Method for preparing refractory metal coating on high-reflectivity metal surface, coating and application

Abstract

The invention discloses a method for preparing a refractory metal coating on a high-reflectivity metal surface, the coating and application, nickel-based or copper-based cladding alloy powder and / or a reinforcing phase with different components and proportions are used as cladding powder, the reinforcing phase is WC, TiB2, B4C, C3N4, BN, SiC and VN, in other words, in-situ formation can be achieved, and the coating can be additionally added; and meanwhile, a small-core-diameter dual-wavelength high-energy-density infrared laser is selected, parameters such as the swing frequency of a laser galvanometer, the laser swing mode, the swing amplitude, the laser defocusing amount, the laser power, the powder feeding amount, the cladding speed and the number of cladding layers are regulated and controlled, and the refractory metal coating is prepared on the high-reflectivity metal surface through laser cladding. According to the method, the surface hardness and the abrasion resistance of the high-reflectivity matrix are improved, the electric conductivity of the matrix is kept or improved, the surface hardness and the abrasion resistance of the prepared metal coating are improved, the problems that the surface coating of the high-reflectivity metal matrix cannot be metallurgically bonded, the coating cracks, pores and is stripped are solved, and the practicability and the engineering application value are improved.

Description

Technical Field

[0001] The present invention belongs to the field of surface treatment of metal materials, especially the technology of using laser cladding to treat the surface of metal materials. Specifically, it relates to a method for preparing a refractory metal coating on the surface of a high-reflectivity metal. Background Art

[0002] Light metals such as copper, aluminum, and magnesium have excellent electrical conductivity and structural strength. However, under the operating requirements of extreme high-temperature wear environments, their wear resistance and ablation resistance are insufficient. Preparing a metallurgical bonding coating on their surface can effectively solve the above problems. However, these light metals exhibit a high reflectivity to lasers, which makes it extremely difficult to clad a wear-resistant and ablation-resistant coating that does not affect the electrical conductivity on their surface.

[0003] Methods for preparing refractory metal coatings on the surface of high-reflectivity metals mainly include physical vapor deposition, thermal spraying, electroplating, electroless plating, and laser cladding. Coatings prepared by methods such as electroplating, spraying, or physical vapor deposition have poor bonding strength with the substrate, are brittle and thin, and are prone to phenomena such as cracking and peeling during actual application. Relatively speaking, the laser cladding method is a method with better comprehensive performance, especially suitable for scenarios with high requirements for coating bonding strength and weather resistance. During laser additive manufacturing and laser cladding, due to the high reflectivity and high thermal conductivity of high-reflectivity metal materials (such as copper, aluminum, magnesium, and titanium) to lasers, there are extremely high requirements for the selection of laser wavelengths and the energy distribution of laser spots, resulting in problems such as a narrow process window and poor forming quality, making it difficult to achieve good forming quality with traditional laser cladding methods. In addition, the high thermal conductivity of these substrate materials makes it difficult to form a metallurgical bond between the coating material and the substrate surface during the laser cladding process. Therefore, improving the cladding quality and metallurgical bonding strength and suppressing defects are the main problems faced when preparing refractory metal coatings on the surface of high-reflectivity metals.

[0004] To solve the above problems, Chinese Patent Application No. 202410855505.X discloses a method for infrared-blue light composite laser cladding on the surface of a copper substrate. It emits infrared-blue light coaxial composite laser to the surface of the copper substrate and conveys metal powder, scans according to a predetermined cladding track, and performs laser cladding to obtain the required cladding layer on the surface of the copper substrate. Although this method can improve the bonding strength between the cladding layer and the copper substrate, the blue laser is expensive. Especially, the coaxial optical path design of the composite laser is complex, and problems such as beam coupling and spot superposition accuracy need to be solved, resulting in a high equipment cost and difficulty in industrialization. In addition, the combination of infrared and blue light makes the laser energy too concentrated, which will lead to an excessive temperature gradient, resulting in serious thermal expansion mismatch between the two materials and generating thermal cracks. As can be seen from the Figure 5 SEM pictures it discloses, there are indeed thermal cracks in the finally obtained laser cladding layer.

[0005] The galvanometer swing technology can achieve dynamic scanning of the laser beam, expand the molten pool coverage range, improve the uniformity of heat input, avoid ablation defects caused by local overheating, reduce the thermal stress difference between the coating and the substrate, and enhance the interfacial bonding strength. If a high-efficiency method of combining a small-spot dual-wavelength high-energy-density infrared laser with galvanometer swing is designed, and the power density, powder feeding amount, swing frequency, and swing mode are flexibly matched according to the surface quality and thickness requirements of the coating, a multi-functional coating with high strength, wear resistance, high conductivity, and ablation resistance can be obtained by cladding on different high-reflectivity substrates, and it has a high metallurgical bonding strength, which can enhance the development related to the damage protection of high-reflectivity materials in extreme environment applications. There are no reports at home and abroad yet. Summary of the Invention

[0006] In order to overcome the defects of high cost and difficulty in industrialization and easy cracking of the coating due to heat concentration in the current technology for preparing refractory metal coatings on the surface of high-reflectivity metals, the present invention provides a method for preparing refractory metal coatings on the surface of high-reflectivity metals. This method solves the problems of cracking, low laser absorption rate, and difficult metallurgical bonding during the cladding of metal coatings on the surface of high-reflectivity materials through the design of high-efficiency cladding combining galvanometer swing with a small-spot dual-wavelength high-energy-density infrared laser, coordinates the contradictions between the coating and the substrate in terms of wear resistance, strength, and conductivity, thereby enhancing the application of high-reflectivity metals such as copper, magnesium, aluminum, and titanium in extreme environments and meeting the performance requirements of engineering components.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for preparing a refractory metal coating on the surface of a high-reflectivity metal, characterized in that it is carried out according to the following steps:

[0009] Step 1: Preparation of cladding alloy powder

[0010] The cladding alloy powder at least includes high-entropy alloy powder. The cladding alloy powder is successively mechanically ground in a nitrogen environment, vacuum dried, and cooled before use.

[0011] Step 2: Pretreatment of the workpiece surface

[0012] The surface of the high-reflectivity metal substrate is polished, cleaned, dried, and preheated to 200 °C before use.

[0013] Step 3: Design of swing laser cladding process parameters

[0014] Cladding is carried out by a composite method combining a dual-wavelength infrared laser and a galvanometer swing. Among them, the infrared laser wavelength range is 780nm to 1100nm, the laser spot size range is 20μm to 40μm, the laser galvanometer swing frequency is 40Hz to 300Hz, the swing amplitude range is 300 to 700μm, the laser defocus amount range is +3 to -3mm, the laser power range is 1000W to 3000W, the powder feeding rate is 3g / min to 20g / min, the cladding speed range is 5mm / s to 30mm / s, the protective gas and the powder feeding gas are both Ar gas, and the number of cladding layers is 2 to 6 layers;

[0015] Step Four: Laser cladding of metal coating

[0016] Adopt the synchronous powder feeding form and use the process parameters specified in Step Three to melt the cladding alloy powder and form a metallurgical bond with the highly reflective metal substrate to obtain a metal coating.

[0017] Furthermore: The laser swing modes in Step Three include circular swing, figure-eight swing, triangular swing, sine-cosine curve swing, and Z-shaped swing.

[0018] Furthermore, the high-entropy alloy powder is NiCuMo, TiNbZrCu, or NiCuMoTiB.

[0019] Furthermore, for the high-entropy alloy powder NiCuMoTiB, the mass percentage of each element by mass fraction is: Ni 55 - 65wt%, Cu 10 - 25wt%, Mo 10 - 15wt%, Ti 0 - 5wt%, B 0 - 5wt%.

[0020] Furthermore, for the high-entropy alloy powder NiCuMo, the mass percentage of each element by mass fraction is: Ni 65 - 75wt%, Cu 10 - 25wt%, Mo 10 - 25wt%.

[0021] Furthermore, for the high-entropy alloy powder TiNbZrCu, by mass percentage, the combined content of Ti, Nb, and Zr accounts for 45 - 65wt%, the rest is Cu, and Ti, Nb, and Zr are in an equimolar ratio.

[0022] Furthermore, the particle sizes of the TiNbZrCu powder and the NiCuMo(Ti,B) powder are both 40 - 200μm.

[0023] Furthermore, the molten powder also includes one or more of reinforcing phases WC, TiB2, B4C, C3N4, BN, SiC, and VN.

[0024] Furthermore, the detailed method of Step Four is:

[0025] The clad alloy powder obtained in Step 1 is sent to the surface of the copper alloy substrate pretreated in Step 2 through a powder feeding tube by the pressure of Ar gas. At the same time, according to the infrared laser parameters designed in Step 3, the dual-wavelength laser is transmitted through an optical fiber, collimated and focused by a movable lens and a focusing lens to reach a swinging galvanometer. The swinging galvanometer reflects and focuses the laser onto the substrate surface according to the designed swinging frequency, swinging amplitude, and swinging pattern, melting the clad alloy powder and forming a metallurgical bonding coating with the substrate.

[0026] The high-reflectivity substrates of the present invention include metal substrates such as Cu alloys, Al alloys, Mg alloys, and Ti alloys.

[0027] The coating prepared by the above method has a dual-network structure with wear resistance, ablation resistance, and conductivity. The conductivity of the metal coating is 65-85% IACS, and the hardness is 400-600 HV.

[0028] The coating of the present invention is mainly used in extreme environments, especially on conductive rails with high temperature resistance and ablation resistance.

[0029] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0030] The present invention discloses a method for preparing a refractory metal coating on a high-reflectivity metal surface. A refractory metal coating is cladded on the surface of a high-reflectivity substrate, using nickel-based or copper-based clad alloy powders and reinforcing phases with different compositions and ratios. The reinforcing phases are WC, TiB2, B4C, C3N4, BN, SiC, and VN, which can be formed in-situ or added externally. At the same time, a small-core diameter dual-wavelength high-energy density infrared laser is selected to control parameters such as the swinging frequency of the laser galvanometer, the laser swinging mode, the amplitude, the laser defocus amount, the laser power, the powder feeding amount, the cladding speed, and the number of cladding layers. The preparation process has three advantages:

[0031] 1) The dual-wavelength high-energy density infrared laser plays a preheating role for high-reflectivity materials. By preheating, the substrate temperature is increased, which is beneficial to improving the absorption efficiency of the laser. At the same time, the cooling rate of the substrate is reduced to facilitate the establishment of a molten pool. Combined with the disturbing effect of the swinging laser on the molten pool, the gas in the molten pool floats up, the porosity is low, and cracks are reduced. It has the characteristics of high cladding efficiency and few defects.

[0032] 2) The compounding method of dual-wavelength high-energy density infrared laser and oscillating laser. First, it is beneficial for refractory alloy elements such as Ni, Mo, Ti, Nb, Zr, etc. to form ceramic phases such as TiB2, NbB, ZrB2, etc. with B. Second, it is beneficial for refractory alloy elements such as Ni, Mo, Ti, Nb, Zr, etc. to form multi-component ceramic phases such as (Ti,Mo)B2, (Ti,Nb,Zr)B2, etc. with B, and it is beneficial for the aggregation of these refractory alloy elements and ceramic phases at the grain boundaries of the copper alloy coating matrix to form an abrasion-resistant and ablation-resistant grid. At the same time, because the aggregation of refractory alloy elements and ceramic phases at the grain boundaries of the copper alloy coating matrix is complete, rather than being dissolved in the copper alloy lattice, the lattice distortion is reduced, and the integrity of the copper alloy conductive network in the coating is maintained, reducing the impact on the conductivity, that is, forming an abrasion-resistant, ablation-resistant and conductive dual network, as Figure 2 shown, which can ensure that the coating has no defects, high thermal conductivity and conductivity, and good abrasion resistance and corrosion resistance. The hardness, thickness, conductivity, abrasion resistance, ablation resistance and other properties of the laser cladding coating are measured. The conductivity of the obtained metal coating is 65-85% IACS, the hardness is 400-600 HV. After the coating is ablated by heat flow, the mass loss rate is reduced by 60-70% compared with the mass loss rate of the copper matrix (that is, only about 30% of the mass of the copper matrix is lost), while the conductivity of the Cu alloy matrix is only 75% IACS, and the hardness of the Cu alloy matrix is 150 HV. This shows that the coating prepared by the present invention has far better abrasion resistance and ablation resistance than the copper matrix on the premise of maintaining good conductivity of the coating.

[0033] 3) The oscillating laser stirs the molten pool and performs multi-layer cladding, breaks dendrites and inhibits their growth, so that the coating is mainly composed of equiaxed grains, with high bonding strength and good toughness of the coating, reducing problems such as cracking and peeling of the coating, and providing a reliable technical means for the protection of materials such as Cu alloys, Al alloys, Mg alloys, Ti alloys, etc. used in large equipment lightweight and extreme environments. The diameter of the oscillating laser spot is smaller than that of the ordinary laser, and the swing amplitude is significantly several times larger than the laser spot diameter. This working method of increasing the working area with high energy density in a small area will form a smaller molten pool in the small area, and due to the small molten pool and fast heat dissipation, the grains are sufficiently refined and it is not easy to form thermal cracks. And the large swing amplitude will produce a certain overlapping area. After the oscillating laser sweeps through the overlapping area for the second time, the larger grains will be broken again, and the pores will be eliminated due to the laser oscillation. Therefore, the oscillating laser cladding with a high swing amplitude is beneficial to rapid solidification and the formation of a finer solidification microstructure and the elimination of defects.

[0034] 4) The laser used in the present invention belongs to an infrared laser, which is the lowest-cost laser in the field of laser processing. Secondly, the optical path components, galvanometers and other components are all common standard parts, and the procurement cost is low, making the cladding process of the present invention easy to industrialize. Description of the Drawings

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the description of the embodiments. The accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0036] Figure 1 Process schematic diagram of combining a small spot dual-wavelength high energy density infrared laser designed by the present invention with a galvanometer swing;

[0037] Figure 2 Schematic diagram of the coating structure of a double network with wear resistance, ablation resistance, and conductivity prepared by the present invention;

[0038] Figure 3 Cross-sectional morphology diagram of the metal coating prepared by the present invention;

[0039] Figure 4 Microstructure diagram of the coating with an added reinforcing phase prepared by the present invention.

[0040] Figure 5 Comparison results of the ablation resistance performance of the coatings prepared in the embodiments of the present invention. Detailed implementation manners

[0041] In order to enable those skilled in the art to better understand the technical solutions in this specification, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0042] Embodiment 1

[0043] A method for preparing a refractory metal coating on a high reflectivity metal surface, comprising the following steps:

[0044] Step 1 Powder preparation: Weigh each component according to the following ratio to form a clad alloy powder NiCuMoTiB. Mechanically grind the NiCuMoTiB clad alloy powder in a nitrogen environment for 60 minutes, then place it in a vacuum drying oven at 60 °C for 6 hours, then cool it to room temperature in a vacuum environment, and then place it in a powder feeding barrel for use;

[0045] In the clad alloy powder NiCuMoTiB, each element is calculated by mass fraction: Ni 65wt%, Cu 20wt%, Mo 10wt%, Ti 3wt%, B 2wt%, and the particle size is 40 - 200 μm.

[0046] Step 2 Workpiece surface pretreatment: Grind the surface of the copper alloy substrate smoothly, clean it successively with absolute ethanol and deionized water, dry it, and preheat it to 200 °C on a heating table for standby;

[0047] Step 3 Oscillating laser cladding process: The present invention adopts a cladding process combining a dual-wavelength infrared laser and a galvanometer (see Figure 1 ), the infrared laser wavelengths of the dual-wavelength infrared laser are 915 nm and 976 nm, the laser spot size range is 34 μm, the laser galvanometer oscillation frequency is 50 Hz, the laser oscillation mode includes circular oscillation, the swing amplitude is 400 μm, the laser defocus range is 0 mm, the laser power is 3000 W, the powder feeding rate is 10 g / min, the cladding speed range is 15 mm / s, the protective gas and the powder feeding gas are both Ar gas, and the number of cladding layers is 2 layers;

[0048] Step 4 Laser cladding preparation:

[0049] 4.1: Arrange the galvanometer system, focusing lens, movable lens, dual-wavelength infrared laser and substrate according to the Figure 1 shown positional relationship;

[0050] 4.2: Send the dry cladding alloy powder obtained in Step 1 to the surface of the copper alloy substrate treated in Step 2 through a powder feeding tube by using the Ar gas pressure. At the same time, use the laser with the process parameters specified in Step 3 to melt the powder and form a metallurgical bond with the copper alloy substrate to obtain a metal coating; First, the dual-wavelength laser is transmitted through a fiber with a core diameter of 38 μm, collimated and focused by the movable lens and the focusing lens, reaches the oscillating galvanometer, the galvanometer X-axis motor and Y-axis motor swing to adjust the angle, and reflects and focuses the laser onto the substrate surface, and melts the refractory alloy powder and the substrate to form a metallurgical bond coating. The schematic diagram of the obtained coating structure and the cross-sectional morphology diagram are shown in Figure 2 and Figure 3 .

[0051] Step 5 Measure the hardness, conductivity, wear resistance, ablation resistance and other properties of the laser cladding coating in Example 1 and compare them with the Cu alloy substrate. The conductivity of the Cu alloy substrate is 75% IACS, and the conductivity of the obtained metal coating is 75% IACS. The hardness range is 450 ± 50 HV, which is about 3 times that of the substrate. The wear resistance and ablation resistance are improved by 70% compared with the copper substrate, far better than the copper substrate.

[0052] Example 2

[0053] As described in Example 1, a method for preparing a refractory metal coating on a high-reflectivity metal surface, except that in this example, the cladding powder used in Step 1 is a high-entropy alloy such as TiNbZrCu. Among them, TiNbZr is in an equimolar fraction of Ti: Nb: Zr = 1: 1: 1, accounting for 60 wt%, and the rest is Cu, with a particle size of 40 - 200 μm; in Step 3, the laser galvanometer swing frequency is 100 Hz, the laser swing mode is circular swing, the swing amplitude is 500 μm, the laser defocus amount is +1 mm, the laser power is 1500 W, and the number of cladding layers is 2 layers; in Step 5, the conductivity and wear and ablation resistance of the laser cladding coating are measured. The conductivity of the obtained metal coating is ≥ 80% IACS, the hardness range is 600 ± 50 HV, which is about 4 times that of the substrate, and the wear and ablation resistance performance is improved by 60% compared with the copper substrate.

[0054] Example 3

[0055] As described in Example 1, a method for preparing a refractory metal coating on a high-reflectivity metal surface, except that in this example, for the swing laser cladding process, it is characterized in that: the laser galvanometer swing frequency is 60 Hz, the laser swing mode is figure-eight swing, the swing amplitude is 600 μm, the laser defocus amount is -1 mm, the laser power is 3000 W, and the number of cladding layers is 2 layers; and after each layer of cladding, circular swing is used for remelting; in Step 5, the conductivity and wear and ablation resistance of the laser cladding coating are measured. The conductivity of the obtained metal coating is 80% IACS, the hardness range is 500 ± 50 HV, which is about 3.5 times that of the substrate, and the wear and ablation resistance performance is improved by 69% compared with the copper substrate.

[0056] Example 4

[0057] As described in Example 1, a method for preparing a refractory metal coating on a high-reflectivity metal surface, except that in this example, the cladding powder used in Step 1 is a high-entropy alloy such as TiNbZrCu, and TiB2 is added as a second reinforcing phase. For the TiNbZrCu high-entropy alloy, it accounts for 60 wt% of the total powder mass, among which TiNbZr is in an equimolar fraction of Ti: Nb: Zr = 1: 1: 1, accounting for 60 wt%, and the rest is Cu, with a particle size of 40 - 200 μm; in the overall powder, TiB2 accounts for 40 wt% of the total mass. The swing laser cladding process is characterized in that: the laser galvanometer swing frequency is 160 Hz, the laser swing mode is circular swing, and after each layer of cladding, figure-eight swing is used for remelting; in Step 5, the conductivity and wear and ablation resistance of the laser cladding coating are measured. The conductivity of the obtained metal coating is 80% IACS, the hardness range is 650 ± 50 HV, which is about 4.3 times that of the substrate, and the wear and ablation resistance performance is improved by 65% compared with the copper substrate. The coating microstructure obtained in Example 4 is shown inFigure 4 。

[0058] From Figure 2 the schematic diagram of the coating structure, it can be seen that the coating obtained by the composite method of double-wavelength high-energy density infrared laser and oscillating laser in the present invention has a double network with wear resistance, ablation resistance and conductivity. From Figure 3 the cross-sectional morphology diagram of the coating, it can be seen that there are few defects in the coating and no thermal cracks, which indicates that the obtained coating has high bonding strength and good toughness. From Figure 4 the microstructure diagram of the coating, it can be seen that adding reinforcing phases to the molten powder can also obtain a refractory alloy coating structure with few or no defects.

[0059] In order to prove that the ablation resistance of the coating of the present invention is better than that of the substrate, the mass loss rates of the coatings obtained from four embodiments were tested. The test method is to carry out oxyacetylene ablation on the coating and the substrate within 20 s and measure the mass loss rate. The test results are shown in Figure 5 , from Figure 5 it can be seen that the mass losses of the coatings after heat flux ablation from Example 1 to Example 4 are 6.09×10-4 g / s, 8.21×10-4 g / s, 7.08×10-4 g / s, and 6.28×10-4 g / s in sequence, and the mass loss of the copper substrate is 20.4×10-4 g / s. Compared with the substrate, the ablation resistance of the coating of the present invention is improved by 60%-70%.

[0060] It should be noted that the key point protected by the present invention is to combine a double-wavelength infrared laser and a galvanometer mirror. The cladding mode with a small spot and a large swing amplitude not only improves the energy density but also increases the cladding area, and simultaneously improves the bonding strength, hardness, wear resistance, electrical and thermal conductivity of the cladding layer on the surface of high-reflectivity metal materials, and improves the damage protection reliability of high-reflectivity metal material components in extreme environment applications. As for the selection of the reinforcing phase in the cladding powder and the ratio of each component, it is not the key point concerned by the present invention.

[0061] The above are only preferred embodiments of the present invention, and do not impose any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a refractory metal coating on a high-reflectivity metal surface, characterized in that, Follow these steps: Step 1: Preparation of cladding alloy powder The cladding alloy powder at least comprises high entropy alloy powder, and the cladding alloy powder is mechanically ground, vacuum dried and cooled in a nitrogen environment in sequence for standby use; Step 2: Workpiece surface pretreatment The surface of the highly reflective metal substrate is polished, cleaned, dried, and preheated to 200°C for use; Step 3: Design the process parameters of oscillating laser cladding The composite method of dual-wavelength infrared laser and galvanometer swing is used for cladding, wherein the infrared laser wavelength range is 780nm~1100nm, the laser spot size range is 20μm~40μm, the laser galvanometer swing frequency is 40Hz~300Hz, the swing range is 300~700μm, the laser defocus range is +3~-3mm, the laser power range is 1000W~3000W, the powder feeding amount is 3g / min~20g / min, the cladding speed range is 5mm / s~30mm / s, the protective gas and powder feeding gas are both Ar gas, and the number of cladding layers is 2~6 layers; Step 4: Laser cladding metal coating The synchronous powder feeding method is adopted and the process parameters specified in step three are used to melt the cladding alloy powder and form a metallurgical bond with the highly reflective metal substrate to obtain a metal coating.

2. The method for preparing a refractory metal coating on a high-reflectivity metal surface according to claim 1, characterized in that, The laser oscillation modes in step three include circular oscillation, figure-8 oscillation, triangle oscillation, sine-cosine curve oscillation and zigzag oscillation.

3. The method for preparing a refractory metal coating on a high-reflectivity metal surface according to claim 1, characterized in that, The high entropy alloy powder is NiCuMo, TiNbZrCu or NiCuMoTiB.

4. The method for preparing a refractory metal coating on a high-reflectivity metal surface according to claim 3, wherein, The high entropy alloy powder NiCuMoTiB, in terms of mass fraction, comprises the following elements: Ni 55-65wt%, Cu 10-25wt%, Mo 10-15wt%, Ti 0-5wt%, B 0-5wt%; the high entropy alloy powder NiCuMo, in terms of mass fraction, comprises the following elements: Ni 65-75wt%, Cu 10-25wt%, Mo 10-25wt%; the high entropy alloy powder TiNbZrCu, in terms of mass percentage, comprises Ti, Nb and Zr together accounting for 45-65wt%, the remainder being Cu, and Ti, Nb and Zr being in an equal molar ratio.

5. The method for preparing a refractory metal coating on a high-reflectivity metal surface according to claim 3, characterized in that, Furthermore, the particle sizes of the NiCuMo, TiNbZrCu and NiCuMoTiB powders are all 40-200 μm.

6. The method for preparing a refractory metal coating on a high-reflectivity metal surface according to claim 1, characterized in that, The molten powder also includes one or more of the reinforcing phases WC, TiB2, B4C, C3N4, BN, SiC and VN.

7. The method for preparing a refractory metal coating on a high-reflectivity metal surface according to claim 1, characterized in that, The detailed method of step four is: the cladding alloy powder obtained in step one is delivered to the surface of the copper alloy substrate pretreated in step two through a powder delivery pipe using Ar gas pressure; at the same time, according to the infrared laser parameters designed in step three, the dual-wavelength laser is transmitted through the optical fiber, and is collimated and focused by the movable lens and focusing mirror to reach the oscillating galvanometer, and the oscillating galvanometer reflects and focuses the laser onto the substrate surface according to the designed oscillation frequency, oscillation amplitude and oscillation form, so as to melt the cladding alloy powder and form a metallurgical bonding coating with the substrate.

8. The method for preparing a refractory metal coating on a high-reflectivity metal surface according to claim 1, characterized in that, The high-reflection substrate includes Cu alloy, Al alloy, Mg alloy and Ti alloy metal substrates.

9. A refractory metal coating prepared by a method of preparing a refractory metal coating using a high reflectivity metal surface according to any one of claims 1-8, characterized in that, The refractory metal coating has a dual-network structure with wear resistance, ablation resistance, and electrical conductivity. The electrical conductivity of the metal coating is 65-85% IACS, and the hardness is 400-600 HV.

10. Application of a refractory metal coating as described in claim 9 on a high-temperature resistant and ablation-resistant conductive rail.

Images