WO2010074260A1 - Method for producing aluminum titanate ceramic sintered body, and aluminum titanate ceramic sintered body - Google Patents

Abstract

Disclosed is a method for producing an aluminum titanate ceramic sintered body, wherein the shrinkage of a green body during sintering is reduced.  Also disclosed is an aluminum titanate ceramic sintered body having a low thermal expansion coefficient and a high porosity.  In the method for producing an aluminum titanate ceramic sintered body, 2-25 parts by weight of an inorganic oxide powder is mixed per 100 parts by weight of an aluminum titanate ceramic powder, the thus-obtained mixture is formed into a green body, and the thus-obtained green body is sintered.  The aluminum titanate ceramic sintered body is obtained by the method.

Description

Method for producing aluminum titanate ceramic sintered body and aluminum titanate ceramic sintered body

The present invention relates to a method for producing an aluminum titanate ceramic sintered body and an aluminum titanate ceramic sintered 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. Conventionally, aluminum titanate-based ceramics have been used as a sintering jig such as a crucible. Among such aluminum titanate-based ceramic sintered bodies, porous sintered bodies have recently become ceramic filters for collecting fine carbon particles contained in exhaust gas discharged from internal combustion engines such as diesel engines. Industrial use value is increasing as a constituent material.

2. Description of the Related Art A diesel particulate filter (DPF) for collecting suspended fine particles such as soot discharged from a diesel engine is generally formed of a honeycomb-shaped ceramic sintered body having a high porosity. When using the DPF made of this porous ceramic, a regeneration process is performed to recover the airflow resistance by burning the soot collected on the honeycomb wall surface of the filter on the filter. At this time, a rapid temperature rise occurs in the DPF honeycomb, and the DPF honeycomb is exposed to a high temperature and receives a large thermal shock. Further, when a diesel engine is used as a power source for a passenger car or a construction machine, it is always exposed to a large mechanical vibration during use. For this reason, a ceramic sintered body used as a DFP honeycomb is required to have high thermal shock resistance and mechanical strength, and small deterioration in characteristics due to thermal fatigue.

As a method for producing such an aluminum titanate ceramic sintered body, a method is known in which a pore-forming agent, a binder, water, etc. are added to an aluminum titanate ceramic powder, and the resulting mixture is molded and sintered. ing.

Japanese Patent No. 3185960

However, when an aluminum titanate ceramic powder is formed to obtain a porous sintered body, the aluminum titanate ceramic powder has poor shape retention and large shrinkage during sintering. The molded body tends to collapse or crack. Especially in diesel engines for automobiles and construction machinery, there is a recent tightening of exhaust gas regulations. Generally, the shape of the porous honeycomb that constitutes the DPF is 100 mm in diameter × 100 mm in length or larger, and the wall thickness is as thin as 0.5 mm or less. The cell structure is 300 cells or more, the effective porosity is 30 to 60 vol%, the average pore diameter is 1 to 20 μm, and the pore size distribution is (D50-D10) / D50 and has a narrow pore distribution of less than 0.5. A very fragile structure is required. On the other hand, DPF has both a low thermal expansion characteristic (preferably a thermal expansion coefficient of less than 1.5 × 10 ^-6 K ^-1 ), which is a major factor that determines thermal shock resistance, and a high mechanical strength. Is also sought. For this reason, when producing a sintered body for DPF, aluminum titanate-based ceramics having a low thermal expansion coefficient while ensuring the formability and shape retention during sintering and reducing the shrinkage rate. Development of a ligation and a method for producing the same is desired.

As a method for ensuring the shape retention, Patent Document 1 discloses a method for producing an aluminum titanate powder having a bimodal particle size distribution. Since the porosity of the resulting sintered body is low and the coefficient of thermal expansion is large, it is insufficient as a method for producing an aluminum titanate ceramic sintered body for DPF.

An object of the present invention is to produce an aluminum titanate-based ceramic sintered body in which the shrinkage rate of the sintered body during sintering is reduced, and to sinter the aluminum titanate-based ceramics having a low thermal expansion coefficient and a high porosity. Is to provide a body.

The method for producing an aluminum titanate ceramic sintered body according to the present invention comprises mixing 2 to 25 parts by weight of an inorganic oxide powder to 100 parts by weight of an aluminum titanate ceramic powder, and molding the resulting mixture. The molded body thus obtained is sintered.

The inorganic oxide is preferably alumina. The average particle diameter of the aluminum titanate ceramic powder is preferably 5 to 50 μm.

The average particle size of the inorganic oxide powder is preferably 0.1 to 15 μm. The ratio of the average particle size of the aluminum titanate-based ceramic powder to the average particle size of the inorganic oxide powder is preferably 3 or more, more preferably 5 to 50.

In the present invention, the sintering temperature is preferably 1300 to 1650 ° C.

The present invention can also be obtained by mixing 2 to 25 parts by weight of an inorganic oxide powder with 100 parts by weight of an aluminum titanate ceramic powder, molding the resulting mixture, and sintering the resulting molded body. An aluminum titanate ceramic sintered body is also provided.

The aluminum titanate-based ceramic sintered body is preferably a porous sintered body having a porosity of 30 to 60%.

The present invention also includes a diesel particulate filter comprising the aluminum titanate ceramic sintered body.

According to the present invention, the aluminum titanate-based ceramic powder is mixed with an inorganic oxide powder in an amount within a specific range, the resulting mixture is molded, and the resulting molded body is sintered. In addition to reducing the shrinkage rate of the molded body, the sintered body obtained can achieve a high porosity and a low thermal expansion coefficient. Moreover, it becomes possible to control the shrinkage rate of the aluminum titanate-based ceramic formed body during sintering by adjusting the mixing amount of the inorganic oxide.

In the method for producing an aluminum titanate-based ceramic sintered body of the present invention, 2 to 25 parts by weight of inorganic oxide powder is mixed with 100 parts by weight of aluminum titanate-based ceramic powder, and then molded and sintered. As a result, it was conventionally made of aluminum titanate-based ceramic powder that was easily collapsed during sintering, cracked or cracked in the molded body, and the molded body often showed large sintering shrinkage. The obtained porous sintered body can be obtained stably. In addition, the sintering shrinkage rate (linear shrinkage rate) of the aluminum titanate-based ceramic formed body during the sintering is specifically a certain shape of a mixture of aluminum titanate-based ceramic powder and inorganic oxide powder. It can be calculated by measuring the side length of the compact that has been compression-molded and measuring the side length after sintering the compact.

In the present invention, by mixing the inorganic oxide powder with the aluminum titanate ceramic powder, the shrinkage ratio of the aluminum titanate ceramic molded body during sintering can be reduced, and the degree of the shrinkage ratio is inorganic. It can be controlled by adjusting the mixing amount of the oxide powder. The inorganic oxide powder also has the effect of improving the mechanical strength of the aluminum titanate ceramic sintered body. When the mixing amount of the inorganic oxide powder is less than 2 parts by weight with respect to 100 parts by weight of the aluminum titanate ceramic powder, there is a problem that the above-described shrinkage reduction effect is not sufficiently exhibited. On the other hand, when the mixing amount of the inorganic oxide exceeds 25 parts by weight with respect to 100 parts by weight of the aluminum titanate ceramic powder, the coefficient of thermal expansion is greatly increased and the porosity is decreased as compared with the case of no addition. Furthermore, depending on the type of the inorganic oxide powder, there is a problem that the shrinkage rate of the molded body also increases. The mixing amount of the inorganic oxide powder is more preferably in the range of 5 to 20 parts by weight with respect to 100 parts by weight of the aluminum titanate ceramic powder.

Examples of inorganic oxides include alumina, titania, magnesia, silica, iron oxide, mullite, cordierite, and the like. Two or more of these inorganic oxides may be used simultaneously. Above all, it does not dissolve in aluminum titanate ceramics, does not react with aluminum titanate ceramics to form new compounds, has a higher melting point than aluminum titanate ceramics, and is difficult to sinter. For this reason, it is preferable to use alumina as the inorganic oxide powder for controlling the sintering shrinkage behavior of the aluminum titanate ceramic. Examples of the crystal form of alumina applicable to the present invention include γ-type, δ-type, θ-type, and α-type, and the alumina may be amorphous. As the alumina, α-type alumina having no crystal transformation accompanied by volume shrinkage during sintering is preferable.

The average particle size of the aluminum titanate ceramic powder used in the present invention is preferably in the range of 5 to 50 μm, and more preferably in the range of 10 to 30 μm. When the average particle size of the aluminum titanate ceramic powder is less than 5 μm, a large amount of pore-forming agent tends to be required to obtain a desired porosity and pore diameter, and when it exceeds 50 μm, There exists a tendency for a moldability to fall remarkably and it to become difficult to obtain the molded object of a desired shape. The average particle size of the powder described here is a particle size (D50) in which the cumulative volume of particles is 50% of the total volume measured in the particle size distribution measured by laser diffraction.

When the above-described alumina is used as the inorganic oxide, it is preferable to use alumina having an average particle diameter (D50) in the range of 0.1 to 15 μm, and use alumina having an average particle diameter in the range of 0.3 to 10 μm. It is more preferable. The average particle diameter (D50) of the inorganic oxide powder other than alumina is preferably 0.1 to 15 μm. When the average particle size of the inorganic oxide powder is less than 0.1 μm, the shrinkage shrinkage is reduced because the size is small enough to occupy the particle gap of the aluminum titanate ceramic powder with the average particle size of 5 to 50 μm. Thus, even if a small amount is added, the coefficient of thermal expansion of the aluminum titanate ceramic is increased. In addition, when the average particle size of the inorganic oxide powder exceeds 15 μm, the inorganic oxide powder does not enter the particle gap of the aluminum titanate-based ceramics, and therefore, it tends not to contribute to the reduction of the shrinkage of the molded body. It is. The average particle size of the inorganic oxide powder is a value measured by a laser diffraction method as a particle size (D50) equivalent to a volume-based cumulative percentage of 50%.

Further, the ratio of the average particle diameter of the aluminum titanate-based ceramic powder to the average particle diameter of the inorganic oxide powder ((average particle diameter of the aluminum titanate-based ceramic powder) / (average particle diameter of the inorganic oxide powder)) is 3. Preferably, it is preferably 5 to 50, more preferably 5 to 20. When the ratio of the average particle diameter is within the above range, the inorganic oxide particles (for example, alumina particles) efficiently occupy the particle gaps of the aluminum titanate ceramic powder.

When the ratio of the average particle diameter of the aluminum titanate ceramic powder to the average particle diameter of the inorganic oxide powder is in the range of 5 to 20, the mixing amount of the inorganic oxide powder is 100 weights of the aluminum titanate ceramic powder. The amount is preferably 2 to 15 parts by weight per part.

The constituent phase of the aluminum titanate ceramic powder may be only aluminum titanate (Al ₂ TiO ₅ ). For the purpose of improving the heat resistance stability of aluminum titanate and lowering the sintering temperature, it is a solid solution in which magnesium (Mg) or iron (Fe) is dissolved in aluminum titanate (Al ₂ TiO ₅ ). In particular, it is preferable to further contain a magnesium source powder. Aluminum titanate in which magnesium is dissolved is represented by the composition formula: Al _{2 (1-x)} Mg _x Ti _{1 + x} O ₅ , where x is preferably in the range of 0.01 to 0.5. More preferably, it is in the range of 0.05 to 0.3.

Such aluminum titanate powder and aluminum magnesium titanate powder may contain a SiO ₂ component in the range of 1 to 10% by weight for the purpose of improving the strength of the sintered body. Specific examples of the SiO ₂ component include SiO ₂ glass, aluminosilicate glass, alkali feldspar, and glass frit. The SiO ₂ component is uniformly dispersed at the grain boundaries of the aluminum titanate crystal particles in an amorphous state. It is preferable.

An aluminum titanate ceramic sintered body is obtained by molding a mixture obtained by mixing an inorganic oxide powder with the aluminum titanate ceramic powder described above to obtain a molded body, and then sintering the molded body. Is obtained. By performing sintering after forming, shrinkage of the formed body during sintering can be suppressed, and cracking of the obtained aluminum titanate ceramic sintered body can be suppressed and prevented. 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 include a uniaxial press, an extrusion molding machine, a tableting machine, and a granulator. When performing extrusion molding, for example, additives such as pore former, binder, lubricant, plasticizer, dispersant, solvent are added to the aluminum titanate ceramic powder and inorganic oxide powder. Can do.

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 0.5 to 40 parts by weight, preferably 1 to 25 parts by weight with respect to 100 parts by weight of the total amount of the aluminum titanate ceramic powder and the inorganic oxide powder. is there.

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. The added amount of the binder is usually 0.5 to 20 parts by weight, preferably 1 to 15 parts by weight with respect to 100 parts by weight of the total amount of the aluminum titanate ceramic powder and the inorganic oxide powder.

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 weight with respect to 100 parts by weight of the total amount of the aluminum titanate ceramic powder and the inorganic oxide powder.

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 amount of the dispersant added is usually 0 to 20 parts by weight, preferably 2 to 8 parts by weight, based on 100 parts by weight of the total amount of the aluminum titanate ceramic powder and the inorganic oxide powder.

As the solvent, for example, monohydric alcohols such as methanol, ethanol, butanol and propanol; dihydric alcohols such as propylene glycol, polypropylene glycol and ethylene glycol; 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 to 100 parts by weight, preferably 20 to 80 parts by weight with respect to 100 parts by weight of the total amount of the aluminum titanate ceramic powder and the inorganic oxide powder.

The aluminum titanate ceramic powder described above, the inorganic oxide powder and the various additives described above are mixed (kneaded), and this mixture is subjected to molding such as extrusion to obtain a molded body having a desired shape.

The sintering temperature in sintering the compact is usually 1300 ° C. or higher, preferably 1400 ° C. or higher. The sintering temperature is usually 1650 ° C. or lower, preferably 1550 ° C. or lower. The rate of temperature increase up to the sintering temperature is not particularly limited, but is usually 1 ° C./hour to 500 ° C./hour. When the molded body contains an additive combustible organic material such as a binder, the sintering process includes a degreasing process for removing it. Degreasing is typically done in a temperature rising stage (eg, a temperature range of 150-400 ° C.) up to the sintering temperature. In the degreasing step, it is preferable to suppress the temperature rising rate as much as possible.

Sintering is usually performed in the air, but may be performed in an inert gas such as nitrogen gas or argon gas, or in a reducing gas such as carbon monoxide gas or hydrogen gas. May be. Moreover, you may sinter in the atmosphere which made the water vapor partial pressure low.

Sintering is usually carried out using a conventional sintering furnace such as a tubular electric furnace, box electric furnace, tunnel furnace, far-infrared furnace, microwave heating furnace, shaft furnace, reflection furnace, rotary furnace, roller hearth furnace, etc. It is. Sintering may be performed batchwise or continuously. Moreover, you may carry out by a stationary type and may carry out by a fluid type.

The time required for the sintering is sufficient as long as the formed body transitions to the aluminum titanate-based sintered body. The amount of the aluminum titanate-based ceramic powder, inorganic oxide powder, etc., the type of the sintering furnace Depending on the sintering temperature, sintering atmosphere, etc., it is usually 10 minutes to 24 hours.

As described above, the target aluminum titanate ceramic sintered body can be obtained. Such an aluminum titanate ceramic sintered body has a shape that substantially maintains the shape of the formed body immediately after the forming. The obtained aluminum titanate-based ceramics sintered body can be processed into a desired shape by grinding or the like.

The aluminum titanate ceramic sintered body of the present invention is preferably a porous sintered body having a porosity of 30 to 60%, more preferably 35 to 55%, and still more preferably 37 to It is 50% and can be suitably used for a diesel particulate filter.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

<Example 1>
Alumina powder (AL-M41, Sumitomo Chemical Co., Ltd.) having an average particle diameter (D50) of 2.3 μm per 100 parts by weight of aluminum magnesium titanate powder (Recotherm, manufactured by Aucera Corporation) having an average particle diameter (D50) of 24 μm. 5 parts by weight was mixed. When the aluminum magnesium titanate powder was represented by the composition formula: Al _{2 (1-x)} Mg _x Ti _{1 + x} O ₅ , the value of x was 0.24. To 100 parts by weight of the total amount of aluminum magnesium titanate powder and alumina powder, 15 parts by weight of a pore-forming agent (Flowsen UF1.5, manufactured by Sumitomo Seika Co., Ltd.) and 3 parts by weight of water are added, and 3 MPa. After uniaxial molding for 60 seconds, sintering was performed at 1450 ° C. for 5 hours to obtain an aluminum magnesium titanate ceramic sintered body.

A master sizer (manufactured by Sysmex Corporation) was used for measuring the particle size of the powder. In addition, the underwater weight M2 (g), the saturated water weight M3 (g) and the dry weight M1 (g) of the sintered body are measured by the Archimedes method based on JIS R1634, and the porosity is calculated by the following formula. Calculated.
Porosity (%) = 100 × (M3-M1) / (M3-M2)

Further, the linear shrinkage rate was calculated by measuring the side length of a molded body obtained by compression-molding aluminum titanate ceramic powder into a certain shape, and measuring the side length after sintering the molded body.

The thermal expansion coefficient (K ⁻¹ ) of the aluminum magnesium titanate ceramic sintered body is about 4 mm × about 4 mm × about 10 mm test piece from the aluminum titanate ceramic sintered body obtained in each example and each comparative example. Using this thermomechanical analyzer (TMA6300, manufactured by SII NanoTechnology Co., Ltd.), the temperature was increased from room temperature to 1000 ° C. at a rate of 600 ° C./h, and the thermal expansion curve of the above-mentioned prism sample was obtained. Measurement was performed, and the expansion coefficient in the temperature range between room temperature and 1000 ° C. was calculated.

<Example 2>
An aluminum magnesium titanate ceramic sintered body was obtained in the same manner as in Example 1 except that 10 parts by weight of alumina powder was mixed with 100 parts by weight of aluminum magnesium titanate powder.

<Example 3>
Example except that 5 parts by weight of alumina powder (AM-29B, manufactured by Sumitomo Chemical Co., Ltd.) having an average particle diameter (D50) of 6.6 μm as alumina powder was mixed with 100 parts by weight of aluminum magnesium titanate powder. In the same manner as in Example 1, an aluminum magnesium titanate ceramic sintered body was obtained.

<Example 4>
Example 1 except that 5 parts by weight of alumina powder (AluC, manufactured by Nippon Aerosil Co., Ltd.) having an average particle diameter (D50) of 0.01 μm as alumina powder was mixed with 100 parts by weight of aluminum magnesium titanate powder. Similarly, an aluminum magnesium titanate ceramic sintered body was obtained.

<Example 5>
Example 1 except that 5 parts by weight of alumina powder (AT-50, manufactured by Sumitomo Chemical Co., Ltd.) having an average particle diameter (D50) of 16 μm as alumina powder was mixed with 100 parts by weight of aluminum magnesium titanate powder. Similarly, an aluminum magnesium titanate ceramic sintered body was obtained.

<Comparative Example 1>
An aluminum magnesium titanate ceramic sintered body was obtained in the same manner as in Example 1 except that the alumina powder was not mixed.

Table 1 shows the results of Examples 1 to 5 and Comparative Example 1.

<Example 6>
Alumina powder (AL-M41, Sumitomo Chemical Co., Ltd.) having an average particle diameter (D50) of 2.3 μm per 100 parts by weight of aluminum magnesium titanate powder (Recotherm, manufactured by Aucera Corporation) having an average particle diameter (D50) of 24 μm. 5 parts by weight was mixed. When the aluminum magnesium titanate powder was represented by the composition formula: Al _{2 (1-x)} Mg _x Ti _{1 + x} O ₅ , the value of x was 0.24. For 100 parts by weight of the total amount of aluminum magnesium titanate powder and alumina powder, 10 parts by weight of polyethylene particles (D50 = 2.3 μm) as a pore-forming agent, 7.5 parts by weight of methyl cellulose as a binder, and surface activity 9.3 parts by weight of polyoxyethylene alkylene alkyl ether as an agent, 0.8 part by weight of glycerin as a lubricant are added to form a raw material, and 38 parts by weight of water is added as a dispersion medium. A honeycomb formed body was prepared by preparing and extruding the kneaded material. The honeycomb formed body was dried at 100 ° C. for 12 hours with a dryer, and after a degreasing process for removing the binder at 400 ° C. in an air atmosphere in a box-type electric furnace, the speed was 300 ° C./h up to 1450 ° C. And sintered at 1450 ° C. for 5 hours to obtain a honeycomb sintered body of aluminum magnesium titanate ceramics.

<Example 7>
A honeycomb sintered body of an aluminum magnesium titanate ceramic ceramic was obtained in the same manner as in Example 6 except that 10 parts by weight of alumina powder was mixed with 100 parts by weight of aluminum magnesium titanate powder.

<Example 8>
Example except that alumina powder (AES-11, manufactured by Sumitomo Chemical Co., Ltd.) having an average particle diameter (D50) of 0.4 μm as alumina powder was mixed with 10 parts by weight with respect to 100 parts by weight of aluminum magnesium titanate powder. In the same manner as in Example 6, a honeycomb sintered body of aluminum magnesium titanate ceramics was obtained.

<Example 9>
Example except that 20 parts by weight of alumina powder (AES-11, manufactured by Sumitomo Chemical Co., Ltd.) having an average particle diameter (D50) of 0.4 μm as alumina powder was mixed with 100 parts by weight of aluminum magnesium titanate powder. In the same manner as in Example 6, a honeycomb sintered body of aluminum magnesium titanate ceramics was obtained.

<Comparative example 2>
A honeycomb sintered body of aluminum magnesium titanate ceramics was obtained in the same manner as in Example 6 except that the alumina powder was not mixed.

<Comparative Example 3>
Example except that alumina powder (AES-11, manufactured by Sumitomo Chemical Co., Ltd.) having an average particle diameter (D50) of 0.4 μm as alumina powder was mixed with 30 parts by weight with respect to 100 parts by weight of aluminum magnesium titanate powder. In the same manner as in Example 6, a honeycomb sintered body of aluminum magnesium titanate ceramics was obtained.

Table 2 summarizes the evaluation results of the honeycomb sintered bodies obtained in Examples 6 to 9 and Comparative Examples 2 and 3. The evaluation of the crushing strength was carried out by the following procedure by preparing a sintered body under the same conditions as the honeycomb formed body except that the clay was extruded into a tube shape having a diameter of 5 mm and an inner diameter of 2 mm. The tube-shaped sintered body is provided in a pressure drive device having a movable moving indenter, and the indenter is lowered at a constant speed, thereby lowering the tube-shaped sintered body at a constant speed downward. An increasing load was applied, and the crushing strength of the tubular sintered body in the extrusion direction was measured by a load cell apparatus.

Compared with Comparative Example 2 in which no alumina powder was added, the honeycomb sintered bodies of Examples 6 to 9 to which 25 parts by weight or less of alumina particles were added remained substantially constant and the shrinkage rate was reduced by 1 to 3%, resulting in thermal expansion. The rate was small and the mechanical strength was improved. On the other hand, the honeycomb sintered body of Comparative Example 3 in which alumina particles were excessively added in an amount of 30 parts by weight had a porosity lower by 5% or more than that of Comparative Example 2 to which no alumina powder was added, and the inherent high thermal expansion coefficient of alumina. As a result, the thermal expansion coefficient of the honeycomb sintered body tended to increase.

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.

The aluminum titanate-based ceramic sintered body obtained by the present invention is used, for example, for sintering furnace jigs such as crucibles, setters, mortars, and furnace materials; exhaust gas purification of internal combustion engines such as diesel engines and gasoline engines. Exhaust gas filter, filter carrier used for filtering food and drink such as beer, selective permeation filter for selectively permeating gas components generated during petroleum refining, such as carbon monoxide, carbon dioxide, nitrogen, oxygen, etc. The ceramic filter can be suitably applied to electronic parts such as substrates and capacitors. In particular, when used as a ceramic filter, the aluminum titanate-based ceramic sintered body of the present invention has a larger porosity than the conventional one, so that the filter performance (exhaust gas treatment capacity, high soot deposition capacity, pressure loss) Etc.).

Claims (9)

Aluminum titanate-based ceramics sintered by mixing 2 to 25 parts by weight of inorganic oxide powder with 100 parts by weight of aluminum titanate-based ceramics powder, molding the resulting mixture, and sintering the resulting molded body Body manufacturing method. The method according to claim 1, wherein the inorganic oxide is alumina. The method according to claim 1 or 2, wherein the average particle diameter of the aluminum titanate ceramic powder is 5 to 50 µm. The method according to any one of claims 1 to 3, wherein the inorganic oxide powder has an average particle size of 0.1 to 15 µm. The method according to any one of claims 1 to 4, wherein the ratio of the average particle diameter of the aluminum titanate-based ceramic powder to the average particle diameter of the inorganic oxide powder is 3 or more. The method according to any one of claims 1 to 5, wherein the sintering temperature is 1300 to 1650 ° C. Aluminum titanate obtained by mixing 2 to 25 parts by weight of inorganic oxide powder with 100 parts by weight of aluminum titanate ceramic powder, molding the resulting mixture, and sintering the resulting molded body Ceramic sintered body. The aluminum titanate-based ceramic sintered body according to claim 7, which is a porous sintered body having a porosity of 30 to 60%. A diesel particulate filter comprising the aluminum titanate-based ceramic sintered body according to claim 7 or 8.