Metal carbide coated material

Abstract

This invention relates to a metal carbide coating material, comprising a carbon substrate (14) with carbon as the main component and a metal carbide coating film comprising at least a portion of the coated carbon substrate (14) and metal carbide as the main component. The invention is characterized in that, regarding the thickness direction of the metal carbide coating film, when the film depth is between 0% and 80%, the carbon concentration in the metal carbide coating film increases with increasing film depth. According to this invention, a metal carbide coating material with increased reusability can be provided.

Description

Technical Field

[0001] The present invention relates to a metal carbide coating material, comprising: a carbon substrate with carbon as the main component; and a metal carbide coating film covering at least a portion of the carbon substrate and having metal carbide as the main component. Background Technology

[0002] Carbides such as tantalum carbide, niobium carbide, zirconium carbide, hafnium carbide, and tungsten carbide have high melting points and excellent chemical stability, strength, toughness, and corrosion resistance. Therefore, coating carbon substrates with carbides can improve their heat resistance, chemical stability, strength, toughness, and corrosion resistance. Carbide-coated materials, especially tantalum carbide-coated materials, with carbide films on the surface of carbon substrates are used as components in semiconductor single crystal manufacturing devices such as Si (silicon), SiC (silicon carbide), GaN (gallium nitride), and AlN (aluminum nitride).

[0003] Sublimation recrystallization is a well-known method for manufacturing bulk SiC single crystals. In sublimation recrystallization, a crucible is filled with SiC raw material, and a SiC seed crystal is placed on top. Furthermore, a guide member is placed around the SiC seed crystal to guide the sublimation gas to the single crystal. The sublimation gas generated by heating the SiC raw material rises along the inner wall of the guide member, growing a SiC single crystal on the SiC seed crystal.

[0004] Furthermore, SiC single-crystal substrates used in semiconductor devices are manufactured by epitaxial growth of SiC single crystals on a SiC substrate composed of bulk single crystals. Known methods for epitaxial growth of SiC single crystals include liquid phase epitaxy (LPE), vapor phase epitaxy (VPE), and chemical vapor deposition (CVD). CVD is the most common method for epitaxial growth of SiC single crystals. In CVD-based epitaxial growth, a SiC substrate is placed on a substrate within a device, and a feed gas is supplied at a high temperature above 1500°C, thereby growing the SiC single crystal.

[0005] In this method of manufacturing SiC single crystals, to obtain higher quality crystals, Patent Document 1 discloses a method using a crucible with the inner surface of a graphite substrate coated with tantalum carbide. Additionally, Patent Document 2 discloses a method using a guide member with the inner wall coated with tantalum carbide.

[0006] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2019-99453; Patent Document 2: Japanese Patent Application Publication No. 2019-108611. Summary of the Invention

[0007] The problem that the invention aims to solve SiC single crystals grown using a metal carbide-coated material as a crucible or guide component have a known significantly higher yield compared to crystal growth using uncoated carbon materials. From the viewpoint of crystal manufacturing costs, it is desirable to reuse the metal carbide-coated material multiple times. Therefore, the object of the present invention is to provide a metal carbide-coated material that can increase the number of times it can be reused.

[0008] Methods for solving problems Through in-depth research, the inventors discovered that focusing on the carbon concentration in the metal carbide coating can increase the number of times the metal carbide coating material can be reused, thus completing this invention. The main points of this invention are as follows.

[0009] [1] A metal carbide coating material, characterized in that: it is a metal carbide coating material comprising a carbon substrate with carbon as the main component and a metal carbide coating film covering at least a portion of the carbon substrate and with metal carbide as the main component. Regarding the thickness direction of the metal carbide coating, when the film depth is between 0% and 80% as expressed by the following formula, the carbon concentration in the metal carbide coating increases with the increase of the film depth.

[0010] Mathematical Formula 1 [2] A metal carbide coating material, characterized in that: it is a metal carbide coating material comprising a carbon substrate with carbon as the main component and a metal carbide coating film covering at least a portion of the carbon substrate and with metal carbide as the main component. Regarding the thickness direction of the metal carbide coating, when the film depth is between 20% and 80% as expressed by the following formula, the carbon concentration in the metal carbide coating increases with the increase of the film depth.

[0011] Mathematical formula 2 [3] The metal carbide coating material according to [1] or [2] above is characterized in that: the metal carbide is a carbide of at least one metal element selected from tantalum and niobium.

[0012] Invention Effects According to the present invention, a carbide metal coating material that can increase the number of times it can be reused can be provided. Attached Figure Description

[0013] [ Figure 1 A schematic diagram of an externally heated vacuum CVD unit.

[0014] [ Figure 2A schematic diagram of a vacuum furnace for semiconductor single crystal growth.

[0015] [ Figure 3 GDMS analysis results of the tantalum carbide coated material in Example 1.

[0016] [ Figure 4 GDMS analysis results of the tantalum carbide coated material in Comparative Example 1. Detailed Implementation

[0017] The metal carbide coating material of the present invention comprises: a carbon substrate with carbon as the main component; and a metal carbide coating film covering at least a portion of the carbon substrate and having metal carbide as the main component. Here, "carbon as the main component" means that carbon accounts for 50% or more of the total mass of the carbon substrate, and "metal carbide as the main component" means that metal carbide accounts for 50% or more of the total mass of the metal carbide coating film. The metal carbide coating film can be a coating film of high-melting-point carbides such as tantalum carbide, niobium carbide, zirconium carbide, hafnium carbide, and tungsten carbide, as well as a composite coating film composed of two or more of these high-melting-point carbides. The metal carbide in the metal carbide coating film is preferably a carbide of at least one metal element selected from tantalum and niobium.

[0018] The following describes the carbide metal coating material of the present invention using tantalum carbide coating material as an example.

[0019] [About tantalum carbide coating materials] The following is for reference Figure 1 The present invention will describe a tantalum carbide coating material according to one embodiment of the present invention.

[0020] One embodiment of the tantalum carbide coating material of the present invention comprises: a carbon substrate 14 with carbon as the main component; and a tantalum carbide coating film covering the carbon substrate 14 and having tantalum carbide as the main component. It should be noted that the tantalum carbide coating film may cover a portion of the carbon substrate 14 or cover all of the carbon substrate 14.

[0021] The carbon substrate 14 can be made of carbon materials such as isotropic graphite, extruded graphite, pyrolytic graphite, or carbon fiber reinforced carbon composites (C / C composites). There are no particular limitations on the shape or properties of the carbon substrate 14. The carbon substrate 14 can be processed into any shape for use, etc.

[0022] According to one embodiment of the present invention, the tantalum carbide coated material can be manufactured by forming a tantalum carbide coated film on the surface of a carbon substrate 14. The tantalum carbide coated film can be formed on the surface of the carbon substrate 14 by methods such as chemical vapor deposition (CVD), sintering, and carbide formation. Among these methods, CVD can form a uniform and dense film, and is therefore preferred as a method for forming the tantalum carbide coated film.

[0023] Furthermore, CVD methods include thermal CVD, photochemical CVD, and plasma CVD, among others. For example, thermal CVD can be used to form tantalum carbide coatings. Thermal CVD offers advantages such as simpler equipment configuration and the absence of damage caused by plasma. For instance, thermal CVD can be used to form tantalum carbide coatings. Figure 1 The externally heated vacuum CVD apparatus 10 shown is used for this process. In the externally heated vacuum CVD apparatus 10, the carbon substrate 14 is supported by a support device 15 inside the reaction chamber 12, which includes a heater 13, a raw material supply section 16, an exhaust section 17, etc.

[0024] Reference Figure 1 The following describes a method for manufacturing tantalum carbide coated material according to one embodiment of the present invention.

[0025] First, a carbon substrate 14 is placed in the reaction chamber 12 of the externally heated vacuum CVD apparatus 10. The carbon substrate 14 is supported by a support device 15 having a support portion with a pointed front end.

[0026] Next, the reaction chamber 12 is heated. For example, the reaction chamber 12 is heated under conditions of a pressure of 10 to 1000 Pa and a temperature of 800 to 2200 °C.

[0027] Next, a tantalum carbide coating is formed on the surface of the carbon substrate 14. As raw material gases, gases containing carbon atoms, such as methane (CH4), hydrogen (H2), and tantalum halide gases, such as tantalum pentachloride (TaCl5), are supplied from the raw material supply section 16 to the reaction chamber 12. The tantalum halide gases can be generated, for example, by heating and vaporizing tantalum halide or by reacting metallic tantalum with halogen gases. Then, the raw material gases supplied from the raw material supply section 56 are subjected to a thermal CVD reaction at a high temperature and reduced pressure of 800–2200°C and 1–1000 Pa to form a tantalum carbide coating on the carbon substrate 14.

[0028] [Methods for controlling carbon content in tantalum carbide coatings] The prepared tantalum carbide coating material is annealed at a heating temperature above 2000°C for a heating time of 50 hours or more. During this process, it is preferable to first create a reducing gas atmosphere in the reactor. The reducing gas is preferably a compound that will not become an impurity for the growth of SiC single crystals; specifically, hydrogen and SiC are preferred. xGas. If annealing is performed with this gas, decarburization occurs from the surface of the tantalum carbide coating. On the other hand, through prolonged annealing, carbon atoms in the carbon substrate diffuse into the tantalum carbide coating. Due to these two effects, a tantalum carbide coating is formed such that a carbon concentration gradient exists from the film surface of the tantalum carbide coating towards the carbon substrate. As a result, with respect to the thickness direction of the tantalum carbide coating, when the film depth is between 0% and 80% as expressed by the following formula, the carbon concentration in the tantalum carbide coating increases with increasing film depth.

[0029] [Mathematical Expression 3] Furthermore, regarding the thickness direction of the tantalum carbide coating, even when the film depth expressed by the above formula is between 20% and 80%, the carbon concentration in the tantalum carbide coating increases with increasing film depth. It should be noted that setting the film depth between 20% and 80% is to prevent carbon from impurities adhering to the surface of the tantalum carbide coating from being measured as carbon within the tantalum carbide coating itself when determining the carbon concentration in the tantalum carbide coating.

[0030] It should be noted that the distance from the surface of the tantalum carbide coating to the carbon substrate specifically refers to the distance between the surface of the tantalum carbide coating and the interface between the tantalum carbide coating and the carbon substrate in the thickness direction of the tantalum carbide coating.

[0031] The tantalum carbide coating material of one embodiment of the present invention described above is an example of the metal carbide coating material of the present invention. The metal carbide coating material of the present invention is not limited to the tantalum carbide coating material of one embodiment of the present invention. Furthermore, the carbide metal in the metal carbide coating film of the present invention is not limited to tantalum carbide. Examples of carbide metals in the metal carbide coating film of the present invention include: tantalum carbide, niobium carbide, zirconium carbide, hafnium carbide, tungsten carbide, etc. These carbides can be used alone or in combination of two or more. Among these carbide metals, tantalum carbide and niobium carbide are preferred from the perspective of having the highest melting point and excellent chemical stability, strength, and corrosion resistance, and tantalum carbide is more preferred.

[0032] [Regarding film thickness] There is no particular limitation on the thickness of the metal carbide coating. However, if the metal carbide coating is too thin, gases generated from the carbon substrate may pass through it and adversely affect the semiconductor single crystal. On the other hand, if the metal carbide coating is too thick, the film formation time is prolonged, and the film formation cost may increase. Taking these factors into consideration, the thickness of the metal carbide coating is preferably 10 μm or more and 100 μm or less, more preferably 20 μm or more and 50 μm or less.

[0033] It should be noted that the thickness of the metal carbide coating here is a value determined based on cross-section observation of the metal carbide coating under a scanning electron microscope (SEM).

[0034] [Regarding the carbon concentration in the membrane and the number of times it can be reused] When the film depth of the metal carbide coating material of the present invention is between 0% and 80% or between 20% and 80%, the carbon concentration in the metal carbide coating film increases with the increase of film depth, thereby increasing the number of times the metal carbide coating material can be reused.

[0035] The following description uses tantalum carbide coated materials as examples to examine the mechanism by which the metal carbide coated materials of the present invention can increase the number of times they can be reused, but this examination does not limit the present invention.

[0036] Tantalum carbide is typically hard and prone to cracking. If a tantalum carbide coating with cracks is exposed to a high-temperature corrosive environment, the carbon substrate will corrode through the cracks, causing the tantalum carbide coating, which was originally located in the corroded area, to peel off. If the tantalum carbide film peels off, it cannot be reused. Therefore, it is preferable to have a tantalum carbide coating free of cracks.

[0037] On the other hand, even if the thermal expansion coefficient of the tantalum carbide coating is matched with that of the carbon material, cracks can still occur in the tantalum carbide coating due to factors such as the shape of the carbon substrate or differences in local thermal expansion coefficients. Therefore, even in tantalum carbide coating materials with perfectly uniform thermal expansion coefficients, there is a limit to the number of times they can be reused.

[0038] In contrast, the tantalum carbide coating film is considered to have a surface that is close to ductile metallic tantalum, where the carbon concentration gradually increases from the film surface towards the carbon substrate, and the surface of the tantalum carbide coating film is closer to tantalum carbide as it approaches the carbon substrate. Furthermore, in one embodiment of the tantalum carbide coating material of the present invention, the metallic tantalum layer and the tantalum carbide layer are not separated by an interface, thus suppressing the formation of cracks near the surface and achieving corrosion resistance equivalent to that of a tantalum carbide coating film where the entire film is tantalum carbide.

[0039] [Explanation of GDMS Analysis] The contents (mass standard) of Ta, Nb, Hf, Zr, W, C, O, Cl, Fe, Al, Ca, and S in metal carbide coated materials can be determined by glow discharge mass spectrometry (GDMS) under the following measurement conditions. For example, a glow discharge mass spectrometer (manufactured by VG Elemental, trade name "VG9000") can be used for glow discharge mass spectrometry.

[0040] (Measurement conditions) • Discharge gas: Ar(7N); • Insulator: ceramic; • Secondary electrode: Indium orifice plate; • Pool: FlatCell component; • Normalized: 1kV, 1.6mA; • Ion current: Ta ~ 1.2 × E -11 A; • Detector: Faraday cup: 160 milliseconds; • Daly multiplier: 500 milliseconds.

[0041] It should be noted that 0% film depth refers to the initial sputtering position in GDMS analysis, while 100% film depth refers to the point where the mass ratio of the main component metal element in the metal carbide coating to the carbon content in the metal carbide coating is 1 in GDMS analysis. Furthermore, an increase in carbon concentration refers to an approximate straight line obtained by using the least squares method to calculate the slope between the sputtering position (number of sputterings) and the elemental analysis value reaching 80% film depth during analysis along the film depth direction, and this slope has a positive value. For example, this means that in analyses involving at least 10 sputtering points before reaching 100% depth, the slope obtained by using the least squares method to calculate the elemental analysis values ​​reaching 0%–80% film depth has a positive value.

[0042] The slope of the carbon concentration from 0% to 80% of the membrane depth, obtained by the least squares method, is preferably 100 to 20,000 ppm / μm, more preferably 500 to 15,000 ppm / μm, and even more preferably 700 to 9,000 ppm / μm.

[0043] Furthermore, the slope of the carbon concentration up to 20% to 80% of the membrane depth obtained by the least squares method is preferably 100 to 20,000 ppm / μm, more preferably 500 to 15,000 ppm / μm, and even more preferably 700 to 9,000 ppm / μm. Example

[0044] The following examples are given to illustrate the present invention in more detail, but the present invention is not limited to these examples.

[0045] The following procedures were followed to prepare tantalum carbide coated materials for Examples 1-10 and Comparative Example 1.

[0046] (Example 1) First, such as Figure 2 As shown, isotropic graphite is processed into a bottomed cylindrical shape (crucible 21) and a frustum-shaped cone shape (guide member 22), which are used as carbon substrate 14. The arithmetic mean surface roughness Ra of carbon substrate 14 is 6.0 μm, and the coefficient of thermal expansion of carbon substrate 14 is 7.0 × 10⁻⁶. -6 / ℃. It should be noted that in the determination of the thermal expansion rate of carbon substrate 14, a thermomechanical analysis apparatus (TMA7300) from Hitachi High-Tech Science Co., Ltd. was used, and the thermal expansion rate value in the temperature range of 200℃ to 1200℃ was taken as the thermal expansion rate of carbon substrate 14.

[0047] Next, in Figure 1 Two sets of carbon substrates 14 are placed in the reaction chamber 12 of the externally heated vacuum CVD apparatus 10 shown. The carbon substrates 14 are supported by a support device 15 having three support portions with pointed front ends. It should be noted that the front ends of the support portions contact the outer surface of the carbon substrate 14 for the frustum-shaped carbon substrate 14, the outer surface of the carbon substrate 14 for the bottomed cylindrical carbon substrate 14, the lower surface of the carbon substrate 14 for the disc-shaped carbon substrate 14, and the outer side surface of the carbon substrate 14 for the cylindrical carbon substrate 14. It should be noted that in... Figure 1 In the reaction chamber 12 of the externally heated vacuum CVD apparatus 10 shown, only a bottomed cylindrical shape (crucible) is arranged as the carbon substrate 14. However, in reality, two combinations of bottomed cylindrical shapes (crucibles) and frustum cylindrical shapes (guide components) are arranged as the carbon substrate 14.

[0048] Next, 0.25 SLM of methane (CH4) gas, 1.0 SLM of argon (Ar) gas as a carrier gas, 0.125 SLM of hydrogen (H2) gas, and 0.25 SLM of tantalum pentachloride (TaCl5) gas heated to 220°C and vaporized are supplied from the raw material supply section 16. The reaction is carried out at a pressure of 100 Pa and a temperature of 1250°C in the reaction chamber 12, and a tantalum carbide coating is formed on the entire surface of the carbon substrate 14.

[0049] The carbon substrate 14 coated with tantalum carbide film was removed from the reaction chamber 12, thus completing the crucible and guide component made of tantalum carbide coated carbon material.

[0050] The removed carbon substrate 14 was placed back into the reaction chamber 12 and heated to 2000°C. Then, 0.125 SLM hydrogen (H2) gas was introduced to maintain the pressure inside the reaction chamber 12 at 5000 Pa abs, while heating for 50 hours for annealing. Two sets of samples (crucible and guide component) were produced.

[0051] For the two sets of samples prepared, one set of samples (crucible and guide components) was destroyed, and the film thickness was calculated by observing the cross-section of the tantalum carbide coating under a scanning electron microscope (SEM).

[0052] Furthermore, the carbon concentration in the tantalum carbide coating was evaluated using glow discharge mass spectrometry (GDMS). The results are shown below. Figure 4 .

[0053] In addition, by spraying a flaw detection agent onto the sample, cracks generated in the tantalum carbide coating can be made visible, and their presence can be investigated.

[0054] For another set of samples (crucible and guide components), in such cases... Figure 2 The prepared crucible 21 and guide member 22 are installed inside the vacuum furnace 20, and SiC single crystals are grown by sublimation recrystallization. SiC raw material 25 is placed in the crucible 21, and a 2-inch diameter SiC seed crystal 24 is placed on top of it. Argon gas is introduced into the vacuum furnace 20 at a rate of 10–30 SLM, with a pressure of 500–1000 Pa and a temperature of 2000–2500 °C, causing the SiC raw material 25 to sublimate and grow a 5 mm thick SiC single crystal on the SiC seed crystal 24.

[0055] The number of times the crucible 21 and guide member 22 could be reused was confirmed by repeating the SiC single crystal fabrication process. As a result, after 7 uses, peeling of the tantalum carbide coating was observed, necessitating replacement with new members. These conditions and results are shown in Table 1. Additionally, the results of Example 1 are shown in... Figure 3 The vertical axis represents concentration (ppm by mass), and the horizontal axis represents depth (μm). The depth is calculated based on the measured value of the crater depth after analysis, assuming a constant sputtering velocity during the analysis. It should be noted that due to the presence of an unevenness of several μm at the bottom of the analyzed crater, an error in depth resolution is considered.

[0056] The definition of "in tantalum carbide coated film" is as follows: The measured film thickness obtained through SEM cross-sectional observation is taken as the film thickness. Furthermore, the measurement point where the carbon concentration increases and the Ta concentration decreases in GDMS analysis is defined as the interface between the tantalum carbide coated film and the carbon substrate. Moreover, the first measurement is defined as 0% film depth, and the measurement point at the interface between the tantalum carbide coated film and the carbon substrate is defined as 100% film depth.

[0057] For example, in Example 1, GDMS analysis revealed an increase in carbon concentration and a decrease in Ta concentration in the 25 μm region. Therefore, measurements from the 0th measurement (defined as film depth 0%) to the 25th measurement (defined as film depth 100%) were defined as "in tantalum carbide coated film".

[0058] Furthermore, the film depth from the surface of the tantalum carbide-coated film towards the carbon substrate was set as 0% at the outermost surface, and the interface between the carbon substrate and the tantalum carbide-coated film was set as 100%. Although GDMS measurements are performed in the direction of increasing film depth, the actual sputtering, viewed from the cross-sectional direction, occurs in an approximately hemispherical pattern. Therefore, the sputtering depth at which a certain element is detected will be subject to error.

[0059] In this study, since the focus is on the carbon concentration in tantalum carbide coatings, the range of 0–80% of the film depth is used as the scope to ensure a reliable discussion of the carbon concentration in tantalum carbide coatings.

[0060] Furthermore, similarly, impurities adhering to the outermost surface can be detected in the initial stage of GDMS measurement. Therefore, it is considered preferable to investigate the film depth range of 20% to 80%.

[0061] [Table 1] Table 1 (Example 2) In the annealing process, the heating temperature was set to 2100°C. Otherwise, the same procedures as in Example 1 were performed. The results are shown in Table 1.

[0062] (Example 3) In the annealing process, the heating temperature was set to 2200°C. Otherwise, the same procedures as in Example 1 were performed. The results are shown in Table 1.

[0063] (Example 4) In the annealing process, the heating temperature was set to 2300°C. Otherwise, the same procedures as in Example 1 were performed. The results are shown in Table 1.

[0064] (Example 5) In the annealing process, the heating temperature was set to 2400°C. Otherwise, the same procedures as in Example 1 were performed. The results are shown in Table 1.

[0065] (Example 6) In the annealing process, the heating temperature was set to 2500°C. Otherwise, the same procedures as in Example 1 were performed. The results are shown in Table 1.

[0066] (Example 7) In the annealing process, the heating time was set to 100 hours. Otherwise, the same procedures as in Example 1 were performed. The results are shown in Table 1.

[0067] (Example 8) In the annealing process, the heating time was set to 500 hours. Otherwise, the same procedures as in Example 1 were performed. The results are shown in Table 1.

[0068] (Example 9) In the annealing process, the heating time was set to 1000 hours. Otherwise, the same procedures as in Example 1 were performed. The results are shown in Table 1.

[0069] (Example 10) In the annealing process, SiC produced during the sublimation of SiC powder... x Gases (SiC, Si2C, SiC2) were used instead of hydrogen. Otherwise, the same procedures as in Example 1 were performed. The results are shown in Table 1.

[0070] (Example 11) Niobium pentachloride (NbCl5) was used instead of tantalum pentachloride (TaCl5). Otherwise, the same procedures as in Example 1 were performed. The results are shown in Table 1.

[0071] (Comparative Example 1) The annealing process was not performed. Otherwise, the same procedures as in Example 1 were followed. The results are shown in Table 1 and... Figure 4 .

[0072] Comparing the results of Examples 1 to 10 with those of Comparative Example 1, in Examples 1 to 10 where annealing was performed, regarding the thickness direction of the tantalum carbide coating (film thickness 25 μm), when the film depth is defined as 0% to 100% from the film surface to the carbon substrate, a trend of increasing carbon concentration with increasing film depth is observed within the range of 0% to 80% of the film depth. On the other hand, in Comparative Example 1 where annealing was not performed, regarding the thickness direction of the tantalum carbide coating (film thickness 15 μm), when the film depth is defined as 0% to 100% from the film surface to the carbon substrate, a trend of increasing carbon concentration with increasing film depth is not observed within the range of 0% to 80% of the film depth.

[0073] The same result was observed within the membrane depth range of 20% to 80%.

[0074] Furthermore, when confirming the number of reuses in SiC single crystal manufacturing, it was found that Examples 1 to 10 had more reuses than Comparative Example 1.

[0075] The results above show that Examples 1-10, which have an increasing gradient of carbon concentration in the membrane, can be reused more times than Comparative Example 1, which has no gradient, making them suitable for cost reduction.

[0076] Symbol Explanation 10: Externally heated reduced-pressure CVD device; 11: Top chamber; 12: Reaction chamber; 13: Heater; 14: Carbon substrate; 15: Support device; 16: Raw Material Supply Department; 17: Exhaust section; 20: SiC single crystal growth apparatus; 21: Crucible; 22: Guide components; 23: Top cover; 24: SiC seed crystal; 25: SiC raw materials.

Claims

1. A metal carbide-coated material, characterized by: It is a metal carbide coating material comprising a carbon substrate with carbon as the main component and a metal carbide coating film covering at least a portion of the carbon substrate and with metal carbide as the main component. Regarding the thickness direction of the metal carbide coating, when the film depth is between 0% and 80% as expressed by the following formula, the carbon concentration in the metal carbide coating increases with the increase of the film depth. Mathematical Formula 1 。 2. A metal carbide coated material, characterized by: It is a metal carbide coating material comprising a carbon substrate with carbon as the main component and a metal carbide coating film covering at least a portion of the carbon substrate and with metal carbide as the main component. Regarding the thickness direction of the metal carbide coating, when the film depth, as expressed by the following formula, is between 20% and 80%, the carbon concentration in the metal carbide coating increases with the increase of the film depth. Mathematical formula 2 。 3. The metal carbide coating material according to claim 1 or 2, characterized in that: The carbide metal is a carbide of at least one of the metal elements selected from tantalum and niobium.

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