錠機、造粒機などが挙げられる。押出し成形を行なう際には、原料混合物に、たとえば、造孔剤、潤滑剤および可塑剤、分散剤、ならびに溶媒などの添加剤を添加して成形することができる。また、押出し成形を行なう際には、原料混合物に、バインダを添加してもよいが、本発明においては、バインダを添加しなくても、あるいはバインダの添加量が僅少な場合であっても、良好な機械的特性を有するチタン酸アルミニウム系焼成体を作製することができる。なお、物質によっては造孔剤とバインダの両方の役割を兼ねるものがある。このような物質は、成形時には粒子同士を接着して成形体を保形させることができ、その後の焼成時にそれ自身が燃焼して空孔を形成させることができるものであり、具体的にはポリエチレンなどが該当し得る。 Examples of the molding machine used for molding the raw material mixture include a uniaxial press, an extrusion molding machine, a tableting machine, and a granulator. When performing extrusion molding, for example, additives such as a pore former, a lubricant and a plasticizer, a dispersant, and a solvent can be added to the raw material mixture. In addition, when performing extrusion molding, a binder may be added to the raw material mixture, but in the present invention, even if no binder is added or the amount of binder added is small, An aluminum titanate-based fired body having good mechanical properties can be produced. Some substances may serve as both a pore-forming agent and a binder. Such a substance is capable of adhering particles at the time of molding to maintain the shape of the molded body, and can burn itself to form pores at the time of subsequent firing, specifically, Polyethylene and the like may be applicable.
　上記造孔剤としては、グラファイト等の炭素材；ポリエチレン、ポリプロピレン、ポリメタクリル酸メチル等の樹脂類；でんぷん、ナッツ殻、クルミ殻、コーンなどの植物系材料；氷；およびドライアイス等などが挙げられる。造孔剤の添加量は、アルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末およびケイ素源粉末の合計量１００質量部に対して、通常、０～４０質量部であり、好ましくは０～２５質量部である。 Examples of the pore former include carbon materials such as graphite; resins such as polyethylene, polypropylene and polymethyl methacrylate; plant materials such as starch, nut shells, walnut shells and corn; ice; and dry ice. It is done. The amount of pore-forming agent added is usually 0 to 40 parts by mass, preferably 0 to 25 parts by mass with respect to 100 parts by mass of the total amount of aluminum source powder, titanium source powder, magnesium source powder and silicon source powder. It is.
　上記潤滑剤および可塑剤としては、グリセリンなどのアルコール類；カプリル酸、ラウリン酸、パルミチン酸、アラギン酸、オレイン酸、ステアリン酸などの高級脂肪酸；ステアリン酸アルミニウムなどのステアリン酸金属塩などが挙げられる。潤滑剤および可塑剤の添加量は、アルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末およびケイ素源粉末の合計量１００質量部に対して、通常、０～１０質量部であり、好ましくは１～５質量部である。 Examples of the lubricant and plasticizer include alcohols such as glycerin; higher fatty acids such as caprylic acid, lauric acid, palmitic acid, alginic acid, oleic acid, and stearic acid; and stearic acid metal salts such as aluminum stearate. . The addition amount of the lubricant and the plasticizer is usually 0 to 10 parts by mass, preferably 1 to 5 parts per 100 parts by mass of the total amount of the aluminum source powder, the titanium source powder, the magnesium source powder and the silicon source powder. Part by mass.
　上記分散剤としては、たとえば、硝酸、塩酸、硫酸などの無機酸；シュウ酸、クエン酸、酢酸、リンゴ酸、乳酸などの有機酸；メタノール、エタノール、プロパノールなどのアルコール類；ポリカルボン酸アンモニウム、ポリオキシアルキレンアルキルエーテルなどの界面活性剤などが挙げられる。分散剤の添加量は、アルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末およびケイ素源粉末の合計量１００質量部に対して、通常、０～２０質量部であり、好ましくは２～８質量部である。 Examples of the dispersant include inorganic acids such as nitric acid, hydrochloric acid and sulfuric acid; organic acids such as oxalic acid, citric acid, acetic acid, malic acid and lactic acid; alcohols such as methanol, ethanol and propanol; ammonium polycarboxylate; Surfactants such as polyoxyalkylene alkyl ethers may be mentioned. The addition amount of the dispersant is usually 0 to 20 parts by mass, preferably 2 to 8 parts by mass with respect to 100 parts by mass of the total amount of the aluminum source powder, titanium source powder, magnesium source powder and silicon source powder. is there.
　また、上記溶媒としては、たとえば、モノオール類（メタノール、エタノール、ブタノール、プロパノールなど）、グリコール類（プロピレングリコール、ポリプロピレングリコール、エチレングリコールなど）などのアルコール類；および水などを用いることができる。なかでも、水が好ましく、不純物が少ない点で、より好ましくはイオン交換水が用いられる。溶媒の使用量は、アルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末およびケイ素源粉末の合計量１００質量部に対して、通常、１０質量部～１００質量部、好ましくは２０質量部～８０質量部である。 As the solvent, for example, alcohols such as monools (methanol, ethanol, butanol, propanol, etc.), glycols (propylene glycol, polypropylene glycol, ethylene glycol, etc.); and water can be used. Of these, water is preferable, and ion-exchanged water is more preferably used from the viewpoint of few impurities. The amount of the solvent used is usually 10 parts by mass to 100 parts by mass, preferably 20 parts by mass to 80 parts by mass with respect to 100 parts by mass of the total amount of the aluminum source powder, titanium source powder, magnesium source powder and silicon source powder. It is.
　上記バインダとしては、メチルセルロース、カルボキシルメチルセルロース、ナトリウムカルボキシルメチルセルロースなどのセルロース類；ポリビニルアルコールなどのアルコール類；リグニンスルホン酸塩などの塩；パラフィンワックス、マイクロクリスタリンワックス等のワックス；ＥＶＡ、ポリエチレン、ポリスチレン、液晶ポリマー、エンジニアリングプラスチックなどの熱可塑性樹脂などが挙げられる。バインダの添加量は、アルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末およびケイ素源粉末の合計量１００質量部に対して、０．３質量部以下であることが好ましい。バインダを添加する場合、バインダは焼成されることによってＣＯ2やＨ2Ｏのガス成分となって焼成体の外へ飛散するが、バインダが焼成、除去された後は空隙が存在し、焼成体の機械的強度に悪影響を与える場合がある。このようの観点からバインダは添加しないことがより好ましい。 Examples of the binder include celluloses such as methyl cellulose, carboxymethyl cellulose, and sodium carboxymethyl cellulose; alcohols such as polyvinyl alcohol; salts such as lignin sulfonate; waxes such as paraffin wax and microcrystalline wax; EVA, polyethylene, polystyrene, liquid crystal Examples thereof include thermoplastic resins such as polymers and engineering plastics. It is preferable that the addition amount of a binder is 0.3 mass part or less with respect to 100 mass parts of total amounts of aluminum source powder, titanium source powder, magnesium source powder, and silicon source powder. When the binder is added, the binder becomes a gas component of CO 2 or H 2 O by being fired and scattered out of the fired body, but after the binder is fired and removed, there are voids, and the fired body. May adversely affect the mechanical strength. From this viewpoint, it is more preferable not to add a binder.
　成形体の焼成における焼成温度は、通常、１３００℃以上、好ましくは１４００℃以上である。また、生成されるチタン酸アルミニウム系焼成体を加工しやすいものにするため、焼成温度は、通常、１６５０℃以下、好ましくは１６００℃以下、より好ましくは１５５０℃以下である。焼成温度までの昇温速度は特に限定されるものではないが、通常、２℃／時間～５００℃／時間である。ケイ素源粉末を用いる場合には、焼成工程の前に、１１００～１３００℃の温度範囲で３時間以上保持する工程を設けることが好ましい。これにより、ケイ素源粉末の融解、拡散を促進させることができる。原料混合物がバインダ等を含む場合、焼成工程には、これを除去するための脱脂工程が含まれる。脱脂は、典型的には、焼成温度に至るまでの昇温段階（たとえば、１５０～４００℃の温度範囲）になされる。脱脂工程おいては、昇温速度を極力おさえることが好ましい。 The firing temperature in firing the molded body is usually 1300 ° C. or higher, preferably 1400 ° C. or higher. Moreover, in order to make the produced aluminum titanate-based fired body easy to process, the firing temperature is usually 1650 ° C. or lower, preferably 1600 ° C. or lower, more preferably 1550 ° C. or lower. The rate of temperature increase up to the firing temperature is not particularly limited, but is usually 2 ° C./hour to 500 ° C./hour. When the silicon source powder is used, it is preferable to provide a step of holding at a temperature range of 1100 to 1300 ° C. for 3 hours or more before the firing step. Thereby, melting and diffusion of the silicon source powder can be promoted. When the raw material mixture includes a binder or the like, the firing process includes a degreasing process for removing the binder. Degreasing is typically performed in a temperature rising stage (for example, a temperature range of 150 to 400 ° C.) up to the firing temperature. In the degreasing step, it is preferable to suppress the temperature rising rate as much as possible.
　焼成は通常、大気中で行なわれるが、用いる原料粉末（すなわちアルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末およびケイ素源粉末）の種類や使用量比によっては、窒素ガス、アルゴンガスなどの不活性ガス中で焼成してもよいし、一酸化炭素ガス、水素ガスなどのような還元性ガス中で焼成してもよい。また、水蒸気分圧を低くした雰囲気中で焼成を行なってもよい。 Firing is usually performed in the atmosphere, but depending on the type of raw material powder used (ie, aluminum source powder, titanium source powder, magnesium source powder and silicon source powder) and the ratio of the amount used, inert gases such as nitrogen gas and argon gas are used. It may be fired in a gas, or may be fired in a reducing gas such as carbon monoxide gas or hydrogen gas. Further, the firing may be performed in an atmosphere in which the water vapor partial pressure is lowered.
　焼成は、通常、管状電気炉、箱型電気炉、トンネル炉、遠赤外線炉、マイクロ波加熱炉、シャフト炉、反射炉、ロータリー炉、ローラーハース炉などの通常の焼成炉を用いて行なわれる。焼成は回分式で行なってもよいし、連続式で行なってもよい。また、静置式で行なってもよいし、流動式で行なってもよい。 Calcination is usually performed using a normal firing furnace such as a tubular electric furnace, a box-type electric furnace, a tunnel furnace, a far-infrared furnace, a microwave heating furnace, a shaft furnace, a reflection furnace, a rotary furnace, or a roller hearth furnace. Firing may be performed batchwise or continuously. Moreover, you may carry out by a stationary type and may carry out by a fluid type.
　焼成に要する時間は、原料混合物の成形体がチタン酸アルミニウムマグネシウム結晶に遷移するのに十分な時間であればよく、原料混合物の量、焼成炉の形式、焼成温度、焼成雰囲気などにより異なるが、通常は１０分～７２時間である。 The time required for firing may be sufficient time for the raw material mixture compact to transition to aluminum magnesium titanate crystals, and varies depending on the amount of the raw material mixture, the type of firing furnace, firing temperature, firing atmosphere, etc. Usually, it is 10 minutes to 72 hours.
　以上のようにして、チタン酸アルミニウム系焼成体を得ることができる。このようなチタン酸アルミニウム系焼成体は、成形直後の成形体の形状をほぼ維持した形状を有する。得られたチタン酸アルミニウム系焼成体は、研削加工等により、所望の形状に加工することもできる。 Thus, an aluminum titanate-based fired body can be obtained. Such an aluminum titanate-based fired body has a shape that substantially maintains the shape of the molded body immediately after molding. The obtained aluminum titanate-based fired body can be processed into a desired shape by grinding or the like.
　本発明により得られるチタン酸アルミニウム系焼成体は、Ｘ線回折スペクトルにおいて、チタン酸アルミニウムマグネシウムの結晶パターンを含むものであるが、そのほかに、たとえばシリカ、アルミナ、チタニアなどの結晶パターンを含んでいてもよい。本発明のチタン酸アルミニウム系焼成体は、組成式：Ａｌ2(1-x)ＭｇxＴｉ(1+x)Ｏ5で表すことができる。ｘの値は０．０１以上であり、好ましくは０．０１以上０．７以下、より好ましくは０．０２以上０．５以下である。 The aluminum titanate-based fired body obtained by the present invention includes a crystal pattern of aluminum magnesium titanate in the X-ray diffraction spectrum, but may further include a crystal pattern of, for example, silica, alumina, titania, etc. . The aluminum titanate-based fired body of the present invention can be represented by a composition formula: Al 2 (1-x) Mg x Ti (1 + x) O 5 . The value of x is 0.01 or more, preferably 0.01 or more and 0.7 or less, more preferably 0.02 or more and 0.5 or less.
　以下、本発明を実施例によりさらに詳細に説明するが、本発明はこれらに限定されるものではない。なお、得られたチタン酸アルミニウム系焼成体のチタン酸アルミニウム化率（ＡＴ化率）、三点曲げ強度、および用いた原料粉末のＤ５０は、下記方法により測定した。 Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, aluminum titanate conversion rate (AT conversion rate), three-point bending strength, and D50 of the raw material powder used were measured by the following methods.
　（１）ＡＴ化率
　チタン酸アルミニウム化率（ＡＴ化率）は、粉末Ｘ線回折スペクトルにおける２θ＝２７．４°の位置に現れるピーク〔チタニア・ルチル相（１１０）面に帰属される〕の積分強度(ＩT)と、２θ＝３３．７°の位置に現れるピーク〔チタン酸アルミニウムマグネシウム相（２３０）面に帰属される〕の積分強度（ＩAT）とから、下記式により算出した。
ＡＴ化率＝ＩAT／（ＩT＋ＩAT）×１００（％）
　（２）三点曲げ強度
　各実施例および比較例で得られたチタン酸アルミニウム系焼成体の三点曲げ強度を、ＪＩＳ　Ｒ　１６０１に準じて測定し、その機械的強度を評価した。 (1) AT conversion rate The aluminum titanate conversion rate (AT conversion rate) is a peak [attributed to the titania-rutile phase (110) plane) that appears at the position of 2θ = 27.4 ° in the powder X-ray diffraction spectrum. From the integrated intensity (I T ) and the integrated intensity (I AT ) of the peak appearing at the position of 2θ = 33.7 ° (attributed to the aluminum magnesium titanate phase (230) plane), it was calculated by the following formula.
AT conversion rate = I AT / (I T + I AT ) × 100 (%)
(2) Three-point bending strength The three-point bending strength of the aluminum titanate-based fired bodies obtained in the examples and comparative examples was measured according to JIS R 1601 and the mechanical strength was evaluated.
　（３）原料粉末の粒度分布
　体積基準の累積百分率５０％相当粒子径（Ｄ５０）は、レーザ回折式粒度分布測定装置〔日機装社製「Ｍｉｃｒｏｔｒａｃ　ＨＲＡ（Ｘ－１００）」〕を用いて測定した。 (3) Particle Size Distribution of Raw Material Powder A particle size (D50) equivalent to a volume-based cumulative percentage of 50% was measured using a laser diffraction particle size distribution measuring apparatus [“Microtrac HRA (X-100)” manufactured by Nikkiso Co., Ltd.].
　＜実施例１＞
　原料粉末および添加剤として以下のものを用いた。下記に示す「質量部」は、原料粉末（アルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末およびケイ素源粉末）、添加剤、ならびに水の合計量を１００質量部としたときの値である。下記の原料粉末の仕込み組成は、アルミナ〔Ａｌ2Ｏ3〕、チタニア〔ＴｉＯ2〕、マグネシア〔ＭｇＯ〕およびシリカ〔ＳｉＯ2〕換算のモル比で、〔Ａｌ2Ｏ3〕／〔ＴｉＯ2〕／〔ＭｇＯ〕／〔ＳｉＯ2〕＝３４．３％／５０．２％／９．４％／６．１％である。
（１）アルミニウム源粉末
　酸化アルミニウム粉末（α型結晶、Ｄ５０：０．５μｍ）
　　　　　　　　　　　　　　　　　　　　　　　　　１９．５質量部
（２）チタニウム源粉末
　酸化チタン粉末（ルチル型結晶、Ｄ５０：０．５μｍ）
　　　　　　　　　　　　　　　　　　　　　　　　　２４．３質量部
（３）マグネシウム源粉末
　ハイドロタルサイト類化合物粉末（協和化学工業（株）、「ＤＨＴ－４Ａ」、Ｄ５０：０．４μｍ）
　　　　　　　　　　　　　　　　　　　　　　　　　　３．６質量部
（４）ケイ素源粉末
　ガラスフリット（タカラスタンダード社製「ＣＫ０８３２」、Ｄ５０：６．０μｍ）
　　　　　　　　　　　　　　　　　　　　　　　　　　２．０質量部
（５）添加剤
　バインダ（ポリビニルアルコール）
　　　　　　　　　　　　　　　　　　　　　　　　　　０．１質量部
（６）水
　　　　　　　　　　　　　　　　　　　　　　　　　５０．５質量部
　上記アルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末、ケイ素源粉末、添加剤および水（合計量１９８ｇ）を、アルミナビーズ〔直径１５ｍｍ〕５００ｇと共にプラスチック製容器〔内容積１Ｌ〕に投入した。その後、該容器をボールミルにより振動数３０Ｈｚにて４時間回転させることにより、容器内の原料を混合し、前駆体混合物を得た。得られた前駆体混合物を１２０℃で、４時間乾燥させた後、乳鉢を用いて解砕し、原料混合物を得た。得られた原料混合物の２ｇを一軸プレスにて０．３ｔ／ｃｍ2の圧力下で成形することにより、長さ約５０ｍｍ、幅約５ｍｍ、厚さ約４ｍｍの成形体を作製した。次に、この成形体を箱型電気炉にて昇温速度３００℃／ｈで１４５０℃まで昇温し、同温度で４時間保持することにより、チタン酸アルミニウムマグネシウム焼成体を得た。得られた焼成体を組成式：Ａｌ2(1-x)ＭｇxＴｉ(1+x)Ｏ5で表した時のｘの値は０．２４であった。 <Example 1>
The following were used as raw material powders and additives. The “part by mass” shown below is a value when the total amount of raw material powder (aluminum source powder, titanium source powder, magnesium source powder and silicon source powder), additive, and water is 100 parts by mass. The feed composition of the following raw material powder is alumina [Al 2 O 3 ], titania [TiO 2 ], magnesia [MgO] and silica [SiO 2 ] converted molar ratio, [Al 2 O 3 ] / [TiO 2 ] / [MgO] / [SiO 2 ] = 34.3% / 50.2% / 9.4% / 6.1%.
(1) Aluminum source powder Aluminum oxide powder (α-type crystal, D50: 0.5 μm)
19.5 parts by mass (2) Titanium source powder Titanium oxide powder (rutile crystal, D50: 0.5 μm)
24.3 parts by mass (3) Magnesium source powder Hydrotalcite compound powder (Kyowa Chemical Industry Co., Ltd., “DHT-4A”, D50: 0.4 μm)
3.6 parts by mass (4) Silicon source powder Glass frit (manufactured by Takara Standard Co., Ltd. “CK0832”, D50: 6.0 μm)
2.0 parts by mass (5) additive binder (polyvinyl alcohol)
0.1 part by mass (6) water 50.5 parts by mass The above aluminum source powder, titanium source powder, magnesium source powder, silicon source powder, additive and water (total amount 198 g) together with 500 g of alumina beads (diameter 15 mm) It put into the plastic container [internal volume 1L]. Thereafter, the container was rotated at a frequency of 30 Hz for 4 hours by a ball mill to mix the raw materials in the container and obtain a precursor mixture. The obtained precursor mixture was dried at 120 ° C. for 4 hours, and then crushed using a mortar to obtain a raw material mixture. 2 g of the obtained raw material mixture was molded under a pressure of 0.3 t / cm 2 with a uniaxial press to produce a molded body having a length of about 50 mm, a width of about 5 mm, and a thickness of about 4 mm. Next, this molded body was heated to 1450 ° C. at a temperature rising rate of 300 ° C./h in a box-type electric furnace, and kept at the same temperature for 4 hours to obtain an aluminum magnesium titanate fired body. When the obtained fired body was represented by the composition formula: Al 2 (1-x) Mg x Ti (1 + x) O 5 , the value of x was 0.24.
　得られた焼成体を乳鉢にて解砕し、粉末Ｘ線回折法により、得られた粉末の回折スペクトルを測定したところ、この粉末は、チタン酸アルミニウムマグネシウムの結晶ピークを示した。この粉末のＡＴ化率を求めたところ、１００％であった。また、焼成体の三点曲げ強度は、１０ＭＰａであり、良好な機械的強度を示した。 The obtained fired body was crushed in a mortar, and the diffraction spectrum of the obtained powder was measured by a powder X-ray diffraction method. The powder showed a crystal peak of aluminum magnesium titanate. The AT conversion rate of this powder was determined to be 100%. Moreover, the three-point bending strength of the fired body was 10 MPa, which showed good mechanical strength.
　＜実施例２＞
　バインダ（ポリビニルアルコール）を添加しなかったこと以外は実施例１と同様にしてチタン酸アルミニウムマグネシウム焼成体を得た。 <Example 2>
A calcined aluminum magnesium titanate was obtained in the same manner as in Example 1 except that no binder (polyvinyl alcohol) was added.
　得られた焼成体を乳鉢にて解砕し、粉末Ｘ線回折法により、得られた粉末の回折スペクトルを測定したところ、この粉末は、チタン酸アルミニウムマグネシウムの結晶ピークを示した。この粉末のＡＴ化率を求めたところ、１００％であった。また、焼成体の三点曲げ強度は、１２ＭＰａであり、良好な機械的強度を示した。 The obtained fired body was crushed in a mortar, and the diffraction spectrum of the obtained powder was measured by a powder X-ray diffraction method. The powder showed a crystal peak of aluminum magnesium titanate. The AT conversion rate of this powder was determined to be 100%. Moreover, the three-point bending strength of the fired body was 12 MPa, which showed good mechanical strength.
　＜比較例１＞
　原料粉末として以下のものを用いた。下記に示す「質量部」は、原料粉末（アルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末およびケイ素源粉末）、ならびに水の合計量を１００質量部としたときの値である。下記の原料粉末の仕込み組成は、アルミナ〔Ａｌ2Ｏ3〕、チタニア〔ＴｉＯ2〕、マグネシア〔ＭｇＯ〕およびシリカ〔ＳｉＯ2〕換算のモル比で、〔Ａｌ2Ｏ3〕／〔ＴｉＯ2〕／〔ＭｇＯ〕／〔ＳｉＯ2〕＝３４．３％／５０．２％／９．４％／６．１％である。
（１）アルミニウム源粉末
　酸化アルミニウム粉末（α型結晶、Ｄ５０：０．５μｍ）
　　　　　　　　　　　　　　　　　　　　　　　　　１４．６質量部
（２）チタニウム源粉末
　酸化チタン粉末（ルチル型結晶、Ｄ５０：０．５μｍ）
　　　　　　　　　　　　　　　　　　　　　　　　　２５．１質量部
（３）マグネシウム源粉末
　マグネシアスピネル粉末（Ｄ５０：５．５μｍ）
　　　　　　　　　　　　　　　　　　　　　　　　　　９．３質量部
（４）ケイ素源粉末
　ガラスフリット（タカラスタンダード社製「ＣＫ０８３２」、Ｄ５０：６．０μｍ）
　　　　　　　　　　　　　　　　　　　　　　　　　　２．０質量部
（５）水
　　　　　　　　　　　　　　　　　　　　　　　　　４９．０質量部
　上記アルミニウム源粉末、チタニウム源粉末、マグネシウム源粉末、ケイ素源粉末および水（合計量２０４ｇ）を、アルミナビーズ〔直径１５ｍｍ〕５００ｇと共にプラスチック製容器〔内容積１Ｌ〕に投入した。その後、該容器をボールミルにより振動数３０Ｈｚにて４時間回転させることにより、容器内の原料を混合し、前駆体混合物を得た。得られた前駆体混合物を１２０℃で、４時間乾燥させた後、乳鉢を用いて解砕し、原料混合物を得た。得られた原料混合物の２ｇを一軸プレスにて０．３ｔ／ｃｍ2の圧力下で成形することにより、長さ約５０ｍｍ、幅約５ｍｍ、厚さ約４ｍｍの成形体を作製した。次に、この成形体を箱型電気炉にて昇温速度３００℃／ｈで１４５０℃まで昇温し、同温度で４時間保持することにより、チタン酸アルミニウムマグネシウム焼成体を得た。得られた焼成体を組成式：Ａｌ2(1-x)ＭｇxＴｉ(1+x)Ｏ5で表した時のｘの値は０．２４であった。 <Comparative Example 1>
The following were used as the raw material powder. The “part by mass” shown below is a value when the total amount of raw material powder (aluminum source powder, titanium source powder, magnesium source powder and silicon source powder) and water is 100 parts by mass. The feed composition of the following raw material powder is alumina [Al 2 O 3 ], titania [TiO 2 ], magnesia [MgO] and silica [SiO 2 ] converted molar ratio, [Al 2 O 3 ] / [TiO 2 ] / [MgO] / [SiO 2 ] = 34.3% / 50.2% / 9.4% / 6.1%.
(1) Aluminum source powder Aluminum oxide powder (α-type crystal, D50: 0.5 μm)
14.6 parts by mass (2) Titanium source powder Titanium oxide powder (rutile crystal, D50: 0.5 μm)
25.1 parts by mass (3) Magnesium source powder Magnesia spinel powder (D50: 5.5 μm)
9.3 parts by mass (4) Silicon source powder Glass frit (“CK0832” manufactured by Takara Standard Co., D50: 6.0 μm)
2.0 parts by mass (5) water 49.0 parts by mass The above aluminum source powder, titanium source powder, magnesium source powder, silicon source powder and water (total amount 204 g) together with 500 g of alumina beads (diameter 15 mm) and a plastic container [Internal volume 1 L] was charged. Thereafter, the container was rotated at a frequency of 30 Hz for 4 hours by a ball mill to mix the raw materials in the container and obtain a precursor mixture. The obtained precursor mixture was dried at 120 ° C. for 4 hours, and then crushed using a mortar to obtain a raw material mixture. 2 g of the obtained raw material mixture was molded under a pressure of 0.3 t / cm 2 with a uniaxial press to produce a molded body having a length of about 50 mm, a width of about 5 mm, and a thickness of about 4 mm. Next, this molded body was heated to 1450 ° C. at a temperature rising rate of 300 ° C./h in a box-type electric furnace, and kept at the same temperature for 4 hours to obtain an aluminum magnesium titanate fired body. When the obtained fired body was represented by the composition formula: Al 2 (1-x) Mg x Ti (1 + x) O 5 , the value of x was 0.24.
　得られた焼成体を乳鉢にて解砕し、粉末Ｘ線回折法により、得られた粉末の回折スペクトルを測定したところ、この粉末は、チタン酸アルミニウムマグネシウムの結晶ピークを示した。この粉末のＡＴ化率を求めたところ、１００％であった。また、焼成体の三点曲げ強度は、７．５ＭＰａであり、機械的強度が低いことが確認された。 The obtained fired body was crushed in a mortar, and the diffraction spectrum of the obtained powder was measured by a powder X-ray diffraction method. The powder showed a crystal peak of aluminum magnesium titanate. The AT conversion rate of this powder was determined to be 100%. Moreover, the three-point bending strength of the fired body was 7.5 MPa, and it was confirmed that the mechanical strength was low.
　今回開示された実施の形態および実施例はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
　本発明により得られるチタン酸アルミニウム系焼成体は、たとえば、ルツボ、セッター、コウ鉢、炉材などの焼成炉用冶具；ディーゼルエンジン、ガソリンエンジンなどの内燃機関の排気ガス浄化に用いられる排ガスフィルターや、触媒担体、ビールなどの飲食物の濾過に用いる濾過フィルター、石油精製時に生じるガス成分、たとえば一酸化炭素、二酸化炭素、窒素、酸素などを選択的に透過させるための選択透過フィルターなどのセラミックスフィルター；基板、コンデンサーなどの電子部品などに好適に適用することができる。 The aluminum titanate-based fired body obtained by the present invention includes, for example, firing furnace jigs such as crucibles, setters, mortars, and furnace materials; exhaust gas filters used for exhaust gas purification of internal combustion engines such as diesel engines and gasoline engines Ceramic filters such as selective permeation filters for selectively permeating gas components generated during petroleum refining, such as carbon monoxide, carbon dioxide, nitrogen, oxygen, etc. It can be suitably applied to electronic parts such as substrates and capacitors.

Claims (10)

  1. 　アルミニウム源粉末、チタニウム源粉末およびマグネシウム源粉末を含む原料混合物の成形体を焼成する工程を備え、
    　前記マグネシウム源粉末は、ハイドロタルサイト系化合物を含有するチタン酸アルミニウム系焼成体の製造方法。     A step of firing a molded body of a raw material mixture containing an aluminum source powder, a titanium source powder and a magnesium source powder;
    The said magnesium source powder is a manufacturing method of the aluminum titanate type sintered body containing a hydrotalcite type compound.
  2. 　前記原料混合物は、前記アルミニウム源粉末、前記チタニウム源粉末および前記マグネシウム源粉末の合計量１００質量部に対して、０．３質量部以下のバインダを含む請求項１に記載の方法。 The method according to claim 1, wherein the raw material mixture contains a binder of 0.3 parts by mass or less with respect to 100 parts by mass of a total amount of the aluminum source powder, the titanium source powder, and the magnesium source powder.
  3. 　マグネシウム源粉末中の、ハイドロタルサイト系化合物以外のマグネシウム源の含有量は、ＭｇＯ換算で４０質量％以下である請求項１または２に記載の方法。 The method according to claim 1 or 2, wherein the content of magnesium source other than the hydrotalcite compound in the magnesium source powder is 40% by mass or less in terms of MgO.
  4. 　ＭｇＯ換算のマグネシウム源粉末の使用量は、ＴｉＯ2換算のチタニウム源粉末の使用量とＡｌ2Ｏ3換算のアルミニウム源粉末の使用量との合計量１００質量部に対して０．１～１５質量部である請求項１～３のいずれかに記載の方法。 The amount of magnesium source powder converted to MgO is 0.1 to 15 masses per 100 parts by mass of the total amount of titanium source powder converted to TiO 2 and aluminum source powder converted to Al 2 O 3. The method according to any one of claims 1 to 3, wherein
  5. 　マグネシウム源粉末の体積基準の累積百分率５０％相当粒子径（Ｄ５０）が０．１～１０μｍである請求項１～４のいずれかに記載の方法。 The method according to any one of claims 1 to 4, wherein the magnesium source powder has a volume-based cumulative percentage 50% equivalent particle diameter (D50) of 0.1 to 10 µm.
  6. 　ＴｉＯ2換算のチタニウム源粉末の使用量は、ＴｉＯ2換算のチタニウム源粉末の使用量とＡｌ2Ｏ3換算のアルミニウム源粉末の使用量との合計量１００質量部に対して３０～７０質量部である請求項１～５のいずれかに記載の方法。 The amount of the titanium source powder in terms of TiO 2 is 30 to 70 parts by weight of the total amount of 100 parts by mass of the amount of the aluminum source powder consumption and in terms of Al 2 O 3 of the titanium source powder in terms of TiO 2 The method according to any one of claims 1 to 5, wherein
  7. 　アルミニウム源粉末の体積基準の累積百分率５０％相当粒子径（Ｄ５０）が０．１～５０μｍである請求項１～６のいずれかに記載の方法。 The method according to any one of claims 1 to 6, wherein the aluminum source powder has a volume-based cumulative particle size equivalent to 50% (D50) of 0.1 to 50 µm.
  8. 　チタニウム源粉末の体積基準の累積百分率５０％相当粒子径（Ｄ５０）が０．１～５０μｍである請求項１～７のいずれかに記載の方法。 8. The method according to claim 1, wherein the titanium source powder has a volume-based cumulative particle size equivalent to 50% (D50) of 0.1 to 50 μm.
  9. 　前記原料混合物は、ケイ素源粉末をさらに含む請求項１～８のいずれかに記載の方法。 The method according to any one of claims 1 to 8, wherein the raw material mixture further contains a silicon source powder.
  10. 　ＳｉＯ2換算のケイ素源粉末の使用量は、ＴｉＯ2換算のチタニウム源粉末の使用量とＡｌ2Ｏ3換算のアルミニウム源粉末の使用量との合計量１００質量部に対して０．１～１０質量部である請求項９に記載の方法。 The amount of the silicon source powder converted to SiO 2 is 0.1 to 10 with respect to 100 parts by mass of the total amount of the amount of titanium source powder converted to TiO 2 and the amount of aluminum source powder converted to Al 2 O 3. The method according to claim 9, wherein the method is part by mass.
PCT/JP2010/052280 2009-02-17 2010-02-16 Method for manufacturing aluminum titanate-based sintered bodies WO2010095615A1 (en)

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