Wide-temperature-range wear-resistant high-entropy alloy coating as well as preparation method and application thereof

Abstract

The invention discloses a wide-temperature-range wear-resistant high-entropy alloy coating as well as a preparation method and application thereof, and belongs to the technical field of wear-resistant materials. The wide-temperature-range wear-resistant high-entropy alloy coating comprises a high-entropy alloy bottom layer and a high-entropy alloy oxide surface layer, the high-entropy alloy in the high-entropy alloy bottom layer comprises at least four elements of Ti, Nb, Cr, Mo, V and Ta; the high-entropy alloy oxide surface layer is formed after high-entropy alloy in the surface area in the high-entropy alloy bottom layer is subjected to in-situ oxidation. The wide-temperature-range wear-resistant high-entropy alloy coating has high hardness and wide-temperature-range mechanical property stability, has excellent wear resistance and corrosion resistance in the range of room temperature to 700 DEG C, and can greatly improve the use performance and prolong the service life of a high-temperature moving part.

Description

Technical Field

[0001] This invention relates to the field of wear-resistant materials technology, and more specifically, to a wide-temperature-range wear-resistant high-entropy alloy coating, its preparation method, and its application. Background Technology

[0002] In aerospace, nuclear energy, and other fields, extreme operating conditions such as high temperature, high speed, and high load cause severe friction and wear on the surfaces of moving mechanical parts, posing a significant challenge to their performance and lifespan. Furthermore, most mechanical parts start at low temperatures and operate at high temperatures, requiring surfaces to possess excellent wear resistance over a wide temperature range.

[0003] Most wear-resistant coatings currently available exhibit excellent wear resistance at low temperatures. However, as temperatures rise, especially above 500°C, the coating material softens and oxidizes, leading to problems such as mechanical property degradation and coating peeling failure. These factors prevent most wear-resistant coating materials from being used at high temperatures.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a wide-temperature-range wear-resistant high-entropy alloy coating, its preparation method and application, in order to solve or improve the above-mentioned technical problems.

[0006] This invention can be implemented as follows: In a first aspect, the present invention provides a wide-temperature-range wear-resistant high-entropy alloy coating, comprising a high-entropy alloy underlayer and a high-entropy alloy oxide surface layer; the high-entropy alloy in the high-entropy alloy underlayer comprises at least four elements selected from Ti, Nb, Cr, Mo, V and Ta; the high-entropy alloy oxide surface layer is formed by in-situ oxidation of the high-entropy alloy in the surface region of the high-entropy alloy underlayer.

[0007] In an optional embodiment, the content of each metal element contained in the high-entropy alloy in the high-entropy alloy bottom layer is independently 15 at.% to 30 at.%.

[0008] In an optional embodiment, the wide-temperature-range wear-resistant high-entropy alloy coating has at least one of the following characteristics: Feature 1: High-entropy alloys include at least one of TiNbCrMo alloy, TiNbCrMoV alloy, and TiNbCrMoTa alloy; Feature 2: The thickness of the wide-temperature-range wear-resistant high-entropy alloy coating is 1μm~10μm.

[0009] In an optional embodiment, the wide-temperature-range wear-resistant high-entropy alloy coating also has at least one of the following characteristics: Feature 3: The surface hardness of the wide-temperature-range wear-resistant high-entropy alloy coating is not less than 900 HV; Feature 4: The wear rate of the wide-temperature-range wear-resistant high-entropy alloy coating does not exceed 5×10⁻⁶ within the range of room temperature to 700℃. - 6 mm 3 / ( N·m).

[0010] In a second aspect, the present invention provides a method for preparing a wide-temperature-range wear-resistant high-entropy alloy coating as described in any of the foregoing embodiments, comprising the following steps: preparing a high-entropy alloy underlayer on the surface of a substrate by magnetron sputtering, and then subjecting the surface region of the high-entropy alloy underlayer to an oxidation heat treatment to form a high-entropy alloy oxide surface layer in situ on the surface region of the high-entropy alloy underlayer.

[0011] In an optional embodiment, the matrix includes at least one of nickel-based superalloys, alloy steels, and titanium alloys.

[0012] In an optional implementation, the magnetron sputtering process conditions include: a vacuum level better than 5 × 10⁻⁶. -3 Pa, the introduced gas includes argon, the gas pressure is 0.2Pa~1Pa, the matrix negative bias voltage is 30V~200V, the target current is 2A~15A, the ion source power is 0.2kW~2kW, and the time is 1h~10h.

[0013] In an optional embodiment, the substrate is pretreated before preparing the high-entropy alloy underlayer; In an optional embodiment, the pretreatment includes grinding and polishing the substrate, then cleaning and drying it to remove oil and rust, and then placing the substrate in a vacuum chamber for ion sputtering cleaning.

[0014] In an optional implementation, ion sputtering cleaning includes: evacuating to a vacuum level better than 5 × 10⁻⁶. -3 Pa, the introduced gas includes argon, the gas pressure is 0.2Pa~1Pa, the matrix negative bias voltage is 500V~1000V, the ion source power is 1kW~4kW, and the time is 30min~120min.

[0015] In an optional embodiment, the process conditions for the oxidation heat treatment include: a temperature of 500°C to 700°C, a time of 30 min to 120 min, and air or an oxygen-containing gas.

[0016] Thirdly, the present invention provides a method for improving the tribological properties of a substrate over a wide temperature range, comprising the following steps: preparing a high-entropy, wear-resistant alloy coating over a wide temperature range as described in any of the foregoing embodiments on the surface of the substrate.

[0017] Fourthly, the present invention provides a mechanical moving part having a wide-temperature-range wear-resistant high-entropy alloy coating as described in any of the foregoing embodiments.

[0018] The beneficial effects of this invention include: Compared to ordinary high-entropy alloy coatings, this invention first prepares a high-entropy alloy underlayer comprising at least four elements selected from Ti, Nb, Cr, Mo, V, and Ta, and then forms a high-entropy alloy oxide surface layer by in-situ oxidation on the surface of the high-entropy alloy underlayer to obtain a wide-temperature-range wear-resistant high-entropy alloy coating. The surface layer in this wide-temperature-range wear-resistant high-entropy alloy coating can maintain high hardness and wear resistance within a temperature range from room temperature to 700°C. The good performance and structural stability of the underlayer within a wide temperature range can provide good support for the high-entropy alloy coating and have good bonding strength with the substrate.

[0019] During low-temperature friction and wear, the high-entropy alloy oxide surface layer provides excellent wear resistance and friction reduction. During high-temperature friction and wear, the high-entropy alloy underlayer does not soften, and the surface oxide layer remains stable, thus maintaining excellent wear resistance over a wide temperature range without a decrease in wear resistance. Furthermore, under high-temperature friction and wear, the oxidation of high-entropy alloy elements continues, and the oxide layer is replenished promptly after frictional wear, maintaining the high-entropy alloy coating's wear resistance and friction reduction effect at high temperatures. In addition, the partially oxidized high-entropy alloy oxide surface layer bonds well with the high-entropy alloy underlayer, preventing peeling. This composite high-entropy alloy coating exhibits superior coating bonding strength and excellent wear resistance over a wide temperature range, showing great application potential in high-temperature engines, nuclear energy, and tooling applications. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the wide-temperature-range wear-resistant high-entropy alloy coating provided by the present invention; Figure 2 The surface morphology of the high-entropy alloy coating prepared for Comparative Example 2. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0023] The following is a detailed description of the wide-temperature-range wear-resistant high-entropy alloy coating, its preparation method, and its application provided by the present invention.

[0024] This invention provides a wide-temperature-range wear-resistant, high-entropy alloy coating, such as... Figure 1 As shown, it includes a high-entropy alloy bottom layer and a high-entropy alloy oxide top layer.

[0025] The high-entropy alloy in the high-entropy alloy substrate includes at least four elements selected from Ti, Nb, Cr, Mo, V, and Ta; the high-entropy alloy oxide surface layer is formed by in-situ oxidation of the high-entropy alloy in the surface region of the high-entropy alloy substrate.

[0026] It should be noted that the high-entropy alloy of this invention does not contain elements such as Fe, Al, and Co commonly used in conventional high-entropy alloys. Instead, it uses metallic elements with refractory properties to achieve higher wear resistance. Furthermore, if the refractory metallic elements in this invention form a high-entropy alloy coating on the substrate surface as nitrides or carbides, the high internal stress of the nitride or carbide system can lead to insufficient bonding strength with the substrate. In addition, nitrides or carbides have high coefficients of friction, especially at high temperatures, where oxidation can cause the coating structure to become porous, reducing its wear resistance. Therefore, this invention effectively avoids the above problems by first preparing a high-entropy alloy underlayer comprising at least four elements selected from Ti, Nb, Cr, Mo, V, and Ta, and then oxidizing the surface of the high-entropy alloy underlayer in situ to form a high-entropy alloy oxide surface layer. Compared to ordinary high-entropy alloy coatings, the wide-temperature-range wear-resistant high-entropy alloy coating provided by this invention can maintain high hardness and wear resistance in the range of room temperature to 700°C due to the dense high-entropy alloy oxide surface layer. The good performance and structural stability of the high-entropy alloy underlayer in the wide temperature range provide good support for the high-entropy alloy coating and have good bonding strength with the substrate.

[0027] Specifically, the high-entropy alloy substrate provided by this invention possesses excellent hardness and toughness, good oxidation resistance, and high bonding strength with the substrate, providing excellent support. The high-entropy alloy oxide surface layer has even higher hardness and superior wear resistance, and the oxides also have a certain lubricating effect. Therefore, the high-entropy alloy oxide surface layer provides good wear resistance and friction reduction during friction and wear. In other words, during low-temperature friction and wear, the surface high-entropy alloy oxide layer provides good wear resistance and friction reduction; during high-temperature friction and wear, the high-entropy alloy substrate does not soften, and the surface oxide layer remains stable, thus preventing a decrease in wear resistance at high temperatures and maintaining excellent wear resistance over a wide temperature range. Furthermore, under high-temperature friction and wear, the oxidation of high-entropy alloy elements continues, and the oxide layer can be replenished in time after frictional wear, thereby maintaining the wear resistance and friction reduction effect of the high-entropy alloy coating at high temperatures. In addition, the partially oxidized high-entropy alloy oxide surface layer bonds well with the high-entropy alloy substrate, and there is no peeling problem. This composite high-entropy alloy coating has superior coating bonding strength and excellent wear resistance over a wide temperature range, making it a promising candidate for applications in high-temperature engines, nuclear energy, and mold making.

[0028] In some alternative embodiments, the high-entropy alloy may include at least one of TiNbCrMo alloy, TiNbCrMoV alloy, and TiNbCrMoTa alloy.

[0029] In some optional embodiments, the content of each metal element contained in the high-entropy alloy in the high-entropy alloy substrate is independently 15 at.% to 30 at.%, such as 15 at.%, 18 at.%, 20 at.%, 22 at.%, 25 at.%, 28 at.%, or 30 at.%, or other values ​​within the range of 15 at.% to 30 at.%. If the content of a certain metal element in the aforementioned high-entropy alloy is less than 15 at.%, the content of other elements will increase, thereby losing the high-entropy effect under the preparation conditions of the present invention, resulting in a reduction in coating effect; similarly, if the content of a certain metal element in the aforementioned high-entropy alloy is greater than 30 at.%, the content of other elements will decrease, thereby also easily losing the high-entropy effect under the preparation conditions of the present invention, resulting in a reduction in coating effect.

[0030] In some optional embodiments, the thickness of the wide-temperature-range wear-resistant high-entropy alloy coating is 1 μm to 10 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, or other values ​​within the range of 1 μm to 10 μm. In some preferred embodiments, the thickness of the wide-temperature-range wear-resistant high-entropy alloy coating is 2 μm to 8 μm.

[0031] If the thickness of the wide-temperature-range wear-resistant high-entropy alloy coating is too thin, it will easily lead to insufficient wear resistance; if the thickness of the wide-temperature-range wear-resistant high-entropy alloy coating is too thick, the coating adhesion will be reduced, and the coating will easily peel off and fail.

[0032] In some optional embodiments, the surface hardness of the wide-temperature-range wear-resistant high-entropy alloy coating is not less than 900 HV, for example, it can be 940 HV~1231 HV.

[0033] In some alternative implementations, the wear rate of the wide-temperature-range wear-resistant high-entropy alloy coating does not exceed 5 × 10⁻⁶ within the range of room temperature to 700°C. -6 mm 3 / ( N·m).

[0034] In some alternative implementations, the wear rate of the wide-temperature-range wear-resistant high-entropy alloy coating at room temperature does not exceed 3.73 × 10⁻⁶. -6 mm 3 / (N·m), for example, can be 2.01×10 -6 mm 3 / (N·m)~3.73×10 -6 mm 3 / (N·m).

[0035] In some alternative implementations, the wear rate of the wide-temperature-range wear-resistant high-entropy alloy coating at 300°C does not exceed 4.25 × 10⁻⁶. -6 mm 3 / (N·m), for example, can be 2.14×10 -6 mm 3 / (N·m)~4.25×10 -6 mm 3 / (N·m).

[0036] In some alternative implementations, the wear rate of the wide-temperature-range wear-resistant high-entropy alloy coating at 500°C does not exceed 4.13 × 10⁻⁶. -6 mm 3 / (N·m), for example, can be 2.17×10 -6 mm 3 / (N·m)~4.13×10 -6 mm 3 / (N·m).

[0037] In some alternative implementations, the wear rate of the wide-temperature-range wear-resistant high-entropy alloy coating at 700°C does not exceed 3.01 × 10⁻⁶. -6 mm 3 / (N·m), for example, can be 2.51×10 -6 mm 3 / (N·m)~3.01×10 -6mm 3 / (N·m).

[0038] In other words, the wide-temperature-range wear-resistant high-entropy alloy coating provided by the present invention has high hardness and high mechanical stability over a wide temperature range. This wide-temperature-range wear-resistant high-entropy alloy coating has excellent wear resistance and corrosion resistance in the range from room temperature to 700°C, which can significantly improve the performance and lifespan of high-temperature moving parts.

[0039] Accordingly, the present invention also provides a method for preparing the above-mentioned wide-temperature-range wear-resistant high-entropy alloy coating, comprising the following steps: preparing a high-entropy alloy underlayer on the substrate surface by magnetron sputtering, and then subjecting the surface area of ​​the high-entropy alloy underlayer to oxidative heat treatment to form a high-entropy alloy oxide surface layer in situ on the surface area of ​​the high-entropy alloy underlayer.

[0040] In some alternative embodiments, the matrix may exemplary include at least one of nickel-based superalloys, alloy steels, and titanium alloys.

[0041] In some alternative embodiments, the substrate is pretreated before preparing the high-entropy alloy underlayer. Pretreatment may include grinding and polishing the substrate, followed by degreasing, derusting, cleaning, and drying, and then placing the substrate in a vacuum chamber for ion sputtering cleaning. Ion sputtering cleaning may include: vacuuming better than 5×10 -3 The gas introduced is argon, with a pressure of 0.2 Pa to 1 Pa (e.g., 0.2 Pa, 0.5 Pa, or 1 Pa), a matrix negative bias of 500 V to 1000 V (e.g., 500 V, 600 V, 700 V, 800 V, 900 V, or 1000 V), an ion source power of 1 kW to 4 kW (e.g., 1 kW, 2 kW, 3 kW, or 4 kW), and a time of 30 min to 120 min (e.g., 30 min, 50 min, 80 min, 100 min, or 120 min). The above-mentioned "vacuuming is better than 5 × 10⁻⁶" indicates a vacuum level of 5 × 10⁻⁶. -3 "Pa" refers to the final vacuum environment created, whose pressure must be lower than 5 × 10⁻⁶. -3 Pa, meaning a vacuum level higher than this value. The following "vacuum level better than 5 × 10⁻⁶" refers to a vacuum level exceeding 5 × 10⁻⁶. -3 The same applies to "Pa".

[0042] In some alternative implementations, the magnetron sputtering process conditions may include: a vacuum level better than 5 × 10⁻⁶. -3 Pa, the introduced gas includes argon, the gas pressure is 0.2Pa~1Pa, the matrix negative bias voltage is 30V~200V, the target current is 2A~15A, the ion source power is 0.2kW~2kW, and the time is 1h~10h.

[0043] The air pressure can be 0.2 Pa, 0.5 Pa, or 1 Pa, or other values ​​within the range of 0.2 Pa to 1 Pa.

[0044] The substrate negative bias voltage can be 30V, 50V, 80V, 100V, 120V, 150V, 180V or 200V, or other values ​​within the range of 30V to 200V.

[0045] The target current can be 2A, 5A, 8A, 10A, 12A or 15A, or other values ​​within the range of 2A to 15A.

[0046] The ion source power can be 0.2kW, 0.5kW, 0.8kW, 1kW, 1.2kW, 1.5kW or 2kW, or other values ​​within the range of 0.2kW to 2kW.

[0047] The deposition time can be 1h, 2h, 5h, 8h or 10h, or other values ​​within the range of 1h to 10h, and further, it can be 5h to 10h.

[0048] It should be noted that during the magnetron sputtering process described above, both the substrate negative bias voltage and the ion source power affect the hardness and density of the wide-temperature-range wear-resistant high-entropy alloy coating. If the substrate negative bias voltage is below 30V, the coating structure is prone to being loose and the mechanical properties are poor; if the substrate negative bias voltage is above 200V, the deposition rate is prone to decreasing and the coating density is reduced. If the ion source power is below 0.2kW, insufficient ion bombardment is prone to resulting in a loose coating structure; if the ion source power is above 2kW, excessive bombardment ion energy is prone to resulting in a decrease in coating thickness and coating density.

[0049] In some optional embodiments, the process conditions for the oxidative heat treatment may include: a temperature of 500°C to 700°C, a time of 30 min to 120 min, and air or an oxygen-containing gas.

[0050] The temperature can be 500℃, 550℃, 600℃, 650℃ or 700℃, or other values ​​within the range of 500℃ to 700℃.

[0051] The time can be 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min or 120min, or other values ​​within the range of 30min to 120min.

[0052] During the above-mentioned oxidation heat treatment process, temperature affects the formation of high-entropy alloy oxides. If the temperature is below 500℃, it is not conducive to oxide formation; if the temperature is above 700℃, it will lead to rapid element oxidation and diffusion, which will easily cause element segregation or volatilization, which is not conducive to achieving a good effect on the surface layer, such as potentially causing the surface layer to form more pores.

[0053] In the above-mentioned oxidation heat treatment process, the time affects the thickness of the high-entropy alloy oxide surface layer. If the time is less than 30 minutes, the thickness of the high-entropy alloy oxide surface layer is relatively thin, and the coating is easily worn through during the wear process. If the time exceeds 120 minutes, the thickness of the high-entropy alloy oxide surface layer is relatively thick, and the entire high-entropy alloy substrate is oxidized, which is not conducive to improving the wear resistance life of the coating.

[0054] In conclusion, the preparation method provided by this invention is simple, the coating structure is dense, the coating thickness is uniform and controllable, the repeatability is good, and it is suitable for mass production.

[0055] Furthermore, this invention also provides a method for improving the tribological properties of a substrate over a wide temperature range, comprising the following steps: preparing the aforementioned high-entropy, wear-resistant alloy coating over a wide temperature range on the surface of the substrate. This method can effectively improve the tribological properties of the substrate over a wide temperature range.

[0056] Furthermore, the present invention also provides a mechanical moving part having the aforementioned wide-temperature-range wear-resistant high-entropy alloy coating. This mechanical moving part can exhibit superior performance and a longer service life.

[0057] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0058] Example 1 This embodiment provides a wide-temperature-range wear-resistant high-entropy alloy coating, the preparation method of which includes: S1: The nickel-based superalloy substrate is ground and polished, then degreased, derusted, cleaned, and dried. Next, the substrate is placed in a vacuum chamber for ion sputtering cleaning. The ion sputtering cleaning process involves a vacuum level better than 5×10⁻⁶. -3 Argon gas was introduced at a pressure of 0.5 Pa, the matrix negative bias was 800 V, the ion source power was 2 kW, and the time was 60 min.

[0059] S2: Vacuuming performance is better than 5×10 -3Under conditions of 0.5 Pa and argon gas introduction, a high-entropy alloy coating was deposited using a magnetron sputtering target. The target material was a TiNbCrMoV target, the gas pressure was 0.5 Pa, the substrate negative bias voltage was 100 V, the target current was 10 A, the ion source power was 1 kW, and the deposition time was 5 h, resulting in a high-entropy alloy underlayer with a thickness of 8 μm. This high-entropy alloy underlayer contained 20 at.% Ti, 15 at.% Nb, 25 at.% Cr, 20 at.% Mo, and 20 at.% V.

[0060] S3: The high-entropy alloy substrate in S2 is subjected to oxidation heat treatment in a muffle furnace in an atmospheric environment at a temperature of 600°C for 60 minutes, so that the high-entropy alloy in the surface area of ​​the high-entropy alloy substrate is oxidized in situ to form a high-entropy alloy oxide surface layer; the substrate is then cooled to room temperature in the furnace to obtain a wide-temperature-range wear-resistant high-entropy alloy coating.

[0061] Example 2 This embodiment provides a wide-temperature-range wear-resistant high-entropy alloy coating, the preparation method of which includes: S1: The alloy steel substrate is ground and polished, then degreased, derusted, cleaned, and dried. The substrate is then placed in a vacuum chamber for ion sputtering cleaning. The ion sputtering cleaning process involves a vacuum level better than 5×10⁻⁶. -3 Argon gas was introduced at a pressure of 1 Pa, the matrix negative bias voltage was 500 V, the ion source power was 4 kW, and the time was 30 min.

[0062] S2: Vacuuming performance is better than 5×10 -3 Under conditions of 1 Pa and argon gas introduction, a high-entropy alloy coating was deposited using a magnetron sputtering target. The target material was a TiNbCrMo target, the gas pressure was 1 Pa, the substrate negative bias voltage was 200 V, the target current was 15 A, the ion source power was 0.2 kW, and the deposition time was 5 h, resulting in a high-entropy alloy underlayer with a thickness of 5 μm. This high-entropy alloy underlayer contained 25 at.% Ti, 20 at.% Nb, 30 at.% Cr, and 25 at.% Mo.

[0063] S3: The high-entropy alloy substrate in S2 is subjected to oxidation heat treatment in a muffle furnace in an atmospheric environment at a temperature of 500°C for 120 minutes, so that the high-entropy alloy in the surface area of ​​the high-entropy alloy substrate is oxidized in situ to form a high-entropy alloy oxide surface layer; the substrate is then cooled to room temperature in the furnace to obtain a wide-temperature-range wear-resistant high-entropy alloy coating.

[0064] Example 3 This embodiment provides a wide-temperature-range wear-resistant high-entropy alloy coating, the preparation method of which includes: S1: The titanium alloy substrate is ground and polished, then degreased, derusted, cleaned, and dried. Next, the substrate is placed in a vacuum chamber for ion sputtering cleaning. The ion sputtering cleaning process involves a vacuum level better than 5×10⁻⁶. -3 Argon gas was introduced at a pressure of 0.2 Pa, the matrix negative bias voltage was 1000 V, the ion source power was 1 kW, and the time was 120 min.

[0065] S2: Vacuuming performance is better than 5×10 -3 Under conditions of 0.2 Pa and argon gas introduction, a high-entropy alloy coating was deposited using a magnetron sputtering target. The target material was a TiNbCrMoTa target, the gas pressure was 0.2 Pa, the substrate negative bias voltage was 30 V, the target current was 5 A, the ion source power was 1.5 kW, and the deposition time was 5 h, resulting in a high-entropy alloy underlayer with a thickness of 2 μm. This high-entropy alloy underlayer contained 20 at.% Ti, 17 at.% Nb, 23 at.% Cr, 20 at.% Mo, and 20 at.% Ta.

[0066] S3: The high-entropy alloy substrate in S2 is subjected to oxidation heat treatment in a muffle furnace in an atmospheric environment at a temperature of 700°C for 30 minutes, so that the high-entropy alloy in the surface area of ​​the high-entropy alloy substrate is oxidized in situ to form a high-entropy alloy oxide surface layer; the substrate is then cooled to room temperature in the furnace to obtain a wide-temperature-range wear-resistant high-entropy alloy coating.

[0067] Example 4 The difference between this embodiment and embodiment 1 is that in S2, the target current is 2A and the deposition time is 10h.

[0068] Comparative Example 1 The difference between this comparative example and Example 1 is that step S3 was not performed.

[0069] Comparative Example 2 The difference between this comparative example and Example 1 is that in S3, the temperature of the oxidation heat treatment is 800°C and the time is 30 min.

[0070] Comparative Example 3 The difference between this comparative example and Example 1 is that in S3, the temperature of the oxidation heat treatment is 450°C and the time is 120 min.

[0071] Comparative Example 4 The difference between this comparative example and Example 1 is that, in S2, no bias voltage was applied when depositing the high-entropy alloy coating.

[0072] Comparative Example 5 The difference between this comparative example and Example 1 is that, in S2, the substrate bias voltage is 300V when depositing the high-entropy alloy coating.

[0073] Comparative Example 6 The difference between this comparative example and Example 1 is that, in S2, no ion source was applied when depositing the high-entropy alloy coating.

[0074] Comparative Example 7 The difference between this comparative example and Example 1 is that, in S2, the ion source power is 4kW when depositing the high-entropy alloy coating.

[0075] Comparative Example 8 The difference between this comparative example and Example 2 is that in S2, the target material is replaced with a TiNbCrZr target, and the high-entropy alloy bottom layer prepared accordingly contains 20 at.% Ti, 20 at.% Nb, 20 at.% Cr, 20 at.% Zr and 20 at.% V.

[0076] Comparative Example 9 The difference between this comparative example and Example 1 is that, in S2, the elemental content of the target material is changed so that the high-entropy alloy bottom layer contains 20 at.% Ti, 20 at.% Nb, 20 at.% Cr and 40 at.% Mo.

[0077] Comparative Example 10 The difference between this comparative example and Example 1 is that, in S2, the elemental content of the target material is changed so that the high-entropy alloy bottom layer contains 10 at.% Ti, 30 at.% Nb, 30 at.% Cr and 30 at.% Mo.

[0078] Comparative Example 11 The difference between this comparative example and Example 1 is that, in S2, the thickness of the wide-temperature-range wear-resistant high-entropy alloy coating is 15 μm.

[0079] Test case The performance of the wide-temperature-range wear-resistant high-entropy alloy coatings prepared in Examples 1-4 and Comparative Examples 1-11 was compared, and the results are shown in Table 1.

[0080] The thickness was obtained by measuring the cross-section using a scanning electron microscope; the surface hardness was determined according to GB / T4340.1-2009; and the wear rate was determined by the following friction and wear test: using a ball-and-disc friction and wear testing machine, with a load of 2N, a wear radius of 5mm, a rotation speed of 200rpm, and a time of 30min, using silicon nitride balls with a diameter of 6mm as the grinding balls, and the wear rate was determined according to... It is calculated by the formula, where V Wear volume (mm) 3 ), L The sliding distance (m) F NThe load is (N). The wear track depth is measured using a 3D profilometer, and the wear volume is calculated based on the wear track depth.

[0081] Table 1 Performance Results

[0082] As can be seen from Table 1, the wide-temperature-range wear-resistant high-entropy alloy coating provided in the embodiments of the present invention has high hardness and low wear rate.

[0083] In Table 1, the high-entropy alloy substrate corresponding to Comparative Example 2 formed volatile oxides during the oxidation heat treatment, resulting in numerous pores and elemental segregation on the surface of the high-entropy alloy oxide layer (e.g., Figure 2 (As shown). In Comparative Example 4, due to the lack of bias voltage during the preparation of the wide-temperature-range high-entropy alloy coating, the deposited ion energy was insufficient, resulting in a loose coating structure and poor adhesion to the substrate. Consequently, the coating quickly peeled off and failed during friction and wear. In Comparative Example 7, the wide-temperature-range wear-resistant high-entropy alloy coating was relatively thin, and the coating was completely worn through during the wear process.

[0084] In summary, the high-entropy alloy substrate provided by this invention possesses excellent hardness and toughness, good oxidation resistance, and high bonding strength with the substrate, providing excellent support. The high-entropy alloy oxide surface layer exhibits even higher hardness and superior wear resistance, and the oxides also possess a certain lubricating effect. Therefore, the high-entropy alloy oxide surface layer provides excellent wear resistance and friction reduction during friction and wear. In other words, during low-temperature friction and wear, the surface high-entropy alloy oxide layer provides excellent wear resistance and friction reduction; during high-temperature friction and wear, the high-entropy alloy substrate does not soften, and the surface oxide layer remains stable, thus preventing a decrease in wear resistance at high temperatures and maintaining excellent wear resistance over a wide temperature range. Furthermore, under high-temperature friction and wear, the oxidation of high-entropy alloy elements continues, and the oxide layer can be replenished promptly after frictional wear, thereby maintaining the wear resistance and friction reduction effect of the high-entropy alloy coating at high temperatures. In addition, the partially oxidized high-entropy alloy oxide surface layer bonds well with the high-entropy alloy substrate, eliminating the problem of peeling. This composite high-entropy alloy coating has superior coating bonding strength and excellent wear resistance over a wide temperature range, making it a promising candidate for applications in high-temperature engines, nuclear energy, and mold making.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wide-temperature-range wear-resistant high-entropy alloy coating, characterized in that, It includes a high-entropy alloy underlayer and a high-entropy alloy oxide surface layer; the high-entropy alloy in the high-entropy alloy underlayer includes at least four elements selected from Ti, Nb, Cr, Mo, V and Ta; the high-entropy alloy oxide surface layer is formed by in-situ oxidation of the high-entropy alloy in the surface region of the high-entropy alloy underlayer.

2. The wide-temperature-range wear-resistant high-entropy alloy coating according to claim 1, characterized in that, The content of each metal element in the high-entropy alloy bottom layer is independently 15 at.% to 30 at.%.

3. The wide-temperature-range wear-resistant high-entropy alloy coating according to claim 1 or 2, characterized in that, The wide-temperature-range wear-resistant high-entropy alloy coating has at least one of the following characteristics: Feature 1: The high-entropy alloy includes at least one of TiNbCrMo alloy, TiNbCrMoV alloy, and TiNbCrMoTa alloy; Feature 2: The thickness of the wide-temperature-range wear-resistant high-entropy alloy coating is 1μm~10μm.

4. The wide-temperature-range wear-resistant high-entropy alloy coating according to claim 1, characterized in that, The wide-temperature-range wear-resistant high-entropy alloy coating also has at least one of the following characteristics: Feature 3: The surface hardness of the wide-temperature-range wear-resistant high-entropy alloy coating is not less than 900 HV; Feature 4: The wear rate of the wide-temperature-range wear-resistant high-entropy alloy coating does not exceed 5×10⁻⁶ within the range of room temperature to 700℃. - 6 mm 3 / (N·m).

5. A method for preparing a wide-temperature-range wear-resistant high-entropy alloy coating as described in any one of claims 1 to 4, characterized in that, Includes the following steps: The high-entropy alloy underlayer is prepared on the substrate surface by magnetron sputtering, and then the surface area of ​​the high-entropy alloy underlayer is subjected to oxidative heat treatment to form the high-entropy alloy oxide surface layer in situ on the surface area of ​​the high-entropy alloy underlayer. Preferably, the matrix comprises at least one of nickel-based superalloys, alloy steels, and titanium alloys.

6. The preparation method according to claim 5, characterized in that, The process conditions for magnetron sputtering include: a vacuum level better than 5 × 10⁻⁶. -3 Pa, the introduced gas includes argon, the gas pressure is 0.2Pa~1Pa, the matrix negative bias voltage is 30V~200V, the target current is 2A~15A, the ion source power is 0.2kW~2kW, and the time is 1h~10h.

7. The preparation method according to claim 5, characterized in that, Before preparing the high-entropy alloy bottom layer, the substrate is pretreated. Preferably, the pretreatment includes grinding and polishing the substrate, then cleaning and drying it to remove oil and rust, and then placing the substrate in a vacuum chamber for ion sputtering cleaning. Preferably, ion sputtering cleaning includes: vacuuming better than 5 × 10⁻⁶. -3 Pa, the introduced gas includes argon, the gas pressure is 0.2Pa~1Pa, the matrix negative bias voltage is 500V~1000V, the ion source power is 1kW~4kW, and the time is 30min~120min.

8. The preparation method according to claim 5, characterized in that, The process conditions for oxidation heat treatment include: temperature of 500℃~700℃, time of 30min~120min, and gas of air or oxygen-containing gas.

9. A method for improving the tribological properties of a substrate over a wide temperature range, characterized in that, Includes the following steps: A wide-temperature-range wear-resistant high-entropy alloy coating as described in any one of claims 1 to 4 is prepared on the surface of the substrate.

10. A mechanical moving part, characterized in that, The mechanical moving parts have a wide temperature range wear-resistant high-entropy alloy coating as described in any one of claims 1 to 4.

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