Metal carbide film coated member and method of manufacturing same

Abstract

To provide a metal carbide coated member capable of improving an adhesion between a steel material and a metal carbide film in a Rockwell indentation test of the metal carbide coated member, and a manufacturing method of the same.SOLUTION: A metal carbide coated member 1 is manufactured, the metal carbide coated member including a steel material 2 of which surface has a carbide layer 2a, a metal carbide film 3 that includes one or more types of metals selected from a group consisting of V, Ti, Al, Cr, Nb and Si and carbon on the carbide layer 2a. When a ratio between a maximum intensity of an X-ray diffraction peak attributed to a metal carbide of the steel material [a carbide intensity] and a maximum intensity of an X-ray diffraction peak attributed to a α-Fe [an Fe intensity] is defined, a peak intensity ratio of the carbide layer 2a, [the carbide intensity / the Fe intensity] is 0.5 - 4.0.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a metal carbide film coated member in which a metal carbide film is formed on a steel material, and a method for producing the same. [Background technology]

[0002] It has been known to coat steel materials with hard coatings in press-forming dies, cutting tools, gear cutting tools, forging tools, etc. to prevent damage caused by contact friction with the workpiece or the mating material of the tool. For example, Patent Document 1 discloses coating the steel materials of cutting tools, gear cutting tools, or forging tools with a film containing vanadium and carbon, such as a vanadium carbide film (VC film) or a vanadium carbonitride film (VCN film), which has excellent lubricity. Patent Document 2 discloses coating the steel materials of dies, tools, etc. with a titanium carbide film (TiC). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-046975 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-015636 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the investigations of the present inventors, it has been found that a metal carbide film-coated member in which a metal carbide film containing a metal such as vanadium or titanium and carbon is formed directly on the surface of a steel material has poor adhesion between the steel material and the metal carbide film in a Rockwell indentation test. Therefore, it is desired to improve the adhesion between the steel material and the metal carbide film in order to improve the performance of the metal carbide film-coated member.

[0005] The present invention has been made in view of the above circumstances, and aims to provide a metal carbide film-coated member and a manufacturing method thereof that can improve the adhesion between a steel material and a metal carbide film in a Rockwell indentation test of the metal carbide film-coated member. [Means for solving the problem]

[0006] As a result of extensive research into solving the above problems, the inventors have found that coating a metal carbide film on a specific carbide layer formed on the surface of a steel material improves the adhesion of the metal carbide film-coated member in a Rockwell indentation test, thereby achieving the above-mentioned object, and have completed the present invention.

[0007] The present invention that solves the above problems is disclosed below. [1] A steel material having a carbide layer on its surface; a metal carbide film containing carbon and one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si on the carbide layer; When the ratio of the maximum peak intensity of X-ray diffraction [carbide intensity] derived from metal carbide of the steel material to the maximum peak intensity of X-ray diffraction [Fe intensity] derived from α-Fe is defined as the peak intensity ratio [carbide intensity / Fe intensity], the peak intensity ratio of the carbide layer is 0.5 to 4.0. the law of nature, the metal carbide film is a vanadium silicon carbide film containing vanadium, silicon, and carbon; The vanadium silicocarbide film has a total of vanadium element concentration, silicon element concentration, and carbon element concentration of 90 at % or more. A metal carbide film-coated member characterized by: [2] The metal carbide film-coated member according to [1], wherein the peak intensity ratio of the carbide layer is 2.0 or less. [3] The metal carbide film-coated member according to [1], wherein the peak intensity ratio of the carbide layer is 1.0 or less. [ 4 The vanadium silicon carbide film has a vanadium element concentration of 8 to 30 at %, a silicon element concentration of 8 to 30 at %, and a carbon element concentration of 40 to 80 at %, Either [1] to [3] The metal carbide film-coated member according to claim 1. [ 5] a plasma carbonization treatment step for forming a carbide layer on the surface of the steel material; a metal carbide film forming step of forming a metal carbide film containing carbon and one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si on the carbide layer, When the ratio of the maximum peak intensity of X-ray diffraction [carbide intensity] derived from metal carbide of the steel material to the maximum peak intensity of X-ray diffraction [Fe intensity] derived from α-Fe is defined as the peak intensity ratio [carbide intensity / Fe intensity], in the plasma carbonization treatment step, the carbide layer is formed so that the peak intensity ratio of the carbide layer after the plasma carbonization treatment step is 0.5 to 4.0. death, the metal carbide film is a vanadium silicon carbide film containing vanadium, silicon, and carbon; The vanadium silicocarbide film has a total of vanadium element concentration, silicon element concentration, and carbon element concentration of 90 at % or more. 1. A method for producing a metal carbide film-coated member, comprising: [ 6 In the plasma carbonization treatment step, the carbide layer is formed so that [the peak intensity ratio of the steel material after the plasma carbonization treatment step / the peak intensity ratio of the steel material before the plasma carbonization treatment step] satisfies 2.4 to 19, 5 ] A method for producing a metal carbide film-coated member according to the above. [ 7 ] a plasma carbonization treatment step for forming a carbide layer on the surface of the steel material; a metal carbide film forming step of forming a metal carbide film containing carbon and one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si on the carbide layer, The plasma carbonization treatment step is carried out in an atmosphere in which a carbon source gas and hydrogen gas supplied as treatment gases are plasmatized. 、 the metal carbide film is a vanadium silicon carbide film containing vanadium, silicon, and carbon; The vanadium silicocarbide film has a total of vanadium element concentration, silicon element concentration, and carbon element concentration of 90 at % or more. 1. A method for producing a metal carbide film-coated member, comprising: [ 8 a flow rate ratio of the carbon source gas to the hydrogen gas, that is, carbon source gas flow rate / hydrogen gas flow rate, of 0.01 to 0.40; 7 ] A method for producing a metal carbide film-coated member according to the above. [ 9] characterized in that hydrogen gas, carbon source gas, and argon gas are supplied as treatment gases in the plasma carbonization treatment step, and when the volumetric flow rate of the hydrogen gas is taken as 1, the volumetric flow rate ratio of hydrogen gas:carbon source gas:argon gas is 1:0.01-0.40:0.01-0.10. [8] 10. A method for producing a metal carbide film-coated member according to claim 9. [ 10 ] the carbon source gas is methane gas, 7 ]~[ 9 10. A method for producing a metal carbide film-coated member according to any one of claims 1 to 9. [ 11 ] the vanadium element concentration in the vanadium silicon carbide film is 8 to 30 at %, the silicon element concentration is 8 to 30 at %, and the carbon element concentration is 40 to 80 at %; [ 5 ] ~

[10] 10. A method for producing a metal carbide film-coated member according to claim 9. The symbol "~" used to express a range of values ​​in this specification indicates a range that is equal to or greater than a specified value and equal to or less than a specified value. [Effects of the Invention]

[0008] According to the present invention, it is possible to improve the adhesion between a steel material and a metal carbide film in a Rockwell indentation test of a metal carbide film-coated member. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a schematic configuration of a metal carbide film-coated member according to an embodiment of the present invention; [Figure 2] FIG. 1 is a diagram illustrating an example of a plasma processing apparatus. [Figure 3] FIG. 2 is a diagram showing the shape of a test piece. [Figure 4] FIG. 1 is a diagram showing the results of X-ray diffraction analysis of the test piece surface before and after the plasma carbonization treatment step. [Figure 5] FIG. 1 is a diagram showing the results of a Rockwell indentation test for Example 1. [Figure 6] FIG. 10 is a diagram showing the results of a Rockwell indentation test for Example 2. [Figure 7] FIG. 10 is a diagram showing the results of a Rockwell indentation test for Example 3. [Figure 8] FIG. 10 is a diagram showing the results of a Rockwell indentation test for Comparative Example 1. [Figure 9] 1 is an electron microscope image showing a cross section of a sample of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0011] As shown in Figure 1, the metal carbide film coated member 1 of this embodiment is composed of a steel material 2 having a carbide layer 2a formed on its surface, and a metal carbide film 3 formed directly on the carbide layer 2a of the steel material 2.

[0012] <Steel> The type of steel used is not particularly limited, and may be any type of steel suitable for the intended use of the metal carbide film coated member 1. Examples of steel types that may be used include high-speed tool steels (high-speed steels) such as SKH51, so-called cold-work tool steels such as SKD11 and DC53 (trade name) manufactured by Daido Steel Co., Ltd., and cold-work die steels (cold-work die steels).

[0013] <Carbide layer 2a> The carbide layer 2a is a layer formed by diffusing carbon from the steel surface to precipitate metal carbides within the steel. Specifically, the carbide layer 2a is a layer that exhibits peaks derived from α-Fe and peaks derived from metal carbides such as M6C-type carbides, M23C6-type carbides, and M7C3-type carbides when measured using an X-ray diffraction analyzer under an oblique incidence method. The amount of metal carbide on the steel surface can be evaluated by determining the ratio of the peak intensity derived from α-Fe to the peak intensity derived from metal carbides such as M6C-type carbides, M23C6-type carbides, and M7C3-type carbides. The peak intensities herein are calculated based on the results of X-ray diffraction analysis performed under the conditions described in the Examples below.

[0014] In this specification, the maximum X-ray diffraction peak intensity derived from α-Fe in a steel material refers to the intensity of the maximum peak appearing near 2θ=44.6° (for example, between 44.4° and 44.8°). In this specification, the maximum X-ray diffraction peak intensity derived from metal carbides in a steel material refers to the intensity of the maximum peak appearing near 2θ=42.5° (for example, between 42.3° and 42.7°) for M6C-type carbides, and refers to the intensity of the maximum peak appearing near 2θ=44° for M23C6-type carbides and M7C3-type carbides. In an X-ray diffraction pattern, when both an X-ray diffraction peak appearing near 2θ=42.5° and an X-ray diffraction peak appearing near 2θ=44° (for example, between 43.8° and 44.2°) appear as X-ray diffraction peaks derived from metal carbides in a steel material, the intensity of the peak with the stronger peak intensity is taken as the maximum X-ray diffraction peak intensity derived from metal carbides. Furthermore, the measurement of peak intensity in this specification is performed by fitting a curve representing the intensity distribution obtained by an X-ray diffractometer and using the fitted curve. For example, the maximum X-ray diffraction peak intensity derived from α-Fe refers to the intensity of the maximum peak appearing near 2θ = 44.6° on the fitted intensity curve.

[0015] In addition, if the steel type is high-speed tool steel (HSS) such as SKH51, so-called cold work tool steel such as SKD11 or DC53 (trade name) manufactured by Daido Steel Co., Ltd., or cold work die steel (cold work die steel), it is presumed that Fe6C, W6C, Cr6C, V6C, etc. will precipitate as M6C-type carbides.

[0016] Here, the ratio of the maximum peak intensity of X-ray diffraction derived from metal carbides in the steel material [carbide intensity] obtained by the oblique incidence method to the maximum peak intensity of X-ray diffraction derived from α-Fe [Fe intensity] is defined as the peak intensity ratio [carbide intensity / Fe intensity]. The carbide layer 2a is a layer having a peak intensity ratio of 0.5 to 4.0. If the peak intensity ratio is less than 0.5, the amount of metal carbide precipitated in the steel material 2 is small, and the effect of improving the adhesion between the steel material 2 and the metal carbide film 3 cannot be obtained. On the other hand, if the peak intensity ratio exceeds 4.0, a large amount of cementite precipitates in the steel material 2, making the steel material brittle and failing to obtain the effect of improving adhesion.

[0017] When a metal carbide film 3 (described later) is formed on a carbide layer 2a having a peak intensity ratio of 0.5 to 4.0, the adhesion between the steel material 2 and the metal carbide film 3 is improved in a Rockwell indentation test. While the reason for the improved adhesion is unclear, it is believed that the improved adhesion is due to improved chemical compatibility between the steel material 2 and the metal carbide film 3 and elimination of lattice mismatch. When the metal carbide film 3 is, for example, a vanadium silicocarbide film, the peak intensity ratio is preferably 0.6 or more, and more preferably 0.7 or more. Furthermore, when the metal carbide film 3 is, for example, a vanadium silicocarbide film, the peak intensity ratio is preferably 2.0 or less, and more preferably 1.0 or less.

[0018] <Metal carbide film> The metal carbide film 3 formed on the steel material 2 is a film containing carbon and one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si. For example, the metal carbide film 3 is a film containing, in the entirety or in part, a metal carbide such as VC (vanadium carbide), TiC (titanium carbide), AlC (aluminum carbide), CrC (chromium carbide), NbC (niobium carbide), SiC (silicon carbide), VSiC (vanadium silicocarbide), or TiSiC (titanium silicocarbide). Note that when the metal carbide film-coated member 1 is applied to press-molding dies or various tools (cutting tools, gear cutting tools, forging tools, etc.), the metal carbide film 3 is preferably a vanadium-based film such as VC (vanadium carbide) or VSiC (vanadium silicocarbide). Vanadium-based films are highly lubricating films for high-speed tool steels such as SKH51, cold-work tool steels such as SKD11 and DC53, and cold-work die steels, which are commonly used as the workpieces for press-formed products and steel materials for various tools, and can effectively suppress damage caused by contact friction with the mating material.

[0019] The metal carbide film 3 preferably has a total concentration of one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si and a carbon concentration of 90 at% or more. It is more preferably 93 at% or more, and even more preferably 95 at% or more. The metal carbide film 3 may also contain 10 at% or less of non-metallic elements, excluding carbon. Examples of non-metallic elements include fluorine, argon, chlorine, and hydrogen contained in the source gas supplied in the process of forming the metal carbide film 3, and oxygen and nitrogen contained in the residual gas in the chamber of the film forming apparatus. The non-metallic elements contained in the metal carbide film 3 are preferably 7 at% or less, and even more preferably 5 at% or less. The metal element concentrations and carbon element concentrations in the metal carbide film 3 can be measured by composition analysis using an EPMA.

[0020] When the metal carbide film 3 is a vanadium silicocarbide film, the vanadium element concentration is preferably 8 to 30 at%, the silicon element concentration is 8 to 30 at%, and the carbon element concentration is preferably 40 to 80 at%. When the vanadium element concentration is 8 to 30 at%, the lubricity improvement effect derived from vanadium is easily obtained, and the coefficient of friction between the vanadium silicocarbide film and other members is easily reduced. When the silicon element concentration is 8 to 30 at%, amorphous silicon carbide (SiC) is easily formed in the vanadium silicocarbide film, and an oxide film is formed on the film surface when the vanadium silicocarbide film slides against other members, and the coefficient of friction between the vanadium silicocarbide film and other members is easily reduced. When the carbon element concentration is 40 to 80 at%, amorphous silicon carbide (SiC) and amorphous carbon are easily formed in the vanadium silicocarbide film, and the coefficient of friction between the vanadium silicocarbide film and other members is easily reduced. The vanadium element concentration is more preferably 9 at% or more. The vanadium element concentration is more preferably 25 at% or less. The silicon element concentration is more preferably 9 at% or more. The silicon element concentration is more preferably 25 at% or less. The carbon element concentration is more preferably 50 at% or more. The carbon element concentration is more preferably 80 at% or less.

[0021] The thickness of the metal carbide film 3 may be changed as appropriate depending on the properties required of the metal carbide film-coated member 1, but is preferably 0.5 to 4 μm, for example.

[0022] When the metal carbide film 3 is used as a hard film for, for example, molds, tools, automobile parts such as gears, etc., the hardness of the metal carbide film 3 is preferably 2000 HV or more and 4000 HV or less.

[0023] Next, we will explain the method for manufacturing the metal carbide film-coated member 1. The manufacturing method described below comprises a plasma carbonization treatment step of forming a carbide layer 2a on the surface of a steel material, and a metal carbide film formation step of coating a metal carbide film 3 on the steel material 2 that has been subjected to the plasma carbonization treatment step.

[0024] <Plasma carbonization process> The plasma carbonization process for steel is a process in which, before forming a metal carbide film 3 on a steel material 2, carbon is penetrated and diffused from the steel material surface, and metal carbides are precipitated in the steel material, forming a carbide layer 2a with a peak intensity ratio of 0.5 to 4.0. Even for steel materials that originally have a low peak intensity ratio, this process can increase the peak intensity ratio. In the case of SKH51, a type of high-speed tool steel, this process can increase the peak intensity ratio by more than three times.

[0025] In the plasma carbonization process, a method for forming the carbide layer 2a on the steel material 2 can be plasma carbonization. Plasma carbonization is a process in which hydrogen gas and a carbon source gas supplied as process gases are converted into plasma, and the steel material is placed in the plasma atmosphere, thereby precipitating metal carbide on the surface of the steel material. Plasma carbonization makes it possible to set the atmospheric temperature during the plasma carbonization process to 350 to 650°C, thereby suppressing distortion of the steel material 2 due to heat. Furthermore, plasma carbonization can suppress the generation of soot, making maintenance work easier.

[0026] In the plasma carbonization process, for example, a film formation apparatus 10 as shown in FIG. 2 can be used. The film formation apparatus 10 includes a chamber 11 into which the steel material 2 is carried, an anode-side electrode member 12, a cathode-side electrode member 13, and a pulse power supply 14. A gas supply pipe 15 through which a process gas or raw material gas is supplied is connected to the upper part of the chamber 11, and a gas exhaust pipe 16 through which gas inside the chamber 11 is exhausted is connected to the lower part of the chamber 11. A vacuum pump (not shown) is provided in the gas exhaust pipe 16. The cathode-side electrode member 13 also serves as a support base for supporting the steel material 2, and the steel material 2 carried into the chamber 11 is placed on the cathode. A heater (not shown) is provided inside the chamber 11, and the heater adjusts the atmospheric temperature inside the chamber 11, thereby adjusting the temperature of the steel material. 2, when the metal carbide film 3 is formed by plasma CVD, the plasma carbonization process of the steel material 2 and the metal carbide film formation process can be performed in the same apparatus, and the metal carbide film coated member 1 can be manufactured more efficiently than when separate apparatuses are used. Furthermore, by performing the plasma carbonization process of the steel material 2 and the metal carbide film formation process in the same apparatus, the formation of an oxide layer at the interface between the carbide layer 2a and the metal carbide film 3 can be suppressed.

[0027] In the plasma carbonization process, hydrocarbon gases such as methane, ethane, ethylene, and acetylene are used as the carbon source gas used as the process gas. The gases exemplified here may be supplied alone or in combination. It is preferable to use the same carbon source gas as that used in the metal carbide film 3 formation process described below. From the perspective of obtaining a metal carbide film-coated member 1 with superior adhesion, it is preferable to use methane as the carbon source gas. Furthermore, argon gas may be supplied as the process gas in addition to hydrogen and carbon source gases. Argon gas is preferably supplied as needed because argon ions ionize other molecules, contributing to plasma stabilization and increased ion density. The flow rates of each gas are "volumetric flow rates" and are controlled by a mass flow controller. In this specification, "volumetric flow rates" refer to "flow rates converted to standard conditions" that are independent of the actual gas temperature and pressure used. "Standard conditions" are 101.3 kPa (1 atm) and 0°C.

[0028] In the plasma carbonization treatment, the flow rate ratio of the carbon source gas to the hydrogen gas supplied as the treatment gas [carbon source gas flow rate / hydrogen gas flow rate] is preferably 0.01 to 0.40. When the carbon source gas flow rate / hydrogen gas flow rate is 0.01 or more, the carbide layer 2a is more easily formed in the steel material 2, and the adhesion between the steel material 2 and the metal carbide film 3 in the metal carbide film-coated member 1 can be further improved. When the carbon source gas flow rate / hydrogen gas flow rate is 0.40 or less, the formation of amorphous carbon that reduces adhesion is suppressed, and the adhesion between the steel material 2 and the metal carbide film 3 in the metal carbide film-coated member 1 can be further improved. The carbon source gas flow rate / hydrogen gas flow rate may be varied during the plasma carbonization treatment process within the range of 0.01 to 0.40, but is preferably kept constant. The carbon source gas flow rate / hydrogen gas flow rate is preferably 0.02 or more. Furthermore, the carbon source gas flow rate / hydrogen gas flow rate is preferably 0.20 or less.

[0029] In plasma carbonization using hydrogen gas, carbon source gas, and argon gas as processing gases, the volumetric flow ratio of hydrogen gas:carbon source gas:argon gas is preferably 1:0.01-0.40:0.01-0.10 when the volumetric flow rate of hydrogen gas is 1. More preferably, the volumetric flow ratio of hydrogen gas:carbon source gas:argon gas is 1:0.02-0.20:0.01-0.10.

[0030] 2, a pulse voltage is applied between the anode electrode member 12 and the cathode electrode member 13 while hydrogen gas and a carbon source gas are supplied into the chamber 11. By adjusting the atmospheric temperature, duty ratio, voltage, and pressure inside the chamber 11, the hydrogen gas and the carbon source gas can be converted into plasma.

[0031] In order to prevent the steel material 2 from being softened by heat during the carbonization treatment, the atmospheric temperature in the chamber 11 is preferably 350 to 650° C. The atmospheric temperature in the chamber 11 is preferably 400° C. or higher and preferably 550° C. or lower. The atmospheric temperature in the chamber 11 can be adjusted by changing the heater setting temperature according to the plasma conditions.

[0032] The duty ratio is defined as the voltage application time per pulse period, and is calculated as follows: Duty ratio (%) = 100 × voltage application time (ON time) / {voltage application time (ON time) + voltage application stop time (OFF time)}. When a DC pulse power supply 14 is used, the duty ratio in the plasma carbonization treatment is preferably 5% to 90%. The duty ratio is preferably 15% or more and preferably 60% or less. The voltage of the pulse power supply 14 in the plasma carbonization treatment is preferably 1000 to 2000V. The voltage of the pulse power supply 14 is preferably 1100V or more and preferably 1800V or less.

[0033] In the plasma carbonization treatment, the power density when a pulse voltage is applied between the anode electrode member 12 and the cathode electrode member 13 is, for example, 1200 to 2000 W / m2 The power density is preferably 1400 W / m 2 The power density is preferably 1800 W / m 2 Power density [W / m 2 ] is the power [W] / cathode surface area [m 2 ] is the value calculated by the surface area of ​​the cathode [m 2 ]" is the total value of the surface area of ​​the steel material 2 and the surface area of ​​the cathode-side electrode member 13. For example, in the film-forming apparatus 10 of FIG. 2, the steel material is placed on the cathode-side electrode member 13, so when electricity is applied, a voltage is also applied to the steel material via the cathode-side electrode member 13. In other words, the steel material 2 becomes the cathode by being electrically connected to the cathode-side electrode member 13. For this reason, the surface area of ​​the cathode in the film-forming apparatus 10 is the total value of the surface area of ​​the cathode-side electrode member 13 and the surface area of ​​the steel material. Note that the area of ​​the contact surfaces between electrically connected members is not included in the surface area of ​​the cathode. In addition, the steel material is set in a jig (not shown), and the jig When performing plasma carbonization treatment by placing the jig on the cathode-side electrode member 13, the cathode-side electrode member 13, the jig, and the steel are electrically connected. In this case, the surface area of ​​the cathode is the sum of the surface area of ​​the cathode-side electrode member 13, the surface area of ​​the jig, and the surface area of ​​the steel, excluding the areas of the contact surfaces between the cathode-side electrode member 13 and the jig and the contact surfaces between the jig and the steel. "Power [W]" is a value calculated by voltage [V] x current [A]. "Voltage" is the set voltage of the pulse power supply 14, and "current" is a value calculated by (maximum current + minimum current) / 2 during the plasma carbonization treatment process using the current value displayed on the pulse power supply 14.

[0034] The pressure inside the chamber 11 is preferably set to 30 to 200 Pa. To stabilize the plasma and facilitate carbonization, the pressure inside the chamber 11 is preferably 40 Pa or more and preferably 100 Pa or less. The treatment time for the plasma carbonization process varies depending on the type and shape of the steel material. For this reason, the carbonization treatment time may be changed as appropriate, but is preferably, for example, 60 to 360 minutes. The carbonization treatment time is preferably 120 minutes or more and preferably 300 minutes or less.

[0035] In the plasma carbonization treatment step, the means for converting the processing gas into plasma is not particularly limited as long as the hydrogen gas and carbon source gas, which are processing gases, can be converted into plasma.

[0036] By the above-described plasma carbonization treatment process, a steel material 2 having a carbide layer 2a with a peak intensity ratio [carbide intensity / Fe intensity] of 0.5 to 4.0 is obtained.

[0037] The peak intensity ratio of the steel material 2 after the plasma carbonization treatment process / the peak intensity ratio of the steel material before the plasma carbonization treatment process is preferably 2.4 to 19. By performing the plasma carbonization treatment process so that the peak intensity ratio of the steel material 2 after the plasma carbonization treatment process and the peak intensity ratio of the steel material before the plasma carbonization treatment process satisfy the above relationship, the adhesion between the steel material 2 and the metal carbide film 3 is likely to be improved.

[0038] <Metal carbide film formation process> Next, a metal carbide film forming process is carried out to coat the surface of the steel material after the plasma carbonization process with a metal carbide film 3 containing one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si and carbon.

[0039] In the metal carbide film formation step, the metal carbide film 3 may be formed by any method as long as it can form the metal carbide film 3. Methods for forming the metal carbide film 3 include, for example, plasma CVD, arc ion plating, sputtering, and unbalanced magnetron sputtering. Plasma CVD is preferred. When the metal carbide film 3 is formed by plasma CVD, the plasma carbonization treatment of the steel material 2 and the formation of the metal carbide film 3 can be performed in the same plasma processing apparatus. This allows the metal carbide film-coated member 1 to be manufactured more efficiently than when separate apparatuses are used. Furthermore, by performing the plasma carbonization treatment of the steel material 2 and the formation of the metal carbide film 3 in the same apparatus, the formation of an oxide layer at the interface between the carbide layer 2a and the metal carbide film 3 can be suppressed.

[0040] When forming the metal carbide film 3 by plasma CVD, a gas containing one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si, a carbon source gas, and hydrogen gas are supplied as source gases into a chamber 11, and a pulse voltage is applied between an anode electrode member 12 and a cathode electrode member 13 using a pulse power supply 14. This converts the source gas into plasma between the anode electrode member 12 and the cathode electrode member 13, and the metal carbide film 3 is formed on the surface of the steel material 2. Examples of the gas containing one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si include vanadium chloride gas as an example of V, titanium chloride gas as an example of Ti, aluminum chloride gas as an example of Al, chromium chloride gas as an example of Cr, niobium chloride gas as an example of Nb, and silicon chloride gas as an example of Si.

[0041] When forming a vanadium silicocarbide film as the metal carbide film 3, for example, vanadium tetrachloride (VCl4) gas or vanadium oxide trichloride (VOCl3) gas is used as the vanadium chloride gas. Note that vanadium tetrachloride gas is preferably used as the vanadium chloride gas, from the viewpoint that the number of elements constituting the gas is small and it becomes easy to remove impurities in the vanadium silicocarbide film. Furthermore, vanadium tetrachloride gas is also preferred in that it is easily available, is a liquid at room temperature, and can be easily supplied as a gas.

[0042] Examples of silicon source gases that can be used include silane-based gases such as monosilane gas, disilane gas, dichlorosilane gas, trichlorosilane gas, silicon tetrachloride gas, and silicon tetrafluoride gas. The gases exemplified here may be supplied alone or in combination of two or more gases. Among these gases, it is preferable to use silicon tetrachloride (SiCl4) gas, which can easily remove chlorine atoms with hydrogen plasma, is thermally stable, and decomposes only in plasma.

[0043] As the carbon source gas, for example, a hydrocarbon gas such as methane gas, ethane gas, ethylene gas, or acetylene gas is used. The gases exemplified here may be supplied alone or in a mixture of two or more types. Methane gas is preferably used. The use of methane gas makes it easier to control the carbon content, and the inclusion of a large amount of hydrogen in the film reduces the amount of chlorine in the film.

[0044] Furthermore, when a vanadium silicocarbide film is formed as the metal carbide film 3, an organosilane gas having a molecular structure in which a hydrocarbon functional group is bonded to silicon may be used as a gas that serves as both the silicon source gas and the carbon source gas. The organosilane gas is not particularly limited as long as it has a molecular structure in which a hydrocarbon functional group is bonded to silicon, and examples of the organosilane gas that may be used include monomethylsilane gas, dimethylsilane gas, trimethylsilane gas, and tetramethylsilane gas. Note that when a vanadium silicocarbide film is formed as the metal carbide film 3, a mixed gas of an organosilane gas and a carbon source gas may be used.

[0045] When forming a vanadium silicocarbide film as the metal carbide film 3, if the source gas contains vanadium chloride gas, the vanadium silicocarbide film will inevitably contain chlorine as an impurity in the remainder, excluding vanadium, silicon, and carbon. Since hydrogen gas easily combines with chlorine, when the source gas contains hydrogen gas, chlorine generated from the vanadium chloride gas combines with hydrogen and is easily discharged outside the system. This makes it possible to prevent chlorine from being mixed into the vanadium silicocarbide film. The remainder of the vanadium silicocarbide film may contain unavoidable impurities other than chlorine.

[0046] In the metal carbide film forming process, when vanadium chloride gas and silicon tetrachloride gas are supplied as raw material gases, the volumetric flow rate of hydrogen gas supplied into chamber 11 is preferably 5 to 25 times the total volumetric flow rate of the vanadium chloride gas and the silicon tetrachloride gas.

[0047] In the metal carbide film forming step, when vanadium chloride gas, silicon source gas, carbon source gas, hydrogen gas, and argon gas are supplied as raw material gases, the volumetric flow ratio of the vanadium chloride gas, silicon source gas, carbon source gas, hydrogen gas, and argon gas is preferably 1:0.25-2:3-20:20-35:0.5-2, where the volumetric flow rate of the vanadium chloride gas is 1. This makes it easier to obtain a vanadium silicon carbide film in which the total of the elemental vanadium concentration, elemental silicon concentration, and elemental carbon concentration in the film is 90 at% or more.

[0048] Argon gas is supplied into the chamber 11 as needed in the metal carbide film forming process, since argon ions ionize other molecules, thereby contributing to plasma stabilization and improving ion density.

[0049] The pressure inside the chamber 11 in the metal carbide film formation process is preferably set to, for example, 30 to 200 Pa. The pressure inside the chamber 11 is more preferably 50 to 150 Pa. The power supplied in the metal carbide film formation process is preferably 200 to 2500 W. "Power [W]" is a value calculated by voltage [V] x current [A]. "Voltage" is the set voltage of the pulsed power supply 14. "Current" is a value calculated by (maximum current + minimum current) / 2 in the metal carbide film formation process using the current value displayed on the pulsed power supply 14. The power can be adjusted by changing the set value of the duty ratio. When a DC pulsed power supply 14 is used, the voltage in the metal carbide film formation process is preferably 1000 to 2000 V. When a DC pulsed power supply 14 is used, the duty ratio in the metal carbide film formation process is preferably 5% to 60%.

[0050] By the metal carbide film forming process as described above, a metal carbide film 3 containing carbon and one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si is formed on the carbide layer 2a of the steel material 2. This makes it possible to manufacture a metal carbide film-coated member 1 that has excellent adhesion in a Rockwell indentation test.

[0051] The above is an example of an embodiment of the present invention, but the present invention is not limited to such an example. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims, and it is naturally understood that those also belong to the technical scope of the present invention.

Example

[0052] A test piece of a metal carbide-coated member was prepared by subjecting a steel material to plasma carbonization treatment to form a carbide layer on the surface and then forming a vanadium silicon carbide film as a metal carbide film on the steel material, and the following measurements were performed.

[0053] <X-ray diffraction analysis> For the X-ray diffraction analysis, in order to obtain only the information near the surface of the test piece, an X-ray diffraction analyzer (SmartLab manufactured by Rigaku Corporation) was used, and the analysis was carried out under the following conditions by the inclined incidence method. ------------------------------------------------------------------------------- Incident angle: 1.0° X-ray source: CuKα ray X-ray output: 40 kV, 20 mA Scan axis: 2θ / θ Goniometer: RINT2000 wide-angle goniometer Scan range: 20° to 80° Detector: Scintillation counter Incident slit: 1° Scan mode: STEP Longitudinal limit slit: 10 mm Scan speed: 1.0 sec Receiving slit 1: 1.25 mm Step width: 0.05° Receiving slit 2: 0.3 mm ------------------------------------------------------------------------------- The maximum X-ray diffraction peak intensity (carbide intensity) derived from metal carbides and the maximum X-ray diffraction peak intensity (Fe intensity) derived from α-Fe were determined from the X-ray diffraction pattern obtained by the X-ray diffraction analysis under the above conditions. The maximum peak intensity was determined using the Solver function of Excel® 2010 as follows. First, peaks with peak tops near diffraction angles 2θ = 42.5° and 2θ = 44.6° from the X-ray diffraction pattern obtained by the X-ray diffraction analysis were approximated by superimposing a Gaussian fundamental waveform and a linear background. Next, the peak intensity, full width at half maximum, and peak position were optimized, and the two overlapping peaks contained within the peak were each curve-fitted to separate the peaks. The maximum value of the Gaussian function obtained by the fitting was then taken as the maximum peak intensity. The curve fitting was performed using the least squares method.

[0054] <Film hardness measurement> Nanoindentation was performed using a Fischer Instruments FISCHER SCOPE® H100C. Specifically, a Berkovich-type diamond indenter was pressed into the test piece with a maximum indentation load of 3 mN, and the indentation depth was continuously measured. From the obtained indentation depth measurement data, Martens hardness and Vickers hardness converted from Martens hardness were calculated using Fischer Instruments' software "WIN-HCU®." The calculated Vickers hardness was displayed on the screen of the measuring device, and this value was treated as the hardness of the film at the measurement point. In this example, the Vickers hardness was measured at 20 random points on the outermost surface of each test piece, and the average of the obtained hardness values ​​was used as the Vickers hardness of the vanadium silicate film.

[0055] <Film thickness measurement> The thickness of the vanadium silicocarbide film was measured by cutting the test piece vertically, mirror-polishing the cut surface, observing the cut surface with a metallurgical microscope at a magnification of 1000x, and calculating the thickness based on the observed image information.

[0056] <Composition analysis of vanadium silicate film> The composition of the vanadium silicocarbide film formed on the test piece was analyzed under the following analysis conditions: EPMA: JEOL Ltd. JXA-8530F Measurement mode: semi-quantitative analysis Accelerating voltage: 15 kV Irradiation current: 1.0×10 -7 A Beam Shape: Spot Beam diameter setting value: 0 Spectroscopic crystal: LDE6H, TAP, LDE5H, PETH, LIFH, LDE1H

[0057] <Rockwell indentation test> A Rockwell hardness tester was set to the C scale, and an indentation was made on the surface of the vanadium silicocarbide film of the test piece. The area around the indentation was then observed using a metallurgical microscope. The degree of film peeling of the test piece was then determined based on the well-known indentation peeling criteria in the Rockwell indentation test, and the adhesion of the vanadium silicocarbide film-coated member was evaluated.

[0058] The test specimens were prepared using the following procedure. First, a φ22 round bar made of SKH51, a type of high-speed tool steel, was cut at 6-7 mm intervals, and the coating surfaces of the cut round bars were mirror-polished as shown in Figure 3 to be used as the steel material for the test specimens. The coating equipment used was one with the structure shown in Figure 2, and a pulse power supply was used as the power source.

[0059] <Confirmation of oxide layer formation> A plating solution was prepared by preparing 10 ml of Sumer plating solution (Blue Sumer 2L) manufactured by Nippon Kanigen Co., Ltd., and adding 40 ml of purified water to make a total of 50 ml. The above test piece for microstructure photograph measurement was placed in this plating solution and kept at 120°C for 2 hours. After keeping for 2 hours, the test piece was removed from the plating solution and cut into pieces perpendicular to the film-formed surface using a cutting machine. The cut test piece was embedded in resin to prepare a specimen. The cross section of the specimen was then polished with emery paper, and the polished surface was mirror-finished with a buff. Then, based on the nitric acid alcohol method (nital method) specified in JIS G 0553, nitric acid (JIS The specimen was immersed in a 3% nitric acid etching solution prepared by mixing ethanol with 62% nitric acid (equivalent to 62% of K 1308). The specimen was then immersed for 5 minutes in this etching solution. The cross-section of the specimen was then observed at 10,000x magnification using a field-emission scanning electron microscope (JEOL JSM-7001F) to obtain cross-sectional images. The cross-sectional images were then used to observe whether an oxide layer had formed at the interface between the carbide layer and the metal carbide film. Oxide layers are typically preferentially oxidized at the grain boundaries, and appear darker than normal structures when observed under an electron microscope. Therefore, the presence or absence of an oxide layer can be determined by its color and shape.

[0060] Example 1 First, the steel material to be used as the test specimen is placed in the chamber of the deposition equipment, and the chamber is evacuated for 30 minutes to reduce the pressure inside the chamber to 10 Pa or less. The heater is not operated during this process. The heater is installed inside the chamber, and the ambient temperature inside the chamber is measured with a sheathed thermocouple. Next, the heater is set to 200°C, and the steel material is baked for 10 minutes. After that, the heater is turned off, and the deposition equipment is left for 30 minutes to cool the chamber.

[0061] Next, hydrogen gas is supplied into the chamber at a flow rate of 100 ml / min, and the exhaust rate is adjusted to set the pressure inside the chamber to 100 Pa. Then, the atmosphere inside the chamber is heated for 30 minutes so that the atmospheric temperature inside the chamber reaches 525°C.

[0062] Next, the voltage is set to 800V, the duty ratio is set to 40%, and the DC pulse power supply is operated in unipolar output mode. This turns the hydrogen gas into plasma between the electrodes in the chamber. After that, the hydrogen gas flow rate is set to 98ml / min, and argon gas is supplied into the chamber at a flow rate of 3ml / min. The exhaust rate is also adjusted so that the total pressure inside the chamber is 58Pa. Next, the voltage of the pulse power supply is set to 1400V, the duty ratio is set to 40%, and the atmospheric temperature inside the chamber is set to 525°C. This turns the hydrogen gas and argon gas into plasma between the electrodes.

[0063] <Plasma carbonization process> Next, hydrogen gas was supplied into the chamber at a flow rate of 98 ml / min as the process gas, and methane gas and argon gas were supplied at a flow rate of 5 ml / min and 3 ml / min as the carbon source gas. The total pressure in the chamber was maintained at 58 Pa, the ambient temperature in the chamber was set to 525°C, the voltage of the pulse power supply was set to 1400 V, and the duty ratio was set to 40%. Plasma carbonization was performed on the steel for 120 minutes in an atmosphere of hydrogen, methane, and argon gas plasma. The flow rate ratio of methane gas, the carbon source gas supplied as the process gas, to hydrogen gas [carbon source gas flow rate / hydrogen gas flow rate] was 0.05.

[0064] Figure 4 shows the results of X-ray diffraction analysis of the test specimens carbonized under the above conditions. As shown in Figure 4, both the test specimens before and after plasma carbonization exhibited a diffraction peak at 2θ = 44.6° attributable to α-Fe and a diffraction peak at 2θ = 42.5° attributable to M6C carbides. The test specimen after plasma carbonization exhibited a weaker diffraction peak intensity attributable to α-Fe than the test specimen before plasma carbonization, while the diffraction peak intensity attributable to metal carbides, namely M6C carbides, was stronger. The results in Figure 4 confirmed that carbon penetrated and diffused from the steel surface, resulting in the precipitation of metal carbides within the steel, forming a carbide layer within the steel.

[0065] The conditions for the plasma carbonization treatment step in Example 1 are shown in Table 1 below. Table 1 also shows the carbonization conditions for Examples 2 and 3 and Comparative Example 1, which will be described later.

[0066] [Table 1]

[0067] <Vanadium silicon carbide film formation process> After the plasma carbonization process, the flow rates of vanadium tetrachloride gas (as a vanadium chloride gas) and silicon tetrachloride gas (as a silicon source gas) were set to 3 ml / min, 4.5 ml / min, 15 ml / min, 98 ml / min, and 3 ml / min, respectively, and the flow rates of methane gas (as a carbon source gas) and hydrogen gas were set to 98 ml / min and 3 ml / min, respectively, and the gases were supplied into the chamber. In other words, the flow rates of vanadium tetrachloride gas, silicon tetrachloride gas, carbon source gas, hydrogen gas, and argon gas were supplied so that the flow ratio of vanadium tetrachloride gas, silicon tetrachloride gas, carbon source gas, hydrogen gas, and argon gas was 1:1.5:5:33:1, assuming the flow rate of vanadium tetrachloride gas to be 1. The exhaust volume was adjusted to a pressure of 58 Pa in the chamber. The voltage of the pulsed power supply was set to 1400 V, and the duty ratio was set to 40%. The power of the pulsed power supply was 420 W. As a result, each gas is converted into plasma, and vanadium, silicon, and carbon are adsorbed onto the steel material, and a vanadium silicocarbide film containing vanadium, silicon, and carbon is formed on the steel material having a carbide layer on its surface. The vanadium silicocarbide film formation treatment under the above conditions was carried out for 4 hours, and a vanadium silicocarbide film with a film thickness of 1.2 μm was coated on the steel material, thereby obtaining a test piece of Example 1.

[0068] A Rockwell indentation test was performed on the test piece of Example 1 using the method described above. As a test result, an image of the indentation on the test piece of Example 1 after the Rockwell indentation test is shown in Figure 5. The result of the Rockwell indentation test was determined to be HF1 based on the indentation peeling criteria.

[0069] Example 2 Test pieces were prepared under the same conditions as in Example 1, except that the plasma carbonization treatment was carried out for 4 hours. An image of the indentation of the test piece of Example 2 after the Rockwell indentation test is shown in Figure 6. The result of the Rockwell indentation test was determined to be HF1 based on the indentation peeling criteria.

[0070] Example 3 Test pieces were prepared under the same conditions as in Example 1, except that in the plasma carbonization treatment step, the flow rate of methane gas supplied as the treatment gas was set to 3 ml / min, the flow rate ratio of methane gas (carbon source gas) to hydrogen gas (carbon source gas flow rate / hydrogen gas flow rate) was set to 0.03, and the plasma carbonization treatment step was carried out for 4 hours. An image of the indentation area of ​​the test piece of Example 3 after the Rockwell indentation test is shown in Figure 7. The Rockwell indentation test result was determined to be HF1 based on the indentation peeling criteria.

[0071] Comparative Example 1 A test piece was prepared under the same conditions as in Example 1, except that the plasma carbonization treatment step was not performed. An image of the indentation portion of the test piece of Comparative Example 1 after the Rockwell indentation test is shown in Figure 8. The result of the Rockwell indentation test was determined to be HF4 based on the indentation peeling criteria.

[0072] From the above results of the Rockwell indentation test, it can be seen that the test pieces of Examples 1 to 3, in which a vanadium silicocarbide film was formed on a carbide layer of steel, were members with superior adhesion in the Rockwell indentation test compared to the test piece of Comparative Example 1, in which a vanadium silicocarbide film was formed directly on steel without a carbide layer.

[0073] Table 2 below shows the results of X-ray diffraction analysis performed on the test pieces before the vanadium silicocarbide film was formed. Table 2 compares the peak intensity ratios of the test pieces before the vanadium silicocarbide film was formed. Note that in Examples 1 and 3, the peak intensity ratio of the test piece before the vanadium silicocarbide film was formed refers to the peak intensity ratio of the carbide layer formed by plasma carbonization. On the other hand, in Comparative Example 1, no plasma carbonization was performed, so the peak intensity ratio of the test piece before the vanadium silicocarbide film was formed refers to the peak intensity ratio of a steel material that was not subjected to plasma carbonization. Table 2 also shows the ratio of the peak intensity ratio of the steel material after the plasma carbonization process in Example 1 to the peak intensity ratio of the steel material before the plasma carbonization process.

[0074] [Table 2]

[0075] As shown in Table 2, the peak intensity ratio of the test piece of Example 1, for which the indentation peeling judgment in the Rockwell indentation test was HF1, was 0.82, and the peak intensity ratio of the test piece of Example 3 was 0.63. On the other hand, the peak intensity ratio of the test piece of Comparative Example 1, for which the indentation peeling judgment was HF4, was 0.16. That is, according to the results of this example, it is clear that when the peak intensity ratio is within a specific range, the adhesion between the steel material and the metal carbide film can be improved.

[0076] The ratio of the peak intensity ratio of the test piece of Example 1 to the peak intensity ratio of the test piece of Comparative Example 1, i.e., the peak intensity ratio of the carbide layer after plasma carbonization / the peak intensity ratio of the steel material before plasma carbonization, was 5.1. Furthermore, in Example 3, the peak intensity ratio of the carbide layer after plasma carbonization / the peak intensity ratio of the steel material before plasma carbonization was 3.9.

[0077] Next, film thickness measurements and compositional analysis of the vanadium silicocarbide film were performed by the methods described above for the test pieces of Examples 1 to 3. Furthermore, film hardness measurements were also performed by the methods described above for the test piece of Example 1. The results of the film hardness measurements, film thickness measurements, and compositional analysis of the vanadium silicocarbide film are shown in Table 3 below.

[0078] [Table 3]

[0079] Next, electron microscope images of the cross sections of the samples prepared according to the procedure described above in <Confirmation of Oxide Layer Formation> were obtained. FIG. 9 is an electron microscope image showing the cross section of the sample of Example 1. It was confirmed that no oxide layer was formed at the interface between the carbide layer and the metal carbide film in the sample of Example 1. Similarly, electron microscope images were obtained for the samples of Examples 2 and 3, and no oxide layer was formed in either sample. [Industrial Applicability]

[0080] The present invention can be used for hard film coating treatment of molds, tools, automobile parts such as gears, etc. That is, the metal carbide film coated member according to the present invention is used as, for example, molds, tools, or automobile parts. [Explanation of symbols]

[0081] 1 Metal carbide film coated member 2 Steel material 2a Carbide layer 3. Metal carbide film 10 Film deposition equipment 11 Chambers 12 Anode side electrode member 13 Cathode side electrode member 14 Pulse power supply 15 Gas supply pipe 16 Gas exhaust pipe

Claims

1. a steel material having a carbide layer on its surface; a metal carbide film containing carbon and one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si on the carbide layer; when the ratio of the maximum peak intensity of X-ray diffraction derived from metal carbide of the steel material [carbide intensity] to the maximum peak intensity of X-ray diffraction derived from α-Fe [Fe intensity] is defined as a peak intensity ratio [carbide intensity / Fe intensity], the peak intensity ratio of the carbide layer is 0.5 to 4.0, the metal carbide film is a vanadium silicon carbide film containing vanadium, silicon, and carbon; The vanadium silicon carbide film is a metal carbide film-coated member characterized in that the total concentration of vanadium, silicon and carbon in the film is 90 at % or more.

2. 2. The metal carbide film-coated member according to claim 1, wherein the peak intensity ratio of the carbide layer is 2.0 or less.

3. 2. The metal carbide film-coated member according to claim 1, wherein the peak intensity ratio of the carbide layer is 1.0 or less.

4. 4. The metal carbide film-coated member according to claim 1, wherein the vanadium silicon carbide film has a vanadium element concentration of 8 to 30 at %, a silicon element concentration of 8 to 30 at %, and a carbon element concentration of 40 to 80 at %.

5. a plasma carbonization treatment step of forming a carbide layer on the surface of the steel material; a metal carbide film forming step of forming a metal carbide film containing carbon and one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si on the carbide layer, wherein the carbide layer is formed in the plasma carbonization treatment step so that the peak intensity ratio of the carbide layer after the plasma carbonization treatment step is 0.5 to 4.0, when the ratio of the maximum peak intensity of X-ray diffraction [carbide intensity] derived from metal carbide of the steel material to the maximum peak intensity of X-ray diffraction [Fe intensity] derived from α-Fe is defined as the peak intensity ratio [carbide intensity / Fe intensity]; the metal carbide film is a vanadium silicon carbide film containing vanadium, silicon, and carbon; The method for producing a metal carbide film-coated member is characterized in that the vanadium silicon carbide film has a total concentration of vanadium, silicon and carbon elements of 90 at % or more.

6. 6. The method for producing a metal carbide film-coated member according to claim 5, wherein in the plasma carbonization treatment step, the carbide layer is formed so that [the peak intensity ratio of the steel material after the plasma carbonization treatment step / the peak intensity ratio of the steel material before the plasma carbonization treatment step] satisfies 2.4 to 19.

7. a plasma carbonization treatment step of forming a carbide layer on the surface of the steel material; a metal carbide film forming step of forming a metal carbide film containing carbon and one or more metals selected from the group consisting of V, Ti, Al, Cr, Nb, and Si on the carbide layer, The plasma carbonization treatment step is carried out in an atmosphere in which a carbon source gas and a hydrogen gas, which are supplied as treatment gases, are converted into plasma, the metal carbide film is a vanadium silicon carbide film containing vanadium, silicon, and carbon; The method for producing a metal carbide film-coated member is characterized in that the vanadium silicon carbide film has a total concentration of vanadium, silicon and carbon elements of 90 at % or more.

8. 8. The method for producing a metal carbide film-coated member according to claim 7, wherein the flow rate ratio of the carbon source gas to the hydrogen gas, carbon source gas flow rate / hydrogen gas flow rate, is 0.01 to 0.

40.

9. 9. The method for producing a metal carbide film-coated member according to claim 8, wherein hydrogen gas, a carbon source gas, and an argon gas are supplied as treatment gases in the plasma carbonization treatment step, and when the volumetric flow rate of the hydrogen gas is taken as 1, the volumetric flow rate ratio of the hydrogen gas:carbon source gas:argon gas is 1:0.01-0.40:0.01-0.

10.

10. The method for producing a metal carbide film-coated member according to any one of claims 7 to 9, wherein the carbon source gas is methane gas.

11. The method for producing a metal carbide film-coated member according to any one of claims 5 to 10, wherein the vanadium silicon carbide film has a vanadium element concentration of 8 to 30 at%, a silicon element concentration of 8 to 30 at%, and a carbon element concentration of 40 to 80 at%.

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