JP2013075799A - METHOD FOR JOINING SiC/Si COMPOSITE MATERIAL BODY AND SiC/Si COMPOSITE MATERIAL JOINED BODY - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for joining each SiC/Si composite material body capable of obtaining an SiC/Si composite material joined body having a hollow structure aiming at improvement of joining strength.SOLUTION: A plurality of SiC/Si composite material bodies are allowed to abut together on each joining surface, and joined together by being heated at 1,000-1,414°C and held in the state where a pressure of 0.05-10.0 MPa is applied onto each joining surface under an inert gas atmosphere.

Description

  The present invention relates to a method for joining a SiC / Si composite material body and a SiC / Si composite material joined body obtained by joining SiC / Si composite material bodies.

  A SiC / Si composite material composed of a SiC / Si (silicon carbide / silicon) composite material has excellent characteristics such as light weight, rigidity and low thermal expansion, and is a configuration of precision equipment such as semiconductor manufacturing equipment and liquid crystal manufacturing equipment. It is used for goods.

  When producing a SiC / Si composite material having a hollow structure, it is necessary to go through a joining step. Conventionally, a method of bonding an SiC porous body using an organic binder and impregnating the SiC porous body with metal Si (for example, refer to Patent Document 1), a plurality of SiC using a brazing material such as a metal foil The SiC / Si composite material having a hollow structure was obtained by a method of joining the / Si composite material.

JP 2008-50181 A

  However, in the method of impregnating SiC porous body bonded with an organic binder with metal Si, it is difficult to adjust the coating amount of the organic binder on the bonding surface. If the amount applied is excessive, the internal space of the joined body may be blocked, and if it is too small, the joining strength and airtightness of the joined body may be reduced. Moreover, since metal Si expand | swells when it solidifies, metal Si oozes out from a SiC porous body at the time of temperature fall, and may block | close the internal space of a joined body. Thus, this method is not suitable for producing a SiC / Si composite material having a hollow structure.

  On the other hand, in the method of joining using a brazing material, it is difficult to join without a gap, and the joining strength may be significantly reduced.

  The present invention has been made in view of these problems, and it is possible to obtain a SiC / Si composite material bonding method capable of obtaining a hollow structure SiC / Si composite material bonded body with improved bonding strength, and An object is to provide a SiC / Si composite material joined body.

  The SiC / Si composite material bonding method of the present invention is such that a plurality of SiC / Si composite materials are brought into contact with each other at the bonding surfaces, and 0.05 MPa to 10 MPa with respect to the bonding surfaces in an inert gas atmosphere. It joins by heating and holding at 1000 to 1414 degreeC in the state which applied the pressure of 0.0 MPa.

  According to the joining method of the SiC / Si composite material of the present invention, the joint surface of the SiC / Si composite material can be directly joined, and the SiC / Si composite material joined as in the case of using an organic binder. It is possible to eliminate the possibility of blocking the internal space. As can be seen from the examples described later, the bonding strength of the bonding portion is equivalent to the strength of the original SiC / Si composite material (base material), which is superior to the case where a brazing material is used. .

  Note that when the heating temperature is less than 1000 ° C., Si does not diffuse, so the SiC / Si composite materials are not joined together. On the other hand, when the heating temperature exceeds 1414 ° C., Si melts from the SiC / Si composite material body, which may cause problems such as a decrease in the strength of the entire bonded body and blockage of the internal space due to the eluted Si. .

  On the other hand, when the applied pressure is less than 0.05 MPa, the non-contact ratio is increased in the bonding surface, so that bonding becomes difficult. On the other hand, when the applied pressure exceeds 10.0 MPa, the amount of deformation increases or the base material is damaged.

  In the SiC / Si composite material bonding method of the present invention, it is preferable that the SiC filling rate of the SiC / Si composite material body is 20% by volume to 95% by volume. In addition, a SiC filling rate means the occupation rate of SiC in a SiC / Si composite material.

  When the SiC filling rate is less than 20% by volume, the SiC / Si composite material body has low rigidity, and the range in which the SiC / Si composite material joined body can be applied to the structural member is very limited. On the other hand, when the SiC filling rate exceeds 95% volume, the proportion of metal Si is small, and the number of portions where Si contacts with each other decreases, resulting in poor bonding strength.

  However, the SiC filling rate of the SiC / Si composite material body is more preferably 20% by volume to 80% by volume. In this case, no defect occurs in the joint portion, and the strength of the joint portion is equivalent to the strength of the SiC / Si composite material body as the base material.

  And in the joining method of the SiC / Si composite material of this invention, it is preferable that the surface roughness of the said joint surface does not exceed 0.1 micrometer by centerline average roughness Ra.

  If the surface roughness Ra of the joint surface exceeds 0.1 μm, it cannot be satisfactorily joined.

  In the SiC / Si composite material bonding method of the present invention, the heating and holding time is preferably 1 hour to 12 hours.

  When the holding time is less than 1 hour, the diffusion of Si is insufficient, so that the bonding becomes insufficient. On the other hand, if the holding time exceeds 12 hours, the surface roughness of the joint surface increases due to the evaporation of Si, so that joining becomes difficult.

  The SiC / Si composite material assembly of the present invention is heated to 1000 ° C. to 1414 ° C. in a state where a pressure of 0.05 MPa to 10.0 MPa is applied to the joint surface abutted in an inert gas atmosphere. In this case, a plurality of SiC / Si composite materials are joined together.

  According to the SiC / Si composite material joined body of the present invention, the joint surface of the SiC / Si composite material body is directly joined without using an organic binder. Therefore, it is possible to eliminate the possibility that the internal space of the SiC / Si composite material bonded body is blocked as in the case where an organic binder is used. Therefore, the SiC / Si composite material joined body is more preferably a hollow structure.

  As can be seen from the examples described later, the strength of the bonded portion is equivalent to the strength of the original SiC / Si composite material, and is superior to that bonded using a brazing material.

(A) is a top view of the test piece, (b) is a front view of the test piece, and (c) is a front view of the joined body.

  In the present invention, a SiC / Si composite material body is held under pressure and heating (hot pressing) in a state where the SiC / Si composite material body is in contact with the joint surface, so that an SiC / Si composite material can be used without using an organic binder or brazing material. The present invention relates to a method for obtaining a SiC / Si composite material joined body (hereinafter also simply referred to as a joined body) by directly joining the joined surfaces of the material bodies, and an SiC / Si composite material joined body obtained thereby.

  First, a plurality of SiC / Si composite materials used for bonding are prepared. The SiC filling rate of the SiC / Si composite material body is preferably 20% by volume to 95% by volume. In addition, a SiC filling rate means the occupation rate of SiC in a SiC / Si composite material.

  When the SiC filling rate is less than 20% by volume, the SiC / Si composite material body has low rigidity, and the range in which the SiC / Si composite material joined body can be applied to the structural member is very limited. On the other hand, when the SiC filling rate exceeds 95% volume, the proportion of metal Si is small, and the number of portions where Si contacts with each other decreases, resulting in poor bonding strength.

  However, the SiC filling rate of the SiC / Si composite material body is more preferably 20% by volume to 80% by volume. In this case, no defect occurs in the joint portion, and the strength of the joint portion is equivalent to the strength of the SiC / Si composite material body as the base material.

  The production method of the SiC / Si composite material is not limited, and can be produced by, for example, a casting method, a pressure casting method, a pressure infiltration method, a non-pressure infiltration method, a powder metallurgy method, or the like. When producing a SiC / Si composite material by the non-pressure infiltration method, after processing a molded body obtained by molding a mixture of SiC powder and organic binder with a press or the like into a predetermined shape, this is impregnated with metal Si. Done.

  The plurality of SiC / Si composite materials are each ground and cut into appropriate shapes. At this time, by processing a groove or the like on the joining surface side of the SiC / Si composite material body, the joined body can be formed into a hollow structure after completion.

  Then, mirror polishing is applied to each joint surface of the plurality of SiC / Si composite materials. At this time, the surface roughness of the joint surface is preferably at least 0.1 μm or less in terms of the center line average roughness Ra. When the surface roughness Ra of the joint surface exceeds 0.1 μm, the joint cannot be satisfactorily joined and the joint strength is poor.

  Next, the plurality of SiC / Si composite materials are brought into contact with each other at the bonding surface and maintained in a pressurized and heated state. The configuration for maintaining the pressurized and heated state is not limited. For example, a hydraulic cylinder may be installed in the furnace.

  At this time, it heats to 1000 to 1414 degreeC. When the heating temperature is less than 1000 ° C., Si does not diffuse, so the SiC / Si composite materials are not joined together. On the other hand, when the heating temperature exceeds 1414 ° C., Si melts out of the SiC / Si composite material, so that problems such as a decrease in strength of the entire bonded body and a clogging of the groove due to eluted Si occur.

  Moreover, it pressurizes to 0.05 MPa-10.0 MPa. If the applied pressure is less than 0.05 MPa, the proportion of the portions that are not in contact with each other in the joining surface becomes large, so that joining becomes difficult. On the other hand, when the applied pressure exceeds 10.0 MPa, the amount of deformation increases or the base material is damaged.

  Although an appropriate holding time varies depending on the area and shape of the bonding surface, it is preferable to hold the pressurized and heated state for 1 to 12 hours. When the holding time is less than 1 hour, the diffusion of Si is insufficient, so that the bonding becomes insufficient. On the other hand, if the holding time exceeds 12 hours, the surface roughness of the joint surface increases due to the evaporation of Si, so that joining becomes difficult.

  In addition, it is desirable to perform pressure heating in an inert gas atmosphere such as argon or nitrogen. When pressure heating is performed in an air atmosphere, an oxide film is formed on Si and becomes a barrier when Si diffuses. In addition, when pressure heating is performed in a vacuum state, Si actively evaporates in the above temperature range, so that the surface roughness of the bonding surface increases and bonding becomes difficult.

  By maintaining a state in which a plurality of SiC / Si composite materials are brought into contact with each other at the bonding surface and pressurized and heated, Si is solid-phase diffused, and the bonding surface of the SiC / Si composite material is directly bonded. / Si composite material joined body can be obtained. And since it is not necessary to use an organic binder, the problem mentioned above does not generate | occur | produce.

  Hereinafter, the present invention will be described in detail with specific examples and comparative examples of the present invention.

[Example 1]
SiC powder (GP # 500 manufactured by Shinano Denki Smelting Co., Ltd., average particle size 30 μm) is prepared as a raw material powder, and 15% by mass of phenol resin powder (OI-305A manufactured by DIC Corporation) as an organic binder. Added. Then, this was filled in a mold and subjected to hot press molding. Thus, a square plate-shaped porous molded body having a side of 100 mm and a thickness of 10 mm was produced.

  And this porous molded object was installed in a furnace with metal Si (made by Nippon Electric Works), and the state heated to 1200 degreeC in the vacuum atmosphere was hold | maintained for 12 hours, and the phenol resin was degreased and carbonized. . After that, the SiC porous sintered body was impregnated with molten Si by maintaining the furnace heated to 1645 ° C. for 22 hours. This obtained the SiC / Si composite material body whose SiC filling rate is 55 volume%.

  Then, two square plate-shaped test pieces each having a side of 50 mm and a thickness of 10 mm were cut out from the SiC / Si composite material body. Further, as shown in FIGS. 1A and 1B, three grooves each having a width of 2.0 mm and a depth of 1.5 mm were processed in each test piece. Thereafter, the surface (joint surface) on which the grooves were processed was mirror-finished to have a surface roughness Ra of 0.05 μm. And as shown in FIG.1 (c), these test pieces are pressurized in 1.0 MPa, and it installs in a furnace in the state which contacted each other's joining surface, and it heats to 1300 degreeC by inert gas atmosphere. This state was maintained for 6 hours. Thereby, a test piece was joined and the SiC / Si composite-material joined body was obtained.

  As a result of observing a cross section of the joined portion of the obtained SiC / Si composite material bonded body with an optical microscope, no void was observed in the joined portion. The four-point bending strength of the joint was 300 MPa, which was the same strength as the SiC / Si composite material (base material). The results are summarized in Table 1.

[Example 2]
As Example 2, joining of test pieces was tried in the same manner as in Example 1 except that the heating temperature at the time of joining was 1020 ° C. As a result of observing a cross section of the joined portion of the obtained SiC / Si composite material bonded body with an optical microscope, no void was observed in the joined portion. Further, the four-point bending strength of the joint portion was 260 MPa, and the joint portion had sufficient joint strength.

Example 3
As Example 3, the test piece was tried to be joined in the same manner as in Example 1 except that the heating and pressurizing holding time at the time of joining was 11 hours. As a result of observing a cross section of the joined portion of the obtained SiC / Si composite material bonded body with an optical microscope, no void was observed in the joined portion. The four-point bending strength of the joint was 290 MPa.

[Examples 4 and 5]
In Examples 4 and 5, joining of test pieces was attempted in the same manner as in Example 1 except that the pressure applied during joining was 0.05 MPa and 9.5 MPa, respectively. As a result of observing a cross section of the joined portion of the obtained SiC / Si composite material bonded body with an optical microscope, no void was observed in the joined portion. The four-point bending strength of the joint was 300 MPa.

Example 6
SiC powder 100% by mass (60% by mass of NG90 manufactured by Taihei Random Co., Ltd. and 40% by mass of GP # 800 manufactured by Shinano Denki Smelting Co., Ltd.) and 12% by mass of coke powder (Oriental Sangyo Co., Ltd.) AT.No. 40-C) manufactured by the manufacturer was prepared, and 12% by mass of phenol resin powder (OI-305A manufactured by DIC Corporation) as an organic binder was added thereto. Then, this was filled in a mold and subjected to hot press molding. Thus, a square plate-shaped porous molded body having a side of 100 mm and a thickness of 10 mm was produced.

  And this porous molded object was installed in a furnace with metal Si (made by Nippon Electric Works), and the state heated to 1200 degreeC in the vacuum atmosphere was hold | maintained for 12 hours, and the phenol resin was degreased and carbonized. . After that, the SiC porous sintered body was impregnated with molten Si by maintaining the furnace heated to 1645 ° C. for 22 hours. Thereby, a SiC / Si composite material having a SiC filling rate of 90% by volume was obtained.

  And like Example 1, the test piece was produced from this SiC / Si composite material body, these test pieces were hold | maintained in the state heated and pressurized, and joining of the test piece was tried.

  As a result of observing a cross section of the joined portion of the obtained SiC / Si composite material bonded body with an optical microscope, no void was observed in the joined portion. The four-point bending strength of the joint was 180 MPa, which was lower than the four-point bending strength of 260 MPa of the SiC / Si composite material (base material), but sufficient joining was confirmed.

Example 7
As raw material powder, SiC powder 100% by mass (GP # 800 manufactured by Shinano Denki Smelting Co., Ltd., average particle size 17 μm) and metal Si powder 120% by mass (Si-S-10 μm manufactured by Fukuda Metal Foil Co., Ltd.) An average particle size of 10 μm) was prepared. Moreover, a phenol resin (OI-305A manufactured by Dainippon Ink Co., Ltd.) was prepared as an organic binder. The amount of phenol resin added was 10% by weight with respect to the SiC powder, and this was filled in a mold and subjected to hot press molding. Thus, a square plate-shaped porous molded body having a side of 100 mm and a thickness of 10 mm was produced.

  And this porous molded object was installed in a furnace with metal Si (made by Nippon Electric Works), and the state heated to 1200 degreeC in the vacuum atmosphere was hold | maintained for 12 hours, and the phenol resin was degreased and carbonized. . After that, the SiC porous sintered body was impregnated with molten Si by maintaining the furnace heated to 1645 ° C. for 22 hours. This obtained the SiC / Si composite material body whose SiC filling rate is 22 volume%.

  And like Example 1, the test piece was produced from this SiC / Si composite material body, these test pieces were hold | maintained in the state heated and pressurized, and joining of the test piece was tried.

  As a result of observing a cross section of the joined portion of the obtained SiC / Si composite material bonded body with an optical microscope, no void was observed in the joined portion. Moreover, the four-point bending strength of the joint was 130 MPa, which was the same strength as the SiC / Si composite material (base material).

Example 8
As Example 8, joining of the test pieces was tried in the same manner as in Example 1 except that the surface roughness Ra of the joint surfaces of the two test pieces was 0.09 μm. As a result, the four-point bending strength was 260 MPa, and the joint strength was sufficient.

[Comparative Example 1]
SiC powder 100% by mass (60% by mass of NG90 manufactured by Taihei Random Co., Ltd. and 40% by mass of GP # 800 manufactured by Shinano Denki Smelting Co., Ltd.) and 15% by mass of coke powder (Oriental Sangyo Co., Ltd.) AT.No. 40-C) manufactured by the manufacturer was prepared, and 12% by mass of phenol resin powder (OI-305A manufactured by DIC Corporation) as an organic binder was added thereto. Then, this was filled in a mold and subjected to hot press molding. A SiC / Si composite material having a SiC filling rate of 96% by volume was obtained. Thus, a square plate-shaped porous molded body having a side of 100 mm and a thickness of 10 mm was produced.

  And this porous molded object was installed in a furnace with metal Si (made by Nippon Electric Works), and the state heated to 1200 degreeC in the vacuum atmosphere was hold | maintained for 12 hours, and the phenol resin was degreased and carbonized. . After that, the SiC porous sintered body was impregnated with molten Si by maintaining the furnace heated to 1645 ° C. for 22 hours. As a result, a SiC / Si composite material having a SiC filling rate of 96% by volume was obtained.

  And like Example 1, the test piece was produced from this SiC / Si composite material body, and joining of the test piece was tried. However, it was not joined at all. The four-point bending strength of the SiC / Si composite material (base material) was 250 MPa.

[Comparative Examples 2 and 3]
As Comparative Examples 2 and 3, the joining of the test pieces was tried in the same manner as in Example 1 except that the surface roughness Ra of the joining surface of the two test pieces was 0.12 μm and 0.18 μm, respectively. . However, the four-point bending strength of the joint was 90 MPa and 40 MPa, respectively, and the joint was insufficient.

[Comparative Examples 4 and 5]
As Comparative Examples 4 and 5, the test pieces were joined in the same manner as in Example 1 except that the heating temperatures at the time of joining were 900 ° C. and 980 ° C., respectively. However, it was not joined at all in Comparative Examples 4 and 5.

[Comparative Example 6]
As Comparative Example 6, joining of test pieces was attempted in the same manner as in Example 1 except that the heating temperature at the time of joining was 1450 ° C. However, metal Si eluted from the test piece. Further, the four-point bending strength of the joint was 80 MPa, and the joint was insufficient.

[Comparative Examples 7 and 8]
As Comparative Examples 7 and 8, a test piece was tried to be joined in the same manner as in Example 1 except that the heating and pressurizing holding times at the time of joining were 0.5 hours and 15 hours, respectively. However, the four-point bending strength of the joint was 90 MPa and 180 MPa, respectively, and the joint was insufficient. In Comparative Example 8, a defect occurred in the joint. This is considered to be because Si evaporated by heating for a long time.

[Comparative Examples 9 and 10]
As Comparative Examples 9 and 10, joining of test pieces was attempted in the same manner as in Example 1 except that the pressure applied during joining was 0.01 MPa and 10.5 MPa, respectively. However, in Comparative Example 9, it was not joined at all. In Comparative Example 10, the four-point bending strength of the joint was 300 MPa, but cracks occurred in the base material.

Claims (6)

  In a state where a plurality of SiC / Si composite materials are brought into contact with each other at the joint surfaces and a pressure of 0.05 MPa to 10.0 MPa is applied to the joint surfaces in an inert gas atmosphere, 1000 ° C. to 1414 A method for joining SiC / Si composite materials, characterized by joining by heating and holding at ° C.   The SiC / Si composite material joining method according to claim 1, wherein the SiC filling rate of the SiC / Si composite material is 20% by volume to 95% by volume.   3. The method of joining SiC / Si composite materials according to claim 1, wherein a surface roughness of the joining surface does not exceed 0.1 μm as a center line average roughness Ra. 4.   The SiC / Si composite material bonding method according to any one of claims 1 to 3, wherein the heating and holding time is 1 hour to 12 hours.   A plurality of SiC / Si are heated and held at 1000 ° C. to 1414 ° C. in a state in which a pressure of 0.05 MPa to 10.0 MPa is applied to the joint surface abutted in an inert gas atmosphere. A SiC / Si composite material joined body, wherein the composite material body is joined.   The SiC / Si composite material assembly according to claim 5, wherein the SiC / Si composite material assembly has a hollow structure.

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