JP2007138303A - Diamond-coated carbon member and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diamond-coated carbon member capable of preventing cracking or peeling at a boundary between a base material and a diamond coating film by improving the adhesiveness therebetween, ensuring advantages of properties of a carbon material itself and making full advantage of excellent properties of the diamond coating film, and also to provide a method for manufacturing the same. <P>SOLUTION: A surface of a carbonaceous base is converted into silicon carbide by a CVR (Chemical Vapor Reaction) method to form a coating layer whose boundary surface between the layer and the base reflects the state of the surface. The diamond coating film is formed on the surface of the coating layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a carbon member whose surface is coated with diamond, and more specifically, elements used for various sensors such as tools, various semiconductor device constituent materials, magnetic recording media, various electric / The present invention relates to a diamond-coated carbon member used for electronic members, optical elements and optical devices of various optical devices, materials for nuclear fusion devices, components of acoustic devices, and the like, and a method for manufacturing the same.

  Diamond is the hardest of the currently known materials, has excellent thermal conductivity, is very scientifically stable, has a large modulus of elasticity, good electrical insulation, etc. It is attracting attention as a new material applicable to a wide range of industrial fields such as machinery and aerospace. As a diamond synthesis method, in addition to a high-pressure synthesis method for synthesis under high temperature and ultra-high pressure, a low-pressure synthesis method capable of forming a large-area diamond thin film on the surface of a substrate such as ceramic or metal is widely known. Yes.

  Further, the low-pressure synthesis method can be broadly divided into a physical vapor deposition method {(Physical Vapor Deposition) or below, abbreviated as PVD method} and a chemical vapor deposition method {(Chemical Vapor Deposition) or below, abbreviated as CVD method}. In recent years, the synthesis method by the CVD method has become the main force because it has an advantage that diamond having higher crystallinity than a PVD method can be formed over a large area and at a high speed.

  Further, as a base for forming a diamond film (hereinafter simply referred to as a base material), diamond, tungsten sintered body, silicon carbide sintered body, silicon single crystal, molybdenum, niobium, tantalum, vanadium, chromium, hafnium, Metals such as germanium, nickel, copper, and gold, and ceramics such as cubic boron nitride sintered body, silicon nitride sintered body, aluminum oxide, silicon dioxide, stellite, and cermet are used.

  When the diamond coating is formed on the base material, it is heated to about 500 Kelvin (hereinafter abbreviated as K) to 1500 K, and gas such as methane, ethylene, propane, acetylene, carbon monoxide, carbon dioxide and methyl A raw material gas that vaporizes a liquid such as alcohol, ethyl alcohol, benzene, acetone, etc. is diluted with hydrogen gas, the inside of the furnace is made an argon gas atmosphere or a hydrogen gas atmosphere, the raw material gas is excited, a chemical transport method, a thermal CVD method The object is achieved by implementing an appropriate method among various CVD methods such as a plasma CVD method, a combustion method, and a photo-CVD method.

  However, in forming a diamond coating on the base material, there are various considerations, specifically (1) it is necessary to select a base material with good heat resistance, and (2) the base material is In the case of ceramic, since it is very hard, it is difficult to process, and (3) the adhesion between the base material and the diamond coating is not very good. In order to reduce these defects, it is necessary to take care to reduce these defects, and even if processing is performed under such consideration, a satisfactory product may not always be obtained under the request of ensuring economic efficiency. It was.

  Therefore, while the study for improving the diamond-coated member is proceeding, attention has been paid to the excellent properties of the carbon material, such as good heat resistance, easy processing, and economical cost. Attempts have also been made to form a diamond coating directly on the surface of the base material. However, since the thermal expansion coefficient is greatly different, the adhesion with the diamond film is not good, and when the CVD method is performed, the carbon material is directly exposed to a reducing atmosphere containing a large amount of hydrogen. There is a drawback that the carbon material is consumed due to reaction with hydrogen gas, and the superior characteristics of the carbon material itself cannot be utilized.

  Furthermore, for the purpose of eliminating such defects, a diamond-coated carbon member in which a silicon carbide coating layer is formed on the surface of a carbon material molded body by a CVD method as a base material and a diamond coating is formed on the base material is provided. It has been proposed (see Patent Document 1 below).

JP-A-1-2014478

  However, when the present inventors actually use the above diamond-coated carbon member, cracks and peeling are likely to occur in the base material, and when applied to the cutting edge of an application, such as a cutting tool, the life is short and the cutting edge It has been found that there is a problem that the production cost is rather high as the number of replacements increases.

  The present invention has been made in view of the above circumstances, improves the adhesion between the base material and the diamond coating, eliminates the occurrence of cracks and peeling that are likely to occur at the interface between the two, and the properties of the carbon material itself. An object of the present invention is to provide a diamond-coated carbon member capable of maximally effectively exhibiting excellent characteristics of a diamond coating while ensuring superiority.

Means and effects for solving the problems

  The method for producing a diamond-coated carbon member of the present invention converts the surface of a carbonaceous substrate into silicon carbide by a chemical vapor reaction (hereinafter referred to as “CVR (Chemical Vapor Reaction) method”). A diamond film is formed on a coating layer having a boundary surface reflecting the state between the substrate and the substrate. As another aspect, the method for producing a diamond-coated carbon member according to the present invention converts a surface of a carbonaceous substrate into silicon carbide by a chemical vapor reaction, thereby forming a coating layer and roughening the surface of the coating layer. After the formation, a diamond film may be formed on the surface. These manufacturing methods eliminate the cracks and delamination at the interface between the base material and the diamond coating, which were previously considered problems, and maximize the superior properties of the diamond coating while ensuring the superiority of the properties of the carbon material itself. It becomes possible to produce a diamond-coated carbon member that can be effectively exhibited.

  In the diamond-coated carbon member of the present invention, the surface of the carbonaceous substrate is converted into silicon carbide by chemical vapor reaction to form a coating layer, and after roughening the surface of the coating layer, A diamond film is formed. As another aspect, the diamond-coated carbon member of the present invention converts the surface of a carbonaceous substrate into silicon carbide by a chemical vapor reaction so that a boundary surface reflecting the surface state is formed between the substrate and the substrate. The coating layer may be formed, and after the surface of the coating layer is roughened, a diamond coating may be formed on the surface. These diamond-coated carbon members eliminate cracks and peeling at the interface between both the base material and the diamond coating, which has been considered a problem in the past, while ensuring the superiority of the properties possessed by the carbon material itself. The characteristics can be exhibited as effectively as possible.

  In the diamond-coated carbon member of the present invention, the cobalt content contained in the carbonaceous substrate is preferably 10 ppm or less. As a result, the adhesion strength between the diamond coating and the carbonaceous substrate as the base material can be reduced, and the growth rate of the diamond coating can be suppressed.

  The present invention will be described in detail below. The inventors of the present invention have also been diligently researching to develop a high-quality diamond-coated carbon member, and the SiC layer in the vicinity of the interface (carbon member surface layer portion) of the conventional diamond-coated carbon member is considered as a crystal structure. Focusing on the fact that it is dense and layered, the low adhesion between the base material and the diamond coating was attributed to the presence of this form. That is, a laminated form in which a boundary surface between a lower surface of a layer converted to silicon carbide (hereinafter simply referred to as a converted layer) and an upper surface of a carbonaceous molded body (hereinafter referred to as a carbonaceous substrate) is not layered but corrugated. If so, since the two are engaged and joined, the method developed by the present inventors, that is, silicon monoxide (SiO) gas is applied under the expectation that the adhesion can be improved. As a result of applying a method of forming a silicon carbide molded body (SiC film) on a graphite substrate by chemical reaction, it can be confirmed that a diamond-coated member that is satisfactory in terms of adhesion can be obtained. The completion of the invention is seen.

  Further, if the experiment is advanced and the film thickness of the conversion layer and the film thickness of the diamond film formed thereon are optimized, the diamond film and the base material (hereinafter referred to as the base material in the present invention have the conversion layer). The improvement of the adhesion with the surface layer portion of the carbonaceous substrate) becomes even more remarkable, and the knowledge that cracks and peeling can be completely avoided at the interface between the carbonaceous substrate and the conversion layer is obtained. The present invention has been achieved.

  Among the configurations of the present invention, the carbonaceous substrate will be described first. The carbonaceous substrate used in the present invention may be substantially composed of carbon and manufactured by a conventional method. Examples thereof include graphitized carbon materials, carbon fiber reinforced carbon composite materials (so-called C / C materials), and glassy materials. Carbon molded bodies and expanded graphite molded bodies can be used.

  It is desirable to reduce impurities contained in the carbonaceous substrate as much as possible, and it is more desirable to use a high-purity graphite material shown in Japanese Industrial Standard (hereinafter simply referred to as JIS) R7221-1979. Above all, the carbonaceous substrate is heated to 2000K to 3000K with chlorine gas, fluorine gas, and gas containing these chlorine gas and fluorine gas, such as monochlorotrifluoromethane, dichlorodifluoromethane, trichloromonofluoromethane, etc. It is particularly desirable to select and use a carbonaceous substrate that is purified and has an ash content of 50 ppm or less. Among them, it is most desirable to use a carbonaceous substrate with a cobalt content of 10 ppm or less, which lowers the adhesion strength between the diamond coating and the base material and suppresses the growth rate of diamond.

  In addition, as a method of measuring the content rate of cobalt, for example, “Analytical Chemistry” Vol. 42 (1993) on page 486 of the reprint. The method shown in "Inductively coupled plasma mass spectrometry (also called ICP-MS method)" can be exemplified.

In addition, it is desirable to select a carbonaceous substrate having a high strength in consideration of prevention of breakage, for example, a carbonaceous substrate having a bending strength measured by a three-point strength test of 40 MPa or more. Among the carbonaceous substrates, a carbonaceous substrate having a thermal expansion coefficient close to the thermal expansion coefficient of silicon carbide, for example, a carbon association standard (hereinafter referred to as JCAS) in order to prevent peeling and cracking of the carbonaceous substrate and silicon carbide. was measured in the "method of measuring the average thermal expansion coefficient of quartz dilatometer", average thermal expansion coefficients from room temperature to 1273K is ^{4.0 × (10 -6 /K)~5.0×(10 -6 /} K) It is further desirable to select a carbonaceous substrate, and among them, it is particularly desirable to use an isotropic graphite material having an anisotropic ratio of 1.2 or less, in order to convert the surface layer portion of the carbonaceous substrate into silicon carbide. It is desirable to select an isotropic graphite material having an average pore radius of 0.5 μm to 1.8 μm by mercury porosimetry. The measurement of the cumulative pore volume and the average pore radius can be exemplified by, for example, a mercury intrusion method, and the amount of pores when pressurized to a maximum pressure of 98 MPa is defined as the cumulative pore volume (× 10 ⁻² Mg / m ³ ). A value (μm) corresponding to ½ of the pore volume can be determined as the average pore radius. The isotropic graphite material here refers to a graphite material having an anisotropy of a thermal expansion coefficient of 1.2 or less in an arbitrarily perpendicular direction.

Next, the silicon carbide conversion layer will be described. As a method for converting the surface layer portion of the carbonaceous substrate into silicon carbide, basically, the CVR method described in JP-A-1-264969 previously disclosed by the present inventors may be used. The carbonaceous substrate processed into a predetermined shape is placed in an electric furnace to make an inert gas atmosphere, and then, for example, metal silicon and SiO ₂ are reacted to generate SiO gas, and the carbonaceous substrate at about 2000K. And a SiO gas may be reacted to form a conversion layer on the surface layer of the carbonaceous substrate. Note that it is possible to convert only a part of the surface layer portion of the carbonaceous substrate or the entire surface layer portion of the conversion layer.

  The thickness of the conversion layer is desirably 1 μm or more from the surface of the carbonaceous substrate in the depth direction. The reason is that if the depth of the conversion layer is thinner than 1 μm, the carbonaceous substrate cannot be sufficiently prevented from being etched by hydrogen gas when the diamond film is formed. In addition, although there is no upper limit to the thickness of the conversion layer, if it is thicker than 1000 μm, the gas enclosed in the pores existing in the conversion layer, such as water vapor, silicon monoxide, carbon monoxide, oxygen, and carbon powder, may become a diamond coating. In addition to affecting the rate at which the diamond film grows due to thermal diffusion during the formation of carbon, carbon monoxide and carbon powder precipitate as an amorphous hard carbon film by thermal excitation. It may also affect the purity of the diamond coating. Therefore, in order to obtain a more reliable and remarkable effect, it is safe and desirable that the thickness of the conversion layer be 10 μm to 500 μm.

Further, by forming a conversion layer so that the average pore radius is 0.5 μm or less and the cumulative pore volume is 5 (× 10 ⁻² Mg / m ³ ) or less, the above effect, that is, the acceleration of the crystal speed of the diamond film is promoted. The inventors have also found that the purity of the diamond coating can be further improved.

  Furthermore, the pores existing in the conversion layer are impregnated with glassy carbon having a thermal expansion coefficient intermediate between diamond and the conversion layer and having high airtightness and high hardness, and silicon having excellent adhesion to the diamond coating ( The present inventors have also found that it is effective in sealing the pores of the conversion layer and improving the strength of the base material.

The base material prepared by the above operation is put into a liquid containing diamond powder (also referred to as diamond compound) having a particle size of 0.1 μm to 1 μm, and is subjected to ultrasonic cleaning, or using a diamond sandpaper. The growth rate of the diamond film is formed by forming scratches (hereinafter referred to as scratches) on the surface so that the maximum surface roughness (R _max ) shown in JIS B0601-1982 is 0.5 μm to 1.0 μm. It is also possible to further improve the adhesion to the base material. The scratching operation in this case is simpler than the case of scratching the surface of the CVD-SiC layer in the conventional diamond-coated carbon member. That is, the conventional CVD-SiC layer is very dense and the surface thereof is flat, and thus requires a stronger scratching operation, whereas the CVR-SiC layer of the present invention is relatively porous (porous). Since the surface is also quite undulating, a light scratch is sufficient, which can be said to be advantageous in reducing the work cost.

  The diamond film formed on the surface of the base material will be described. The thickness of the diamond coating formed on the surface of the base material is desirably 1 μm to 100 μm. The reason is that if the thickness of the diamond coating is less than 1 μm, the diamond coating formed on the surface of the base material will be worn away quickly. If the thickness of the diamond coating is thicker than 100 μm, the thermal expansion coefficient of diamond will be higher than that of the conversion layer. Therefore, tensile stress is generated in the base material, and not only peeling and cracking are likely to occur between the base material and the diamond coating, but also the time for forming the diamond coating is increased. Therefore, the thickness of the diamond coating to be formed on the surface of the base material is preferably 10 μm to 50 μm, which is safe and desirable.

  The conditions for forming the diamond coating will be described as follows. Examples of the diamond film forming means include a microwave plasma CVD method, a hot filament method, a high frequency plasma CVD method, an electron impact CVD method, a photo CVD method, a direct current CVD method, and the like. Is possible.

  An example of forming a diamond film by the microwave plasma CVD method is as follows. First, the base material on which the scratch is formed is put into the apparatus. The inside of the apparatus is in a reduced pressure state of an argon gas atmosphere of about 1 Torr to 100 Torr, and the base material is heated by induction heating. The temperature for heating the base material is preferably as low as possible so as not to cause peeling or cracking of the base material, and is preferably set to 1000K or less.

  Subsequently, a 2.45 GHz microwave is launched from the waveguide. As a source gas that is a supply source of diamond, methane gas is used as a carrier gas, and hydrogen gas is used as a carrier gas. Hydrogen gas is supplied to methane gas 1 at a volume ratio of 50 to 200. In this case, it is possible to reduce the concentration of methane gas at first and gradually increase the concentration of methane gas. When the deposition rate of the diamond coating is less than 1 μm per hour, it takes a long time to obtain a predetermined film thickness, and the heating time becomes long, which causes an influence on the base material, that is, causes peeling and cracking. Moreover, when the deposition rate is faster than 10 μm, in addition to the polycrystalline diamond film having a high purity, an amorphous hardened carbon film is deposited, so that not only the purity of the diamond is lowered, but also the adhesion to the base material is improved. Is not desirable.

  Thus, although the diamond-coated carbon product of the present invention can be produced, the characteristics of diamond can be further utilized depending on the application. When used for the most frequently used cutting tools such as tools, dressers, cutters, drills, glass cutters, etc., not only high hardness is required, but also high processing accuracy must be imparted to the workpiece. is there. In addition, a problem when used as the cutting tool is that the sharpness of the cutting edge is lost due to wear. Therefore, in the case of forming for use in the cutting tool, it is necessary to ensure a sufficient film thickness to sufficiently withstand wear while making use of the sharpness of the cutting edge, and the diamond film thickness is 10 μm to It is desirable to be about 30 μm.

  Moreover, when using for the use for which high heat conductivity is requested | required, it is desirable to make it high heat conductivity of a base material in addition to the high heat conductivity of a diamond. In such a case, the conversion layer having a low thermal conductivity is made as thin as possible, for example, about 1 μm, and a carbonaceous substrate having a high thermal conductivity of 100 W / (m · k) or more is selected as the carbonaceous substrate. It is desirable to increase the thermal conductivity of the entire base material.

  As described above, in the present invention, a carbonaceous substrate having specific physical properties is selected, and a coating layer converted to silicon carbide by the CVR (Chemical Vapor Reaction) method is formed on the surface layer of the carbonaceous substrate with a thickness of 1 μm to 1000 μm. Therefore, no peeling or cracking occurs at the interface between the conversion layer and the carbonaceous substrate. If necessary, the average pore radius and cumulative pore volume of the conversion layer can be adjusted, and in some cases, the pores of the conversion layer can be impregnated with glassy carbon or silicon to improve the hermeticity of the base material. Therefore, when the diamond coating is formed, there is almost no formation of an amorphous hard carbide film, etc., and a high-purity diamond coating can be obtained, the adhesion between the diamond coating and the base material is good, and there is no occurrence of peeling or cracking .

  Hereinafter, the present invention will be specifically described based on examples while showing reference examples.

<Reference Example 1>
(Preparation of carbonaceous substrate)
Average pore radius by mercury intrusion method is 1.1 μm, bending strength by 3-point bending test method is 60 MPa, average thermal expansion coefficient from room temperature to 1273 K by quartz thermal dilatometer is 4.7 (× 10 ⁻⁶ / K) An isotropic graphite material was prepared. This isotropic graphite material was processed into a size of 50 mm square and a thickness of 10 mm, and then purified to obtain a test piece. The ash content contained in the test piece was 10 ppm.
(Preparation of base material)
On the other hand, a graphite crucible having an inner diameter of 100 mm, a thickness of 10 mm, and a height of 100 mm was filled with 0.3 kg of metal silicon, and the metal silicon was melted at 1800 K by high frequency induction heating. A test piece was put in molten silicon, and a 200 μm conversion layer was formed of β-silicon carbide on the entire surface layer portion of the test piece, which was used as a base material. When the accumulated pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 4.0 (× 10 ⁻² Mg / m ³ ) and 0.4 μm, respectively. This base material was impregnated with 95% of the pores of the conversion layer in silicon at 2000K for 2 hours. It was 1.8 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. Put a diamond compound with an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this to disperse the diamond compound, and put the base material subjected to the above ultrasonic treatment into it. After that, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.5 μm.
(Diamond coating on the base material)
A base material is put into the apparatus, methane gas is used as a source gas, hydrogen gas is used as a carrier gas, a gas with a methane gas concentration of 0.5% by volume in hydrogen gas is flowed into the apparatus, and the pressure in the apparatus is 50 Thor, the substrate (base material) temperature is 1200K, and 2.45 GHz microwave is introduced into the center of the reaction tube through the waveguide to deposit a diamond film of 1 μm per hour, and the reaction is continued for 20 hours. A diamond film having a thickness of 20 μm was formed by a wave plasma CVD method.

<Example 1>
(Preparation of carbonaceous substrate)
Average pore radius by mercury intrusion method is 1.8 μm, bending strength by 3 point bending test method is 40 MPa, average thermal expansion coefficient from room temperature to 1273 K by quartz thermal dilatometer is 4.7 (× 10 ⁻⁶ / K) An isotropic graphite material was prepared. This isotropic graphite material was processed into a dimension of 50 mm square and 10 mm thickness to obtain a test piece. The ash content in the test piece was 12 ppm.
(Preparation of base material)
On the other hand, a partition was provided in the electric furnace, a graphite crucible was placed in a part of the partition, and 0.1 kg of metal silicon and 0.1 kg of silicon dioxide were placed in the graphite crucible. In addition, a test piece was placed in a separate chamber, and the entire interior of the electric furnace was made to be an inert gas atmosphere by flowing argon gas at a rate of 1 liter per minute, and then heated to 2300 K to generate silicon monoxide gas. A base material was formed by reacting a carbonaceous substrate and silicon monoxide gas to form a conversion layer of 500 μm over the entire surface of the carbonaceous substrate. When the cumulative pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 2.0 (× 10 ⁻² Mg / m ³ ) and 0.2 μm, respectively. It was 0.5 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. Put a diamond compound with an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this to disperse the diamond compound, put the above base material in this, and give ultrasonic vibration for 10 minutes. Scratches were formed. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JIS B0601-1982. As a result, the maximum surface roughness (R _max ) was 0.7 μm.
(Diamond coating on the base material)
A base material is put into the apparatus, methane gas is used as a source gas, hydrogen gas is used as a carrier gas, a gas with a methane gas concentration of 0.5% by volume in hydrogen gas is flowed into the apparatus, and the pressure in the apparatus is 50 Toll, substrate temperature is 1200K, 2.45 GHz microwave is introduced into the center of the reaction tube through the waveguide to make the diamond coating 1 μm volume per hour, and the reaction is continued for 20 hours to microwave plasma A 20 μm diamond film was formed by CVD.

<Reference Example 2>
(Preparation of carbonaceous substrate)
Isotropic graphite with an average pore radius of 0.5 μm by mercury intrusion method, a three-point bending strength of 90 MPa, and an average thermal expansion coefficient from room temperature to 1273 K by a quartz thermal dilatometer of 4.9 (× 10 ⁻⁶ / K) Made the material. This isotropic graphite material was processed into a dimension of 50 mm square and 10 mm thickness to obtain a test piece. The ash content in the test piece was 12 ppm.
(Preparation of base material)
The same operation as in Reference Example 1 was performed, and a base material was formed by forming a conversion layer of 250 μm on the entire surface layer portion of the carbonaceous substrate. When the cumulative pore area and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 1.8 (× 10 ⁻² Mg / m ³ ) and 0.1 μm, respectively. It was 0.9 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. Put a diamond compound with an average particle diameter of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this to disperse the diamond compound, put the above-mentioned base material in this, and apply ultrasonic vibration for 10 minutes. A scratch was formed. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.9 μm.
(Diamond coating on the base material)
The base material is put into the device, methane gas is used as the raw material gas, hydrogen gas is used as the carrier gas, a gas with a methane gas concentration of 0.5% by volume in the hydrogen gas is flowed into the device, and the pressure in the device is 50 Torr. The substrate temperature was set to 1200 K, a diamond film was deposited at 1 μm per hour, and the reaction was continued for 20 hours to form a 20 μm diamond film by a hot filament CVD method.

<Reference Example 3>
(Preparation of carbonaceous substrate)
Average pore radius by mercury intrusion method is 1.1 μm, bending strength by 3-point bending test method is 60 MPa, average thermal expansion coefficient from room temperature to 1273 K by quartz thermal dilatometer is 5.0 (× 10 ⁻⁶ / K) An isotropic graphite material was prepared. This isotropic graphite material was processed into a dimension of 50 mm square and 10 mm thickness to obtain a test piece. The ash content in the test piece was 14 ppm.
(Preparation of base material)
The same operation as in Reference Example 1 was performed, and a base material was formed by forming a conversion layer of 250 μm on the entire surface layer portion of the carbonaceous substrate. When the cumulative pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 3.4 (× 10 ⁻² Mg / m ³ ) and 0.6 μm, respectively. It was 3.8 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. A diamond compound having an average particle size of 0.1 μm was dispersed in a commercially available 0.5-liter beaker, and the above base material was placed therein, and ultrasonic vibration was applied for 10 minutes to form a scratch. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JISB0601-1982, and as a result, the maximum surface roughness (R _max ) was 1.0 μm.
(Diamond coating on the base material)
A base material is put into the apparatus, methane gas is used as a source gas, hydrogen gas is used as a carrier gas, a gas with a methane gas concentration of 0.5% by volume in hydrogen gas is flowed into the apparatus, and the pressure in the apparatus is 50 The substrate temperature was 1200 K and a diamond film was deposited at 2 μm per hour, and the reaction was continued for 10 hours to form a 20 μm diamond film by hot filament CVD.

<Reference Example 4>
(Preparation of carbonaceous substrate)
The average pore radius by the mercury intrusion method is 1.1 μm, the bending strength by the three-point bending test method is 60 MPa, and the average thermal expansion coefficient from room temperature to 1273 K by a quartz thermal dilatometer is 4.0 (× 10 ⁻⁶ / K). An isotropic graphite material was prepared. This isotropic graphite material was processed into a dimension of 50 mm square and 10 mm thickness to obtain a test piece. The ash contained in the test piece was 2.1 ppm.
(Preparation of base material)
The same operation as in Reference Example 1 was performed, and a base material was formed by forming a conversion layer of 250 μm on the entire surface layer portion of the carbonaceous substrate. When the cumulative pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 2.8 (× 10 ⁻² Mg / m ³ ) and 0.4 μm, respectively. It was 0.1 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. In a commercially available 0.5 liter beaker, diamond having an average particle diameter of 0.1 μm was dispersed, and the above base material was placed therein, and ultrasonic vibration was applied for 10 minutes to form a scratch. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured as shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.9 μm.
(Diamond coating on the base material)
A base material is put into the apparatus, methane gas is used as a source gas, hydrogen gas is used as a carrier gas, a gas with a methane gas concentration of 0.5% by volume in hydrogen gas is flowed into the apparatus, and the pressure in the apparatus is 50 The substrate temperature was 1200 K and a diamond film was deposited at 2 μm per hour, and the reaction was continued for 10 hours to form a 20 μm diamond film by hot filament CVD.

<Reference Example 5>
(Preparation of carbonaceous substrate)
The test piece prepared in Reference Example 1 was used.
(Preparation of base material example 1)
A base material was prepared by performing the same operation as in Reference Example 1 and forming a conversion layer of 950 μm on the entire surface of the carbonaceous substrate. When the cumulative pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 2.8 (× 10 ⁻² Mg / m ³ ) and 0.4 μm, respectively. It was 0.1 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. Put a diamond compound with an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this to disperse the diamond compound, put the base material in this, and apply ultrasonic vibration for 10 minutes. A scratch was formed. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.5 μm.
(Diamond coating on the base material)
A 20 μm diamond film was formed in the same manner as in Reference Example 1.

<Reference Example 6>
(Preparation of carbonaceous substrate)
The test piece prepared in Reference Example 1 was used.
(Preparation of base material)
The same operation as in Reference Example 1 was performed, and a base material was obtained by forming a conversion layer of 1.1 μm on the entire surface layer portion of the carbonaceous substrate. When the cumulative pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 3.3 (× 10 ⁻² Mg / m ³ ) and 0.8 μm, respectively. It was 2.2 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. In a commercially available 0.5 liter beaker, diamond having an average particle diameter of 0.1 μm was dispersed, and the above base material was placed therein, and ultrasonic vibration was applied for 10 minutes to form a scratch. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.5 μm.
(Diamond coating on the base material)
A 20 μm diamond film was formed in the same manner as in Reference Example 1.

<Reference Example 7>
(Preparation of carbonaceous substrate)
Average pore radius by mercury intrusion method is 1.2 μm, bending strength by 3-point bending test method is 60 MPa, average thermal expansion coefficient from room temperature to 1273 K by quartz thermal dilatometer is 4.7 (× 10 ⁻⁶ / K) An isotropic graphite material was prepared. This isotropic graphite material was processed into a dimension of 50 mm square and 10 mm thickness to obtain a test piece. The ash content contained in the test piece was 50 ppm.
(Preparation of base material)
The same operation as in Reference Example 1 was performed, and a base material was formed by forming a conversion layer of 200 μm on the entire surface layer portion of the carbonaceous substrate. When the cumulative pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 4.9 (× 10 ⁻² Mg / m ³ ) and 0.8 μm, respectively. It was 9.8 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. Place a diamond compound with an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this to disperse the diamond compound, put the above base material in this, and apply ultrasonic vibration for 10 minutes. A scratch was formed. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.5 μm.
(Diamond coating on the base material)
A 20 μm diamond film was formed in the same manner as in Example 1.

<Reference Example 8>
(Preparation of base material)
Using the base material prepared in Reference Example 1, put a diamond compound with an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this and disperse the diamond compound, and in this The material was placed and subjected to ultrasonic vibration for 10 minutes to form a scratch. After taking out the base material subjected to the ultrasonic treatment, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.8 μm.
(Diamond coating on the base material)
A base material is put into the apparatus, methane gas is used as a source gas, hydrogen gas is used as a carrier gas, a gas with a methane gas concentration of 0.5% by volume in hydrogen gas is flowed into the apparatus, and the pressure in the apparatus is 50 Thor, the substrate (base material) temperature is 1200K, and 2.45 GHz microwave is introduced into the center of the reaction tube through the waveguide to deposit the diamond film at 1 μm per hour, and the reaction is continued for 1.5 hours. Then, a diamond film of 1.5 μm was formed by a microwave plasma CVD method.

<Reference Example 9>
(Preparation of base material)
Using the same base material as in Example 1, put a diamond compound having an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to the bead, and disperse the diamond compound therein. The material was placed and subjected to ultrasonic vibration for 10 minutes to form a scratch. After taking out the base material subjected to the ultrasonic treatment, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.8 μm.
(Diamond coating on the base material)
A base material is put into the apparatus, methane gas is used as a source gas, hydrogen gas is used as a carrier gas, a gas with a methane gas concentration of 0.5% by volume in hydrogen gas is flowed into the apparatus, and the pressure in the apparatus is 50 Thor, substrate (base material) temperature of 1200 K, microwave of 2.45 GHz is introduced into the center of the reaction tube through the waveguide, diamond film is deposited at 1 μm per hour, and the reaction is continued for 100 hours. A diamond film of 100 μm was formed by plasma CVD.

<Comparative Example 1>
(Preparation of base material)
The test piece prepared in Reference Example 1 is put in a CVD apparatus, silicon tetrachloride is used as a source gas, propane gas is used as a carrier gas, 1800 K, gas is 0.3 liters per minute, and dense silicon carbide is formed on the surface of the test piece. A layer of 200 μm was formed. When the accumulated pore area and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 2.0 (× 10 ⁻² Mg / m ³ ) and 0.1 μm, respectively.
(Diamond coating on the base material)
In the same manner as in Reference Example 1, a diamond film was deposited at 1 μm per hour, and a continuous reaction was performed for 20 hours to form a diamond film of 20 μm by the microwave plasma CVD method.

<Comparative example 2>
(Preparation of carbonaceous substrate)
The average pore radius by the mercury intrusion method is 2.0 μm, the bending strength by the three-point bending test method is 30 MPa, and the average thermal expansion coefficient from room temperature to 1273 K by the quartz thermal dilatometer is 4.7 (× 10 ⁻⁶ / K). An isotropic graphite material was prepared. This isotropic graphite material was processed to a size of 50 mm square and 10 mm thick, and then purified to obtain a test piece. The ash content contained in the test piece was 10 ppm.
(Preparation of base material)
In the same manner as in Reference Example 1, a 200 μm conversion layer was formed of β-silicon carbide on the entire surface of the test piece, and this was used as a base material. When the accumulated pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 4.0 (× 10 ⁻² Mg / m ³ ) and 0.4 μm, respectively. It was 1.8 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. Place a diamond compound with an average particle diameter of 0.1 μm in a commercially available 0.5 liter beaker, add pure water of this to disperse the diamond compound, put the above-mentioned base material in this, and apply ultrasonic vibration for 10 minutes. A scratch was formed. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.5 μm.
(Diamond coating on the base material)
A base material is put into the apparatus, methane gas is used as a source gas, hydrogen gas is used as a carrier gas, a gas with a methane gas concentration of 0.5% by volume in hydrogen gas is flowed into the apparatus, and the pressure in the apparatus is 50 Thor, the substrate (base material) temperature is 1200K, and 2.45 GHz microwave is introduced into the center of the reaction tube through the waveguide to deposit a diamond film at 1 μm per hour, and the reaction is continued for 20 hours to make the micro A diamond film having a thickness of 20 μm was formed by a wave plasma CVD method.

<Comparative Example 3>
(Preparation of carbonaceous substrate)
Average pore radius by mercury intrusion method is 0.15 μm, bending strength by 3-point bending test method is 80 MPa, average thermal expansion coefficient from room temperature to 1273 K by quartz thermal dilatometer is 4.7 (× 10 ⁻⁶ / K) An isotropic graphite material was prepared. This isotropic graphite material was processed to a size of 50 mm square and 10 mm thick, and then purified to obtain a test piece. The ash content contained in the test piece was 10 ppm.
(Preparation of base material)
In the same manner as in Reference Example 1, a 0.8 μm conversion layer was formed of β-silicon carbide on the entire surface layer portion of the test piece, and this was used as a base material. When the accumulated pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 1.0 (× 10 ⁻² Mg / m ³ ) and 0.1 μm, respectively. It was 1.8 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by the IP-MS method was measured. Put a diamond compound with an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this to disperse the diamond compound, put the above base material in this, and give ultrasonic vibration for 10 minutes. Scratches were formed. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.5 μm.
(Diamond coating on base material)
A base material is put into the apparatus, methane gas is used as a source gas, hydrogen gas is used as a carrier gas, a gas with a methane gas concentration of 0.5% by volume in hydrogen gas is flowed into the apparatus, and the pressure in the apparatus is 50 Thor, the substrate (base material) temperature is 1200K, and 2.45 GHz microwave is introduced into the center of the reaction tube through the waveguide to deposit a diamond film at 1 μm per hour, and the reaction is continued for 20 hours to make the micro A diamond film having a thickness of 20 μm was formed by a wave plasma CVD method.

<Comparative example 4>
(Preparation of carbonaceous substrate)
Average pore radius by mercury intrusion method is 1.1 μm, bending strength by 3-point bending test method is 60 MPa, average thermal expansion coefficient from room temperature to 1273 K by quartz thermal dilatometer is 5.2 (× 10 ⁻⁶ / K) An isotropic graphite material was prepared. This isotropic graphite material was processed to a size of 50 mm square and 10 mm thick, and then purified to obtain a test piece. The ash content contained in the test piece was 10 ppm.
(Preparation of base material)
In the same manner as in Reference Example 1, a 200 μm conversion layer was formed of β-silicon carbide over the entire surface layer portion of the test piece, and this was used as a base material. When the accumulated pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 4.0 (× 10 ⁻² Mg / m ³ ) and 0.4 μm, respectively. The cobalt content in the conversion layer of the base material impregnated with silicon was measured by the ICP-MS method and found to be 1.8 ppm. Put a diamond compound with an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this to disperse the diamond compound, put the above base material in this, and give ultrasonic vibration for 10 minutes. Scratches were formed. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.5 μm.
(Diamond coating on the base material)
A diamond film having a thickness of 20 μm was formed in the same manner as in Reference Example 1.

<Comparative Example 5>
(Preparation of carbonaceous substrate)
Average pore radius by mercury intrusion method is 1.1 μm, bending strength by 3-point bending test method is 60 MPa, average thermal expansion coefficient from room temperature to 1273 K by quartz thermal dilatometer is 3.7 (× 10 ⁻⁶ / K) An isotropic graphite material was prepared. This isotropic graphite material was processed to a size of 50 mm square and 10 mm thick, and then purified to obtain a test piece. The ash content in the test piece is 10 ppm.
(Preparation of base material)
In the same manner as in Reference Example 1, a 200 μm conversion layer was formed of β-silicon carbide over the entire surface layer portion of the test piece, and this was used as a base material. When the accumulated pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 4.0 (× 10 ⁻² Mg / m ³ ) and 0.4 μm, respectively. It was 1.8 ppm when the content rate of cobalt contained in the conversion layer of the base material impregnated with silicon by the ICP-MS method was measured. Put a diamond compound with an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this to disperse the diamond compound, put the above base material in this, and give ultrasonic vibration for 10 minutes. Scratches were formed. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.5 μm.
(Diamond coating on the base material)
In the same manner as in Reference Example 1, a diamond film was deposited at 1 μm per hour, and allowed to react for 20 hours to form a diamond film of 20 μm by microwave plasma CVD.

<Comparative Example 6>
(Preparation of carbonaceous substrate)
The average pore radius by mercury porosimetry is 1.1 μm, the bending furnace is 60 MPa by the three-point bending test method, and the average thermal expansion coefficient from room temperature to 1273 K by the quartz thermal dilatometer is 4.7 (× 10 ⁻⁶ / K). An isotropic graphite material was prepared. This isotropic graphite material was processed to a size of 50 mm square and 10 mm thick, and then purified to obtain a test piece. The ash content in the test piece was 100 ppm.
(Preparation of base material)
In the same manner as in Reference Example 1, a 200 μm conversion layer was formed of β-silicon carbide over the entire surface layer portion of the test piece, and this was used as a base material. When the accumulated pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 4.0 (× 10 ⁻² Mg / m ³ ) and 0.4 μm, respectively. It was 11.8 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. Put a diamond compound with an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this to disperse the diamond compound, put the above base material in this, and give ultrasonic vibration for 10 minutes. Scratches were formed. After the base material subjected to the ultrasonic treatment was taken out, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 0.5 μm.
(Diamond coating on the base material)
In the same manner as in Reference Example 1, a diamond film was deposited at 1 μm per hour, and allowed to react for 20 hours to form a diamond film of 20 μm by microwave plasma CVD.

<Comparative Example 7>
(Preparation of carbonaceous substrate)
The test piece prepared in Reference Example 1 was used.
(Preparation of base material)
On the other hand, a graphite crucible having an inner diameter of 100 mm, a thickness of 10 mm, and a height of 100 mm was filled with 0.3 kg of metal silicon, and the metal silicon was melted at 1800 K by high frequency induction heating. A test piece was put in molten silicon, and a 1100 μm conversion layer was formed of β-silicon carbide on the entire surface portion of the test piece, which was used as a base material. When the accumulated pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 10.0 (× 10 ⁻² Mg / m ³ ) and 0.7 μm, respectively. It was 1.8 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. After putting a diamond compound having an average particle diameter of 0.1 μm into a commercially available 0.5 liter beaker, adding pure water to this to disperse the diamond compound, and taking out the base material subjected to the above ultrasonic treatment therein As a result of measuring the surface roughness of the base material by the method described in JIS B0601-1982, the maximum surface roughness (R _max ) was 0.5 μm.
(Diamond coating on the base material)
In the same manner as in Reference Example 1, a diamond film was deposited at 1 μm per hour, and reacted for 20 hours to form a diamond film of 20 μm by microwave plasma CVD.

<Comparative Example 8>
(Preparation of carbonaceous substrate)
The test piece prepared in Reference Example 1 was used.
(Preparation of base material)
On the other hand, a graphite crucible having an inner diameter of 100 mm, a thickness of 10 mm, and a height of 100 mm was filled with 0.3 kg of metal silicon, and the metal silicon was melted at 1800 K by high frequency induction heating. A test piece was put in molten silicon, and a 200 μm conversion layer was formed of β-silicon carbide on the entire surface layer portion of the test piece, which was used as a base material. When the accumulated pore volume and average pore radius of the pores of the conversion layer in the base material were measured by the mercury intrusion method, they were 4.0 (× 10 ⁻² Mg / m ³ ) and 0.4 μm, respectively. It was 1.8 ppm when the content rate of the cobalt contained in the conversion layer of the said base material impregnated with silicon by ICP-MS method was measured. Put a diamond compound with an average particle size of 0.1 μm in a commercially available 0.5 liter beaker, add pure water to this to disperse the diamond compound, put the above base material in it and give ultrasonic vibration for 5 minutes. Scratches were formed. After taking out the base material subjected to the ultrasonic treatment, the surface roughness of the base material was measured by the method shown in JIS B0601-1982, and as a result, the maximum surface roughness (R _max ) was 1.3 μm.
(Diamond coating on the base material)
In the same manner as in Reference Example 1, a diamond film was deposited at 1 μm per hour, and reacted for 20 hours to form a diamond film of 20 μm by microwave plasma CVD.

<Comparative Example 9>
(Base material)
A base material having a conversion layer of 200 μm prepared in Reference Example 1 was used.
(Diamond coating on the base material)
In the same manner as in Reference Example 1, a diamond film was deposited by 0.8 μm per hour, allowed to react for 1 hour, and then formed by a microwave plasma CVD method to form a diamond film of 0.8 μm.

<Comparative Example 10>
(Base material)
A base material having a conversion layer of 200 μm prepared in Reference Example 1 was used.
(Diamond coating on the base material)
In the same manner as in Reference Example 1, a diamond film was deposited at 1 μm per hour and allowed to react for 110 hours to form a microwave plasma film at 110 μm.

  The above Example 1, Reference Examples 1 to 9 and Comparative Examples 1 to 10 are summarized in Table 1.

[Experimental Example 1]
The samples obtained in Example 1 and Reference Examples 1 to 9 were tested for adhesion between the carbonaceous substrate, silicon carbide, and diamond coating (shown in the figure) to confirm the presence or absence of peeling / cracks. .

(Drawer method)
After thoroughly washing the S45C stainless steel rod 11 having a diameter of 7.96 mm and a length of 95.0 mm, a contact agent (polyvinyl acetate) 12 was applied, and the above Example 1, Reference Example 1 to Reference Example 9, And it adhere | attached on the surface of the sample obtained by the comparative example 1 thru | or the comparative example 10. The bonding conditions at this time were maintained at 443 K for 1 hour, and then allowed to cool naturally to cool to room temperature. The pulling rod 11 and the load cell 14 were brought into contact with each other with a wire and pulled in the horizontal direction as shown in FIG. Measurement was performed twice for each sample. The state of the sample at that time was visually observed. The results are shown in Table 2.

[Experiment 2]
Moreover, about the sample obtained in the said Example 1, Reference example 1 thru | or Reference example 9, and Comparative example 1 thru | or Comparative example 10, after heating rapidly to 1273K, it is thrown into water and a thermal shock test is repeated, The number of peeling / cracking was investigated. The results are also shown in Table 2.

<Reference Example 10>
The carbonaceous substrate prepared in Example 1 was processed into a chip shape having a regular triangle of 18.7 mm on one side and a thickness of 4.7 mm. The corner of the chip was chamfered. The surface layer portion of this chip was converted to 200 μm silicon carbide on the entire surface of the chip by the method of Example 1, and a diamond film of 20 μm was further formed by the method of Example 1.

<Comparative Example 11>
A dense silicon carbide film having a thickness of 100 μm was formed by CVD on the chip material prepared in Reference Example 10 (the conditions were the same as in Comparative Example 10), and then a diamond film having a thickness of 20 μm was formed by the same method as in Reference Example 1.

[Experiment 3]
A cutting test was performed using the chips prepared in Reference Example 10 and Comparative Example 11. Aluminum was used as the work material. As a result, the chip produced in Reference Example 10 did not delaminate between the carbonaceous substrate and the silicon carbide even after 1 hour test, but the chip produced in Comparative Example 11 was carbonized in 10 minutes after the start of use. Peeling occurred at the interface between the porous substrate and dense silicon carbide, making it unusable.

<Reference Example 11>
After processing the carbonaceous substrate prepared in Reference Example 1 into a sukiyaki pan having an outer diameter of 240 mm, an inner diameter of 200 mm, and a depth of 40 mm, the outer bottom surface of the pan was converted into 200 μm silicon carbide in the same manner as in Reference Example 1, A 20 μm diamond coating was formed.

<Comparative Example 12>
The carbonaceous substrate prepared in Reference Example 1 was processed into a sukiyaki pan having an outer diameter of 240 mm, an inner diameter of 200 mm, and a depth of 40 mm.

[Experimental Example 4]
The sukiyaki pot created in Reference Example 11 and Comparative Example 12 was filled with water, heated with a gas stove, and the time until the amount of water in the pot was halved was measured. As a result, the pot prepared in Reference Example 11 was 30 minutes, whereas the sukiyaki pot prepared in Comparative Example 12 required 50 minutes.

  As described above, according to the present invention, a diamond-coated carbon member capable of preventing cracks and peeling that has conventionally occurred between a carbonaceous substrate and a silicon carbide layer formed by a CVD method is provided. I was able to provide it. Further, the content of cobalt contained in the carbonaceous substrate is 10 ppm or less, and it is possible to reduce the adhesion strength between the diamond coating and the carbonaceous substrate serving as a base material and to suppress the growth rate of the diamond coating. . As a result, a diamond-coated carbon member capable of improving the adhesion between the base material and the diamond coating and maximally effectively exhibiting the excellent characteristics of the diamond coating while ensuring the superiority of the properties of the carbon material itself. It was possible to provide.

It is the outline | summary of the test | inspection apparatus of the adhesiveness by the drawing-out method. It is a longitudinal cross-sectional view of the diamond-coated carbon product of the present invention.

Explanation of symbols

11 Lead bar 12 Adhesive 13 Sample 14 Load cell 21 Carbonaceous substrate 22 Conversion layer 23 converted to silicon carbide by CVR method Diamond coating

Claims (5)

  A diamond coating that converts the surface of a carbonaceous substrate into silicon carbide by a chemical vapor reaction to form a diamond coating on a coating layer having a boundary surface reflecting the surface state between the substrate and the substrate. Carbon member manufacturing method.   A diamond-coated carbon member in which a surface of a carbonaceous substrate is converted into silicon carbide by a chemical vapor reaction to form a coating layer, and after the surface of the coating layer is roughened, a diamond coating is formed on the surface. Manufacturing method.   The surface of the carbonaceous substrate is converted into silicon carbide by a chemical vapor reaction to form a coating layer, the surface of the coating layer is roughened, and then a diamond coating is formed on the surface. Carbon member.   By converting the surface of the carbonaceous substrate into silicon carbide by chemical vapor reaction, a coating layer having a boundary surface reflecting the state of the surface between the substrate and the surface of the coating layer is roughened. After that, a diamond-coated carbon member obtained by forming a diamond coating on the surface.   The diamond-coated carbon member according to claim 4 or 5, wherein the content of cobalt contained in the carbonaceous substrate is 10 ppm or less.

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