JPH0672062B2 - Method for producing composite sintered body composed of carbide and complex oxide - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a composite sintered body composed of a carbide and a composite oxide, which is used as a cemented carbide tool, a high temperature structural material or various functional materials.

2. Description of the Related Art Conventionally, a composite sintered body composed of a carbide and a composite oxide is first prepared by mixing a carbon powder or solid carbon with a metal or an oxide thereof and reacting the mixture at a high temperature with a carbide powder and a solid phase method or the like. It was manufactured by thoroughly mixing the synthesized composite oxide powders and then sintering them under high temperature and high pressure.

Problems to be Solved by the Invention Since the manufacturing process of this method is long and complicated, impurities are easily mixed in, and energy consumption is very large.

Means for Solving the Problems A feature of the present invention is that it comprises two or more kinds of reducing metal powders (which become complex oxides after the reaction), oxides (which become carbides after the reaction), and carbon. Under pressure, the molded body of the mixture is ignited partly of the molded body to ignite a combustion reaction, and the chemical reaction synthesizes particles of carbides and complex oxides. The purpose is to sinter the particles to obtain a composite sintered body composed of a carbide and a composite oxide.

Effect According to the present invention, a composite sintered body composed of a high-density carbide and a composite oxide can be easily obtained by simply igniting the molded body under pressure. Therefore, compared with the conventional method for producing a sintered body using powders of carbides and complex oxides, energy saving is extremely high, and the obtained sintered body is also extremely high in purity. Further, according to the manufacturing method of the present invention, a composite sintered body of a carbide and a composite oxide, which has been difficult by the conventional manufacturing method, can be manufactured very easily.

Example 1 As starting materials, aluminum powder having a particle size of 10 μm or less, magnesium powder having a particle size of 70 μm or less, titanium dioxide (TiO ₂ ) powder having an average particle size of 0.5 μm, and carbon black using acetylene as a raw material were used. Was mixed at a molar ratio of 1: 2: 2: 2, and then press-molded into a column having a diameter of 10 mm and a height of 10 mm. The compact was sintered using a uniaxial pressure vacuum hot press using a silicon carbide mold material. Ignition of the molded body was performed by energizing the tungsten filament. Under the conditions of room temperature, vacuum (1 mmHg) atmosphere, and pressure of 0.1 GPa, the ignition heater was energized to start the reaction. When the obtained sintered body was identified by X-ray diffraction, only diffraction lines of titanium carbide and magnesium aluminum spinel were found. The relative density of this sintered body was 91.2%.

The chemical reaction formula of the process is as follows.

Mg + 2Al + 2TiO ₂ + 2C → MgAl ₂ O ₄ + 2TiC As can be seen from this chemical reaction formula, in this reaction,
Based on the reduction of TiO ₂ by Al and Mg, the reduced Ti metal reacts with C to form TiO, and Al and Mg combine through oxygen to form MgAl ₂ O ₄ . Since large reaction heat at this time becomes the sample without heating from the outside to a high temperature (increased to about 2000 ° C.), moreover pressurized since MgAl ₂ O ₄ particles and TiC particles are sintered MgAl ₂ O ₄ -TiC composite sintered body can be obtained.

Example 2 As a starting material, zirconium powder having a particle size of 19 μm or less, silicon powder having a particle size of 10 μm or less, titanium oxide powder having an average particle size of 1 μm, and carbon black using acetylene as a raw material were used, and they were used in a ratio of 1: 1: 2: After mixing at a molar ratio of 2, the same process as in Example 1 was carried out. However, in this embodiment, 40
The reaction was started by heating to 0 ° C. When the obtained combustion body was identified by X-ray diffraction, only diffraction lines of titanium carbide and zirconium silicate were found. The relative density of this sintered body was 93.5%.

The chemical reaction formula of this process is Zr + SiO + 2TiO ₂ + 2C → ZrSiO ₄ + 2TiC.

Example 3 As a starting material, titanium powder having a particle size of 10 μm or less, metallic calcium, calcined amorphous silicon dioxide (Carplex CS-5 manufactured by Shionogi Pharmaceutical Co., Ltd.) and carbon black using acetylene as a raw material were used, and they were mixed at 2: 2: After mixing in a molar ratio of 3: 3, the same process as in Example 1 was carried out. However, in this example, the reaction was started by heating to 200 ° C. When the obtained sintered body was identified by X-ray diffraction, only diffraction lines of silicon carbide and calcium titanate were found. The relative density of this sintered body was 87.3%.

Chemical reaction formula of this process is the _{2Ca + 2Ti + 3SiO 3 + 3C} → 2CaTiO 3 + 3SiC.

Example 4 As starting materials, aluminum powder having a particle size of 10 μm or less, titanium powder having a particle size of 10 μm or less, carbon black made of niobium pentoxide (Nb ₂ O ₅ ) and acetylene having an average particle size of 1 μm as raw materials were used. Further, in the embodiment, the average particle diameter is 2 μm.
After mixing aluminum titanate (Al ₂ TiO ₅ ) in a molar ratio of 2: 1: 1: 2: 0.2, the mixture was treated in the same process as in Example 1. When the obtained sintered body was identified by X-ray diffraction, only diffraction lines of niobium carbide and aluminum titanate were found. The relative density of this sintered body was 89.6%.

The chemical reaction formula of this process is 2Al + Ti + Nb ₂ O ₅ + 2C → Al ₂ TiO ₄ + 2NbC.

Aluminum titanate added to the molded body is a chemical reaction control material.

Example 5 As starting materials, aluminum powder having a particle size of 325 mesh or less, iron powder having a particle size of 325 mesh or less, tantalum pentoxide (Ta ₂ O ₅ ) having an average particle size of 1 μm, and carbon black made of acetylene as raw materials were used. In the example, the average particle size is 0.5
μm aluminum oxide powder was added. 5:10:
After mixing at a molar ratio of 4: 8: 0.4, the same process as in Example 1 was carried out. When the obtained sintered body was identified by X-ray diffraction, only diffraction lines of tantalum carbide, iron aluminum oxide and aluminum oxide added as a control material for chemical reaction were seen. The relative density of this sintered body was 93.7%.

The chemical reaction formula of this process is 10Al + 5Fe + 4Ta ₂ O ₅ + 8C → 5FeAl ₂ O ₄ + 8TaC.

Example 6 As starting materials, magnesium powder having a particle size of 200 mesh or less, titanium powder having a particle size of 400 mesh or less, tungsten dioxide (WO ₂ ) having a particle size of 10 μm or less, and carbon black made of acetylene were used. They were mixed in a molar ratio of 2: 2: 3: 3 and then treated in the same process as in Example 1.
When the obtained sintered body was identified by X-ray diffraction, only diffraction lines of α-type tungsten carbide and magnesium titanate were found. The relative density of this sintered body is 88.7.
%Met.

Chemical reaction formula of this process is the _{2Mg + 2Ti + 3WO 3 + 3C} → 2MgTiO 3 + 3WC.

EFFECTS OF THE INVENTION According to the production method of the present invention, in a state in which pressure is applied to a molded body of a mixture of two or more kinds of reducing powders, oxides and carbon, ignition is ignited on a part of the molded body. Then, a composite sintered body composed of a carbide and a composite oxide can be produced only by causing a combustion reaction. Therefore, according to the production method of the present invention, a process comprising a carbide and a complex oxide is performed at a much lower temperature as compared with a conventional production method using a carbide powder and a complex oxide powder, that is, with a very small energy. A sintered body can be produced. Moreover, the obtained sintered body has the same characteristics as the sintered body produced by the conventional manufacturing method. Further, according to the manufacturing method of the present invention, it is also possible to extremely easily manufacture a composite sintered body composed of a carbide and a composite oxide, which has been difficult with the conventional manufacturing method.

Claims (6)

[Claims] 1. A molded body composed of two or more kinds of reducing metal powder, an oxide powder and carbon is ignited on a part of the molded body under a pressurized condition to start a combustion process, and then a metal is formed. A method for producing a composite sintered body composed of a carbide and a composite oxide, wherein the reaction between a powder and an oxide powder and carbon and the sintering of the generated carbide and the composite oxide proceed by heat generated as a result of a combustion process. 2. A combustion process is started by igniting a compact consisting of two or more kinds of reducing metal powder, oxide powder and carbon under pressure and heating conditions. A method for producing a composite sintered body comprising a carbide and a composite oxide according to claim 1. 3. The carbide according to claim 1, wherein at least one of the two or more reducing metal powders is selected from aluminum powder, magnesium powder, zirconium powder, and titanium powder. And a method for producing a composite sintered body comprising a composite oxide. 4. The carbide and complex oxide according to claim 1, wherein the oxide powder is an oxide of any element selected from groups 4, 5b and 6b of the periodic table. Method for manufacturing composite sintered body. 5. A molded body comprising two or more kinds of reducing metal powders, an oxide powder, carbon, and an oxide powder that does not participate in the reaction is formed into a part of the molded body under pressure. The heat generated as a result of the combustion process is ignited to start the combustion process, and the subsequent reaction between the metal powder, the oxide powder and carbon, and the sintering of the generated carbide and the complex oxide with the oxide not involved in the reaction. A method for producing a composite sintered body comprising a carbide and a composite oxide, which is advanced by. 6. The method for producing a composite sintered body composed of a carbide and an oxide according to claim 5, wherein the oxide powder not involved in the reaction is an oxide of a reducing metal powder.