JP2002275556A - Metal-ceramic composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal-ceramic composite material containing extremely little unreacted carbon and having high strength, high rigidity and high thermal conductivity. SOLUTION: The metal-ceramic composite material is obtained by allowing molten Si to permeate SiC powder having particles having <=3 aspect ratio by >=60% in the whole particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal-ceramic composite material in which a metal is combined with a reinforcing material and a method for producing the same, and more particularly, to a metal-ceramic composite material in which metal is Si and a method for producing the same.

[0002]

2. Description of the Related Art As technological innovation progresses rapidly, space development,
In the fields of energy, nuclear power, etc., medium and high temperatures (200 to 2000
(° C.), a material having characteristics such as high strength, high toughness, impact resistance, corrosion resistance, oxidation resistance, and radiation resistance is required. At present, there are ceramics as materials having excellent heat resistance, and among them, silicon carbide and silicon nitride-based ceramics, which are particularly excellent, include ceramics.
It has a disadvantage that it is difficult to manufacture a large member.

On the other hand, metal-ceramic composite materials (commonly referred to as SiC powder reinforced Si-based composite materials, hereinafter sometimes simply referred to as composite materials) using SiC or other ceramic as a reinforcing material and Si as a matrix have been developed. . Since this material is a composite material in which ceramics and a metal having a high melting point are compounded in the order of microns, they have excellent heat resistance like the above-mentioned ceramics, and have high rigidity even at around 1000 ° C.

[0004] For its production, carbon or
A preform of SiC powder is formed with a resin or the like that becomes carbon when fired, and the preform is impregnated with molten Si and simultaneously reacts C and Si in the preform with S
A method of producing a composite material by coexisting SiC produced by a so-called reaction sintering method and the remaining Si to produce iC, or a powder of SiC or the like and carbon or a resin which becomes carbon when fired. A preform is formed, and the preform is impregnated with molten Si. At the same time, carbon (hereinafter referred to as C) in the preform reacts with Si to generate SiC, and the generated SiC and the remaining Si are combined with the Si in advance. SiC containing
It is manufactured by a method of producing a composite material by coexisting with the like. This manufacturing method is extremely advantageous as an industrial process because the dimensions of the compact and the sintered body are hardly changed, so that precision parts and large members having complicated shapes can be produced.

[0005] The composite material produced by such a production method has characteristics such as high strength at high temperature, high rigidity, high thermal conductivity, excellent oxidation resistance, and relatively easy production of large members. are doing. In recent years, SiC filling rate in a composite material has been increased by a method in which a preform made of C is impregnated with molten Si to form SiC, a method of manufacturing a preform using SiC powder having a wide particle size distribution, and the like. Of high rigidity and high thermal conductivity.

[0006]

However, the composite material produced by such a method has a problem that unreacted C remains, or the strength is reduced by mixing coarse particles.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the metal-ceramic composite material, and has as its object to provide a metal-ceramic having high strength, high rigidity, and high thermal conductivity. It is to provide a composite material.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have found that SiC
By setting the particle size and the particle shape of the particles within a predetermined range, it is possible to improve the filling rate of SiC in the preform, and to obtain high rigidity, high thermal conductivity, and high strength with almost no unreacted C. The present invention has been completed based on the knowledge that a SiC-reinforced Si-based composite material can be obtained.

That is, the present invention provides (1) a composite material in which Si and SiC powder are compounded, wherein the number of particles having an aspect ratio of 3 or less is 60% or more of the whole. Powder-reinforced Si-based composite material (Claim 1), wherein (2) the SiC powder has an average particle size of 1-2.
It is preferable that the proportion of particles having a particle size in the range of 0 μm and having a particle size of 25 μm or more in the particle size distribution is 3% or less, and the filling rate of SiC in the composite material is 60 to 75 vol%. 2) and (3) the content of unreacted carbon is preferably 0.1% by weight or less (claim 3).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the present invention, SiC powder is used as a reinforcing material, and the SiC powder needs to have 60% or less of the number of particles having an aspect ratio of 3 or less. In particular, the number of particles having an aspect ratio of 3 or less is 60% or less of the whole,
It is preferable that the average particle size is in the range of 1 to 20 μm and the ratio of particles having a particle size of 25 μm or more in the particle size distribution is 3% or less. If the number of particles having an aspect ratio of 3 or more exceeds 60%, the filling rate of the SiC powder is low, and a composite material having sufficient rigidity cannot be obtained. When the average particle size is larger than 20 μm, or when the ratio of particles having a size of 25 μm or larger is larger than 3%, the strength of the composite material is reduced, and the desired strength cannot be obtained. The average particle size is 1 μm
If it is less than 1, the impregnation failure of Si is likely to occur.

In the present invention, S is used as a matrix.
Use i. This does not particularly limit the composition,
A commercially available product can be used. In order to maintain the rigidity and thermal conductivity of the composite material high, those having few impurities are preferable.

A preform is formed from SiC powder,
By impregnating it with molten Si, the SiC powder-reinforced Si-based composite material of the present invention can be obtained.
Is preferably 60 vol% or more and 75 vol% or less. When the filling rate is less than 60 vol%,
If sufficient rigidity cannot be obtained, and if it is more than 75 vol%, a non-dense part is likely to be formed in the member.

[0013] The filling rate of SiC can be controlled by controlling the grain shape and the average particle diameter of SiC as described above. In the present invention, the filling rate of SiC in this member is considered to include the SiC generated by the reaction between C (derived from the impregnation aid and the organic binder) and Si contained in the preform, but the SiC filling rate is not included in the preform. If the amount of C to be added is too large, unreacted C tends to be generated, while if it is too small, impregnation tends to be poor. An appropriate amount of C is preferably 1 to 10% by weight based on SiC.

The production method of the present invention will be described in more detail. An organic binder such as a phenol resin or a furan resin or an inorganic binder such as an alumina sol is added to the above-mentioned SiC powder as a binder. A material such as a C source or a solvent (a substance that generates C when calcined, and an organic binder or carbon black is appropriate) is added, and the SiC filling rate is 60 to 50% by a casting method or a sediment casting method. A preform of 75 vol% is formed. The obtained preform is brought into contact with Si, and then subjected to vacuum at 1500 to 17 in an inert atmosphere.
The SiC-reinforced Si-based composite material is obtained by heating to 00 ° C. and holding for an appropriate time to melt and impregnate Si into the molded body.

According to the above-described method, the amount of unreacted C is set to 0.1.
An extremely small SiC reinforced Si-based composite material of 1% by weight or less can be produced. As a result, the bending strength 3
High strength, high rigidity, and high thermal conductivity of 20 MPa or more, Young's modulus of 310 GPa or more, and thermal conductivity of 180 W / mK or more can be achieved.

[0016]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples of the present invention and Comparative Examples. (Example 1) (1) Fabrication of composite material ESK (ELECTROSCHMELT) as a reinforcing material
Commercial SiC from Zwerk Kemptem GmbH
Using a powder (C # 800-D DARK), a phenol resin (manufactured by Gunei Chemical Co., Ltd.) and an average particle size of 0.1 μm
m of carbon black, a dispersant, and ion-exchanged water were added to form a slurry. The addition amount is SiC powder 10
70 parts by weight of ion-exchanged water, 35 parts by weight of phenol resin, and 10 parts by weight of carbon black were added to 0 parts by weight. The obtained slurry was poured into a mold to remove water, and then heated to 150 ° C. to cure the resin. The obtained molded body was processed to obtain a preform of 50 × 50 × H10 mm. The C contained in this preform is
Taking into account C lost with the water to be removed and C generated from the phenol resin, 5% by weight with respect to SiC
Becomes The obtained preform and metal Si were brought into contact with each other, and kept at 1600 ° C. for 3 hours in a vacuum to impregnate the preform with molten Si, thereby producing a composite material. (2) Evaluation The obtained composite material was formed into a 3 × 4 × 40 mm test piece by grinding, and the Young's modulus of the obtained test piece was measured by the resonance method (J
IS-R1602), a four-point bending strength test (J
IS-R1601). The measurement of the thermal conductivity is performed by a laser flash method (JIS-R
1611). In addition, the amount of unreacted C in the composite material was measured according to JIS-R6124 after dissolving the composite material with an aqueous sodium hydroxide solution.

(Example 2) C # 700 as SiC powder
Except for using -D DARK (manufactured by ESK, Germany, average particle size: 17 μm), a composite material was prepared and evaluated in the same manner as in Example 1.

Comparative Example 1 GC # 40 as SiC powder
A composite material was prepared and evaluated in the same manner as in Example 1 except that the composite material was 0 (manufactured by Shinano Electric Smelting, GP # 400).

Comparative Example 2 GC # 60 as SiC powder
0 and GC # 1000 (Shinano Electric Refining, GP # 600,
GP # 1000) and a composite material was prepared and evaluated in the same manner as in Example 1 except that a mixed powder obtained by mixing 1: 1 with GP # 1000 was used.

Comparative Example 3 GC # 20 as SiC powder
A composite material was prepared and evaluated in the same manner as in Example 1 except that 00 (Shinano Electric Refining Co., Ltd., GP # 2000) was used.

Comparative Example 4 GC # 80 as SiC powder
0 (Shinano Electric Refining, GP # 800)
A phenol resin (manufactured by Gunei Chemical Co., Ltd.) and activated carbon were mixed, molded by filter press molding, and heated to obtain a molded body. Each mixing ratio is SiC
100 parts by weight of powder and 100 parts by weight of phenol resin and 120 parts by weight of activated carbon were used. The obtained molded body was processed to obtain a preform of 50 × 50 × H10 mm.
C contained in this preform is 17
0% by weight. This preform was impregnated with Si in the same manner as in Example 1 and evaluated.

Table 1 shows the particle size of the SiC powder used, the packing ratio of SiC, and the evaluation results of the composite material for each of the Examples and Comparative Examples 1 to 3.

[0023]

[Table 1]

In Example 1, the average particle size, particle size distribution, aspect ratio, and S
Since the filling rate of iC was within the claimed range, the Young's modulus, the four-point bending strength, and the thermal conductivity were all good. In Example 2, since the ratio of particles having a particle size of 25 μm or more exceeded 3% in the SiC powder, the four-point bending strength was slightly reduced, but other than the above, good properties were exhibited. In Comparative Example 1, the strength was low because the average particle size was outside the claimed range. In Comparative Example 2, since the ratio of particles having a size of 25 μm or more exceeded 3%, the four-point bending strength was slightly low. In Comparative Example 3, the ratio of the number of particles having an aspect ratio of 3 or less was low, so that the filling rate was low and the Young's modulus was low. In Comparative Example 4, the ratio of unreacted C was large, and the strength was low. In Comparative Examples 1 to 4, the thermal conductivity was less than 180 W / mK,
In Examples 1 and 2, a higher thermal conductivity was obtained.

[0025]

As described above, by using the present invention, the content of unreacted C in a SiC-reinforced Si-based composite material can be suppressed to a low level, and a high Young's modulus, high strength and high thermal conductivity Composite materials can be made.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Ichiro Aoki 2-4-2, Osaku, Sakura-shi, Chiba F-term in Pacific Cement Co., Ltd. 4K020 AA22 AC07 BA05 BB22

Claims (3)

[Claims] 1. A SiC composite material comprising Si and SiC powder, wherein the number of particles having an aspect ratio of 3 or less is 60% or more of the whole.
Powder reinforced Si-based composite material. 2. The SiC powder has an average particle size of 1 to 20 μm.
And the proportion of particles having a particle size of 25 μm or more in the particle size distribution is 3% or less, and S in the composite material
The SiC reinforced Si-based composite material according to claim 1, wherein an iC filling rate is 60 vol% or more and 75 vol% or less. 3. The content of unreacted carbon is 0.1% by weight.
The SiC powder reinforced Si-based composite material according to claim 1, wherein: