JPH02212347A - Production of composite material and composition as starting material - Google Patents

Abstract

PURPOSE:To produce a composite material having high strength and stable characteristics, such as fracture-resistant toughness, by preparing a composition as starting material consisting of ceramic raw material, such as oxide, oxides of group IVa elements, etc., carbon, etc., sintering the above composition, and allowing metal carbide to dispersedly precipitate in ceramics. CONSTITUTION:A composition as starting material which consists of a ceramic raw material (Al2O3, Si3N4, etc.) consisting of at least one kind among oxides, nitrides, and nitrogen oxides, the oxides (TiO, VO, Cr2O3, etc.) of the group IVa-VIa elements of the periodic table or/and the precursors (TiZrO, etc.) of the above oxides, and carbon or/and organic substance (carbon black, etc.) forming carbon by thermal decomposition is prepared. The above composition is sintered in vacuum or in a nonoxidizing atmosphere at about 1500-2000 deg.C, by which metal carbide is precipitated and dispersed in ceramics as matrix so that the volume ratio of the matrix to the metal carbide is regulated to about 95:5-50:50. By this method, the composite material reduced in the dispersion of sintered-compact characteristics is produced.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention uses at least one type of ceramics selected from oxides, nitrides, and nitrides as a matrix (mother phase), and contains ceramics listed in the periodic table. The present invention relates to a method for producing a ceramic composite material strengthened by dispersion and precipitation of a carbide of a group IVa to VIa element or a solid solution of nitrogen or oxygen in the carbide, and a raw material composition thereof.

[Conventional technology]

Ceramics of oxides, nitrides, and nitrides such as alumina, mullite, sialon, and silicon nitride are typical structural ceramics, and because of their excellent hardness, strength, and corrosion resistance, they are used in mechanical parts, tools, refractories, etc. Used for a wide range of purposes. By adding carbide particles of elements from groups IVa to VIa of the periodic table to these materials, fracture toughness and hardness can be increased. For example, there is a composite material in which TiC particles are blended into a ceramic matrix mainly composed of alumina, which has excellent properties as a cutting tool (Japanese Patent Publication No. 54266/1983). Also,
Composite materials have also been developed in which carbide particles of group ■a to ■a elements are blended into a ceramic matrix mainly composed of silicon nitride or sialon (Japanese Patent Publication No. 62-5347).
No. 5).

The manufacturing methods for these composite materials include a matrix raw material such as alumina, a carbide of a group IVa to VIa element, or a solid solution of nitrogen, oxygen, etc. in the carbide (carbonitride, carbonate, etc.); This is a method of mixing with a sintering aid added as necessary and performing pressure sintering or normal pressure sintering. However, this manufacturing method has the following drawbacks.

(1) Commercially available carbides of Group IVa to VIa elements and carbides containing solid solutions of nitrogen, oxygen, etc. (carbonitrides,
The particles of powder (carbonate) generally have a large particle size, 10μ
Coarse particles exceeding m are also mixed in.

When carbides of this metal element are dispersed in a composite material, coarse particles tend to become fracture starting points, causing a decrease in strength.

(2) In recent years, with the development of crushing technology, the average particle size has increased to 1 μm.
It has become possible to obtain metal carbide finer than the above, but it still contains coarse particles, and these fine powders are expensive, contain a large amount of impurities such as Fe, and are highly reactive with water. is high.

For this reason, water cannot be used as a mixing medium when mixing raw materials, and it is difficult to maintain constant powder properties.Composite materials using such fine metal carbides as raw materials The variation in characteristics increases.

[Description of the first invention] The first invention (invention as claimed in claim (1)) has been made in view of the problems of the above-mentioned conventional technology. The present invention aims to provide a method that can produce a ceramic composite material in which these carbides are dispersed, without using carbides of group elements or solid solutions of nitrogen and oxygen in the carbides as raw materials.

The first invention has a matrix of at least one ceramic selected from oxides, nitrides, and nitride oxides, and contains at least one carbide of Group IVa to VIa elements and/or nitrogen in the matrix. and/or a method for producing a composite material comprising a dispersed carbide of at least one of the elements of groups IVa to VIa of the periodic table in which oxygen is dissolved as a solid solution, the method comprising: an oxide, a nitride, a nitride; at least one ceramic raw material of the above, an oxide containing at least one of the elements of Groups A to Via of the Periodic Table and/or a precursor of the oxide, and carbon or/and pyrolyzed This is a method for producing a composite material, which is characterized by comprising a step of preparing a raw material composition comprising an organic substance that generates carbon, and a step of firing the raw material composition.

According to the first invention, the carbide of group IVa to VIa elements or the first V in which nitrogen or oxygen is dissolved as a raw material
It is possible to provide a method that can produce a composite material in which carbides of group a to Vla elements are dispersed without using carbides.

That is, in the first invention, in the step of firing the raw material composition, at least one oxide and/or a precursor of the oxide of the Group IVa to VIa elements in the raw material composition and carbon or/and react with an organic substance that generates carbon by thermal decomposition to produce a carbide of at least one of the Group IVa to VIa elements and/or the carbide containing nitrogen or oxygen as a solid solution; The purpose is to manufacture a composite material in which the particles are dispersed.

The above oxides are generally inexpensive, and highly pure submicron powders are easily available. Furthermore, since highly pure and fine oxide particles can be obtained from the oxide precursor by thermal decomposition or the like, the resulting carbide will also be fine and highly pure.

Therefore, the composite material manufactured according to the first invention has high strength and stable properties such as fracture toughness and strength because the particle size of the carbide particles dispersed therein is small.

Furthermore, since the carbide is not used as a raw material, water can be used when mixing the raw material composition, and furthermore, a composite material with small variations in sintered body properties can be manufactured.

[Description of the second invention] The second invention (the invention according to claim (2)) is intended to provide a raw material composition that can be used in the production method of the first invention.

The second invention has a matrix of at least one ceramic selected from oxides, nitrides, and nitride oxides, and in the matrix at least one carbide of elements from groups IVa to VIa of the periodic table. or/and nitrogen or/and oxygen are dissolved in solid solutions IVa to VI of the above periodic table
A raw material composition for a composite material in which at least one carbide of a group A element is dispersed, the ceramic raw material comprising at least one of an oxide, a nitride, and a nitride oxide, and a periodic rule. It is characterized by consisting of an oxide containing at least one of the Group IVa to VIa elements in the table and/or a precursor of the oxide, and carbon or/and an organic substance that generates carbon by thermal decomposition. This is a raw material composition for a composite material.

According to the second invention, it is possible to provide a raw material composition that can be used in the manufacturing method of the first invention.

[Description of other inventions of the first invention and the second invention] Hereinafter, other inventions that make the first invention and the second invention more specific will be described.

The raw material composition used in the present invention includes a ceramic raw material consisting of at least one of oxides, nitrides, and nitrides, and elements of group 1 Va (titanium, zirconium, hafnium) of the periodic table, and elements of group 1 Va of the periodic table. An oxide containing at least one of Group elements (vanadium, niobium, tantalum) or Group VIa elements (chromium, molybdenum, tungsten) and/or a precursor of the oxide (hereinafter referred to as metal oxide) and carbon or/and an organic substance that produces carbon through thermal decomposition.

Note that it is desirable that the raw material composition be used in the form of powder for manufacturing the composite material.

In the present invention, a ceramic raw material made of at least one of oxides, nitrides, and nitride oxides is used as a matrix in the composite material manufacturing method. The above oxides include alumina (Al2O3), silica (S
iO2), mullite (3Ai'xO-・2SiO2),
Ittria (Y2O, ), calcium oxide (CaO),
Magnesium oxide (MgO), stontium oxide (Sr)
O2), titania (TiO2), chromium oxide (Cr20
3), oxides of rare earth elements, etc., and at least one of them is used. Further, as the nitride, silicon nitride (sijN4), aluminum nitride (AI
N), etc., and at least one of them is used. Further, examples of the nitride include aluminum oxynitride, silicon oxynitride, various α- or β-sialons, and at least one of them is used. The raw materials for these ceramics include the ceramic itself, a substance that produces the ceramic by firing, or a precursor substance of the ceramic. For example, a substance that generates Al2O5 by firing is Aj
7 (OH)3, At700H, aluminum alkoxide, etc. Further, the precursor material of 5tsN is S
i (NH) 2 , S 12NsH, and the like.

The raw materials for the ceramics include a sintering aid or Yz
Additives that contribute to improving high-temperature strength or fracture toughness, such as O3 and Zr0t, may be added.

The metal oxides include Tie, Tie, Ti20
3, Zr01 ZrO7, HfO2, VO1VO2, V
2 03 , V, Os , NbO, NbO2, Nb20
5, Ta205, Cr208, MoO2, MoO3
, oxides such as WO2, WOl, or solid solutions between metal oxides, compounds (double oxides) between the above metal oxides such as TiZr0<, ZrSiO4, and silicon compounds with the above metal oxides such as ZrSiO4 (zircon). The compound (S1
02) or solid solutions, compounds of the above metal oxides such as A12T'io5 and aluminum compounds (A
Precursors such as a double oxide with lzOg) or a solid solution, hydroxide salts, alkoxides, and organic substances that are decomposed by heating to become the above-mentioned metal oxides are mentioned, and at least one of these is used. The form of these substances may be particulate, fibrous, or liquid.

Here, the metal oxide reacts with carbon (in the case of using an organic substance that generates carbon through thermal decomposition, the carbon generated from the substance) during the manufacturing process and is dispersed in the composite material.
At least one carbide of group a to VIa elements (hereinafter referred to as metal carbide) is formed. If the metal oxide is in the form of particles or liquid, the metal carbide produced will be in the form of particles.

Furthermore, if the metal oxide is in the form of particles and there is no agglomeration during the manufacturing process, one metal carbide particle is often produced from one metal oxide particle. Therefore, if a fine metal oxide is used, a fine metal carbide will be generated. When an oxide becomes a carbide, some expand in volume while others contract. However, the particle size usually does not change significantly even if it shrinks slightly; submicron metal oxides yield submicron metal carbides, and metal oxides of 0.5 μm or less yield metal carbides of 0.5 μm or less. It is thought that it is generated.

Furthermore, if the metal oxide is in the form of fibers, it becomes a fibrous metal carbide of approximately the same size unless the fibers are damaged during the manufacturing process.

Further, the shape of the metal carbide produced may be particulate, fibrous, or a mixture thereof.

In the case of particles, the average particle size is preferably 1 μm or less, and when such fine particles are dispersed, the strength is extremely high. More preferably, the average particle size is 0.5 μm.
The following should be used. However, the strength of the composite material is improved in the form of fibers than in the form of equiaxed particles.

Examples of carbon or an organic substance that generates carbon through thermal decomposition include carbon blacks, phenol resins, cool pitch, furan resins, and at least one of these is used.

When using a metal oxide, carbon, and/or an organic substance that generates carbon through thermal decomposition in powder form, it is preferable that the powder be fine and non-agglomerated, since the reactivity is better and fine metal carbides can be synthesized.

This metal oxide and carbon react during the firing step when manufacturing the composite material to produce a metal carbide, and the carbide is precipitated and dispersed in the composite material.

Examples of metal carbides include TiC, ZrC, and HfC.

VC, Nb2C5NbCXTaz c, TaC, Cr3
Examples include C2, MO2C, MOC, W2C, WC, and at least one of these.

Further, any of these exhibits a high fracture toughness improving effect when dispersed and precipitated in a ceramic made of at least one of oxides, nitrides, and nitride oxides. Generally, carbides of transition metals do not necessarily exist in the above-mentioned stoichiometric composition, but exhibit a wide range of solid solution. For example, Tic, ZrC, etc. are generally T iC+ -a,
It exists with the chemical formula Z r C+ − (0≦a<1). Even these solid solutions have sufficiently high effects.

When the above metal oxide is MOx and the above metal carbide is MCy (x, y are positive numbers), MO and carbon react to form MC.
, is expressed as MO, + (x+y)C8MC, +xCO↑. Therefore, in this case, for 1 mole of metal element M, (x
+ y) moles of carbon are required.

For example, when producing a composite material in which TiC is precipitated using TiO2 as a raw material, the reaction formula is Tio2+
3C-4Tic+2co↑, and the ratio of TiO□/C required for the reaction is 1 in molar ratio.
/3, giving a weight ratio of 79.9/36.0.

However, the above reaction usually leads to MC via MO, M (C10) (in the reaction for producing the composite material in which TiC is precipitated, TiC via TiO, Ti(C,O) ). Therefore, when the amount of carbon or an organic substance that generates carbon by thermal decomposition is small in the raw material composition, carbides (carbonates) in which oxygen is solidly dissolved, such as M
It may be dispersed in composite materials in the form of (C,O).

Further, when firing in a nitrogen atmosphere, nitrogen may be dispersed in the composite material in the form of a solid solution carbide (carbonitride), for example, M (C,N). These carbides in which oxygen or nitrogen is solidly dissolved also have a cubic crystal shape similar to MC and have properties very similar to those of MC, and composite materials in which these carbides are dispersed also have excellent properties.

In addition, the blending ratio of metal oxide and carbon and/or organic substances that become carbon through thermal decomposition is determined by determining the proportion of metal oxides and carbon and/or organic substances that become carbon through thermal decomposition. It is desirable to have a ratio that makes it count. When the amount of the carbide is less than the above range, there is hardly any effect of improving toughness, and when the amount of the metal carbide is more than the above range, the oxidation resistance at high temperatures is reduced.

For example, Si, N, containing a sintering aid as a matrix,
In the case of , the above ratio is Si, N+:metal carbide = 95:5
In order to achieve a ratio of ~50:50 (volume ratio), the ratio of metal oxide to carbon and/or organic substance that becomes carbon through thermal decomposition is preferably as follows.

For example, when manufacturing a composite material in which MO is used as a metal oxide and MC is dispersed as a metal carbide, MO
The molecular weight of , is M', the molecular weight of MC, is M2, the density of MC, is d, , the density of Si, N4 sintered body is 3.25 g
/c! Then, the metal oxide (converted to oxide in the case of an oxide precursor) is 1.62dc -M' /M2~3 for 4100 parts by weight of 813N including the sintering aid.
0.8dc -M'/M2 parts by weight, carbon or/and organic substances that become carbon by thermal decomposition are 19% in terms of carbon.
．． 4d.

(x+y)7M2~369d. It is desirable to mix within the range of (xy)/M'' parts by weight.

As a method for preparing the raw material composition of the present invention, the above composition is obtained by mixing a ceramic raw material serving as a matrix, a metal oxide, and carbon or/and an organic substance that generates carbon through thermal decomposition. There is a way.

The above-mentioned composition may be mixed by a dry method or a wet method, but a wet method is preferable because a sufficiently uniform mixture can be produced. In the case of a wet method, the mixed medium can be water or an organic solvent (and drying can be done by any drying method such as spray drying, freeze drying, suction filtration, etc.). Any of these may be used.However, when an organic substance is used as a raw material, the mixed medium may be limited to an organic solvent.

Furthermore, when using a sintering aid that easily reacts with water, such as AIN, it is preferable to use an organic solvent.

In cases other than the above, since the powder can be mixed with water and dried in the atmosphere, a large amount of powder can be processed using a conventional spray dryer, that is, a spray dryer that is not explosion-proof.

Furthermore, when carbon powder is added, the dispersibility of the carbon powder can be improved by adding a small amount of surfactant during wet mixing.

In addition, when manufacturing a molded article of composite material, 1. It is preferable to mold the raw material composition before firing.

Molding can be done by any of the methods commonly used to mold ceramics, such as slip casting, injection molding, extrusion molding, die molding, isostatic pressing, wet press molding, doctor blade, etc. Can be done.

In the firing step, the raw material composition is preferably fired in a vacuum or in a non-oxidizing atmosphere. The reason why the atmosphere is vacuum or non-oxidizing is to quickly produce a composite material without oxidizing the non-oxide in the raw material composition. More desirable is a method of heating in a vacuum until a metal oxide is formed, and then firing in a nitrogen or inert atmosphere. In particular, when the matrix raw material contains nitrides or nitride oxides, in order to prevent thermal decomposition of these substances, it is recommended to heat them in a vacuum until metal carbides are formed, and then sinter them in a nitrogen atmosphere of 1 atmosphere or more. good.

The firing temperature is preferably selected from the range of 1500 to 2000°C. As for the firing method, any method can be used, such as pressureless sintering or pressure sintering such as hot press, but pressure sintering usually yields a composite material with a higher density. Cheap. In the case of pressureless sintering, in order to prevent thermal decomposition of the matrix material, it is preferable to arrange the matrix raw material as a so-called fill powder around the raw material composition and then perform the firing. In addition, when performing hot pressing, molding and baking can be performed simultaneously.

During the firing process, metal oxides and carbon react to form metal carbides, which are dispersed and precipitated in the matrix.

In the case of a reaction in which the speed of the carbide production reaction is low, the production reaction occurs, and preferably the matrix is maintained for a sufficient period of time at a temperature lower than the temperature at which the matrix does not decompose thermally and at the same time its densification progresses significantly. It is preferable to raise the temperature again after the carbide generation reaction is completed.

At this time, if the CO gas generated is removed by evacuation during holding, the reaction will proceed even faster. For example, 5% Al2
5tsN4 containing O5 and 5% Y2O3, T l 0
2, and C as raw materials, 20
When producing a composite material in which vol% TiC is dispersed and precipitated, it is desirable to maintain the vacuum at a temperature of 1300-1400°C during firing for at least 2 hours. Re-heat in gas to 1600℃
By completing the calcination at ~2000°C, a dense composite material is obtained. If the vacuum holding time is insufficient, the composite material will have a low relative density.

The conditions for maintaining the temperature during the firing process vary depending on the type of reaction system, the amount of gas generated, the structure of the furnace, and especially the ease with which the generated gas can be exhausted.

Additionally, hot isostatic pressing (HIP) can be used as the sintering method. One of these, sintering HIP, is a sintered body that has been sintered under normal pressure or hot pressed in advance to become densified until almost or all of the open pores have disappeared.
Density and strength can be further increased by applying hydrostatic pressure in a non-oxidizing atmosphere at a temperature range of 700 to 2200°C. Although it is effective if the hydrostatic pressure is 10 MPa or more, it is desirable to apply a pressure of 50 MPa or more. In capsule HIP, the formed body is heat-treated in advance to complete the metal carbide generation reaction, and then the formed body is vacuum-sealed into a glass capsule and subjected to HIP treatment (glass capsule method). Embed it H
Perform IP treatment (glass bath method); After applying glass powder to the surface of the compact, sinter the applied layer by heating to convert it into an airtight sealing layer, and perform HIP treatment (sintered glass method); The molded body is heated while embedded in glass powder, and -
Methods such as applying axial pressure to form an airtight sealing layer on the glass and then performing HIP treatment (press sealing method) are adopted, and by performing HIP treatment under the same conditions as the sintering HIP method, dense composite materials can be created. is obtained.

In this way, metal carbide particles are formed and precipitated by the reaction between the metal oxide and carbon in the first stage of firing, and the matrix is densified in the second stage.

Note that in addition to the matrix and metal carbides, residual carbon may be present in the sintered body, but if it is in a small amount, the characteristics will not be impaired.

When a fibrous substance is used as the metal oxide in the raw material composition, care should be taken to minimize damage to the fibers during mixing, molding, or pressure firing. For example, when performing hot pressing, it is preferable to gradually apply pressure after the metal carbide is generated.

The composite material manufactured according to the present invention consumes a large amount of fracture energy because the metal carbide precipitated during the propagation of the crack causes the crack to bend (crack deflection) and branch (crack blanching). Achieves high fracture toughness values. Moreover, metal carbides are fine and do not act as fracture starting points ((), and do not cause a decrease in strength.

〔Example〕

The present invention will be explained in detail below.

Example 1 AltOn powder (α type average particle size 0.1 μm) and T
As shown in Table 1, iO powder (rutile type, average particle size 0.4 μm) and carbon black powder (average particle size 0.02 μm) were prepared in a molar ratio of T i O2 and carbon black C: 1: 3, and ・A 1 tO8 and T
i T synthesized by stoichiometric reaction of O2 and C
The volume ratio (Aj'20s: T IC) of iC is 9
They were weighed so that the ratio was 0:10.80:20.70:30, and mixed in a wet ball mill using water to form a slurry. This slurry was suction filtered, dried, and crushed to obtain a raw material composition.

This was placed in a graphite die with graphite tape on the inside, and the temperature was raised while evacuation without applying pressure.
It was kept at ℃ for 6 hours to form a molded body.

After that, the exhaust was stopped and Ar gas was introduced into the furnace to raise the temperature again. At the same time, a uniaxial pressure of 2.5 MPa was applied to this molded body to hot press it, and it was held at 1700°C for 1 hour to hot press it. Completed composite material (sample No. in Table 1,
1 to 3) were manufactured.

Also, for comparison, as shown in Table 1, A I 20
(sample NO, CI) or AltOa and T i B 2 powder (average particle size 4 μm)
) was used as the raw material composition (sample Nα
For G2), hot press in the same manner as above,
A sample was manufactured.

Regarding the above samples, relative density, room temperature 4-point bending strength (J
IS standard) and fracture toughness value (K+c, indentation method) were measured. The results are shown in Table 1.

Table 1 The composite material of this example was found to have α-A120,
and TiB2, and TiB in α-AfzOs
2 was confirmed to be dispersed. Furthermore, as is clear from Table 1, the composite material of this example is:
All have relative densities of 99% or more, have higher strength and KIC than comparative sample N11C1, and
It can be seen that it has higher density and strength than Sample No. C2 of the comparative example.

In addition, in sample Nα2.3, the electrical resistivity was 0.1Ωcm
The following results were obtained, and wire cutting and die-sinking could be easily performed by electrical discharge machining.

Example 2 siaN4 powder (α type, average particle size 0.5 μm) and Y2
A raw material for the matrix was prepared by weighing O3 powder (average particle size: 0.7 μm) and AIN powder (average particle size: 1 μm) in a molar ratio of 83:1.7:15.3. When this is hot pressed at 1750-1850'c, the density is 3
．． 22 to 3.23 g/cnr, the theoretical density of 76 Trix formed from this matrix raw material is considered to be 3.23 g/ctl, and the above matrix raw material and TiC2 powder (rutile type, average particle size 0) are used. ,4μm)
and phenol resin (residual carbon percentage 50%) were weighed as follows. The weight value is 1:3 between the matrix and carbon generated by thermal decomposition from TiC2 and phenol resin.
The volume ratio (mole ratio) of TiC synthesized by stoichiometric reaction (matrix: T i C) is 90:10.
．． It was set to 80:20.70:30. These were mixed in a wet ball mill using ethyl alcohol to form a slurry. This slurry was absorbed, filtered, dried, and crushed to obtain a raw material composition. This was placed in a graphite die with a graphite tape attached to the inside, and the temperature was raised while evacuation was performed without applying pressure, and the mixture was held at 1200° C. for 8 hours to form a molded product. After that, the exhaust was stopped, N2 gas was introduced into the furnace, the temperature was raised again, and a uniaxial pressure of 25 MPa was applied to the molded body for hot pressing, and the hot pressing was completed by holding it at 1800°C for 1 hour. Composite material (sample Nα4 in Table 1
-6) were produced.

For comparison, as shown in Table 1, raw material compositions were prepared by mixing only the above matrix raw materials with alcohol, filtering, drying, and crushing them (Samples NQ,
C3) or TiC powder (
The raw material compositions (samples NQ and C4) were prepared by adding a mixture of particles having an average particle size of 2 μm (average particle size: 2 μm), and were hot-pressed in the same manner as described above to produce samples.

Regarding the above sample, relative density, room temperature four-point bending strength, and KIC were measured in the same manner as in Example 1. The results are shown in Table 2.

Table The composite material of this example consists of α'-8i, N, (α-sialon in which Y is dissolved as a solid solution), β' 513N+ (β-sialon), and TiC, and α'513N4 and β' 513N4 as a matrix, and it was confirmed that TiC was dispersed in the matrix. Furthermore, as is clear from Table 1, the composite material of this example has higher strength and KIC than sample kC3 of the comparative example, and has higher density and strength than samples NQ and C2 of the comparative example. It can be seen that it has the following.

Further, sample No. 5.6 could be easily subjected to electrical discharge machining.

Example 3 Mullite powder (average particle size 0.8 μm) or β-sialon powder (average particle size 0.8 μm) was used as the raw material for the matrix, and T
102 carbon black powder, a matrix formed from the matrix raw material, and TiC synthesized by stoichiometrically reacting the TiQ2 and carbon black powder at a volume ratio (matrix: TiC) of 80
:20, and mixed with water in the same manner as in Example 1 to prepare a raw material composition. Thereafter, the raw material composition was hot pressed in the same manner as in Example 1 to create a composite material (
Sample Nα7.8) was manufactured. However, the hot pressing conditions are Ar if mullite is used as the matrix raw material.
The conditions were to pot press in a gas at 1750° C. for 1 hour, and when Sialon was used as the matrix raw material, the gas introduced after vacuum maintenance was N2, and the conditions were hot pressed at 1800° C. for 1 hour.

For comparison, a sample containing only mullite powder as a raw material composition (sample NαC5) and a sample containing only sialon powder as a raw material composition (sample No. C6) were prepared in the same manner as above in an Ar atmosphere and a N2 atmosphere, respectively. Samples were prepared by hot pressing.

Regarding the above sample, relative density, room temperature four-point bending strength, and KIC were measured in the same manner as in Example 1. The results are shown in Tables 3 and 4.

Table 3 Table 4 The composite material of sample Nα7 has a T peak slightly shifted toward the mullite matrix peak and TiO in X-ray diffraction.
From the presence of the iC peak, it was confirmed that the sample was composed of a mullite matrix and TiC in which oxygen was dissolved as a solid solution, and the TiC was dispersed in the matrix. Also,
The composite material of sample Nα8 is composed of a β-sialon matrix and TiC in which nitrogen is solidly dissolved, since there is a peak of β-sialon matrix and a peak of TiC slightly shifted toward TiN in X-ray diffraction. It was confirmed that the TiC was dispersed in the matrix. Furthermore, as is clear from Tables 3 and 4, the composite material of this example has higher strength and KI than that of the comparative example.
It can be seen that it has C.

Example 4 Al120s or 5iaN4 (α
Type (average particle size 0.5 μm): Al 203
(α type average particle size 0.1, czm): Y203
(Average particle size 0.7 μm) = 90:5:5 (weight ratio)
The mixed powder of Example 1 was used as the raw material for the matrix.
The TiO2 powder and carbon black powder used in
i Volume ratio of TiC produced by stoichiometric reaction of O2 and carbon black (matrix: Ti
C) was added in a ratio of 85:15, mixed in a ball mill using water, and dried with a spray dryer to prepare a raw material composition. This raw material composition was molded into a mold at a pressure of 20 MPa, and then subjected to isostatic pressing treatment at 300 MPa.

Each of these molded bodies was placed in a powder filler of matrix raw material, heated in vacuum, and held at 1250° C. for 8 hours.

After that, Ar gas was introduced into the furnace for the Ar20s matrix sample, and N! Gas was introduced, and normal pressure sintering was performed at 1750° C. for 4 hours in N210.5 atm.

The obtained composite material has a peak of α-1120x and a peak of Ti in X-ray diffraction in the Apt Os matrix sample.
Since there is a peak of TiC slightly shifted toward O, it is composed of α-1120x and TiC in which oxygen is solidly dissolved, α-1120x is used as a matrix, and the above TiC is dispersed in the matrix. This was confirmed. In addition, in the case of the 513N matrix sample, there is a peak for β'-3i, N4 in X-ray diffraction and a peak for TiC that is slightly shifted toward TiN.
It consists of N+ and TiC in which nitrogen is dissolved, and β'-3i
3N, as a matrix, and the above T
It was confirmed that iC is dispersed. Also, the relative density of the composite material is 97.4% for the A1203 matrix sample and 97.4% for the S is N4 matrix sample.
It was 9.0% (the theoretical density of the 5iiN* sintered body not containing TiC was 3.25 g/cur).

Example 5 The raw material powder of the 5iaN4 matrix used in Example 4 was used as the raw material for the matrix, and Zr0z (monoclinic type) was added to it.
average particle size 1 μm), carbon black powder (average particle size 0
．． The volume ratio (matrix:
ZrC) was added at a ratio of 80:2.0. In addition, the raw material powder of the 5isN4 matrix similar to the above was used as the raw material for the matrix, and NbgOs (average particle size 0.6 μm) and carbon black (average particle size 0.02 μm) were used as the raw material for the matrix.
The volume ratio (matrix: NbC) of each powder of m) to the matrix formed from the raw material of the matrix and the NbC synthesized by stoichiometric reaction of Nb2o5,c
The mixture was added at a ratio of 80:20. These two types of raw material compositions were mixed, dried, crushed, and hot pressed in the same manner as in Example 1, respectively. However, the gas introduced into the furnace after the intermediate holding was N2 gas, and hot pressing was performed at 1800° C. for 1 hour under N2 pressure.

The obtained composite material has β
' Consisting of 513N4 and ZrC, β'31 s
It was confirmed that N4 was used as a matrix and ZrC was dispersed in the matrix.

In addition, in the case of adding NbO2, β/3i
.

It was confirmed that it is composed of N4 and N b 02, with β'-8i3N4 as a matrix, and Nb is dispersed in the matrix. Also, the relative density is Z r Ot
It was 97.8% in the case where NbO2 was added, and 99.8% in the case where NbO2 was added.

Claims (2)

[Claims] (1) Ceramics made of at least one of oxides, nitrides, and nitride oxides are used as a matrix, and in the matrix, at least one carbide of elements from groups IVa to VIa of the periodic table is contained, or/ A method for producing a composite material comprising a dispersion of at least one carbide of elements of groups IVa to VIa of the periodic table, in which nitrogen and/or oxygen are dissolved in solid solution, the method comprising: A ceramic raw material consisting of at least one kind of oxide, an oxide of a group IVa to VIa element of the periodic table or/and a precursor of the oxide, and carbon or/and carbon produced by pyrolysis. A method for producing a composite material, comprising the steps of preparing a raw material composition comprising an organic substance, and firing the raw material composition. (2) Ceramics made of at least one of oxides, nitrides, and nitroxides are used as a matrix, and the matrix contains at least one carbide of elements from groups IVa to VIa of the periodic table, or/ A raw material composition for a composite material comprising a dispersion of at least one carbide of the elements of groups IVa to VIa of the periodic table, in which nitrogen and/or oxygen are dissolved as a solid solution, the composition comprising an oxide, a nitride, A ceramic raw material consisting of at least one kind of nitride,
Raw material composition of a composite material characterized by consisting of an oxide of a group IVa to VIa element of the periodic table and/or a precursor of the oxide, and carbon or/and an organic substance that generates carbon by thermal decomposition. thing.