JP6236314B2 - Silicon carbide bonded body and method for manufacturing the same - Google Patents

Description

  The present invention relates to a silicon carbide joined body in which silicon carbide sintered bodies are joined together, and a method for manufacturing the same.

  Silicon carbide sintered body is excellent in mechanical strength, heat resistance, corrosion resistance, etc., such as a pin chuck having a water cooling mechanism, a liquid recovery part of an immersion exposure apparatus, a shower plate which is a gas supply part of a CVD apparatus, etc. It is often used as a member for manufacturing equipment.

  However, since the silicon carbide sintered body has a high sintering temperature and is fired in an inert gas atmosphere, there is a limit to the size that can be formed satisfactorily. Therefore, various joining techniques have been proposed.

  For example, Patent Document 1 describes a technique in which silicon carbide sintered bodies are bonded to each other through a degreased body having a thickness of 1 to 100 mm containing silicon carbide as a main component. The bonding strength is increased by making the maximum void diameter of the bonding layer (bonding member) formed by heat treating the degreased body smaller than the maximum void diameter of the silicon carbide sintered body.

JP 2013-216500 A

  However, in the technique described in Patent Document 1, the degreased body is densified by the heat treatment at the time of bonding, and thus strain generated in the silicon carbide sintered body at the time of heat treatment cannot be absorbed. Therefore, a large residual stress remains in the silicon carbide joined body, and the silicon carbide joined body may be damaged during subsequent processing.

  An object of the present invention is to provide a silicon carbide joined body capable of reducing the residual stress remaining in the silicon carbide joined body and a method for manufacturing the same.

  The silicon carbide bonded body of the present invention is a silicon carbide bonded body in which a silicon carbide sintered body is bonded via a bonding layer made of silicon carbide, and the bonding layer has a thickness of 35 to 55 μm and a pore ratio. It is characterized by being 10 to 20% and an average pore diameter of 0.1 to 7.0 μm.

  When the thickness of the bonding layer is less than 35 μm, the internal strain of the silicon carbide sintered body generated by the heat treatment during bonding is not sufficiently absorbed, and the residual stress remaining in the silicon carbide bonded body increases. On the other hand, when the thickness of the bonding layer exceeds 55 μm, the number of defects that cause fracture increases, so that the bonding strength of the silicon carbide bonded body decreases.

  In addition, when the porosity of the bonding layer is less than 10% or the average pore diameter of the bonding layer is less than 0.1 μm, the internal strain of the silicon carbide sintered body generated by the heat treatment during bonding is a pore in the bonding layer. Residual stress that is not sufficiently absorbed and remains in the silicon carbide bonded body increases. On the other hand, when the porosity of the bonding layer exceeds 20% or the average pore diameter of the bonding layer exceeds 7.0 μm, the bonding layer has poor strength due to the large number of pores, and the bonding strength of the silicon carbide bonded body decreases. To do.

  Thus, according to the silicon carbide bonded body of the present invention, it is possible to reduce the residual stress remaining in the silicon carbide bonded body while ensuring the bonding strength.

  Furthermore, if the porosity of the silicon carbide sintered body is less than 1%, the internal strain of the silicon carbide sintered body generated by the heat treatment during bonding is not sufficiently absorbed, and the residual stress remaining in the silicon carbide bonded body growing. On the other hand, if the porosity of the silicon carbide sintered body exceeds 5%, the number of voids in the silicon carbide sintered body increases, so that the strength of the silicon carbide sintered body is inferior and the bonding strength of the silicon carbide bonded body decreases. . The pore ratio of the silicon carbide sintered body is the ratio of the area of the pores in the cut section of the silicon carbide sintered body.

  If the average pore diameter of the silicon carbide sintered body is less than 0.1 μm, the internal strain of the silicon carbide sintered body generated by the heat treatment during bonding is not sufficiently absorbed, and the residual remaining in the silicon carbide bonded body Stress increases. On the other hand, if the average pore diameter of the silicon carbide sintered body exceeds 5.0 μm, the pores of the silicon carbide sintered body increase, so that the strength of the silicon carbide sintered body is inferior, and the bonding strength of the silicon carbide bonded body is low. descend.

  Therefore, in the silicon carbide joined body of the present invention, the silicon carbide sintered body preferably has a pore ratio of 1 to 5% and an average pore diameter of 0.1 to 5.0 μm.

The method for manufacturing the silicon carbide joined body of the present invention, between the silicon carbide sintered body, has a thickness of 50～130Myuemu, said silicon carbide average grain size comprises a binder as silicon carbide and binder 1~20μm Sandwiching a joining sheet having a content of 85 to 95% by mass, performing heat treatment at a temperature of 1900 to 2100 ° C. for 3 to 10 hours while pressing with a load of 2 to 4 MPa, a thickness of 35 to 55 μm, and a porosity ratio A bonding layer having an average pore diameter of 10 to 20% and an average pore diameter of 0.1 to 7.0 μm is formed.

  According to the method for manufacturing a silicon carbide bonded body of the present invention, the above-described preferable silicon carbide bonded body of the present invention can be manufactured.

(A)-(c) is sectional drawing which shows typically the manufacturing method of the silicon carbide sintered joined body which concerns on embodiment of this invention one by one.

  Hereinafter, the manufacturing method of the silicon carbide sintered compact which concerns on embodiment of this invention is demonstrated.

  As shown in FIG. 1A, a plurality of, here two, silicon carbide sintered bodies 11 and 12 are prepared as base materials. Silicon carbide sintered bodies 11 and 12 can be produced by a molding method such as press molding, CIP molding, and cast molding, and a sintering method such as atmospheric pressure sintering, pressure sintering, and reaction sintering. As a sintering aid, 0.1 to 1.0% boron carbide and 1.0 to 5.0% graphite may be added to silicon carbide.

  Silicon carbide sintered bodies 11 and 12 preferably have a pore ratio of 1 to 5%. If the porosity is less than 1%, the internal strain of silicon carbide sintered bodies 11 and 12 generated by the heat treatment during bonding is not sufficiently absorbed, and the residual stress remaining in silicon carbide bonded body 20 increases. On the other hand, if the porosity ratio exceeds 5%, the number of voids in silicon carbide sintered bodies 11 and 12 increases, so that the strength of silicon carbide sintered bodies 11 and 12 is inferior and the bonding strength of silicon carbide bonded body 20 decreases. To do.

  The pore ratio of silicon carbide sintered bodies 11 and 12 is the ratio of the area of the pores in the cut cross section of silicon carbide sintered bodies 11 and 12. The area of the pores can be obtained by taking a photograph of the cut section using a microscope and processing the image.

  Silicon carbide sintered bodies 11 and 12 preferably have an average pore diameter of 0.1 to 5.0 μm. If the average pore diameter of the silicon carbide sintered bodies 11 and 12 is less than 0.1 μm, the internal strain of the silicon carbide sintered bodies 11 and 12 generated by the heat treatment during bonding is not sufficiently absorbed, and the silicon carbide bonded body The residual stress remaining in 20 increases. On the other hand, when the average pore diameter exceeds 5.0 μm, since the pores of silicon carbide sintered bodies 11 and 12 become large, the strength of silicon carbide sintered bodies 11 and 12 is inferior, and the bonding strength of silicon carbide bonded body 20 Decreases.

  Furthermore, the silicon carbide sintered bodies 11 and 12 preferably have a maximum pore diameter of 3 to 10 μm. If the maximum pore diameter of silicon carbide sintered bodies 11 and 12 is less than 3 μm, the internal strain of silicon carbide sintered bodies 11 and 12 generated by the heat treatment during bonding is not sufficiently absorbed, and silicon carbide bonded body 20 The residual stress that remains is increased. On the other hand, when the maximum pore diameter exceeds 10 μm, the strength of silicon carbide sintered bodies 11 and 12 is inferior, and the bonding strength of silicon carbide joined body 20 is lowered.

  It is preferable to perform grinding with a surface grinder, a machining center, or the like so that the surface roughness of the joint surfaces 11a, 12a of the silicon carbide sintered bodies 11, 12 is 0.7 μm or less. This is because if the surface roughness of bonding surfaces 11a and 12a exceeds 0.7 μm, contact between silicon carbide sintered bodies 11 and 12 and bonding sheet 13 is insufficient, bonding becomes insufficient, and peeling occurs. Mirror polishing such as lapping is not necessary. The flatness of the bonding surfaces 11a and 12a is preferably 5 μm or less. If the flatness of the joining surfaces 11a and 12a exceeds 5 μm, insufficient contact between the silicon carbide sintered bodies 11 and 12 and the joining sheet 13 occurs, resulting in insufficient joining and peeling.

  Furthermore, the joining sheet | seat 13 which contains silicon carbide and the binder as a binder as a material, and shape | molded in the sheet form is prepared. The thickness of the bonding sheet 13 is 50 to 130 μm.

  It is preferable that the content rate of the silicon carbide which comprises the joining sheet | seat 13 is 85-95 mass%. When the content is less than 85% by mass, the function as a skeleton in the bonding layer is not expressed, so that the volume of the bonding layer 23 is changed and peeling may occur. On the other hand, when it exceeds 95% by mass, silicon carbide is present in a relatively large amount, and it is difficult to form a sheet.

  Moreover, it is preferable that the average particle diameter of silicon carbide is 1-20 micrometers. When the average particle size is less than 1 μm, the function as a skeleton in the bonding layer is not expressed, so that the volume of the bonding layer 23 is changed and an unbonded portion is easily generated. On the other hand, when the average particle size exceeds 20 μm, the specific surface area in contact with the silicon carbide sintered bodies 11 and 12 is reduced, and thus there is a risk of peeling.

  As the binder, for example, an acrylic resin binder can be used. For example, silicon carbide may be mixed at a ratio of 85 to 95% by volume and a binder at a ratio of 5 to 15% by volume.

  In addition, the bonding sheet 13 may be added with a sintering aid such as boron carbide or graphite to silicon carbide. For example, boron carbide is 0.1 to 1.0% by volume, and graphite is 1.0 to 5%. 0.0% by volume may be added. Further, the joining sheet 13 may be one to which a dispersant such as polycarboxylic acid or a plasticizer such as phthalic acid is added. What is necessary is just to add 40-50 volume% of plasticizers with respect to a binder, for example.

  In order to prevent displacement, the bonding sheet 13 may be bonded to the bonding surfaces 11a and 12a using an adhesive. Note that the bonding sheet 13 is not degreased.

  Next, as shown in FIG. 1B, the bonding sheet 13 is sandwiched between the silicon carbide sintered bodies 11 and 12 and brought into contact with the bonding surfaces 11a and 12a. And it joins by heating, pressing in that state.

  In this joining step, it is preferable to hold at a temperature of 1900 to 2100 ° C. for 3 to 10 hours. If the bonding temperature is lower than 1900 ° C., the bonding sheet 13 is insufficiently melted and does not become densified, and peeling may occur. If the bonding temperature exceeds 2100 ° C., the silicon carbide of the silicon carbide sintered bodies 11 and 12 This is because abnormal grain growth occurs and bonding strength decreases.

  If the holding time is less than 3 hours, the bonding sheet 13 is insufficiently melted and does not become dense, and peeling may occur. On the other hand, when holding time exceeds 10 hours, the silicon carbide of the silicon carbide sintered bodies 11 and 12 grows abnormally, and the bonding strength decreases.

  Then, it is preferable that the vacuum is up to 1800 ° C., and the inert gas atmosphere, for example, the argon atmosphere is used from 1800 ° C. The reason why the vacuum is used up to 1800 ° C. is to remove the surface oxide layer of silicon carbide and carbonize the binder of the bonding material.

  Moreover, it is desirable to apply a load of 2 to 4 MPa at the time of joining. This is because if the bonding load is less than 2 MPa, the bonding sheet 13 and the bonding surfaces 11a and 12a may not be in close contact with each other, and a gap may be formed. If the bonding load exceeds 4 MPa, the bonding sheet 13 may be deformed.

  Thereby, as shown in FIG.1 (c), the silicon carbide joined body 20 which concerns on embodiment of this invention is obtained. The silicon carbide bonded body 20 is obtained by bonding base material layers 21 and 22 made of silicon carbide sintered bodies 11 and 12 via a bonding layer 23 formed by modifying the bonding sheet 13.

  The thickness of the bonding layer 23 is 35 to 55% of the thickness of the bonding sheet 13. Base material layers 21 and 22 contract only 0.04% or less in the thickness direction with respect to silicon carbide sintered bodies 11 and 12, and the dimensional change is very small.

  The thickness of the bonding layer 23 is 35 to 55 μm. When the thickness of the bonding layer 23 is less than 35 μm, the bonding layer 23 cannot sufficiently absorb the internal strain of the base material layers 21 and 22 generated by the heat treatment during bonding. On the other hand, when the thickness of bonding layer 23 exceeds 55 μm, the porosity of silicon carbide bonded body 20 increases, so that the bonding strength of silicon carbide bonded body 20 decreases.

  The bonding layer 23 has a pore ratio of 10 to 20% and an average pore diameter of 0.1 to 7.0 μm. When the porosity of the bonding layer 23 is less than 10%, or the average pore diameter of the bonding layer 23 is less than 0.1 μm, the internal strain of the base material layers 21 and 22 generated by the heat treatment during bonding is reduced in the bonding layer 23. It cannot be sufficiently absorbed by the pores. On the other hand, when the porosity ratio of bonding layer 23 exceeds 20% or the average pore diameter of bonding layer 23 exceeds 7.0 μm, the number of voids is large and the strength of bonding layer 23 is inferior, and silicon carbide bonded body 20 The bonding strength of the is reduced.

  Further, the bonding layer 23 preferably has a maximum pore diameter of 5 to 15 μm and is larger than the maximum pore diameter of the base material layers 21 and 22. When the maximum pore diameter of the bonding layer 23 is less than 5 μm, the internal strain of the base material layers 21 and 22 generated by the heat treatment at the time of bonding cannot be sufficiently absorbed. On the other hand, when the maximum pore diameter of bonding layer 23 exceeds 15 μm, the pores of bonding layer 23 increase, so that the strength of bonding layer 23 is inferior and the bonding strength of silicon carbide bonded body 20 decreases. The maximum pore diameter of the base material layers 21 and 22 is substantially the same as the maximum pore diameter of the silicon carbide sintered bodies 11 and 12.

  Such a bonding layer 23 is formed by densifying the bonding sheet 13 described above by a bonding process. When the bonding layer 23 has a high firing temperature, a high pressing pressure, or a large amount of binder in the bonding sheet 13, the pore ratio, the average pore diameter, and the maximum pore diameter increase.

  Such a silicon carbide bonded body 20 has a high bending strength at room temperature of 78 to 100% of the bending strength of the silicon carbide sintered bodies 11 and 12 as the base materials.

  In addition, the silicon carbide bonded body 20 has a small residual stress of 50 to 150 MPa in terms of tensile stress, and internal strain is suppressed.

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

[Example 1]
As shown in FIG. 1A, two silicon carbide sintered bodies 11 and 12 having a diameter of 100 mm and a thickness of 6 mm were prepared. These silicon carbide sintered bodies 11 and 12 were commercially available silicon carbide powder (UF-10 manufactured by Stark), press-molded, CIP-molded, and sintered at normal pressure. As sintering aids, 0.25% boron carbide and 2.0% graphite were added to silicon carbide. The surface roughness of the joint surface was ground by a surface grinder and adjusted to 0.3 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was measured in accordance with JIS R 1624-2010. The bending strength was 420 MPa.

  And it grind-processed so that the surface roughness of joint surface 11a, 12a might be 0.3 micrometer, and flatness might be 2.3 micrometers.

  Further, a bonding sheet 13 having a diameter of 100 mm and a thickness of 100 μm was prepared. This joining sheet 13 was produced by preparing a slurry to which silicon carbide and a binder as a binder were added, and using a doctor blade method. An acrylic resin binder was used as the binder. The binder was mixed at a ratio of 85% by volume of silicon carbide and 15% by volume of binder.

  Further, 0.25% boron carbide and 2.0% graphite were added to the bonding sheet 13 as sintering aids. Further, the bonding sheet 13 was added with a polycarboxylic acid-based dispersant and a phthalic acid-based plasticizer.

  Next, as shown in FIG.1 (b), the joining sheet | seat 13 was inserted | pinched between the silicon carbide sintered compacts 11 and 12 so that it might contact | abut with the joining surfaces 11a and 12a of the silicon carbide sintered compacts 11 and 12. FIG. In the state, it joins by heating, pressurizing with the pressure of 4.0 Mpa.

  Up to 1800 ° C., an argon atmosphere was used in vacuum from 1800 ° C. to room temperature (end of heat treatment). The temperature was maintained at 2100 ° C. for 6 hours.

  Thereby, as shown in FIG.1 (c), the silicon carbide joined body 20 was obtained. The thickness of the bonding layer 23 was 45 μm. The bonding layer 23 had a porosity ratio of 10%, an average pore diameter of 0.1 μm, and a maximum pore diameter of 5 μm.

  The pore ratio is the ratio (area) of pores in the range of 120 μm × 90 μm, which is obtained by polishing a cut cross section of the silicon carbide bonded body 20 and enlarging the polished surface at a magnification of 2500 times using an optical microscope. Was measured. As for the pore diameter, the total pore diameter within the above-mentioned image range was measured, and the average pore diameter and the maximum pore diameter were determined.

  The bending strength of silicon carbide joined body 20 at room temperature was measured in accordance with JIS R 1624-2010. The bending strength was 423 MPa, which was 101% of the bending strength of the silicon carbide sintered bodies 11 and 12 as the base material, and was high strength.

  Moreover, the measurement of the residual stress of the silicon carbide bonded body 20 was performed according to the method of ASTM-E915 (American Society for Testing and Materials) using LXRD manufactured by Proto Manufacturing Co., Ltd. as a measuring device. The residual stress was as small as 148 MPa.

  The results of Examples 1 to 7 are summarized in Tables 1 and 2.

[Example 2]
As Example 2, a silicon carbide joined body 20 was manufactured in the same manner as in Example 1 except that the firing temperature was 2050 ° C. and the pressure was 3.5 MPa. The bonding layer 23 had a pore ratio of 13%, an average pore diameter of 0.5 μm, and a maximum pore diameter of 7 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was 415 MPa, 99% of the bending strength of silicon carbide sintered bodies 11 and 12 as the base material, and was high strength. Moreover, the residual stress of the silicon carbide joined body 20 was as small as 102 MPa.

Example 3
As Example 3, a silicon carbide joined body 20 was produced in the same manner as in Example 1 except that the firing temperature was 2000 ° C. and the pressure was 3.5 MPa. The bonding layer 23 had a pore ratio of 15%, an average pore diameter of 1.0 μm, and a maximum pore diameter of 10 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was 398 MPa, which was 95% of the bending strength of silicon carbide sintered bodies 11 and 12 as the base material, and was high strength. Moreover, the residual stress of the silicon carbide joined body 20 was as small as 84 MPa.

Example 4
As Example 4, a silicon carbide joined body 20 was produced in the same manner as in Example 1 except that the firing temperature was 1950 ° C. and the pressure was 3.0 MPa. The bonding layer 23 had a porosity ratio of 18%, an average pore diameter of 3.0 μm, and a maximum pore diameter of 12 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was 372 MPa, 89% of the bending strength of silicon carbide sintered bodies 11 and 12 as the base material, and was high strength. Further, the residual stress of silicon carbide joined body 20 was as small as 68 MPa.

Example 5
As Example 5, Example 1 and silicon carbide joined body 20 were manufactured in the same manner as in Example 1 except that the firing temperature was 1900 ° C. and the pressure was 2.0 MPa. The bonding layer 23 had a pore ratio of 20%, an average pore diameter of 5.0 μm, and a maximum pore diameter of 15 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was 359 MPa, 85% of the bending strength of silicon carbide sintered bodies 11 and 12 as the base material, and was high strength. Moreover, the residual stress of the silicon carbide joined body 20 was as small as 50 MPa.

Example 6
As Example 6, Example 1 and the silicon carbide bonded body 20 were manufactured in the same manner as in Example 6 except that the thickness of the bonding sheet 13 was 80 μm, the firing temperature was 2000 ° C., and the pressure was 3.5 MPa. The bonding layer 23 had a thickness of 35 μm, a pore ratio of 15%, an average pore diameter of 1.0 μm, and a maximum pore diameter of 10 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was 402 MPa, which was 96% of the bending strength of silicon carbide sintered bodies 11 and 12 as the base material, and was high strength. Further, the residual stress of silicon carbide joined body 20 was as small as 113 MPa.

Example 7
As Example 7, a silicon carbide bonded body 20 was manufactured in the same manner as in Example 1 except that the thickness of the bonding sheet 13 was 120 μm, the firing temperature was 2000 ° C., and the pressure was 3.5 MPa. The bonding layer 23 had a thickness of 55 μm, a pore ratio of 15%, an average pore diameter of 1.0 μm, and a maximum pore diameter of 10 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was 328 MPa, 78% of the bending strength of silicon carbide sintered bodies 11 and 12 as the base material, and was high strength. Further, the residual stress of silicon carbide joined body 20 was as small as 75 MPa.

[Comparative Example 1]
As Comparative Example 1, silicon carbide joined body 20 was manufactured in the same manner as in Example 1 except that the firing temperature was 2150 ° C. The bonding layer 23 had a thickness of 45 μm, a porosity ratio of 8%, an average pore diameter of 0.08 μm, and a maximum pore diameter of 4 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was 436 MPa, which was 104% of the bending strength of silicon carbide sintered bodies 11 and 12 as the base material, and was high strength.

  However, the residual stress of silicon carbide joined body 20 was as large as 248 MPa. This is because the pore ratio of the bonding layer 23 is as low as 8%, the average pore diameter is 0.08 μm, the maximum pore diameter is 4 μm and the pores are small, and the internal strain of the base material layers 21 and 22 generated by the heat treatment during bonding is reduced. This is thought to be due to insufficient absorption.

  The results of Comparative Examples 1 to 4 are summarized in Table 3 and Table 4.

[Comparative Example 2]
As Comparative Example 2, silicon carbide joined body 20 was produced in the same manner as in Example 1 except that the firing temperature was 1850 ° C. and the pressure was 2.0 MPa. The bonding layer 23 had a thickness of 45 μm, a porosity ratio of 22%, an average pore diameter of 6.0 μm, and a maximum pore diameter of 17 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was 291 MPa, which was only 69% of the bending strength of silicon carbide sintered bodies 11 and 12 as the base material, and the strength was poor. This is considered to be because the pore ratio of the bonding layer 23 is as high as 22, the average pore diameter is 6.0 μm, the maximum pore diameter is 17 μm, the pores are large, and the strength of the base material layers 21 and 22 is reduced. Residual stress of silicon carbide joined body 20 was as small as 48 MPa.

[Comparative Example 3]
As Comparative Example 3, silicon carbide bonded body 20 was manufactured in the same manner as in Example 1 except that the thickness of bonding sheet 13 was 45 μm, the firing temperature was 2000 ° C., and the pressure was 3.5 MPa. The bonding layer 23 had a thickness of 25 μm, a pore ratio of 15%, an average pore diameter of 1.0 μm, and a maximum pore diameter of 10 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was 411 MPa, which was 98% of the bending strength of silicon carbide sintered bodies 11 and 12 as the base material, and was high strength.

  However, the residual stress of silicon carbide joined body 20 was as large as 298 MPa. This is presumably because the thickness of the bonding layer 23 was as thin as 25 μm and the internal strains of the base material layers 21 and 22 generated by the heat treatment during bonding could not be sufficiently absorbed.

[Comparative Example 4]
As Comparative Example 4, a silicon carbide bonded body 20 was manufactured in the same manner as in Example 1 except that the thickness of the bonding sheet 13 was 150 μm, the firing temperature was 2000 ° C., and the pressure was 3.5 MPa. The bonding layer 23 had a thickness of 65 μm, a pore ratio of 15%, an average pore diameter of 1.0 μm, and a maximum pore diameter of 10 μm.

  The bending strength of silicon carbide joined body 20 at room temperature was 284 MPa, which was only 68% of the bending strength of silicon carbide sintered bodies 11 and 12 as the base material, and the strength was poor. This is presumably because the thickness of the bonding layer 23 is as thick as 65 μm, and the number of defects that cause the breakdown has increased. Residual stress of silicon carbide joined body 20 was as small as 52 MPa.

  DESCRIPTION OF SYMBOLS 11, 12 ... Silicon carbide sintered compact, base material, 11a, 12a ... Joining surface, 13 ... Joining sheet, 20 ... Silicon carbide joined body, 21, 22 ... Base material layer, 23 ... Joining layer.

Claims (3)

The silicon carbide sintered body is joined through a joining layer made of silicon carbide,
The bonding layer has a thickness of 35 to 55 μm, a pore ratio of 10 to 20%, and an average pore diameter of 0.1 to 7.0 μm.   2. The silicon carbide bonded body according to claim 1, wherein the silicon carbide sintered body has a pore ratio of 1 to 5% and an average pore diameter of 0.1 to 5.0 μm. Bonding between silicon carbide sintered bodies having a thickness of 50 to 130 μm , an average particle diameter of 1 to 20 μm, a binder as a binder, and a silicon carbide content of 85 to 95% by mass The sheet was sandwiched and heat-treated for 3 to 10 hours at a temperature of 1900 to 2100 ° C. while being pressed with a load of 2 to 4 MPa. A method for producing a silicon carbide sintered joined body, comprising forming a joining layer having a thickness of ˜7.0 μm.