JPH04130056A - Reaction sintering composite ceramics having low porosity and its production - Google Patents

Abstract

PURPOSE:To obtain composite ceramics having extremely low porosity independently of the blending ratio between metal powder and an inorg. compd. by heating a molded body consisting of metal carbide particles and metal powder in an atmosphere of nitriding gas. CONSTITUTION:A molded body consisting of metal (A) carbide particles and/or whiskers and metal (B) powder is heated in an atmosphere of nitriding gas. By this heating, the metal (B) powder reacts with nitrogen to form metal (B) nitride and then the metal (A) carbide reacts with nitrogen to form metal (A) nitride. At the same time, liberated carbon reacts with the metal (B) powder to form metal (B) carbide particles. The title ceramics having <=15vol.% porosity and <=10mum max. pore diameter and contg. particles and whiskers of the nitrides and carbides of the metals A, B bonded to each other is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a low porosity reactive sintered composite ceramic,
In particular, it relates to dense composite ceramics obtained by reactive sintering.

[Conventional technology]

In general, SiC and 513N4, which have excellent heat resistance, are known as engineering ceramics suitable for structural materials such as engines and turbines. However, Si
Since C and SI3N4 are compounds with strong covalent bonding properties, it is difficult to sinter them alone, and a sintering aid is required to obtain a sintered body. For example, when Si, N, are sintered under normal pressure, Y2O3 and Al2O3 are added and 1800
It is known that a high-density sintered body can be obtained by sintering at a high temperature of °C. However, densification using these sintering aids does not result in a highly precise sintered body because it shrinks by about 15 to 20% during sintering. Therefore, in order to produce the product shape, it is necessary to process the sintered body.

However, since ceramics is a difficult-to-process material, the processing cost accounts for more than 50% of the product cost, making it difficult for users to use.

Therefore, for the purpose of low-cost manufacturing of ceramics, the inventors first heated a molded body made of S1 powder and inorganic compound particles such as SiC in nitrogen, and produced a reaction product of Si3.
By bonding SiC and the like with N4 particles and whiskers, it is possible to manufacture highly accurate and high-strength Si3N4 bonded ceramics with a small dimensional change rate during sintering (Japanese Unexamined Patent Publication No. 146754/1983). Here, in this material, when bonding an inorganic compound such as SiC with 5iaNa particles and whiskers, the method was to bond with Si and N without changing the inorganic compound. Therefore, the shape of the inorganic compound particles does not change during sintering, and Si3N,
was generated in a gas phase reaction and deposited on each inorganic compound particle, resulting in a ceramic with excellent near-net shape properties, with a dimensional change rate of 0.1 to 0.3% during sintering.

However, with this method, the voids in the compact can only be filled with Si3N produced from metal Si. Therefore, in the blending ratio of inorganic compounds and metal Si, when the amount of inorganic compounds increases, Si3N.

It has the disadvantage that the amount of pores decreases, making it porous, and there is a limit to its densification.

Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 63-252973, for the purpose of manufacturing conductive ceramics, as described in Example 2.3.5, 80 wt% TiC, TiC 80wt%, 2rC particles 95
A Si3N4 bonded sintered body is produced by heating a molded body in which wt% is mixed with S1 powder in nitrogen. Because of the method of bonding with Si3N4 with a reaction rate of 20% or less), only porous materials with a porosity of 28 to 30% could be produced.

Furthermore, in Japanese Patent Application Laid-open No. 60-200863, Y2O3
It has been disclosed that silicon nitride ceramics can be densified with rare earth oxides such as .

[Problem to be solved by the invention]

An object of the present invention is to provide a reactive sintered composite ceramic having an unprecedentedly low porosity regardless of the blending ratio of metal powder and inorganic compound, and a method for producing the same.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a low porosity reactive sintered composite ceramic in which metal A nitride or metal carbonitride is interposed at the grain boundary between metal carbide A and metal nitride B, In addition, a low porosity reactive sintered composite ceramic is produced in which a metal nitride is interposed at the grain boundary between the A metal silicide and the B metal nitride, and the grain boundary between the A metal boride and the B metal nitride is also provided. In the present invention, the surface layer of the particles and/or whiskers of the A metal carbide is composed of the A metal nitride or the A metal nitride. Consisting of metal carbonitride,
The A metal nitride, the A metal carbonitride, and the B metal carbide particles are dispersed, and at least a portion of the particles and whiskers are formed of the B metal nitride, the A metal nitride, and the A metal carbonitride. Combined porosity 15vo
1% or less and a maximum pore diameter of 10 μm or less, the surface layer of the A metal silicide particles and/or whiskers is made of A metal nitride,
A metal nitride particles are dispersed therein, and at least some of them are bonded to each other by particles and whiskers made of silicon nitride, B metal nitride, and metal nitride, and have a porosity of 15 vol% or less and a maximum pore diameter. The reactive sintered composite ceramic has a low porosity of 10 μm or less, and the surface layer of the A metal boride particles and/or whiskers is made of a metal nitride, and the A metal nitride particles are dispersed, and at least A part of the product is a low-porosity reactive sintered composite ceramic with a porosity of 15 vol% or less and a maximum pore diameter of 10 μm or less, which is formed by bonding particles and whiskers made of B metal nitride and A metal nitride. .

In the above low porosity reactive sintered composite ceramic, A
Metals include Ti, Zr, VSB, Al, Ta1Cr,
at least one selected from Nb, Hf,
The B metal is made of at least one selected from Si, Ti, Al, and Cr.

In addition, in order to achieve the above objectives, as a method for producing the above-mentioned low porosity reactive sintered composite ceramics. By heating a molded body consisting of A metal carbide particles and/or whiskers and B metal powder in a nitriding gas atmosphere, the B metal powder reacts with nitrogen in the sintered body to generate B metal nitride. And then... A metal carbide is reacted with nitrogen to change into metal nitride or A metal carbonitride, and the free carbon generated at this time is reacted with B metal powder to generate B metal carbide particles, and finally , B metal-based nitride, the sintered body being a reaction product. It was decided to obtain a low porosity reactive sintered composite ceramic having a porosity of 15 vol% or less and a maximum pore diameter of 10 μm or less, which is bonded to each other by particles and whiskers made of A metal nitride or A metal carbonitride, and ．． By heating a molded body consisting of A metal silicide particles and/or whiskers and B metal powder in a nitriding gas atmosphere, the B metal powder reacts with nitrogen in the sintered body to form a B metal nitride. Generate and then. The A metal silicide layer reacts with nitrogen and changes into metal nitride, and the free silicon reacts with B metal powder and nitrogen to generate B metal silicide and silicon nitride particles, and finally , B metal-based nitride, the sintered body being at least partially a reaction product. A: Porosity: 15 vol%, bonded to each other by particles consisting of metal nitride and silicon nitride particles and whiskers
In the following, it was decided to obtain a low porosity reactive sintered composite ceramic with a maximum pore diameter of 10 μm or less, and a molded body consisting of A metal boride particles and/or whiskers and B metal powder was placed in a nitriding gas atmosphere. By heating in the sintered body, the B metal powder reacts with nitrogen in the sintered body to generate B metal-based nitride, and then. The A metal boride layer reacts with nitrogen and changes into A metal nitride, and the sintered body finally consists of at least the reaction products B metal nitride and A metal nitride. Porosity bound to each other by particles and whiskers is 15 vol% or less, maximum pore diameter 10 μ
The aim is to obtain a reactive sintered composite ceramic with a low porosity of m or less.

As mentioned above, in the present invention. A metal with Ti and Z
r, V, B, Al, Ta, Cr, Nb,
Using at least one of Hf and W, 81 and T for B metal.
The above process can be achieved by reacting at least one of A metal carbide, A metal silicide, and A metal boride in a nitriding gas with a low content of I, Al, and Cr. .

In the present invention, the ratio of A metal carbide to A metal nitride or A metal carbonitride is determined by the ratio of A metal carbide to A metal nitride and A metal carbonitride to ((A metal nitride and Metal carbonitride)/A metal carbide) x 100
≧50%, the ratio of A metal silicide to A metal nitride is (A metal nitride/A metal silicide}×100≧50%, and the ratio of A metal boride to A metal nitride is , (A metal nitride/A metal silicide}×l()0≧50%.5
This is because studies have shown that if it is less than 0%, there is no effect on lowering the porosity (Figure 4).

In addition, in the present invention, the molded body of the raw material is . It is preferable to use a molded body in which the blending ratio of metal A carbide, metal silicide A, or metal boride A to metal B powder is in the range of 95:5 wt% to 5:95 wt%. FIG. 1 shows the porosity of sintered bodies produced by varying the composition ratio of B metal carbide, silicide or boride and B metal powder. Tic for metal carbide
, TiS+2 for A metal silicide, T for A metal boride
iB2 was used, and Si was used as the B metal powder. For comparison, the porosity is also shown when SiC particles are used as the metal carbide and Sl is used as the B metal powder. Than this. TiC uses Tic as the A metal carbide, TiSi2 as the A metal silicide, and TiB2 as the A metal boride.

It can be seen that within the range of the blending ratio of TiSi2 and TiB of 5 to 9'5 wt%, the porosity is as small as 8 to 12 vol%. On the other hand, it can be seen that in the case of using SiC, the porosity increases from 12 to 3 Qvol% as the amount of SiC increases, making it a porous body. This is because if the voids are filled only with nitride of Sl, when the amount of Sl decreases, the amount of nitride of Si decreases, resulting in a porous structure.

When TiC is used to react with nitrogen, the 11-necked particles change to produce TiN or T1CN, and the free carbon produced in this nitriding reaction reacts with 81 to produce β-3iC. In addition to Si nitride, materials other than Si nitride are also densified to fill the voids in the molded body. Figure 2 shows the results of transmission electron microscopy. It can be seen that TiN and T1CN were generated on the TiC particles.

Moreover, FIG. 3 shows the results of transmission electron microscopy of β-8iC produced in the sintered body.

The above explanation was given using metal carbide as an example. A Metal silicide instead of metal carbide. Similar results were obtained using A metal boride.

Note that the present invention does not require rare earth oxides such as Y2O3.

In the present invention. The particle size of A metal carbide, A metal silicide, and A metal boride is 100 μm or less, preferably 10 μm.
It is best to set it to the following. because. A Metal carbide. A Metal silicide. This is because when a metal boride A is subjected to a nitrogen reaction, if the particle size is large, the reaction rate is slow and the pore shape of the metal nitride A becomes large. Further, in the present invention, the particle size of the B metal powder is 5 μm or less, preferably 1 μm or less, which is suitable for improving the nitriding rate at low temperatures.

In the present invention, the heat treatment includes a first step: a step of nitriding the B metal powder in a nitride gas (nitrogen, ammonia, etc.) atmosphere below the melting point of the B metal, and a second step: a temperature at which the metal carbide reacts thereafter. The purpose is achieved by performing two steps:

This is because it has been found through experiments that if the B metal is heated above its melting point before nitriding is completed, the B metal oozes out and a large amount of alloy with the metal carbide is formed, causing shrinkage and cracking. After the nitridation of the B metal is completed, a reaction rate of 50% or more can be achieved by heating the A metal carbide to a temperature at which it reacts with the nitride gas (nitrogen, ammonia, etc.).

In the present invention, A metal carbide. You may use a mixture of A metal silicide and A metal boride.

There is no particular problem in reducing porosity. but. A
Metal carbide, A metal silicide. When comparing A metal borides, A metal carbides are particularly effective in reducing porosity.

In the present invention, nitrogen reacts with the oxide film on the surface of A metal carbide, A metal silicide, A metal boride, and B metal powder,
Some oxynitrides and oxycarbides may be synthesized, but this does not affect the properties.

In the present invention, the nitride gas atmosphere can be used at normal pressure. However, from reduced pressure (-3 Torr~) to increased pressure (~20
It is also possible under 0.00 atm).

It is not a process that can only be done under pressure.

Therefore, no equipment such as a hot press is required.

In the present invention, the reason why the pore size of the sintered body is set to 10 μm or less is that the maximum pore size becomes a starting point for fracture and causes a decrease in strength. Also, when used as a sliding material, it is better to have uniform and small pore shapes. Because it turned out to be excellent.

It is also possible to impregnate resin, particles, oil, solid lubricant, water, metal, etc. into the pores of the composite ceramic sintered body. By impregnating uniform small pores with the above substance, a sliding material with a low coefficient of friction can be obtained.

Various molding methods are selected depending on the shape and required characteristics, such as injection molding, press molding, cast molding, rubber press molding, extrusion molding, and mold powder molding.

Further, it is also possible to obtain various properties by changing the blending ratio between the type of the inorganic compound and the Sl-based nitride. For example, if a conductive inorganic compound is used, a ceramic composite having conductivity can be obtained.

[Effect]

The particles and/or whiskers of the metal carbide, A metal silicide, and octametal boride change to A metal nitride, etc., and the sintered body becomes B metal nitride. By using ceramics that are bonded together by metal nitrides or the like, a low porosity reactive sintered composite ceramic can be obtained.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

Example I TiC powder with an average particle size of 50 μm and B as metal carbide
7 parts by weight of a wax-based binder was added to a mixed powder of Si powder having an average particle size of 1 μm as a metal powder, kneaded in a kneader, and then ground to obtain a raw material for molding. Next, a molded body having a diameter of 50 mm and a thickness of 10 mm was produced using a mold. After removing the wax content of the compact, 81 powder was nitrided from 1100°C to 1350°C at 4°C/h in nitrogen gas, and then 15
Heat treatment was performed at 00°C for 5 hours. The results of measuring the porosity of the obtained sintered body are shown in FIG.

For comparison, the porosity of the sintered body obtained by molding and sintering in the same manner using S1 powder with an average particle size of 5 μm as the A metal carbide and 81 powder with an average particle size of 1 μm as the B metal powder was also Shown in Figure 1. Than this. It can be seen that the A metal carbide using TiC has a small 8 to 12 vol% regardless of the TiC blending ratio. On the other hand, Si in Δmetal carbide
It can be seen that in the case of using C, the porosity increases from 12 to 3 Q vol% as SiC increases, making it a porous body. This is because when the amount of Sl decreases in a cage whose voids are filled only with Si nitride, the amount of S] nitride decreases, resulting in a porous structure.

When TiC is used to react with nitrogen as in the present invention, 110 particles produce TiN or T1CN, and β-3iC produced by the reaction of free carbon produced in this nitridation reaction with Si is seen. , Sl nitrides are also densified to fill the voids in the compact. Furthermore, on TIC particles that have not completely reacted with nitrogen, Ti
N and T1CN were generated. Figure 2 shows the results of transmission electron microscopy. Furthermore, FIG. 3 shows the results of transmission electron microscopy of βSiC produced in the sintered body. Here, the composition was Si/TiC=40/60 wt%, and the reaction rate of TiC was 65 to 75%.

Note that FIG. 5 shows an enlarged schematic diagram of the sintered body obtained above.

The composite ceramic of the present invention is. It was found that the pore shape was small, 5 μm or less, regardless of the blending ratio of metal carbide A and metal powder B, whereas in the comparative material, the pore shape became larger, 30 μm or more, as the amount of metal carbide increased.

In the composite ceramic of the present invention, Si of the B metal powder
The nitrides produced from the powder were α and β type silicon nitride particles and whiskers.

The dimensional change rate of the composite ceramic of the present invention during sintering expands from 0.2 to 0.7% as the A metal carbide increases, but this value is 1/100 to 1/30 of the pressureless sintered material. It was found that it has excellent precision sinterability.

Example 2 In the same manner as in Example 1, ZrC, νC, V2C1B, C, A1. C
.

TaCXTa2c, Cr3C2, Cr7C3, NbC
% 1lfc and molded and heated in the same way. A Metal nitride. It was found that A metal carbonitride and β-3iC were generated and filled the pores. The porosity of the sintered bodies is 7 to 13 vol%.
A reactive sintered composite ceramic with a small pore shape of 5 μm or less was obtained.

Example 3 In the same manner as in Example 1, Ti, Al, and Cr with an average particle size of 1 μm were used as the B metal powder, and AIC powder with an average particle size of 100 μm was used as the A metal carbide. After nitriding the B metal powder below the melting point of AI
As a result of heating in the temperature range where C powder nitrides, both B
In addition to metal nitrides, A metal nitrides. It was found that A metal carbonitride and βSiC were generated and filled the pores.

The porosity of the sintered bodies is 6 to 14v.

1%, and a reactive sintered composite ceramic with a small pore shape of 5 μm or less was obtained.

Example 4 In place of the TiC particles in Example 1, TiC whiskers having a length of 50 μm and an aspect ratio of 50 were used as raw materials, and molded and sintered in the same manner as before, and a test was conducted. As a result, a low porosity sintered body was obtained as in Example 1, and a low porosity reactive sintered composite ceramic in which TiC whiskers were dispersed was obtained.

Example 5 TIC powder with an average particle size of 10 μm as A metal carbide and B
7 parts by weight of a wax-based binder was added to a mixed powder of 81 powder (TiC: Si = 40: 60 wt%) with an average particle size of 0.5 μm as a metal powder, kneaded in a mixer, and then crushed to form a raw material for molding. did.

Next, a molded body having a diameter of 50 mm and a thickness of 10 mm was produced using a mold. After removing the wax from the molded body, TiC
In order to change the reaction rate between the powder and nitrogen, the powder was heated at various temperatures to produce samples with reaction rates ranging from 0% to 100%. However, the S1 powder was almost completely converted into silicon nitride. The porosity of the obtained sample is shown in FIG. From this figure, the reaction rate is 0
% to 40%, the porosity is not reduced so much,
It can be seen that when the reaction rate is 50% or more, the porosity is reduced. The reason for this is that, for example, when the 11-hole particles react with nitrogen and change into TiN or T1CN and are generated, the sintered body initially expands, so that it is not effective in reducing the porosity.

This is because when the reaction rate becomes 50% or more, the expansion phenomenon disappears, which is effective in reducing the porosity.

When the TiC of this example is reacted with nitrogen, TiC particles change to TiN or T1CN and are produced.
β-3iC particles produced by the reaction of 81 with the free carbon produced in this nitriding reaction can be seen, and particles other than Si nitride are densified to fill the voids in the compact. This shows that nitriding the 110 particles is effective in lowering the porosity.

here. Results similar to those shown in FIG. 4 were obtained even when A metal silicide and A metal boride were used instead of A metal carbide.

Example 6 13 parts by weight of a wax-based binder was added to a mixed powder of Ti5iz powder with an average particle size of 2 μm as metal silicide A and Si powder with an average particle size of 0.4 μm as metal powder B, and the mixture was kneaded with a kneader. It was crushed and used as a molding raw material. Next, a molded article having a diameter of 10 mm and a thickness of 50 mm was produced using an injection molding machine. After removing the wax content of the molded product, 1
After nitriding Si at 200°C, heat treatment was performed at 1300°C.

The results of measuring the porosity of the obtained sintered body are shown in FIG. From this, regardless of the blending ratio of TiSi□, 7 to 14vo
It can be seen that it is as small as 1%.

When 7iSi2 is used to react with nitrogen as in the present invention, TiS+2 particles produce TiN, and silicon nitride produced by the reaction of free S1 produced in this nitriding reaction with nitrogen is seen, and metal S1 Materials other than nitrides are also densified to fill the voids in the molded body. Furthermore, TiN was generated on the TlSi2 particles that had not completely reacted with nitrogen.

Here, the reaction rate of TiSi2 was 61 to 87%.

The dimensional change rate during sintering of the composite ceramic of the present invention is Tl
It expands from 0.4 to 1.2% as the number of 512 increases, but
This value was 1/30 to 1/10 of that of the pressureless sintered material, and it was found that the material had excellent precision sinterability.

Example 7 Tl82 powder with an average particle size of 2 μm and B as metal boride
2 parts by weight of PVB binder was added to a mixed powder of A1 powder having an average particle size of 0.5 μm as a metal powder, mixed in a pot mill, and dried to obtain a raw material for molding. Next, use a mold to make a diameter 4
A molded body having a diameter of 0 mm and a thickness of 10 mm was produced. After removing the binder from the molded body, AI was nitrided at 600°C in nitrogen gas, and then heated to 1500°C. The results of measuring the porosity of the obtained sintered body are shown in FIG. From this, it can be seen that when TiB is used as the metal boride A, the amount is as small as 8 to 1 vol %, regardless of the blending ratio of TlB2.

When TlB2 is used to react with nitrogen as in the present invention, the TlB2 particles generate TiN and are densified to fill the voids in the molded body with materials other than Si nitride. Furthermore, TiN was generated on the T]B2 particles that had not completely reacted with nitrogen. Here, the reaction rate of TlB2 was 86 to 93%.

The dimensional change rate during sintering of the composite ceramic of the present invention is Ti
As B2 increases, the material expands by 0.5 to 1.3%, but this value is 1/20 from 1150 of the pressureless sintered material, indicating that it has excellent precision sinterability.

Example 8 70 parts by weight of metal Si powder with an average particle size of 0.9 μm and 30 parts by weight of 2rC powder with an average particle size of 1 μm were mixed with methanol in a pot mill, dried, and then 9 parts by weight of polyethylene wax was added. The mixture was kneaded at 150°C for 5 hours using a pressure kneader.

Then, the mixture was pulverized at 150℃ and 1000kg/cm.
It was molded into a guide rail shape under the following conditions. After removing the wax content of the molded product, the first step is to heat it to 1380°C in nitrogen gas.
In the second step, the composite ceramic was heat-treated to 1550° C. in nitrogen gas to obtain a composite ceramic. The material of the present invention is Zr
Most of the C particles change to nitrides or carbonitrides (reaction rate 70%), and the surface layer of the remaining ZrC particles also changes to nitrides or carbonitrides, and β-3iC changes to 5
vol% was dispersed, and silicon nitride was produced. The sintered body had a porosity of 3 vol% and a pore diameter of 2 μm or less.

The sliding surface was ground with a grindstone, and the surface roughness of the sliding surface was set to 0.1 μm as a ten-point average roughness. Then, it was impregnated with fluorine oil having a viscosity of 400 centipoise using an autoclave. For evaluation, a test was conducted by incorporating it into a magnetic disk drive. S[l5440C was used for the bearing. The test conditions were that the magnetic head was reciprocated 109 times at a maximum speed of 2.4 m/s and a frequency of 60 Hz. The surface roughness of the sliding surface after the test was 0.1 μm as a ten-point average roughness, which was confirmed to be unchanged from before sliding. Also, the difference in level between the sliding part and the non-sliding part is 0.
．． It was confirmed that the diameter was as small as 0.01 μm or less. After the sliding test, it was found that fluorine oil had impregnated and adhered to the pores of the sliding surface.

From this, it was found that the product of the present invention has excellent wear resistance and is suitable for actuators.

Example 9 The ceramic sintered body obtained in Example 1 was impregnated with glycerin and applied to a valve sliding material for water service. hot water 100
The test was conducted by opening and closing the valve while repeatedly circulating cold water at 10°C and 10°C. As a result, no crank occurs,
It has been found that a highly durable valve sliding material with wear resistance that is unmeasurable can be obtained.

〔Effect of the invention〕

According to the present invention, a low-porosity sintered body having various properties can be obtained in a reactive sintered ceramic that can be sintered to a large size. As a result, dense sintered bodies that could not be produced using conventional reaction sintering methods can be obtained, which can be used for structural parts such as engines, turbines, and sliding materials, as well as for aviation, space-related, steel, etc.
The scope of use of ceramics can be expanded to fields such as ocean development.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the porosity of the sintered body and the blending ratio of inorganic compounds, Figure 2 is a transmission electron micrograph showing the metal structure of the sintered body, and Figure 3 is the β- A transmission electron micrograph showing the 3iC particle structure, FIG. 4 is a graph showing the relationship between the porosity of the sintered body and the reaction rate of metal carbide, and FIG. 5 is an enlarged schematic diagram of the sintered body obtained in Example 1. It is. Patent applicant: Hitachi, Ltd. Representative: Sadako Nakamoto
Akiyoshi Inoue] Figure ゛I〜゜;' M, , fL+1 口 e. Figure 4, bottom 1°C powder vermilion shakuhachi, Takako So)

Claims (24)

[Claims] 1. A low porosity reactive sintered composite ceramic in which metal A nitride or metal carbonitride A is interposed at the grain boundary between metal carbide A and metal nitride B. (However, A metals include Ti, Zr, V, B, Al, Ta,
The B metal is made of at least one selected from Cr, Nb, and Hf, and the B metal is made of at least one selected from Si, Ti, Al, and Cr. ) 2. The surface layer of the A metal carbide particles and/or whiskers is made of A metal nitride or A metal carbonitride, and the A metal nitride, A metal carbonitride, and A metal carbide particles are dispersed, Porosity: 15 vol%, at least a part of which is bonded to each other by particles and whiskers made of B metal nitride, A metal nitride, and A metal carbonitride
The following is a low porosity reactive sintered composite ceramic with a maximum pore diameter of 10 μm or less. (However, A metals include Ti, Zr, V, B, Al, Ta,
The B metal is made of at least one selected from Cr, Nb, and Hf, and the B metal is made of at least one selected from Si, Ti, Al, and Cr. ) 3. In claim 1 or 2, the ratio of A metal carbide to A metal nitride and A metal carbonitride is {(A metal nitride and A metal carbonitride)/A metal carbide}×100≧5.
A low porosity reactive sintered composite ceramic characterized by a porosity of 0%. 4. By heating a molded body consisting of A metal carbide particles and/or whiskers and B metal powder in a nitriding gas atmosphere, the B metal powder reacts with nitrogen in the sintered body to generate B metal nitride. Then, the A metal carbide layer reacts with nitrogen and changes to A metal nitride or A metal carbonitride, and the free carbon reacts with B metal powder to generate B metal carbide particles, and finally has a porosity of 15 vol% or less, in which the sintered body is at least partially bonded to each other by particles and whiskers made of B metal nitride, A metal nitride, and A metal carbonitride, which are reaction products; A method for producing low porosity reactive sintered composite ceramics with a maximum pore diameter of 10 μm or less. 5. In claim 4, the A metal is Ti, Zr, V
, B, Al, Ta, Cr, Nb, Hf, and the B metal is Si, Ti, Al, Cr.
A method for producing a low porosity reactive sintered composite ceramic, characterized by comprising at least one selected from the following. 6. 5. The low porosity reaction according to claim 4, characterized in that the sintered body is formed using a molded body in which the blending ratio of metal carbide A and metal powder B is in the range of 95:5 wt% to 5:95 wt%. Manufacturing method for sintered composite ceramics. 7. In claim 4, the heat treatment comprises B in the first step.
Production of a low-porosity reactive sintered composite ceramic comprising two steps: a step of nitriding metal B powder at a temperature below the melting point of the metal, and then a second step of heating to a temperature at which metal carbide A reacts. Law. 8. A sliding member obtained by impregnating the low porosity reactive sintered composite ceramic according to claim 1 or 2 with oil, water, resin, solid lubricant, and metal. 9. A low porosity reactive sintered composite ceramic in which metal nitride A is interposed at the grain boundary between metal silicide A and metal nitride B. (However, A metal is Ti, Zr, V, Al, Ta, Cr.
, Nb, and Hf;
The metal is made of at least one selected from Si, Ti, Al, and Cr. ) 10. The surface layer of the A metal silicide particles and/or whiskers is made of A metal nitride, and the A metal nitride particles are dispersed, and at least a portion of the particles is made of silicon nitride, B metal-based nitride, and A metal nitride. A low-porosity reactive sintered composite ceramic having a porosity of 15 vol% or less and a maximum pore diameter of 10 μm or less, which is formed by bonding particles and whiskers together. (However, A metal is Ti, Zr, V, Al, Ta, Cr.
, Nb, and Hf;
The metal is made of at least one selected from Si, Ti, Al, and Cr. ) 11. Low porosity reactive sintering according to claim 9 or 10, characterized in that the ratio of A metal silicide to A metal nitride is (A metal nitride/A metal silicide)×100≧50%. Composite ceramics. 12. By heating a molded body consisting of A metal silicide particles and/or whiskers and B metal powder in a nitriding gas atmosphere, the B metal powder reacts with nitrogen in the sintered body and B
A metal nitride is generated, and then the A metal silicide layer reacts with nitrogen to change to A metal nitride, and the free silicon reacts with B metal powder and nitrogen to form B metal silicide and nitride. Silicon particles are produced, and finally, the sintered body is at least partially bonded to each other by particles and whiskers consisting of reaction products B metal nitride, A metal nitride, and silicon nitride particles. A method for producing a low-porosity reactive sintered composite ceramic having a porosity of 15 vol% or less and a maximum pore diameter of 10 μm or less. 13. In claim 12, the A metal is Ti, Zr.
, V, Al, Ta, Cr, Nb, Hf, and W, and the B metal is Si, Ti, Al,
A method for producing a low porosity reactive sintered composite ceramic, characterized by comprising at least one selected from Cr. 14. 13. The low porosity according to claim 12, characterized in that the sintered body is formed using a molded body in which the blending ratio of metal silicide A and metal B powder is in the range of 95:5 wt% to 5:95 wt%. A method for producing reactive sintered composite ceramics. 15. In claim 12, the heat treatment consists of two steps: a step of nitriding the B metal powder at a temperature below the melting point of the B metal in the first step, and then a step of heating to a temperature at which the A metal carbide reacts in the second step. A method for producing low porosity reactive sintered composite ceramics. 16. A sliding member obtained by impregnating the low porosity reactive sintered composite ceramic according to claim 9 or 10 with oil, water, resin, solid lubricant, and metal. 17. A low porosity reactive sintered composite ceramic in which metal nitride A is interposed at the grain boundary between metal boride A and metal nitride B. (However, A metal is Ti, Zr, V, Al, Ta, Cr.
, Nb, and Hf;
The metal is made of at least one selected from Si, Ti, Al, and Cr. ) 18. The surface layer of the A metal boride particles and/or whiskers is made of A metal nitride, and the A metal nitride particles are dispersed, and at least a portion is made of B metal nitride and A metal nitride. Porosity: 15 vol% or less, maximum pore diameter: 1
Reactive sintered composite ceramics with low porosity of 0 μm or less. (However, A metal is Ti, Zr, V, Al, Ta, Cr.
, Nb, and Hf;
The metal is made of at least one selected from Si, Ti, Al, and Cr. ) 19. Low porosity reactive sintering according to claim 17 or 18, characterized in that the ratio of A metal boride to A metal nitride is {A metal nitride/A metal boride}×100≧50%. Composite ceramics. 20. By heating a molded body consisting of A metal magnetized particles and/or whiskers and B metal powder in a nitriding gas atmosphere, the B metal powder reacts with nitrogen in the sintered body and B
A metal-based nitride is produced, and then the A metal boride layer reacts with nitrogen to change to the A metal nitride, and finally the sintered body is at least partially a reaction product. A porosity of 15 vol% or less formed by particles and whiskers made of B metal nitride and A metal nitride,
A method for producing low porosity reactive sintered composite ceramics with a maximum pore diameter of 10 μm or less. 21. 20. In claim 20, the A metal is Ti, Zr.
, V, Al, Ta, Cr, Nb, Hf, and W, and the B metal is composed of at least one of Si, Ti, Al, and Cr. manufacturing method. 22. 21. The low porosity according to claim 20, characterized in that the sintered body is formed using a molded body in which the blending ratio of metal boride A and metal B powder is in the range of 95:5 wt% to 5:95 wt%. A method for producing reactive sintered composite ceramics. 23. In claim 20, the heat treatment consists of two steps: a step of nitriding the B metal powder at a temperature below the melting point of the B metal in the first step, and then a step of heating to a temperature at which the A metal carbide reacts in the second step. A method for producing low porosity reactive sintered composite ceramics. 24. A sliding member obtained by impregnating the low porosity reactive sintered composite ceramic according to claim 17 or 18 with oil, water, resin, solid lubricant, and metal.