JPH0774104B2 - Method for manufacturing multifunctional ceramics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a method for producing a multifunctional ceramic.

(Prior Art) In recent years, fine ceramics such as Si ₃ N ₄ , SiC, and AlN have attracted attention as new materials. Since these materials mainly have excellent mechanical properties at high temperatures, applications focusing on such properties have been considered, and development aimed at high-strength, high-wear resistant materials has been made. However, due to the diversification of applications and improvement of the technical level, there has been a demand for a composite functional material having other functions at the same time while maintaining the characteristics originally possessed by these ceramics. Additional functions include numerous physical functions such as conductivity, lubricity, magnetism, corrosion resistance, thermal conductivity, etc.
It has a chemical function.

From such a demand, various composite functional materials have been conventionally proposed. However, these composite functional materials are ceramics to which substances having other functions or characteristics are simply added. Therefore, it is difficult to compound such a material in manufacturing, and a relatively large amount of additive composition is selected to exert an additional function. Has a problem that it is difficult to obtain a new material having the intended purpose.

(Problems to be Solved by the Invention) The present invention is to establish a technique of a composite technology for retaining two or more functions in a composite material obtained by conventional mixing and the like, and to characterize the manufactured material itself. However, by solving these problems, a multifunctional ceramic having the characteristics of silicon nitride-based or aluminum nitride-based ceramics and the additional function of a specific coating material (powdered material) can be obtained. It is intended to provide a method that can be easily manufactured.

(Means for Solving Problems) In the first invention of the present application, a granule containing a ceramic powder and a powder substance finer than that of the granule are mixed and tumbled to form a surface of the granule. Granules containing the ceramic powder, comprising: uniformly coating with a powder substance and wrapping the powder substance; and compressing the powder substance-coated granules to form an aggregate, and then sintering the compact. Is one kind selected from silicon nitride, a rare earth oxide or a compound that produces the rare earth oxide by heat treatment, Al ₂ O ₃ , AlN, MgO, TiO ₂ and a compound that produces those oxides by heat treatment. Alternatively, the powder substance is different from the ceramic in that Al, B, S
The method for producing a multifunctional ceramic is characterized by comprising at least one ceramic selected from oxides of i and Ti, carbides, nitrides, borides of Al, Si, and Ti. Examples of the compound used here include metal nitrates and metal carbonates.

A second aspect of the present invention is to mix a granule containing ceramic powder with a fine powder substance as compared with the granule and roll the mixture to uniformly coat the surface of the granule with the powder substance. A step of compressing the powder substance-coated granules to form an aggregate, and then sintering the compact, wherein the granules containing the ceramic powder are aluminum nitride and a rare earth oxide, 1 selected from alkaline earth oxides and compounds that form these oxides by heat treatment
And a mixture of two or more kinds, the powder substance is different from the ceramic, and is Al, B, S.
The method for producing a multifunctional ceramic is characterized by comprising at least one ceramic selected from oxides of i and Ti, carbides, nitrides, borides of Al, Si, and Ti. Examples of the compound used here include metal nitrates and metal carbonates.

In the first and second inventions of the present application, the mixing ratio of the granules containing the ceramic powder and the powder substance is preferably in the range of 20 to 40% by volume of the powder substance with respect to the granules. The reason for this is that the blending amount of the powder substance is 20
When the content is less than the volume%, it becomes difficult to sufficiently impart the intended function of the powder substance to the produced multifunctional ceramic. On the other hand, if the content of the powder substance exceeds 40% by volume, the excellent properties of the ceramic itself may be impaired.

In the first and second inventions of the present application, in order to form the granules, for example, a method of adding a solvent, a binder, a surfactant or the like to a substance containing the ceramic powder to form a slurry and treating the slurry with a spray dryer is used. Can be adopted.

In the first and second inventions of the present application, the step of rolling the granular material containing the ceramic powder and the powder substance is performed until the surface of the granular substance is completely covered with the powder substance and the granular substance is wrapped in the granular substance. To do. Therefore, it is desirable that the average particle size of the granules is 10 μm or more, and the average particle size of the powder substance is smaller than 1/10 of the diameter of the granules.

In the first and second inventions of the present application, it is desirable that compression molding of the powder substance-coated granules is performed at a pressure of 500 to 2000 kg / cm ² . The reason for this is that if the molding pressure is less than 500 kg / cm ² , the molding density will be low and the sintering density may not be increased. On the other hand, the molding pressure is 2000 kg / cm ²
If it exceeds, the molded body may be excessively strained and deformed after sintering.

In the first and second inventions of the present application, the sintering temperature of the molded body is selected in accordance with the types of granules and powder substances to be combined and conditions under which the granules and powder substances do not react. It may be carried out in the range of 1300 to 2200 ° C.

(Operation) According to the first invention of the present application, the granules containing the ceramic powder and the powder substance finer than the granules are mixed and rolled to make the surface of the granules uniform by the powder substance. And a step of compressing the powder substance-coated granules to form an agglomerate and sintering the compact, and silicon nitride as a granule containing the ceramic powder, Rare earth oxides or compounds that form the rare earth oxides by heat treatment, and one or more mixtures selected from Al ₂ O ₃ , AlN, MgO, TiO ₂ and compounds that form these oxides by heat treatment. The material of silicon nitride and its sintering aid consisting of and is selected, which is finer than the above-mentioned granules as the powder substance, and is different from the above-mentioned ceramics, oxides, carbides, and nitrides of Al, B, Si, and Ti. , Al, S
By selecting a material composed of at least one ceramic selected from borides of i and Ti, it is possible to obtain the excellent wear resistance of a silicon nitride ceramic that is dense and is formed by good self-sintering of the granules. , A multi-functional ceramic with additional functions such as self-lubricating, high thermal conductivity, electrical conductivity added by a powdered material consisting of a specific ceramic which is uniformly dispersed and integrated in a silicon nitride particle Can be easily manufactured. Moreover, since the powder substance uniformly dispersed and integrated in the mesh form is made of a specific ceramic, it is possible to manufacture a multifunctional ceramic having excellent oxidation resistance and heat resistance in the mesh part.

According to the second invention of the present application, a granule containing ceramic powder and a powder substance finer than the granule are mixed,
A step of rolling to uniformly coat the surface of the granules with the powder substance and wrapping, and a step of compressing the powder substance-coated granules to form an agglomerate and then sintering the compact. And aluminum nitride as a granule containing the ceramic powder, and one or a mixture of two or more selected from rare earth oxides, alkaline earth oxides, and compounds that generate these oxides by heat treatment. A material of aluminum nitride and its sintering aid is selected, which is finer than the above-mentioned granules as the powder substance and different from the above-mentioned ceramics, oxides, carbides of Al, B, Si and Ti,
At least 1 selected from nitrides, borides of Al, Si and Ti
By selecting a material consisting of a variety of ceramics,
Dense and excellent thermal conductivity and wear resistance of aluminum nitride ceramics formed by good self-sintering of the above granules, and added by powder material uniformly dispersed and integrated in aluminum nitride particles in a mesh A multifunctional ceramic having a specified function such as self-lubrication can be easily manufactured. Moreover, since the powder substance uniformly dispersed and integrated in the mesh form is made of a specific ceramic, it is possible to manufacture a multifunctional ceramic having excellent oxidation resistance and heat resistance in the mesh part.

(Examples of the Invention) Examples of the present invention will be described in detail below.

Example 1 First, 90% by weight of Si ₃ N ₄ powder having an average particle size of 0.85 μm, 2% by weight of Al ₂ O ₃ powder having an average particle size of 0.95 μm, and Y having an average particle size of 0.90 μm.
₂ O ₃ powder 5% by weight, average particle diameter 0.85μm of AlN powder 2 wt%
Also, a solvent and an interfacial modifier are added to a mixed powder consisting of 1% by weight of TiO ₂ powder having an average particle size of 0.70 μm to make a slurry, and the slurry is used to produce Si ₃ N ₄ type granules having an average particle size of 100 μm. did.

Next, 80% by weight of the Si ₃ N ₄ system granules and an average particle size of 1.2 μm
20% by weight of the boron nitride (BN) powder was stored in a pot, which was rolled for 30 minutes by rotation to cover the surface of the granule with the BN powder and wrap it. Subsequently, the BN powder-coated granules were molded at a pressure of 1000 kg / cm ² into a size of 30 mm × 30 mm × 6 mm, the molded body was degreased at 700 ° C, and further sintered in a nitrogen atmosphere at 1800 ° C. To produce a sintered body.

The obtained sintered body had a densification degree of 96% and BN of Si ₃ N.
It had a structure in which the ₄ type granules were dispersed and integrated in a mesh shape. In addition, it was confirmed that this sintered body is a new material having a composite function that combines the wear resistance of Si ₃ N ₄ ceramics and the self-lubricating property of BN.

Example 2 As in the case of Example 1, molding with dimensions of 30 mm × 30 mm × 6 mm was performed.
After degreasing at 00 ℃, set it on a carbon mold and set it to 1700
A sintered body was manufactured by hot pressing at 300 ° C. and a pressure of 300 kg / cm ² .

The obtained sintered body has a densification degree of about 100% and S
It was confirmed that the sliding member has a composite function that combines the wear resistance of i ₃ N ₄ ceramics and the self-lubricating property of BN, and that it exhibits good characteristics.

Example 3 80% by weight of Si ₃ N ₄ type granules produced in the above-mentioned Example 1 and 20% by weight of aluminum oxide (Al ₂ O ₃ ) powder having an average particle size of 0.65 μm were placed in a pot, and they were rotated. Then, the surface of the granules was covered with Al ₂ O ₃ powder and wrapped. Subsequently, the Al ₂ O ₃ powder-coated granules were mixed at a pressure of 1000 kg / cm ²
After molding to a size of 0 mm × 30 mm × 6 mm, this molded body is 700
Degreasing was performed at ℃, and further sintered in a nitrogen atmosphere at 1780 ℃ to produce a sintered body.

The obtained sintered body had a densification degree of 98% and Al ₂ O ₃ was S
It had a SIALON structure dispersed and integrated in a mesh with the i ₃ N ₄ system granules. Further, when this sintered body was subjected to an oxidation resistance test at 1200 ° C. in air, it was confirmed that it exhibited extremely excellent oxidation resistance characteristics.

Example 4 First, 95% by weight of AlN powder having an average particle size of 0.85 μm and an average particle size
A solvent and an interfacial modifier were added to a mixed powder of 0.90 μm of Y ₂ O ₃ 5% by weight to prepare a slurry, and this slurry was spray-dried to prepare AlN-based granules having an average particle size of 100 μm.

Next, 80% by weight of the above AlN-based granules and 20% by weight of boron nitride (BN) powder with an average particle size of 1.2 μm were placed in a pot, and they were rolled for 30 minutes by rotation to coat the surface of the granules with BN powder. I wrapped it up. Then, the BN powder-coated granules were molded into a size of 30 mm × 30 mm × 6 mm at a pressure of 1000 Kg / cm ² , the molded body was degreased at 700 ° C, and further sintered in a nitrogen atmosphere at 1800 ° C. A sintered body was manufactured.

The obtained sintered body had a densification degree of 96% and BN was AlN.
It had a structure in which it was dispersed and integrated in a mesh shape with respect to the system granules. In addition, it was confirmed that this sintered body is a new material having a composite function that combines the wear resistance of AlN ceramics and the self-lubricating property of BN.

Example 5 30 mm × 30 mm × manufactured by the same method as in Example 4 above
A compact having a size of 6 mm was degreased at 700 ° C., set in a carbon mold, and hot-pressed at 2000 ° C. and a pressure of 300 Kg / cm ² to produce a sintered compact.

The obtained sintered body has a densification degree of about 100%, and A
It has been confirmed that the sliding member has a composite function that combines the wear resistance of lN ceramics and the self-lubricating property of BN, and that it shows good properties.

Example 6 80% by weight of the AlN-based granules produced in Example 4 and 20% by weight of silicon nitride (Si ₃ N ₄ ) powder having an average particle size of 0.95 μm were placed in a pot and tumbled by rotation. The surface of the granule was covered with Si ₃ N ₄ powder and wrapped. Then this S
i ₃ N ₄ powder coated granules at a pressure of 1000 kg / cm ² 30 mm × 30 mm ×
After molding to a size of 6 mm, degrease this molded body at 700 ° C,
Further, it was sintered in a nitrogen atmosphere at 1780 ° C. to produce a sintered body.

The obtained sintered body had a densification degree of 98% and Si ₃ N ₄ was A
It had a sialon structure that was dispersed and integrated in a mesh with the 1N-based granules. In addition, this sintered body
As a result of an oxidation resistance test at 1200 ° C., it was confirmed that it exhibited extremely excellent oxidation resistance characteristics.

Example 7 80% by weight of the AlN-based granules prepared in the above-mentioned Example 4 and 20% by weight of silicon oxide (SiO ₂ ) powder having an average particle size of 0.1 μm were placed in a pot, and they were tumbled by rotation to make granules. Surface
It was covered with SiO ₂ powder and wrapped. Then this SiO ₂
Powder coated granules at a pressure of 1000 kg / cm ² 30 mm x 30 mm x 6 mm
After being molded into a size of, the molded body was degreased at 700 ° C. and further sintered in a nitrogen atmosphere at 1780 ° C. to manufacture a sintered body.

The obtained sintered body had a densification degree of about 98% and SiO ₂
It had an ALSION structure that was dispersed and integrated in a mesh with the AlN-based granules. In addition, it was confirmed that this sintered body was a special functional material in which an electrically defective conductor portion was formed in a mesh shape.

[Effects of the Invention] As described in detail above, according to the present invention, the properties of a specific ceramic made of silicon nitride or aluminum nitride,
It is possible to provide a method capable of easily manufacturing a multifunctional ceramic having an additional function of a specific coating material (powder material).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeyuki Yonezawa 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Inside the Toshiba Research Institute (72) Inventor Yoshiyuki Onuma Komukai-shiba, Kawasaki-shi, Kanagawa No. 1 in Toshiba Research Institute Co., Ltd. (72) Inventor Toshiaki Mizutani No. 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Inside Toshiba Research Institute Co., Ltd. (56) Reference JP-A-59-97571 (JP, A) ) JP-A-60-46962 (JP, A) JP-A-60-215569 (JP, A) JP-A-54-139620 (JP, A)

Claims (8)

[Claims] 1. A step of mixing a granule containing a ceramic powder and a powder substance finer than the granule, rolling the granule, and uniformly covering the surface of the granule with the powder substance. A step of compressing the powder substance-coated granules to form an agglomerate, and then sintering the compact, wherein the granules containing the ceramic powder are made of silicon nitride, a rare earth oxide, or a heat treatment. A powder that forms the rare earth oxide and one or a mixture of two or more selected from Al ₂ O ₃ , AlN, MgO, TiO ₂ and a compound that forms those oxides by heat treatment; Unlike ceramics, the materials are Al, B, S
A method for producing a multifunctional ceramic, comprising at least one ceramic selected from oxides of i, Ti, carbides, nitrides, borides of Al, Si, and Ti. 2. A granule containing ceramic powder and a powder substance, wherein the powder substance is contained in a volume ratio of 2 to 40 with respect to the granule.
%. The method for producing a multifunctional ceramic according to claim 1, wherein the mixture is mixed and mixed. 3. The molding pressure of the powder substance-coated granules is 500 to 200.
The method for producing a multifunctional ceramic according to claim 1, wherein the value is set to 0 kg / cm ² . 4. The method for producing a multifunctional ceramic according to claim 1, wherein the sintering temperature of the compact is set to 1300 to 2200 ° C. 5. A step of mixing a granule containing ceramic powder and a powder substance finer than that of the granule, rolling the granule, and uniformly covering the surface of the granule with the powder substance. Compressing the powder substance-coated granules to form an aggregate, and then sintering the compact, wherein the granules containing the ceramic powder include aluminum nitride, a rare earth oxide, and an alkaline earth. And a mixture of one or more selected from compounds that generate oxides by heat treatment, wherein the powder substance is different from the above-mentioned ceramic, Al, B, S
A method for producing a multifunctional ceramic, comprising at least one ceramic selected from oxides of i, Ti, carbides, nitrides, borides of Al, Si, and Ti. 6. Granules containing ceramic powder and a powder substance, wherein the powder substance is contained in a volume ratio of 2 to 40 with respect to the granules.
% Compounding and mixing, The manufacturing method of the multifunctional ceramics of Claim 5 characterized by the above-mentioned. 7. The molding pressure of the powder substance-coated granules is 500 to 200.
The method for producing a multifunctional ceramic according to claim 5, wherein the setting is 0 kg / cm ² . 8. The method for producing a multifunctional ceramic according to claim 5, wherein the sintering temperature of the compact is set to 1300 to 2200 ° C.