A method for preparing high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy and high-entropy alloy composite coating

Abstract

A method for preparing a high entropy alloy composite coating based on nitrogen / MnN dual source synergy and a high entropy alloy composite coating, relating to the technical field of high entropy alloy composite coatings, CoCrFeNiAlTi alloy powder, Mo powder and MnN powder are prepared in the form of CoCrFeNiAlTiMo x (MnN) 2‑x The atomic ratio of AlN and TiN is uniformly mixed to form a mixed powder, and the mixed powder is formed on the surface of the substrate through plasma cladding. The protective gas, ion gas and powder feeding gas in the plasma cladding process are all mixed gases formed by 10-25% nitrogen and 75-90% argon. The AlN / TiN strengthening phase is in situ generated in the high-entropy alloy composite coating of the present invention, and the porosity of the high-entropy alloy composite coating is reduced, thereby avoiding the formation of cracks in the high-entropy alloy composite coating and improving the forming quality. At the same time, the mechanical properties and corrosion resistance of the high-entropy alloy composite coating are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of high entropy alloy composite coatings, and in particular to a method for preparing a high entropy alloy composite coating based on nitrogen / MnN dual-source collaboration and the high entropy alloy composite coating. Background Art

[0002] With the rapid development of industrial technology, high-end manufacturing sectors such as aerospace, energy, chemicals, and automotive manufacturing are placing increasing demands on material performance, requiring materials to possess excellent wear resistance, corrosion resistance, and high-temperature performance. High-entropy alloys (HEAs) are composed of multiple elements and possess excellent mechanical properties and high-temperature stability. Preparing HEA coatings on substrates can improve the overall performance of these materials. CoCrFeNiAlTi HEA coatings are widely used due to their excellent ductility, high fracture toughness, and tensile strength. However, their low hardness and insufficient wear resistance limit their application in demanding working conditions.

[0003] At present, in order to improve the performance of CoCrFeNiAlTi high-entropy alloy coatings, TiN, TiC, WC or Al2O3 particles are added to the high-entropy alloy powder to obtain a mixture when preparing the high-entropy alloy coating, and the mixture is coated on the substrate to form a high-entropy alloy composite coating. However, this preparation method has the following problems: 1) During the cladding process, the particles are prone to segregation and agglomeration, resulting in uneven distribution of the particle reinforcement phase. For example, Chinese patent CN118563196A provides a ceramic particle-reinforced high-entropy alloy composite coating and a preparation method thereof, in which WC particles and CoCrFeNiMn high-entropy alloy powder are first mixed and then clad on the substrate surface to form a high-entropy alloy composite coating. Although this method improves the hardness and wear resistance of the coating to a certain extent, it is prone to uneven distribution of the particle reinforcement phase due to WC sinking; 2) The added particles have weak bonding strength with the substrate, which can easily cause interface shedding or coating peeling under extreme working conditions.

[0004] In the prior art, in order to solve the above-mentioned problems, laser cladding is carried out in a mixed atmosphere of nitrogen and argon to obtain a high-entropy alloy coating, generating a dispersed ceramic phase. In order for the coating to achieve the desired strengthening effect, the nitrogen content in the mixed atmosphere is higher than 50%. However, the high-entropy alloy coating prepared by this method is prone to cracks, and the coating after forming is relatively thin (less than 0.5 mm), the coating surface is often defective, and the yield is low. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing a high-entropy alloy composite coating based on the synergistic use of nitrogen / MnN dual sources and a high-entropy alloy composite coating. During the plasma cladding process, AlN / TiN strengthening phases are generated in situ in the high-entropy alloy composite coating, and the porosity of the high-entropy alloy composite coating is reduced, thereby avoiding the formation of cracks in the high-entropy alloy composite coating, improving the surface quality of the coating, and increasing the yield; at the same time, the corrosion resistance of the high-entropy alloy composite coating is improved.

[0006] In order to achieve the above object, the specific scheme adopted by the present invention is: a method for preparing a high entropy alloy composite coating based on nitrogen / MnN dual source synergy, CoCrFeNiAlTi alloy powder, Mo powder and MN powder in the form of CoCrFeNiAlTiMo x (MnN) 2-x The atomic ratio of the mixed powder is uniformly mixed to form a mixed powder, and the mixed powder is formed on the surface of the substrate through plasma cladding to form a high entropy alloy composite coating. The shielding gas, ion gas and powder feeding gas in the plasma cladding process are all mixed gases formed by 10-25% nitrogen and 75-90% argon.

[0007] As an optimization scheme of the above-mentioned method for preparing high-entropy alloy composite coating based on nitrogen / MnN dual-source collaboration: the particle size of the CoCrFeNiAlTi alloy powder is 20-50 μm.

[0008] As another optimization scheme of the above-mentioned method for preparing high-entropy alloy composite coating based on nitrogen / MnN dual-source collaboration: the particle size of the MnN powder is 5-10 μm.

[0009] As another optimization scheme of the above-mentioned method for preparing high-entropy alloy composite coating based on nitrogen / MnN dual-source collaboration: the particle size of Mo powder is 20-50 μm.

[0010] As another optimization scheme of the above-mentioned method for preparing high-entropy alloy composite coating based on the synergistic preparation of nitrogen / MnN dual sources: CoCrFeNiAlTi alloy powder, Mo powder and MnN powder are mixed and ball milled, and the ball milling speed is 400-500r / min, the ball-to-material ratio is 4-6:1, the time is 1-2h, and the grinding ball is made of Al2O3 or ZrO2.

[0011] As another optimization scheme for the above-mentioned method of preparing high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy: the ball milling process is intermittent ball milling, with a one-minute interval every ten minutes of ball milling.

[0012] As another optimization scheme for the above-mentioned method of preparing high-entropy alloy composite coating based on nitrogen / MnN dual-source collaboration: the parameters of plasma cladding include welding current 100-200A, shielding gas flow rate 10-20L / min, powder feeding gas flow rate 2-6L / min, ion gas flow rate 2-6L / min, and welding speed 1-10mm / s.

[0013] As another optimization scheme for the above-mentioned method of preparing high-entropy alloy composite coating based on the synergistic nitrogen / MnN dual-source: the parameters of plasma cladding include welding current 130A, shielding gas flow rate 15L / min, powder feeding gas flow rate 4L / min, ion gas flow rate 4L / min, and welding speed 5mm / s.

[0014] As another optimization scheme of the above-mentioned method for preparing high-entropy alloy composite coating based on the synergistic preparation of nitrogen / MnN dual sources: CoCrFeNiAlTi alloy powder is composed of metal Co, metal Cr, metal Fe, metal Ni, metal Al and metal Ti in equal molar ratios.

[0015] A high entropy alloy composite coating is prepared by adopting the above method.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention provides a method for preparing a high entropy alloy composite coating based on nitrogen / MnN dual-source synergy. MnN powder is added to CoCrFeNiAlTi alloy powder. During the plasma cladding process, the ion gas, the shielding gas and the powder feeding gas are all mixed gases. That is, the interstitial atom N is introduced by the synergistic combination of MnN and nitrogen dual sources, so that the Al element and the Ti element in the mixed powder react with N in situ to form an AlN / TiN strengthening phase. That is, the high entropy alloy composite coating includes TiN phase, AlN phase, BCC phase and (Ni,Co)Ti2 phase. The in situ generated TiN and AlN nanoparticles form a uniformly dispersed strengthening phase, hindering dislocation movement and improving the stability of grain boundaries. Fine grain strengthening and dispersion strengthening significantly increase the microhardness of the coating. At the same time, TiN and AlN particles reduce the shedding of wear particles by enhancing grain boundary strength and filling pores. The pinning effect of the strengthening relative grains further enhances the wear resistance of the coating, thereby improving the overall performance of the high-entropy alloy composite coating. Ultimately, the high-entropy alloy composite coating prepared in a synergistic manner by MnN powder and mixed atmosphere has a high yield, reduces the formation of cracks in the coating, and improves the surface quality of the coating.

[0018] 2. During the cladding process, part of the MnN decomposes. The decomposed N can react with Al and Ti elements in the mixed gas atmosphere to generate AlN / TiN strengthening phases. These strengthening phases are re-precipitated and evenly distributed in the high entropy alloy composite coating, further improving the comprehensive performance of the coating. The decomposed Mn reduces the porosity of the high entropy alloy composite coating by 30-50%, significantly improving the forming ability of the coating. On the other hand, Mn improves the surface composition of the high entropy alloy composite coating, that is, from Al to TiN. 3+ and Fe 3+ Cr 3+ and Fe 3+ It is mainly beneficial to form a dense and stable passivation film on the surface of the high-entropy alloy composite coating, thereby improving the corrosion resistance of the high-entropy alloy composite coating.

[0019] 3. In the present invention, the addition of Al and Ti promotes the transformation of the high-entropy alloy composite coating from the FCC phase to the BCC phase, improving the coating's microhardness and wear resistance. The addition of Mo leads to grain refinement and increases the average nuclear misorientation of the grains. Simultaneously, the synergistic addition of Al, Mo, and Ti guides the formation of the σ phase. The crystal structure transformation, grain refinement, and solid solution strengthening significantly enhance the hardness and wear resistance of the high-entropy alloy coating.

[0020] 4. In the initial stage of high-temperature oxidation, the rapid oxidation of Al reduces the oxidation rate and generates an Al2O3 layer on the coating surface. These dense and slow-growing Al2O3 layers hinder ion diffusion and reduce the oxidation rate. At the same time, the addition of Mo effectively promotes the formation of Al2O3 and further enhances the oxidation resistance. Therefore, the synergistic addition of Al and Mo will enhance the high-temperature oxidation resistance of the coating and further expand the application range of high-entropy alloy composite coatings. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further elaborated in detail below in conjunction with specific embodiments. The parts that are not described and disclosed in detail in the following embodiments of the present invention should be understood as existing technologies known or should be known to those skilled in the art, such as how to process the surface of the substrate.

[0022] A method for preparing a high entropy alloy composite coating based on nitrogen / MnN dual source synergy, CoCrFeNiAlTi alloy powder, Mo powder and MnN powder are prepared in the form of CoCrFeNiAlTiMo x (MnN) 2-xThe CoCrFeNiAlTi alloy powder is uniformly mixed with an atomic ratio of 20 to 50 μm to form a mixed powder, where x∈(0,2). The particle size of the CoCrFeNiAlTi alloy powder is 20-50 μm and the powder purity is greater than 99.5%. The CoCrFeNiAlTi alloy powder is composed of metal Co, metal Cr, metal Fe, metal Ni, metal Al, and metal Ti in equal molar ratios. The CoCrFeNiAlTi alloy powder with a particle size of 20-50 μm used in the present invention is commercially available, and its preparation method is not described in detail here. The particle size of the Mo powder is 20-50 μm, and the particle size of the MnN powder is 5-10 μm, which ensures the fluidity and uniformity of the MnN during the plasma cladding process, thereby ensuring the formation of a dense and uniform high-entropy alloy composite coating. At the same time, it provides a large surface area to promote the in-situ reaction to form the AlN / TiN strengthening phase. CoCrFeNiAlTi alloy powder, Mo powder, and MnN powder are mixed and milled in a ball mill at a speed of 400-500 r / min, a ball-to-material ratio of 4-6:1, and a time of 1-2 hours. The grinding balls are made of Al2O3 or ZrO2 and contain grinding balls of different diameters: 3mm, 5mm, 9mm, 12mm, and 15mm. The milling process is intermittent, with 10 minutes of milling every 1 minute to eliminate the effects of heat on powder formation. The milled powder is then placed in a vacuum drying oven to obtain a mixed powder.

[0023] The Al and Ti in the CoCrFeNiAlTi alloy powder promote the transformation of the high-entropy alloy composite coating from the FCC phase to the BCC phase, improving the coating's hardness and wear resistance. Simultaneously, Al rapidly oxidizes in the initial stages of cladding, forming an Al2O3 layer on the coating's surface. This slow and dense Al2O3 layer hinders ion diffusion and reduces the coating's oxidation rate, thus providing antioxidant properties. In the present invention, Mo not only refines grains and increases the average orientation difference of the grain nuclei, but also synergistically guides the σ phase in the coating. Crystalline structure transformation, grain refinement, and solid solution strengthening significantly enhance the hardness and wear resistance of the high-entropy alloy coating. Furthermore, Mo effectively promotes Al2O3 formation, further enhancing the coating's antioxidant properties and thus broadening the application range of the high-entropy alloy composite coating.

[0024] After treating the substrate surface to remove oil and oxide films, the mixed powder is plasma clad onto the substrate to form a high-entropy alloy composite coating. Plasma cladding is performed using a plasma welder, using a mixture of 10-25% nitrogen, 75-90% argon as the shielding, ionizing, and powder feed gases. Plasma cladding parameters include a welding current of 100-200A, a shielding gas flow rate of 10-20L / min, a powder feed gas flow rate of 2-6L / min, an ionizing gas flow rate of 2-6L / min, a welding speed of 1-10mm / s, and a distance of 5-12.5mm between the welding gun nozzle and the substrate surface.

[0025] During the cladding process, part of the MnN decomposes, and the decomposed N can react with Al and Ti elements in the atmosphere of the mixed gas to produce AlN / TiN strengthening phases in situ. These strengthening phases are re-precipitated and evenly distributed in the high entropy alloy composite coating, further improving the comprehensive performance of the coating. On the one hand, the decomposed Mn reduces the porosity of the high entropy alloy composite coating, specifically reducing the porosity by 30-50%, significantly improving the forming ability of the coating, reducing the formation of cracks, and improving the yield of the coating. On the other hand, Mn improves the surface composition of the high entropy alloy composite coating, that is, from Al to 3+ and Fe 3+ Cr 3+ and Fe 3+ It is mainly beneficial to form a dense and stable passivation film on the surface of the high-entropy alloy composite coating, thereby improving the corrosion resistance of the high-entropy alloy composite coating.

[0026] Example 1

[0027] A method for preparing a high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy, wherein the substrate is Q235 steel, comprises the following steps:

[0028] CoCrFeNiAlTi alloy powder with a particle size of 20-50 μm, Mo powder with a particle size of 20-50 μm, and MnN powder with a particle size of 5-10 μm were mixed at an atomic ratio of CoCrFeNiAlTiMo1(MnN)1 and then ball-milled in a mill for 2 hours. The milling process was performed at a speed of 400 rpm, a ball-to-powder ratio of 4:1, and a grinding time of 2 hours. The milling balls were made of Al2O3 and had different diameters of 3 mm, 5 mm, 9 mm, 12 mm, and 15 mm. The milling process was intermittent, with a one-minute interval between each 10-minute milling. After the milling, the mixed powder was dried in a vacuum oven at 50°C for 6 hours.

[0029] The substrate surface was treated, and the mixed powder was plasma clad to form a high-entropy alloy composite coating on the substrate surface. Plasma cladding was performed using a DML-V03BD plasma welder. The shielding gas, ion gas, and powder feeding gas in the plasma cladding process were all a mixture of 10% nitrogen and 90% argon. The welding current was 100 A, the shielding gas flow rate was 10 L / min, the powder feeding gas flow rate was 2 L / min, the ion gas flow rate was 2 L / min, the welding speed was 1 mm / s, and the distance between the welding gun nozzle and the substrate surface was 5 mm.

[0030] Example 2

[0031] A method for preparing a high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy, wherein the substrate is Q235 steel, comprises the following steps:

[0032] CoCrFeNiAlTi alloy powder with a particle size of 20-50 μm, Mo powder with a particle size of 20-50 μm, and MnN powder with a particle size of 5-10 μm were mixed at an atomic ratio of CoCrFeNiAlTiMo1(MnN)1 and then ball-milled in a mill for 1 hour. The milling process was performed at a speed of 500 r / min, a ball-to-powder ratio of 6:1, and a grinding time of 1 hour. The grinding balls were made of Al2O3 and had diameters of 3 mm, 5 mm, 9 mm, 12 mm, and 15 mm, respectively. The milling process was intermittent, with a 1-minute interval between each 10-minute milling. After the milling, the mixed powder was dried in a vacuum oven at 50°C for 6 hours.

[0033] The substrate surface was treated, and the mixed powder was plasma clad to form a high-entropy alloy composite coating on the substrate surface. Plasma cladding was performed using a DML-V03BD plasma welder. The shielding gas, ion gas, and powder feeding gas in the plasma cladding process were all a mixture of 25% nitrogen and 75% argon. The welding current was 200 A, the shielding gas flow rate was 20 L / min, the powder feeding gas flow rate was 6 L / min, the ion gas flow rate was 6 L / min, the welding speed was 10 mm / s, and the distance between the welding gun nozzle and the substrate surface was 12.5 mm.

[0034] Example 3

[0035] A method for preparing a high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy, wherein the substrate is Q235 steel, comprises the following steps:

[0036] CoCrFeNiAlTi alloy powder with a particle size of 20-50 μm, Mo powder with a particle size of 20-50 μm, and MnN powder with a particle size of 5-10 μm were mixed at an atomic ratio of CoCrFeNiAlTiMo1(MnN)1 and then ball-milled in a mill for 1.5 hours. The milling process was performed at a speed of 450 rpm, a ball-to-powder ratio of 5:1, and a grinding time of 1.5 hours. The grinding balls were made of Al2O3 and had diameters of 3 mm, 5 mm, 9 mm, 12 mm, and 15 mm, respectively. The milling process was intermittent, with a one-minute interval between each 10-minute period. After the milling, the mixed powder was dried in a vacuum oven at 50°C for 6 hours.

[0037] The substrate surface was treated, and the mixed powder was plasma clad to form a high-entropy alloy composite coating on the substrate surface. Plasma cladding was performed using a DML-V03BD plasma welder. The shielding gas, ion gas, and powder feeding gas in the plasma cladding process were all a mixture of 20% nitrogen and 80% argon. The welding current was 130 A, the shielding gas flow rate was 15 L / min, the powder feeding gas flow rate was 5 L / min, the ion gas flow rate was 2.5 L / min, the welding speed was 5 mm / s, and the distance between the welding gun nozzle and the substrate surface was 7.5 mm.

[0038] Comparative Example 1

[0039] The method for preparing a CoCrFeNiAlTi high entropy alloy coating, wherein the substrate is Q235 steel, comprises the following steps:

[0040] Commercial CoCrFeNiAlTi alloy powder with a powder purity of more than 99.5% and an average particle size of 45 μm was selected, and the commercial CoCrFeNiAlTi alloy powder was dried in a vacuum drying oven at 50° C. for 6 h.

[0041] The surface of the substrate was treated, and the CoCrFeNiAlTi alloy powder was plasma clad on the substrate surface using a DML-V03BD plasma welder to form a CoCrFeNiAlTi high-entropy alloy coating. The shielding gas, ion gas and powder feeding gas in the plasma cladding process were all argon. The welding current was 130A, the shielding gas flow rate was 15L / min, the powder feeding gas flow rate was 5L / min, the ion gas flow rate was 2.5L / min, the welding speed was 5mm / s, and the distance between the welding gun nozzle and the substrate surface was 7.5mm.

[0042] Comparative Example 2

[0043] The method for preparing a CoCrFeNiAlTi high entropy alloy coating, wherein the substrate is Q235 steel, comprises the following steps:

[0044] Commercial CoCrFeNiAlTi alloy powder with a powder purity of more than 99.5% and an average particle size of 45 μm was selected, and the commercial CoCrFeNiAlTi alloy powder was dried in a vacuum drying oven at 50° C. for 6 h.

[0045] The surface of the substrate was treated, and the CoCrFeNiAlTi alloy powder was plasma clad on the substrate surface using a DML-V03BD plasma welder to form a CoCrFeNiAlTi high-entropy alloy coating. The shielding gas, ion gas and powder feeding gas in the plasma cladding process were all a mixture of 50% nitrogen and 50% argon. The welding current was 130A, the shielding gas flow rate was 15L / min, the powder feeding gas flow rate was 5L / min, the ion gas flow rate was 2.5L / min, the welding speed was 5mm / s, and the distance between the welding gun nozzle and the substrate surface was 7.5mm.

[0046] Comparative Example 3

[0047] The method for preparing a CoCrFeNiAlTiMo high entropy alloy coating, wherein the substrate is Q235 steel, comprises the following steps:

[0048] Commercial CoCrFeNiAlTi alloy powder with an average particle size of 45 μm and a purity of 99.5% or higher was mixed with Mo powder in an equiatomic ratio and milled in a ball mill for 1.5 hours. The milling process was performed at a speed of 450 rpm, a ball-to-powder ratio of 5:1, and a grinding time of 1.5 hours. The grinding balls were made of Al2O3 and had diameters of 3 mm, 5 mm, 9 mm, 12 mm, and 15 mm. The milling was performed intermittently, with a 1-minute interval between each 10-minute milling cycle. The mixed powder was then dried in a vacuum oven at 50°C for 6 hours.

[0049] The surface of the substrate was treated, and the mixed powder was plasma clad on the substrate surface using a DML-V03BD plasma welder to form a CoCrFeNiAlTiMo high-entropy alloy coating. The shielding gas, ion gas and powder feeding gas in the plasma cladding process were all argon. The welding current was 130A, the shielding gas flow rate was 15L / min, the powder feeding gas flow rate was 5L / min, the ion gas flow rate was 2.5L / min, the welding speed was 5mm / s, and the distance between the welding gun nozzle and the substrate surface was 7.5mm.

[0050] Comparative Example 4

[0051] The method for preparing a CoCrFeNiAlTiMnN high entropy alloy coating, wherein the substrate is Q235 steel, comprises the following steps:

[0052] Commercial CoCrFeNiAlTi alloy powder with an average particle size of 45 μm and a purity of 99.5% or higher was mixed with MnN powder in an equiatomic ratio and milled in a ball mill for 1.5 hours. The milling process was performed at a speed of 450 rpm, a ball-to-powder ratio of 5:1, and a grinding time of 1.5 hours. The grinding balls were made of Al2O3 and had diameters of 3 mm, 5 mm, 9 mm, 12 mm, and 15 mm, respectively. The milling process was intermittent, with 1-minute intervals between each 10-minute period. The mixed powder was then dried in a vacuum oven at 50°C for 6 hours.

[0053] The surface of the substrate was treated, and the mixed powder was plasma clad on the substrate surface using a DML-V03BD plasma welder to form a CoCrFeNiAlTiMnN high-entropy alloy coating. The shielding gas, ion gas and powder feeding gas in the plasma cladding process were all argon. The welding current was 130A, the shielding gas flow rate was 15L / min, the powder feeding gas flow rate was 5L / min, the ion gas flow rate was 2.5L / min, the welding speed was 5mm / s, and the distance between the welding gun nozzle and the substrate surface was 7.5mm.

[0054] Comparative Example 5

[0055] The method for preparing a CoCrFeNiAlTiMnN high entropy alloy coating, wherein the substrate is Q235 steel, comprises the following steps:

[0056] Commercial CoCrFeNiAlTi alloy powder with an average particle size of 45 μm and a purity of 99.5% or higher was mixed with MnN powder in an equiatomic ratio and milled in a ball mill for 1.5 hours. The milling process was performed at a speed of 450 rpm, a ball-to-powder ratio of 5:1, and a grinding time of 1.5 hours. The grinding balls were made of Al2O3 and had diameters of 3 mm, 5 mm, 9 mm, 12 mm, and 15 mm, respectively. The milling process was intermittent, with 1-minute intervals between each 10-minute period. The mixed powder was then dried in a vacuum oven at 50°C for 6 hours.

[0057] The substrate surface was treated, and the mixed powder was plasma clad on the substrate surface to form a CoCrFeNiAlTiMnN high-entropy alloy coating. Plasma cladding was performed using a DML-V03BD plasma welder. The shielding gas, ion gas, and powder feeding gas in the plasma cladding process were all a mixture of 50% nitrogen and 50% argon. The welding current was 1000 A, the shielding gas flow rate was 15 L / min, the powder feeding gas flow rate was 5 L / min, the ion gas flow rate was 2.5 L / min, the welding speed was 5 mm / s, and the distance between the welding gun nozzle and the substrate surface was 7.5 mm.

[0058] The coatings obtained in Example 3 and Comparative Examples 1-5 were tested to obtain the surface hardness and average friction coefficient of the coatings, as shown in Table 1.

[0059] Table 1 shows the surface hardness and average friction coefficient of the coating obtained in Example 3 and Comparative Examples 1-5.

[0060] <![CDATA[Surface hardness (HV 0.2 > Average friction coefficient Example 3 841.4 0.451 Comparative Example 1 520.2 0.662 Comparative Example 2 486.1 0.748 Comparative Example 3 583.5 0.547 Comparative Example 4 615.4 0.533 Comparative Example 5 597.2 0.574

[0061] From the results in Table 1, it can be seen that the high entropy alloy composite coating prepared by the present invention has high hardness and wear resistance.

[0062] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy, characterized by: CoCrFeNiAlTi alloy powder, Mo powder and MnN powder CoCrFeNiAlTiMo x (MnN) 2-x The atomic ratio of x∈(0,2) is uniformly mixed to form a mixed powder, the particle size of the CoCrFeNiAlTi alloy powder is 20-50μm, and the mixed powder is plasma clad on the surface of the substrate to form a high entropy alloy composite coating. The shielding gas, ion gas and powder feeding gas in the plasma cladding process are all mixed gases formed by 10-25% nitrogen and 75-90% argon. The parameters of the plasma cladding include welding current 100-200A, shielding gas flow rate 10-20L / min, powder feeding gas flow rate 2-6L / min, ion gas flow rate 2-6L / min, and welding speed 1-10mm / s.

2. The method for preparing a high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy according to claim 1, characterized in that: The particle size of the MnN powder is 5-10 μm.

3. The method for preparing a high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy according to claim 1, characterized in that: The particle size of the Mo powder is 20-50 μm.

4. The method for preparing a high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy according to claim 1, characterized in that: CoCrFeNiAlTi alloy powder, Mo powder and MnN powder are mixed and ball milled, and the ball milling speed is 400-500r / min, the ball-to-material ratio is 4-6:1, the time is 1-2h, and the material of the grinding ball is Al2O3 or ZrO2.

5. The method for preparing a high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy according to claim 4, characterized in that: The ball milling process is intermittent ball milling, with a one-minute interval every ten minutes of ball milling.

6. The method for preparing a high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy according to claim 1, characterized in that: The parameters of plasma cladding include welding current 130A, shielding gas flow rate 15L / min, powder feeding gas flow rate 4L / min, ion gas flow rate 4L / min, and welding speed 5mm / s.

7. The method for preparing a high-entropy alloy composite coating based on nitrogen / MnN dual-source synergy according to claim 1, characterized in that: The CoCrFeNiAlTi alloy powder consists of metal Co, metal Cr, metal Fe, metal Ni, metal Al and metal Ti in equal molar ratios.

8. A high entropy alloy composite coating, characterized by: The product is prepared by the method according to any one of claims 1 to 7.