JP5388464B2 - Aluminum-ceramic composite and method for producing the same - Google Patents

Description

  The present invention relates to an aluminum-ceramic composite and a method for producing the same.

  Metal-ceramic composites with ceramics added as dispersed particles and a matrix as a metal combine the characteristics of both metals and ceramics, while taking advantage of the characteristics of ceramics such as low thermal expansion and high rigidity. It is a material with added high toughness and workability, and is expected to be used in various fields. Conventionally, materials such as Cu-W and Cu-Mo have been studied as such materials, but the specific gravity is large and there is a problem when used as a large-sized device part. Metal-ceramic composites are attracting attention as next-generation materials.

As metal-ceramic composites, materials using aluminum as a matrix as a metal have been actively studied in recent years (Patent Document 1). Aluminum is lightweight, has excellent heat conduction characteristics, and has a low melting point. As a method for producing such an aluminum-ceramic composite, a method of impregnating aluminum or an aluminum alloy containing aluminum as a main component by a high-pressure forging method is conventionally known. (Hereinafter referred to as a preform), and an aluminum alloy is compounded under high temperature and high pressure.
As for the production method of the aluminum-ceramic composite, in addition to the high-pressure forging method, non-pressure impregnation method in which impregnation is performed without applying pressure (Patent Document 2), ceramic powder and aluminum powder are mixed, and temperature and pressure are applied. There is a manufacturing method such as a powder metallurgy method (Patent Document 3).
JP-A-3-509860. Japanese Patent Application Laid-Open No. 11-116362. Japanese Patent Laid-Open No. 10-8164

  In powder metallurgy and non-pressure impregnation methods, it is difficult for the dissolved metal to get wet with the ceramic particles, so increasing the number of ceramic particles, which are reinforcing materials, makes it difficult to mix the reinforcing materials uniformly. There was a problem that it was difficult to manufacture the body. In the conventional method for producing a composite, the filling amount of the reinforcing material is small, and it cannot be used for applications requiring high rigidity and low thermal expansion. If the content of the reinforcing material is increased forcibly, pores remain in the composite, and the interface between the reinforcing material and the metal cannot be secured, resulting in problems such as a decrease in thermal conductivity and strength.

  The use of titanium or aluminum-ceramic composites with a low coefficient of thermal expansion as semiconductor manufacturing jigs, etc. has been studied, but since titanium and aluminum-ceramic composites are very hard and difficult to process, drilling and grooves For members that require processing, there has been a problem that the processing cost is high.

As a method for reducing the processing cost of an aluminum-ceramic composite, a method of making an aluminum alloy layer with excellent workability at a hole or groove processing portion has been studied, but when manufacturing a large part, an aluminum alloy to be processed There was a problem that peeling or cracking occurred at the interface between the two due to residual stress caused by the difference in thermal expansion between the layer and the aluminum-ceramic composite.

  As a method for solving these problems, a method of making an aluminum-ceramic composite hole / grooved portion into an aluminum-graphite composite having excellent workability has been studied. When used as a ceramic member, there is a problem that peeling of the aluminum-graphite composite occurs due to thermal stress caused by a difference in thermal expansion between the aluminum-ceramic composite and the aluminum-graphite composite due to heating during bonding with the ceramic member. there were.

  The present invention has been made in view of the above-described problems, and the purpose thereof is to adjust the coefficient of thermal expansion while ensuring the workability of the processed part, and further to heat the material by dividing the material of the processed part. An object of the present invention is to provide a low-cost aluminum-ceramic composite that can be applied to large parts that have low thermal expansion with reduced thermal stress and that do not impair characteristics such as thermal conductivity.

As a result of intensive studies to achieve the above-mentioned goal, the present inventors have found that the groove has a shape larger than the shape to be removed when machining into the final shape and is divided when processed into the final shape. By inserting a graphite material having a composite material with an aluminum alloy, the resulting composite has a small difference in thermal expansion from the aluminum-ceramic composite and exists at the interface portion or interface portion between the two. The stress generated in the aluminum alloy layer was reduced, cracks generated during processing were reduced, and workability was improved. Furthermore, aluminum - after processing the graphite composite, aluminum - graphite composite via the aluminum alloy layer exposed to the surface by a plurality of members divided Ru structure, both when loaded with thermal cycling Reduced peeling and the like that occurred at the interface. Further, the present invention will be described in detail below.

That is, the present invention relates to a method for producing an aluminum-ceramic composite by melt impregnating a metal mainly composed of aluminum into a ceramic porous body having a hole and a groove.
(1) In order to expose the aluminum-ceramic composite in the final product, the step of setting the thickness and outer peripheral shape of the ceramic porous body to dimensions larger than the thickness and outer peripheral shape of the final product;
(2) A step of processing a hole or groove having a size larger than the hole size or groove size in the final product into the ceramic porous body obtained in the step (1),
(3) above comprising the steps of inserting a graphite material into the hole and groove of the obtained porous ceramics in the step (2), graphite material, aluminum when processed into final shape - graphite composite is step that having a groove formed as to be divided,
(4) The porous ceramic body obtained in the step (3) is a step of melt-impregnating a metal mainly composed of aluminum, and the aluminum-graphite composite is divided when processed into a final shape. A step of forming an aluminum alloy layer by filling the groove formed as described above with a metal mainly composed of aluminum,
(5) A step of exposing the aluminum-ceramic composite by processing the outer peripheral portion and the surface portion of the aluminum-ceramic composite obtained in the step (4) into a final shape,
(6) A step of processing the aluminum-graphite composite in the hole portion and groove portion of the aluminum-ceramic composite obtained in the step (5) into a final shape, through the aluminum alloy layer exposed on the surface A step of dividing the aluminum-graphite composite into a plurality of members,
To produce an aluminum-ceramic composite.

Further, according to the present invention, the thermal expansion coefficient of the graphite material at 25 ° C. to 550 ° C. is 60% to 120% of the thermal expansion coefficient of the ceramic porous body at 25 ° C. to 550 ° C., and the graphite material is impregnated with metal. The aluminum-ceramic composite is characterized in that the thermal expansion coefficient at 25 ° C. to 550 ° C. of the aluminum-graphite composite is 80% to 150% of the thermal expansion coefficient at 25 ° C. to 550 ° C. of the aluminum-ceramic composite. It is a manufacturing method of a body.

Furthermore, the present invention is the method for producing an aluminum-ceramic composite, wherein the graphite material is an isotropic graphite material having a minimum value of 70% or more with respect to the maximum value of the coefficient of thermal expansion in each direction.

In addition, the present invention is an aluminum-ceramic composite body obtained by the above-described manufacturing method, which is a plate-like structure, and the aluminum-ceramic composite body is exposed on both main surfaces. .

Further, the present invention is a structural component in which the ceramic porous body is made of at least one of silicon carbide, silicon nitride, aluminum nitride, and alumina, and has a thermal conductivity of 120 W / mK or more at a temperature of 25 ° C. And a thermal expansion coefficient at a temperature of 150 ° C. is 10 × 10 ⁻⁶ / K or less.

The structural component of the present invention has characteristics of low thermal expansion and high thermal conductivity, and is suitable as a heat dissipation component used as a large-sized device component such as a semiconductor manufacturing jig. In addition, by making the hole part and the groove part an aluminum-graphite composite having excellent workability, the processing cost can be suppressed, and a structural component having excellent characteristics can be provided at low cost.

  The manufacturing method of the aluminum-ceramic composite can be roughly classified into two types: an impregnation method and a powder metallurgy method. Of these, the large parts are actually commercialized by impregnation methods from the viewpoint of characteristics such as thermal conductivity. There are various methods of impregnation, and there are a method of performing under normal pressure and a method of performing under high pressure (high pressure forging method). High pressure forging methods include a molten metal forging method and a die casting method.

  A method suitable for the present invention is a high-pressure forging method in which impregnation is performed under high pressure, and a molten metal forging method is preferable for obtaining a large and dense composite. The high-pressure forging method is a method in which a ceramic preform is loaded into a high-pressure vessel, and a molten aluminum alloy is impregnated at a high temperature and high pressure to obtain a composite.

  Hereinafter, the example of a manufacturing method by the molten metal forging method is demonstrated about this invention. Ceramic powder as a raw material (adding a binder such as silica as necessary) is molded and fired to prepare a preform. The obtained preform may be subjected to surface processing as necessary in order to ensure a predetermined flatness. In addition, with respect to a portion to be subjected to hole processing or groove processing in the final product, holes or grooves having dimensions larger than those of the final product are processed into a preform. On the other hand, in order to expose the aluminum-ceramic composite in the final product, the thickness and the outer peripheral shape are set to dimensions larger than the thickness dimension and the outer dimension of the final product.

Next, as shown in FIG. 1, a graphite material (1) slightly smaller than the size of the hole or the like is inserted into a hole or groove formed in the preform. These portions become an aluminum-graphite composite (4) through an impregnation step described later (FIG. 2). The dimensional difference between the preform hole or the like and the graphite material is preferably as small as possible within a range where insertion is possible, and is about 0.05 mm to 0.5 mm. When the dimension of the preform hole and the like and the dimensional difference between the graphite materials are large, the thickness of the aluminum alloy layer having a large coefficient of thermal expansion existing between the two is not preferable in the obtained composite. The aluminum-graphite composite is excellent in workability, and can be easily processed by normal machining when performing drilling, grooving or the like.

The graphite material used in the present invention preferably has a thermal expansion coefficient of 25 ° C. to 550 ° C. of 60% to 120% of the thermal expansion coefficient of 25 ° C. to 550 ° C. of the ceramic porous body. If the thermal expansion coefficient at 25 ° C. to 550 ° C. of the graphite material is less than 60% of the thermal expansion coefficient at 25 ° C. to 550 ° C. of the ceramic porous body, the difference in thermal expansion coefficient between the two during the preheating when compounding with the aluminum alloy Therefore, the thickness of the aluminum alloy layer existing between the obtained composites becomes too thick, which is not preferable. On the other hand, when the thermal expansion coefficient of 25 ° C to 550 ° C of the graphite material exceeds 120% of the thermal expansion coefficient of 25 ° C to 550 ° C of the porous ceramic body, it depends on the initial dimensional difference between the two, but the aluminum alloy During preheating when composited, a difference in thermal expansion coefficient between them causes tensile stress in the ceramic porous body, which may cause problems such as cracking of the ceramic porous body during preheating.

In the graphite material used in the present invention, the thermal expansion coefficient at 25 ° C. to 550 ° C. of the composite in which the metal is impregnated with the graphite material is 80% to 150% of the thermal expansion coefficient of the aluminum-ceramic composite. preferable. When the thermal expansion coefficient at 25 ° C. to 550 ° C. of the composite in which the metal is impregnated with the graphite material is less than 80% or 150% of the thermal expansion coefficient of the aluminum-ceramic composite, the cooling process after compounding with the aluminum alloy Thus, the stress generated at the interface between the two becomes too large, and cracks may occur when the aluminum-ceramic composite is processed. In addition, composites in which a metal is impregnated with graphite material partially remain on the processed surface even after being processed into a final product. Therefore, if there is a large difference in coefficient of thermal expansion from the aluminum-ceramic composite, warping may occur during heating. This is not preferable. The porosity of the graphite material to be used is 40% by volume or less, preferably 20% by volume or less, because it is necessary to make the coefficient of thermal expansion close to that of the aluminum-ceramic composite.

Furthermore, the graphite material used in the present invention is preferably an isotropic graphite material having a minimum value of 70% or more with respect to the maximum value of the coefficient of thermal expansion in each direction. The graphite material includes an anisotropic material such as an extruded material. In the present invention, the graphite material is impregnated with an aluminum alloy to form a composite material, and an interface with the aluminum-ceramic composite material is formed. As described above, it is important to match the thermal expansion coefficients of the obtained aluminum-graphite composite material and aluminum-ceramic composite material, and it is not preferable that the thermal expansion coefficient of the graphite material is anisotropic. For this reason, isotropic graphite materials are suitable.

As shown in FIG. 1, the graphite material (1) is preliminarily provided with fine grooves (3) or the like so as to be divided when processed into a final shape, and an aluminum alloy is compounded, thereby producing an aluminum- While increasing the joint area at the interface between the graphite composite (4) and the aluminum-ceramic composite (5), and making a mechanical joint structure, the joint between them can be made stronger. Further, as shown in FIG. 2, when the aluminum-graphite composite (4) is processed into a final shape, the aluminum alloy layer exposed to the surface by the grooves (3) formed in the graphite material in advance. It is divided into a plurality of members via (9). The shape of the groove formed in advance in the graphite material preferably has a width of 0.3 mm to 3 mm. If the width of the groove is 0.3 mm or less, the effect of mitigating thermal stress described later is insufficient, which is not preferable. Further, if the width of the groove exceeds 3 mm, an aluminum alloy layer having a large coefficient of thermal expansion remains excessively, which is not preferable. The depth of the groove is not particularly limited as long as it does not significantly impair the mechanical properties of the graphite material. The number of grooves is preferably as large as possible for the purpose of the present invention as long as the area of the aluminum alloy layer (9) remaining after final processing does not exceed 30% of the area of the aluminum-graphite composite. Furthermore, with respect to the shape of the groove, a taper or the like can be given as necessary.

In the present invention, the aluminum-graphite composite remaining on the product surface when it is processed into a final shape is divided into a plurality of members via an aluminum alloy layer, so that the aluminum-ceramics are heated during bonding with the ceramic member. Generation of thermal stress due to the thermal expansion difference between the composite and the aluminum-graphite composite can be suppressed, and as a result, occurrence of peeling of the aluminum-graphite composite during heating can be suppressed.

In the structure of the present invention, after processing into a substantially final product shape, annealing is performed under conditions of a temperature of 500 ° C. or higher, so that the above-described aluminum alloy layer, aluminum-graphite composite, and aluminum-ceramic composite are between. Residual stress can be released. The aluminum alloy layer may be plastically deformed due to the stress release in this annealing treatment, and in this case, it can be dealt with by reworking the surface portion so that the product has a final shape. Further, after the stress is released by the annealing treatment, the plastic deformation of the aluminum alloy layer in the subsequent heat treatment is almost eliminated.

  The ceramic used for the aluminum-ceramic composite of the present invention is preferably composed of at least one selected from the group consisting of silicon carbide, silicon nitride, aluminum nitride, and alumina. The aluminum-ceramic composite of the present invention is required to have high thermal conductivity from its application. The thermal conductivity of the aluminum-ceramic composite is determined by the thermal conductivity of the ceramic material itself and the interface state with the aluminum alloy. For this reason, the ceramic material is preferably selected from the group of silicon carbide, silicon nitride, aluminum nitride, and alumina from the viewpoints of thermal conductivity, wettability with an aluminum alloy, and adhesion. Furthermore, the porous body according to the present invention may contain a small amount of an oxide or composite oxide such as silica, alumina, magnesia and the like as long as the effects of the present invention are not impaired.

There is no restriction | limiting in particular regarding the manufacturing method of the preform which concerns on this invention, It can manufacture by a well-known method. For example, when the ceramic is silicon carbide, it can be obtained by adding colloidal silica or colloidal alumina or the like as a binder to a silicon carbide powder, mixing, molding, and firing at 800 ° C. or higher. There is no restriction | limiting in particular also about a shaping | molding method, Well-known methods, such as press molding, extrusion molding, and casting, can be used, and the shape-retaining binder can be used together as needed.

  10-50 volume% is preferable and, as for the porosity of the preform used for this invention, 15-40 volume% is more preferable. The characteristics of the aluminum-ceramic composite, particularly the expansion coefficient, are determined by the expansion coefficient, elastic modulus and content of the ceramic used. When the aluminum-ceramic composite of the present invention is used as, for example, a heat radiating component of an electrostatic chuck module, if the difference in expansion coefficient from the electrostatic chuck material (alumina, aluminum nitride, etc.) increases, May occur and parts may warp. For this reason, in order to reduce the expansion coefficient of the aluminum-ceramic composite, the upper limit of the porosity is preferably 50% by volume, more preferably 40% by volume. On the other hand, when the porosity is less than 10% by volume, it is difficult to form a composite with an aluminum alloy, and there are problems such as pores remaining during the composite, resulting in a decrease in thermal conductivity. The porosity of the preform can be controlled by adjusting the type, particle form, particle size and blending ratio of the ceramic powder used. Further, the porosity of the preform can be adjusted by a molding method.

The method of laminating the preform to form one block is not particularly limited, but for example, the following method may be mentioned. A method in which the preform is sandwiched and laminated with a release plate coated with a release agent to form one block, arranged on both surfaces of the preform so that fibers mainly composed of alumina or silica are in direct contact with each other, It is a method of sandwiching between release plates to form one block.

After preheating the block at about 550 to 750 ° C., place one or more in a high-pressure vessel, and supply molten aluminum alloy as quickly as possible to prevent the temperature of the block from decreasing, and at a pressure of 20 MPa or more. The aluminum-ceramic composite is obtained by pressurizing and impregnating the aluminum alloy into the voids of the preform. For the purpose of removing distortion during impregnation, the impregnated product may be annealed.

  The aluminum alloy in the aluminum-ceramic composite of the present invention may contain magnesium or the like in addition to aluminum. As such an aluminum alloy, for example, an aluminum alloy containing 0.2 to 3% by mass of magnesium may be used. By containing magnesium, the bond between the ceramic particles and the metal portion becomes stronger, which is preferable. Furthermore, since the aluminum alloy is sufficiently penetrated into the voids of the preform at the time of impregnation, the melting point of the aluminum alloy is preferably as low as possible. For example, an aluminum alloy containing 5 to 25% by mass of silicon may be used. The metal components other than aluminum and magnesium in the aluminum alloy are not particularly limited as long as the characteristics do not change extremely. For example, copper or the like may be included.

  An example of a method for processing the obtained aluminum-ceramic composite will be described. Since the aluminum-ceramic composite of the present invention is produced by a high-pressure forging method, the periphery is covered with an aluminum alloy. First, this surface aluminum alloy layer is removed with a grinder or the like, and then surface processing is performed with a surface grinder using a diamond tool to obtain a flat aluminum-ceramic composite. In addition, it is also possible to directly perform surface processing with a surface grinder or the like using a diamond tool without removing the surface aluminum alloy layer. Next, peripheral machining, grooving, and hole machining are performed by a machining center, a water jet machine, an electric discharge machine, or the like. In particular, when processing a complicated tap hole or the like, a stainless steel helicate may be inserted as needed for the purpose of improving the strength of the hole. As mentioned above, since the preform of the part to be drilled or grooved is processed larger than the final shape in advance, this part becomes an aluminum-graphite composite and can be easily processed by normal machining Processing costs can be reduced.

  The aluminum-ceramic composite of the present invention is characterized in that the aluminum-ceramic composite is exposed on both main surfaces of a flat plate by performing the above-described processing. If the aluminum alloy layer on the surface cannot be completely removed and remains, warping occurs due to temperature changes during use due to the difference in thermal expansion coefficient between the aluminum-ceramic composite and the aluminum alloy layer, and in an environment with a temperature gradient. When used for jigs used in applications requiring high precision flatness, for example, semiconductor manufacturing jigs, the required flatness may not be ensured.

The aluminum-ceramic composite of the present invention preferably has a thermal expansion coefficient of 10 × 10 ⁻⁶ / K or less at a temperature of 150 ° C., and uses that require high-precision flatness in an environment with a temperature gradient. It is suitable for jigs used in the above, such as semiconductor manufacturing jigs. When the thermal expansion coefficient at a temperature of 150 ° C. exceeds 10 × 10 ⁻⁶ / K, the flatness and the like may be reduced due to the thermal expansion of the composite itself due to a subtle temperature gradient when used in the semiconductor manufacturing jig described above. It may become impossible to secure. About a thermal expansion coefficient, when joining and using members, such as ceramic electrostatic chucks, for example, it is preferable to match | combine with the thermal expansion coefficient of the member to join.

The composite of the present invention preferably has a thermal conductivity of 120 W / mK or higher at a temperature of 25 ° C. This is suitable for use in parts that require heat dissipation, and even when used in the above-mentioned semiconductor manufacturing jigs, etc., the material having excellent heat conduction characteristics is effective in reducing the thermal gradient of the composite itself. Is preferable.

Example 1
1800 g of silicon carbide (hereinafter referred to as SiC) powder A (manufactured by Taiyo Random Company: NG-80, average particle size: 200 μm), silicon carbide powder B (manufactured by Taiyo Random Company: NG-150, average particle size: 100 μm) 900 g, 300 g of silicon carbide powder C (manufactured by Yakushima Electric: GC-1000F, average particle size: 10 μm) and 300 g of silica sol (manufactured by Nissan Chemical Co., Ltd .: Snowtex) are weighed and mixed for 30 minutes with a stirring mixer. The plate was press-molded into a flat plate having a size of Φ300 mm × 18 mm at a surface pressure of 30 MPa.

  The obtained molded body was dried at a temperature of 120 ° C. for 2 hours and then fired in the air at a temperature of 950 ° C. for 2 hours to obtain a SiC preform having a porosity of 23%. The obtained SiC preform was subjected to surface processing to a thickness of 15 mm using a diamond grindstone with a surface grinder, and then the outer peripheral portion was processed into a shape with an outer dimension of Φ290 mm at a machining center.

The obtained SiC preform is processed into a shape of the ceramic porous body (2) in FIG. 1 using a diamond tool and a Φ12 mm through hole, a Φ12 mm intermediate hole having a depth of 10 mm, and a Φ200 mm × 10 mmt groove. It was. Next, isotropic graphite materials of Φ11.9 mm × 15 mmt and Φ11.9 mm × 9.9 mmt having grooves of 1 mm width and 2 mm depth shown in the graphite material (1) of FIG. 1 (manufactured by Tokai Carbon Co., Ltd .: G458) Was inserted into the hole. In addition, an isotropic graphite material (manufactured by Tokai Carbon Co., Ltd .: G458) having a diameter of 2 mm and a depth of 2 mm on the side surface and bottom surface of the graphite material (1) shown in FIG. Inserted into the groove of the reform. Thereafter, both main surfaces were sandwiched between 0.5 mmt graphite sheets (hereinafter referred to as grapho foil plates), and 12 mm thick iron plates were arranged on the top and bottom, and connected with eight M10 bolts to form one block. Next, this block was preheated to 700 ° C. in an electric furnace, and then placed in a pre-heated press mold having an inner diameter of Φ400 mm × 300 mmt, and an aluminum alloy containing 12% by mass of silicon and 1% by mass of magnesium. The molten metal was poured and pressurized at 100 MPa for 25 minutes to impregnate the SiC preform with the aluminum alloy. After cooling to room temperature, cut along the shape of the release plate with a wet band saw, peel off the sandwiched foil foil, and then anneal for 3 hours at a temperature of 530 ° C. to remove distortion during impregnation An aluminum-silicon carbide composite was obtained.

From the obtained SiC preform and isotropic graphite material, a specimen for thermal expansion coefficient measurement (diameter 3 mm, length 10 mm) is prepared by grinding, and each test piece is used at a temperature of 25 ° C. to 550 ° C. The thermal expansion coefficient was measured with a thermal dilatometer (Seiko Denshi Kogyo Co., Ltd .; TMA300). As a result, the thermal expansion coefficient of the temperature of 25 ° C. to 550 ° C. is, SiC preform 4.5 × ¹⁰ -6 / K, isotropic graphite was 3.5 × ^{10 -6} / K. Furthermore, for the isotropic graphite material, a test body for measuring a thermal expansion coefficient (diameter: 3 mm, length: 10 mm) in three orthogonal directions is prepared, and thermal expansion at a temperature of 25 ° C. to 550 ° C. is performed using each test piece. As a result of measuring the coefficient, the maximum value was 3.6 × 10 ⁻⁶ / K, and the minimum value was 3.4 × 10 ⁻⁶ / K.

Next, from the obtained aluminum-silicon carbide composite, a thermal expansion coefficient measurement specimen (diameter 3 mm length 10 mm) and a thermal conductivity measurement specimen (25 mm × 25 mm × 1 mm) were prepared by grinding. Using each test piece, the thermal expansion coefficient at a temperature of 150 ° C. and a temperature of 25 ° C. to 550 ° C. was measured by a thermal dilatometer, and the thermal conductivity at a temperature of 25 ° C. was measured by a laser flash method (manufactured by ULVAC; TC3000). . As a result, the thermal expansion coefficient at a temperature of 150 ° C. is 5.2 × 10 ⁻⁶ / K, the thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. is 5.4 × 10 ⁻⁶ / K, and the thermal conductivity at a temperature of 25 ° C. Was 245 W / mK. Moreover, a test body for measuring a thermal expansion coefficient (diameter: 3 mm, length: 10 mm) was produced by machining from the aluminum-graphite composite in the groove portion of the obtained aluminum-silicon carbide composite, and the temperature was 25 ° C. to 550 ° C. The thermal expansion coefficient was measured. As a result, the thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. was 5.5 × 10 ⁻⁶ / K.

Next, both sides of the obtained aluminum-silicon carbide composite were uniformly ground using a diamond tool with a surface grinder so that the thickness was 14 mm. Thereafter, the outer peripheral portion of the member was ground into a shape having an outer dimension of Φ280 mm. Next, the aluminum-silicon carbide composite subjected to grinding is machined into an aluminum-graphite composite part (4) in the shape of FIG. 2, and a Φ10 mm through hole (8), Φ10 mm in the middle of the depth of 8 mm. Groove processing with a hole (7) and a depth of 8.5 mm was performed at Φ198 mm. The obtained processed product was subjected to heat treatment at a temperature of 520 ° C. for 1 hour in order to remove distortion during processing. The amount of change in flatness before and after the heat treatment was 14 μm. Thereafter, the upper and lower surfaces were ground by a thickness of 0.1 mm on a surface grinder to produce a structural component. The groove part of the obtained structural component had a structure in which the aluminum-graphite composite divided into five parts was exposed by an aluminum alloy layer having a width of 1 mm. Furthermore, although the obtained structural component was heat-treated at a temperature of 560 ° C. for 1 hour, there was no occurrence of peeling of the aluminum-graphite composite in the groove portion.

(Comparative Example 1)
Without placing anything in the hole and groove portions of the SiC preform of Example 1, both main surfaces were sandwiched between 0.5 mmt graphoil plates, 12 mm thick iron plates were placed up and down, and M10 bolts 8 Connected with a book to form one block. Next, this block was preheated to 700 ° C. in an electric furnace, and then placed in a pre-heated press mold having an inner diameter of Φ400 mm × 300 mmt, and an aluminum alloy containing 12% by mass of silicon and 1% by mass of magnesium. The molten metal was poured and pressurized at 100 MPa for 25 minutes to impregnate the SiC preform with the aluminum alloy. After cooling to room temperature, cut along the shape of the release plate with a wet band saw, peel off the sandwiched foil foil, and then anneal for 3 hours at a temperature of 530 ° C. to remove distortion during impregnation An aluminum-silicon carbide composite was obtained.

The obtained aluminum-silicon carbide composite was warped in a shape having a concave surface on the groove portion side, and the amount of warpage was 1.6 mm per 200 mm in length. Next, both sides of this aluminum-silicon carbide composite were uniformly ground using a diamond tool with a surface grinder so that the thickness was 12 mm. The obtained aluminum-silicon carbide composite had cracks in the aluminum-silicon carbide composite on the back side of the portion where the SiC preform was grooved. Similar cracks were also generated at the boundary between the aluminum alloy layer portion and the aluminum-silicon carbide composite portion where the SiC preform was grooved.

(Comparative Example 2)
In Example 1, an extruded graphite material having the same shape as that of Example 1 was placed in the hole and the groove, and an aluminum-silicon carbide composite was produced in the same manner as in Example 1. From the extruded graphite material used, a specimen for thermal expansion coefficient measurement (diameter: 3 mm, length: 10 mm) in three directions orthogonal to each other by grinding is prepared, and each test piece is used to heat at a temperature of 25 ° C. to 550 ° C. The expansion coefficient was measured. As a result, the maximum value of the thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. was 7.6 × 10 ⁻⁶ / K, and the minimum value was 1.6 × 10 ⁻⁶ / K.

From the obtained aluminum-silicon carbide composite and aluminum-graphite composite, a thermal expansion coefficient measurement specimen (diameter 3 mm, length 10 mm) was prepared by grinding. The thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. was measured using each test piece. As a result, the thermal expansion coefficients at temperatures of 25 ° C. to 550 ° C. were 5.4 × 10 ⁻⁶ / K for the aluminum-silicon carbide composite and 8.9 × 10 ⁻⁶ / K for the aluminum-graphite composite. .

Next, both sides of the obtained aluminum-silicon carbide composite were uniformly ground using a diamond tool in a surface grinder so that the thickness was 14 mm. Thereafter, the outer peripheral portion of the aluminum-silicon carbide composite was ground into a shape having an outer dimension of Φ280 mm. Next, the aluminum-silicon carbide composite subjected to grinding is machined into an aluminum-graphite composite part (4) in the shape of FIG. 2, and a Φ10 mm through hole (8), Φ10 mm in the middle of the depth of 8 mm. Hole (7) and groove (6) with a depth of 8.5 mm at Φ116 mm were processed. The obtained processed product was heat-treated at a temperature of 500 ° C. for 1 hour in order to remove distortion during processing. The amount of change in flatness before and after the heat treatment was 350 μm. In the obtained aluminum-silicon carbide composite, cracks occurred in the aluminum-silicon carbide composite on the back side of the portion where the SiC preform was grooved, and aluminum in the portion where the SiC preform was grooved Similar cracks occurred at the boundary between the alloy layer portion and the aluminum-silicon carbide composite.

(Example 2)
In Example 1, an aluminum-silicon carbide composite was prepared in the same manner as in Example 1 except that an aluminum alloy containing 1% by mass of magnesium was used as the aluminum alloy and the preheating temperature was 750 ° C. in a nitrogen atmosphere. Produced.

From the obtained aluminum-silicon carbide composite, a thermal expansion coefficient measurement specimen (diameter 3 mm, length 10 mm) and a thermal conductivity measurement specimen (25 mm × 25 mm × 1 mm) were prepared by grinding. Using each test piece, the thermal expansion coefficient at a temperature of 150 ° C., a temperature of 25 ° C. to 550 ° C., and a thermal conductivity at a temperature of 25 ° C. were measured. As a result, the thermal expansion coefficient at a temperature of 150 ° C. is 5.6 × 10 ⁻⁶ / K, the thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. is 5.8 × 10 ⁻⁶ / K, and the heat conduction at a temperature of 25 ° C. The rate was 250 W / mK.

The obtained aluminum-silicon carbide composite was subjected to the same processing and heat treatment as in Example 1 to produce a structural component having the shape of FIG. There is no occurrence of cracks or the like at the boundary between the aluminum-silicon carbide composite and the aluminum-silicon carbide composite and the aluminum-graphite composite during processing, and the amount of change in flatness before and after heat treatment at a temperature of 520 ° C. is 10 μm. Furthermore, although the obtained structural component was heat-treated at a temperature of 560 ° C. for 1 hour, there was no occurrence of peeling of the aluminum-graphite composite in the groove portion.

(Example 3)
SiC powder A (manufactured by Taiyo Random Company: NG-80, average particle size: 200 μm) 1000 g, SiC powder B (manufactured by Taiyo Random Company: NG-150, average particle size: 100 μm) 1000 g, SiC powder C (Yakushima Electric Works) Company: GC- # 2000, average particle size: 2 μm) 1000 g, and silica sol (Nissan Chemical Co., Ltd .: Snowtex) 300 g were weighed and mixed for 30 minutes with a stirring mixer, and then a flat plate having a size of Φ300 mm × 18 mm It was press-molded at a surface pressure of 20 MPa.

  The obtained molded body was dried at a temperature of 120 ° C. for 2 hours and then fired in the air at a temperature of 950 ° C. for 2 hours to obtain a SiC preform having a porosity of 28%. The obtained SiC preform was subjected to surface processing to a thickness of 15 mm using a diamond grindstone with a surface grinder, and then the outer peripheral portion was processed into a shape with an outer dimension of Φ290 mm at a machining center.

The obtained SiC preform was subjected to Φ12 mm through-hole and Φ200 mm × 10 mmt groove processing using a diamond tool in the shape of the ceramic porous body (2) of FIG. 3. Next, an isotropic graphite material (manufactured by Tokai Carbon Co., Ltd .: G330) of Φ11.9 mm × 15 mmt shown in the graphite material (1) of FIG. 3 was inserted into the hole. In addition, an isotropic graphite material (manufactured by Tokai Carbon Co., Ltd .: G330) having a diameter of 2 mm and a depth of 2 mm on the side surface and bottom surface of the graphite material (1) in FIG. Inserted into the groove of the reform. After that, both main surfaces were sandwiched between 0.5 mmt graphoil plates, iron plates with a thickness of 12 mm were arranged on the top and bottom, and connected with eight M10 bolts to form one block. Next, this block was preheated to 700 ° C. in an electric furnace, and then placed in a pre-heated press mold having an inner diameter of Φ400 mm × 300 mmt, and an aluminum alloy containing 6% by mass of silicon and 1% by mass of magnesium. The molten metal was poured and pressurized at a pressure of 30 MPa for 25 minutes to impregnate the SiC preform with the aluminum alloy. After cooling to room temperature, cut along the shape of the release plate with a wet band saw, peel off the sandwiched foil foil, and then anneal for 3 hours at a temperature of 530 ° C. to remove distortion during impregnation An aluminum-silicon carbide composite was obtained.

From the obtained SiC preform and isotropic graphite material, a specimen for thermal expansion coefficient measurement (diameter 3 mm, length 10 mm) is prepared by grinding, and each test piece is used at a temperature of 25 ° C. to 550 ° C. The thermal expansion coefficient was measured with a thermal dilatometer (Seiko Denshi Kogyo Co., Ltd .; TMA300). As a result, the thermal expansion coefficient of the temperature of 25 ° C. to 550 ° C. is, SiC preform 4.4 × ¹⁰ -6 / K, isotropic graphite was 4.3 × ^{10 -6} / K.

From the obtained aluminum-silicon carbide composite, a thermal expansion coefficient measurement specimen (diameter 3 mm, length 10 mm) and a thermal conductivity measurement specimen (25 mm × 25 mm × 1 mm) were prepared by grinding. Using each test piece, the thermal expansion coefficient at a temperature of 150 ° C., a temperature of 25 ° C. to 550 ° C., and a thermal conductivity at a temperature of 25 ° C. were measured. As a result, the thermal expansion coefficient at a temperature of 150 ° C. is 6.1 × 10 ⁻⁶ / K, the thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. is 6.3 × 10 ⁻⁶ / K, and the heat conduction at a temperature of 25 ° C. The rate was 220 W / mK.

The obtained aluminum-silicon carbide composite was subjected to the same processing and heat treatment as in Example 1 to produce a structural component having the shape of FIG. There is no occurrence of cracks or the like at the boundary between the aluminum-silicon carbide composite and the aluminum-silicon carbide composite and the aluminum-graphite composite during processing, and the amount of change in flatness before and after heat treatment at a temperature of 520 ° C. is 13 μm. Furthermore, although the obtained structural component was heat-treated at a temperature of 560 ° C. for 1 hour, there was no occurrence of peeling of the aluminum-graphite composite in the groove portion.

Example 4
SiC powder A (manufactured by Taiyo Random Company: NG-80, average particle size: 200 μm) 1500 g, SiC powder B (manufactured by Taiyo Random Company: NG-150, average particle size: 100 μm) 1000 g, silicon nitride powder (electrochemistry) Industrial company: SN-9S, average particle size: 2 μm) 500 g, and silica sol (Nissan Chemical Co., Ltd .: Snowtex) 300 g were weighed and mixed for 30 minutes with a stirring mixer, and then a flat plate having a size of Φ300 mm × 18 mmt It was press-molded at a pressure of 30 MPa.

  The obtained molded body was dried at a temperature of 120 ° C. for 2 hours and then fired in a nitrogen atmosphere at a temperature of 1200 ° C. for 2 hours to obtain a preform having a porosity of 22%. The obtained preform was subjected to surface processing to a thickness of 15 mm using a diamond grindstone with a surface grinder, and then the outer peripheral portion was processed into a shape with an outer dimension of Φ290 mm at a machining center.

From the obtained SiC preform, a thermal expansion coefficient measurement specimen (diameter 3 mm, length 10 mm) was prepared by cutting, and the thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. was measured. As a result, the thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. was 4.1 × 10 ⁻⁶ / K.

The obtained preform was processed into the shape of FIG. 1 using a diamond tool in the same manner as in Example 1. Next, an aluminum-silicon carbide / silicon nitride composite was obtained in the same manner as in Example 1 except that Toyo Carbon Co., Ltd .: IG11 was used as the isotropic graphite material. Moreover, from the used isotropic graphite material (Toyo Tanso Co., Ltd .: IG11), a test body for measuring the thermal expansion coefficient (diameter: 3 mm, length: 10 mm) in three directions orthogonal to each other by machining is prepared. Was used to measure the coefficient of thermal expansion at a temperature of 25 ° C to 550 ° C. As a result, the thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. was a maximum value of 4.2 × 10 ⁻⁶ / K and a minimum value of 3.9 × 10 ⁻⁶ / K.

From the obtained aluminum-silicon carbide / silicon nitride composite, a thermal expansion coefficient measurement specimen (diameter 3 mm length 10 mm) and a thermal conductivity measurement specimen (25 mm × 25 mm × 1 mm) were prepared by grinding. Using each test piece, the thermal expansion coefficient at a temperature of 150 ° C., a temperature of 25 ° C. to 550 ° C., and a thermal conductivity at a temperature of 25 ° C. were measured. As a result, the thermal expansion coefficient at a temperature of 150 ° C. is 4.7 × 10 ⁻⁶ / K, the thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. is 4.8 × 10 ⁻⁶ / K, and the heat conduction at a temperature of 25 ° C. The rate was 135 W / mK. Further, from the obtained aluminum-silicon carbide / silicon nitride composite groove-aluminum-graphite composite, a thermal expansion coefficient test specimen (diameter 3 mm, length 10 mm) was prepared by cutting, and the temperature was 25 ° C. to 25 ° C. The thermal expansion coefficient at 550 ° C. was measured. As a result, the thermal expansion coefficient at a temperature of 25 ° C. to 550 ° C. was 6.2 × 10 ⁻⁶ / K.

The obtained aluminum-silicon carbide / silicon nitride composite was processed and heat-treated in the same manner as in Example 1 to produce a structural component having the shape shown in FIG. There was no crack or the like at the boundary between the aluminum-silicon carbide / silicon nitride composite and the aluminum-silicon carbide / silicon nitride composite and the aluminum-graphite composite during processing, and before and after heat treatment at a temperature of 500 ° C. for 1 hour. The amount of change in flatness was 20 μm. Furthermore, although the obtained structural component was heat-treated at a temperature of 560 ° C. for 1 hour, there was no occurrence of peeling of the aluminum-graphite composite in the groove portion.

Filling diagram before impregnation (compositing) showing one embodiment of the present invention Structural drawing of a structural component showing an embodiment of the present invention Filling diagram before impregnation (compositing) showing one embodiment of the present invention Structural drawing of a structural component showing an embodiment of the present invention

Explanation of symbols

(1) Graphite material (2) Ceramic porous body (3) Graphite material groove (4) Aluminum-graphite composite (5) Aluminum-ceramic composite (6) Groove (7) Intermediate hole (8) Through hole (9 ) Aluminum alloy layer

Claims (6)

In a method for producing an aluminum-ceramic composite by melt impregnating a metal mainly composed of aluminum with respect to a ceramic porous body having a hole and a groove,
(1) In order to expose the aluminum-ceramic composite in the final product, the step of setting the thickness and outer peripheral shape of the ceramic porous body to dimensions larger than the thickness and outer peripheral shape of the final product;
(2) A step of processing a hole or groove having a size larger than the hole size or groove size in the final product into the ceramic porous body obtained in the step (1),
(3) above comprising the steps of inserting a graphite material into the hole and groove of the obtained porous ceramics in the step (2), graphite material, aluminum when processed into final shape - graphite composite is step that having a groove formed as to be divided,
(4) The porous ceramic body obtained in the step (3) is a step of melt-impregnating a metal mainly composed of aluminum, and the aluminum-graphite composite is divided when processed into a final shape. A step of forming an aluminum alloy layer by filling the groove formed as described above with a metal mainly composed of aluminum,
(5) A step of exposing the aluminum-ceramic composite by processing the outer peripheral portion and the surface portion of the aluminum-ceramic composite obtained in the step (4) into a final shape,
(6) A step of processing the aluminum-graphite composite in the hole portion and groove portion of the aluminum-ceramic composite obtained in the step (5) into a final shape, through the aluminum alloy layer exposed on the surface A step of dividing the aluminum-graphite composite into a plurality of members,
To produce an aluminum-ceramic composite through the process. An aluminum-graphite composite in which a graphite material has a thermal expansion coefficient of 25 ° C to 550 ° C of 60% to 120% of a thermal expansion coefficient of a ceramic porous body of 25 ° C to 550 ° C, and the graphite material is impregnated with a metal. The aluminum-ceramic composite according to claim 1, wherein the thermal expansion coefficient of 25 to 550 ° C is 80% to 150% of the thermal expansion coefficient of 25 to 550 ° C of the aluminum-ceramic composite. Manufacturing method. The method for producing an aluminum-ceramic composite according to claim 1 or 2, wherein the graphite material is an isotropic graphite material having a minimum value of 70% or more with respect to the maximum value of the coefficient of thermal expansion in each direction. 4. An aluminum-ceramic composite obtained by the manufacturing method according to claim 1, 2 or 3, wherein the aluminum-ceramic composite is flat and the aluminum-ceramic composite is exposed on both main surfaces. 5. The structural component according to claim 4, wherein the ceramic porous body is made of at least one of silicon carbide, silicon nitride, aluminum nitride, and alumina. 6. The structural component according to claim 4, wherein the thermal conductivity at a temperature of 25 ° C. is 120 W / mK or more, and the thermal expansion coefficient at a temperature of 150 ° C. is 10 × 10 ⁻⁶ / K or less.