JP2003105461A - Ceramics/metal composite material and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramics/metal composite material having continuously changed thermal expansion coefficient, and also to provide a manufacturing method therefor. SOLUTION: An Al alloy is brought into contact with a raw material in which an SiC reinforcement is composed with a matrix consisting of Si or an Si alloy, and the Al alloy is held at 1,400 to 1,800 deg.C to diffuse Al component into the matrix. By this method, the ceramics/metal composite material in which the SiC reinforcement is composited with the Al-Si alloy matrix and the Al-Si alloy matrix has continuously graded Al concentration can be obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a metal-ceramic composite material in which a ceramics reinforcing material is composited in a metal matrix, and a method for producing the same.

[0002]

2. Description of the Related Art A composite material of ceramics and metal reinforced with ceramics fibers or particles has both characteristics of ceramics and metal. That is, it has excellent characteristics of ceramics such as high rigidity, low thermal expansion and abrasion resistance, and excellent characteristics of metals such as ductility, high toughness and high thermal conductivity.

Among such composite materials of ceramics and metals, those whose matrix metal is Al or Al alloy and whose ceramics are SiC are Al
Alternatively, since the coefficient of thermal expansion greatly differs between the Al alloy and the ceramic, it is possible to control the coefficient of thermal expansion of the member by changing the content rate of SiC in the member.

The inventors of the present invention firstly laminate a plurality of sheets of which the SiC content is gradually changed to obtain a member whose coefficient of thermal expansion is gradually changed in the laminating direction. (Japanese Patent Application No. 2000-1510)
49). Utilizing such characteristics, for example, when joining members made of different materials having different thermal expansion coefficients,
By inserting the member made of the composite material whose thermal expansion coefficient is gradually changed as described above, it is possible to relieve the stress generated due to the difference in thermal expansion coefficient between different materials.

[0005]

However, although it is possible to change the coefficient of thermal expansion by changing the content of SiC, which is the reinforcing material, in this way,
Since the change of the content rate of SiC must be stepwise, the change of the thermal expansion coefficient may also be stepwise and an ignorable thermal stress may occur. Materials are desired.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a metal-ceramic composite material whose coefficient of thermal expansion continuously changes, and a method for producing the same.

[0007]

Means for Solving the Problems As a result of repeated studies to solve the above problems, the present inventors have found that in a metal-ceramic composite material in which an SiC reinforcement is compounded in an Al--Si alloy matrix, It has been found that it is effective to continuously increase the Al concentration. That is, the coefficient of thermal expansion of Si near room temperature is 2.6 × 10.
⁻⁶ / ° C., which is the thermal expansion coefficient of SiC, 3.0 × 1
Although it is almost equal to 0 ⁻⁶ / ° C., Al has a large thermal expansion coefficient of 23 × 10 ⁻⁶ / ° C., so Al—Si
By continuously grading the Al concentration in the alloy matrix, the thermal expansion coefficient can be continuously changed, and a sufficient thermal stress relaxation effect can be obtained. Also,
As described above, in order to continuously incline Al, a molten Al alloy having a predetermined composition is brought into contact with a material in which a SiC reinforcing material is compounded in a matrix made of Si or a Si alloy, and the Al component is added at a high temperature. It has been found that diffusion in the matrix is effective.

The present invention has been made based on the above findings, and provides the following (1) to (3).

(1) S in an Al-Si alloy matrix
A metal-ceramics composite material in which an iC reinforcing material is composited, wherein the Al-Si alloy matrix has a continuously inclined Al concentration.

(2) In the above (1), the SiC reinforcing material is composed of SiC powder and / or SiC fiber, and the ratio of particles having a particle size or length of 0.3 μm or less is 10% or less. And a content of particles of 300 μm or more is 1% or less, and a content ratio of the SiC reinforcing material in the composite material is in a range of 40 to 80% by volume.

(3) A molten Al alloy is brought into contact with a material in which a SiC reinforcing material is compounded in a matrix made of Si or a Si alloy, and the Al alloy is heated to 1400 to 1800 ° C.
By maintaining the temperature range of 1., the Al component is diffused in the matrix to obtain the metal-ceramic composite material of (1) or (2) above.
Manufacturing method of ceramic composite material.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The metal-ceramic composite material of the present invention is made of Al
An SiC-reinforced Si-Al alloy matrix composite material in which a SiC reinforcement material is compounded in a -Si alloy matrix,
The Si alloy matrix has a continuous Al concentration gradient.

In such a metal-ceramic composite material, a preform in which a SiC reinforcing material is dispersed is impregnated with molten metal Si or a Si alloy to obtain SiC reinforced Si.
Base composite material (hereinafter referred to as "SiC / Si composite material")
It can be suitably obtained by producing a material consisting of and subjecting it to a diffusion treatment described below to diffuse the Al component in the matrix.

The content of the SiC reinforcing material in the composite material of the present invention is preferably in the range of 40 to 80% by volume. S
When the iC content is lower than 40% by volume, not only the strength of the preform during the production of the raw material SiC / Si composite material becomes insufficient, but also the control of the content of the SiC reinforcing material becomes difficult. Yes, thus making it difficult to control the coefficient of thermal expansion. On the other hand, if the content of SiC exceeds 80% by volume, Al that can be added to the composite material
Since the ratio of the components is reduced, it becomes difficult to obtain a sufficient change in the thermal expansion coefficient. The SiC reinforcing material may be uniformly contained in the composite material or the content rate thereof may be inclined. If Al is diffused in the matrix of the material having the graded SiC reinforcing material content, the coefficient of thermal expansion can be further graded. Even when the content of the SiC reinforcing material is inclined as described above, the content of the SiC reinforcing material is preferably in the range of 40 to 80% by volume as a whole.

SiC powder and / or SiC fibers are typically used as the SiC reinforcement. In this case, it is preferable that the proportion of particles having a particle diameter or length of 0.3 μm or less is 10% or less, and the proportion of particles having a particle diameter or length of 300 μm or more is 1% or less. If the proportion of particles of 0.3 μm or less exceeds 10%, it is difficult to impregnate with metallic Si,
Not impregnated easily. On the other hand, particles of 300 μm or more are 1
If it exceeds%, the workability is deteriorated, and it becomes difficult to process with high accuracy, which is not preferable.

Next, a method for producing the metal-ceramic composite material of the present invention will be described. First, molten metal Si or Si in a preform in which a SiC reinforcement is dispersed
An alloy is impregnated to prepare a raw material made of a SiC / Si composite material, and a molten Al alloy is brought into contact with this raw material. Next, the Al alloy is kept in the temperature range of 1400 to 1800 ° C. to diffuse the Al component into the matrix made of metallic Si or Si alloy. If the holding temperature is higher than the melting point of the Al alloy, the Al component diffuses in the matrix, but 1
If the temperature is lower than 400 ° C., the diffusion rate is extremely slow, which is not practical in manufacturing. On the contrary, if the temperature exceeds 1800 ° C, the Al component is evaporated, which is not preferable. Further, the concentration gradient of the Al component can be controlled by controlling the Al concentration, holding temperature and holding time of the added Al alloy. For example, when the diffusion of Al into the matrix progresses by increasing the holding time, the gradient of the Al concentration gradient approaches 0, but as long as there is a slight concentration gradient, it is within the scope of the present invention. The diffusion method at this time is not particularly limited.

The manufacturing method of the present invention will be described in more detail below. First, as the SiC reinforcing material, preferably, a SiC powder and / or a SiC fiber in which the proportion of particles having a particle size or length of 0.3 μm or less is 10% or less and the proportion of particles of 300 μm or more is 1% or less. To prepare. The intended SiC content can be obtained by classifying the prepared SiC powder and / or SiC fibers and then mixing them at a predetermined ratio.

A carbon source such as carbon black, which preferably functions as an impregnation aid, and a binder are mixed with the SiC powder and / or the SiC fiber whose particle size is adjusted so as to obtain a predetermined filling state, and the mixture is cast-molded. A preform having a desired SiC content is formed by various methods such as pressure molding. At this time, an organic binder may be used as a molding binder so that it has a function as a carbon source as well as a function as a binder. The content of SiC in the preform is S
In order to obtain the desired coefficient of thermal expansion, not only the iC powder and / or the SiC fiber blended but also the carbon source and the organic binder added as the impregnation aid change to SiC after alloy impregnation. These also need to be considered.

The formed preform is preferably infiltrated with metallic Si or a Si alloy melted in a vacuum or an inert gas having a nitrogen partial pressure of 1 × 10 ⁻³ Torr (0.133 Pa) or less. Then, the resultant product is cooled to obtain a raw material made of a SiC / Si composite material.

Subsequently, a molten Al alloy is brought into contact with the obtained material composed of the SiC / Si composite material and diffused into the matrix. In this treatment, for example, an Al alloy lump is placed near the material, the material is heated to a predetermined temperature and melted, the material made of the SiC / Si composite material and the Al alloy molten metal are brought into contact with each other, and held for a predetermined time. By this, Al
The Al component of the alloy diffuses into the matrix of the material composed of the SiC / Si composite material, and the temperature of the Al component is lowered, whereby the metal-ceramic composite having the matrix composed of the Si-Al alloy in which the Al concentration is continuously inclined. The material is obtained. As the diffusion treatment at this time, a preform is installed in a container, metal Si or Si alloy is melted in the container, and the preform is impregnated with these to form Si.
After obtaining a raw material composed of a C / Si composite material, a method of successively placing an Al alloy lump in the vicinity of the raw material in the container and melting the Al alloy to diffuse the Al component into the matrix is suitable. Instead of installing the Al alloy in the vicinity of the material, the Al alloy is heated up to a predetermined temperature in advance,
The material may be immersed in this for a predetermined time.

By producing a metal-ceramics composite material by the above method, the Al concentration in the matrix can be continuously graded, so that a composite material whose thermal expansion coefficient continuously changes can be obtained. You can

[0022]

EXAMPLES Examples of the present invention will be shown below together with comparative examples.

(Example) (1) Fabrication of material composed of SiC / Si composite material First, grain size GP # was obtained as a ceramic powder as a reinforcing material.
To 100 parts by mass of 800 SiC powder (manufactured by Shinano Denki Smelting Co., Ltd.), phenol resin (PL482 manufactured by Gunei Chemical Co., Ltd.)
6) 10 parts by mass are added and mixed, and the obtained mixed powder is put into a mold and press-molded to 300 × 300 × 30.
A mm pressed body was prepared. 150 the obtained press body
The resin was cured by heating to ° C to prepare a preform. This preform was fired in N ₂ at 1000 ° C. to obtain a calcined body in which the resin was carbonized. The obtained calcined body has metallic Si
And in this state, the preform is impregnated with molten metal Si by heating to 1600 ° C. in an Ar atmosphere.
A raw material composed of an iC / Si composite material was obtained. Obtained Si
Measure the density of the material consisting of C / Si composite material,
Was estimated. The results are shown in Table 1.

(2) Diffusion of Al component Material obtained from SiC / Si composite material and Al-5
Installed in contact with 0 mass% Si alloy, heating rate 10 ℃
After raising the temperature at 1 / min, the temperature was maintained at 1600 ° C. for 30 minutes.
After cooling to 600 ° C. at 20 ° C./min and then allowing to cool, a SiC reinforced Si—Al alloy matrix composite material having an Al concentration gradient (hereinafter referred to as “Al concentration gradient SiC / Si—Al composite material”) is obtained. Obtained.

(3) Evaluation The obtained Al concentration gradient SiC / Si-Al composite material was
A test piece of 3 × 4 × 20 mm was sampled by processing from a height of 0 mm (Al diffusion port), 15 mm (center), and 30 mm (end opposite to the Al diffusion port) in the installed state when Al component was diffused, Using these test pieces, the coefficient of thermal expansion at 200 ° C. based on 25 ° C. was measured. In addition, a repeated test was performed in which temperature raising and lowering was repeated 500 times between room temperature and 400 ° C. The results are shown in Table 1.

(Comparative Example) As a reinforcing material, GP # 180 was added to SiC powder GP # 1000 manufactured by Shinano Denki Smelting Co. so that the addition ratios were 0% by mass, 30% by mass and 60% by mass, respectively. A colloidal silica and an acrylic resin were mixed to prepare a slurry, and a slurry having a thickness of about 1 mm was prepared using a doctor blade.
Acrylic resin containing colloidal silica was applied to the obtained sheet, and 10 sheets were prepared with each composition.
The preforms of 300 × 300 × 30 mm were produced by stacking them one by one, stacking them in order from the one having the largest amount of GP # 180, and hot-pressing at 100 ° C.
Further, this preform is fired at 1000 ° C. in the atmosphere to form a calcined body, which is N together with an Al alloy (AC8A).
It heated at 850 degreeC in ₂ and obtained the SiC / Al composite material.
The coefficient of thermal expansion of the SiC / Al composite material thus manufactured, in which the SiC content was changed in a stepwise manner, was measured in the same manner as in the example, and further repeated tests were performed. The results are shown in Table 1.

[0027]

[Table 1]

As shown in Table 1, in the examples, the coefficient of thermal expansion monotonically decreased from the end of the Al diffusion hole to the end of the non-diffusion port, and cracking did not occur in the repeated test. It was speculated that the coefficient of thermal expansion was continuously changing. On the other hand, in the comparative example, the change in the thermal expansion coefficient was gradual, so cracking occurred.

[0029]

As described above, according to the present invention,
It is possible to obtain a metal-ceramic composite material having a coefficient of thermal expansion continuously changed and a method for producing the same.

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C22C 49/14 C22C 49/14 C23C 10/22 C23C 10/22 // C22C 101: 14 C22C 101: 14 (72) Invention Tatsuya Shiogai 2-4 Daisaku, Sakura City, Chiba Prefecture, Taiheiyo Cement Co., Ltd. (72) Inventor Ichiro Aoki F-4 Term, 2-4, Daisaku Cement Co., Ltd., Sakura City, Chiba Prefecture (reference) 4K020 AA08 AA22 AC01 BA08 BB02 BB27 BB41

Claims (3)

[Claims] 1. SiC in an Al--Si alloy matrix.
A metal-ceramics composite material in which a reinforcing material is composited, wherein the Al-Si alloy matrix has a continuously inclined Al concentration. 2. The SiC reinforcing material is composed of SiC powder and / or SiC fiber, and the ratio of particles having a particle size or length of 0.3 μm or less is 10% or less and that of 300 μm or more. The metal-ceramic composite material according to claim 1, wherein the ratio is 1% or less and the content of the SiC reinforcing material in the composite material is in the range of 40 to 80% by volume. 3. A molten Al is added to a material in which a SiC reinforcing material is compounded in a matrix made of Si or a Si alloy.
A metal-ceramic composite material according to claim 1 or 2, wherein the alloy is contacted and the Al alloy is maintained in a temperature range of 1400 to 1800 ° C. to diffuse the Al component into the matrix. A method for producing a characteristic metal-ceramic composite material.