Endogenous phosphide reinforced antifriction wear-resistant multi-component alloy coating and preparation method thereof

Abstract

The invention discloses an endogenous phosphide reinforced antifriction wear-resistant multi-component alloy coating and a preparation method thereof, the multi-component alloy coating is cladded on the surface of a metal matrix through laser cladding, and the multi-component alloy coating is composed of an FCC phase, a BCC phase and metal phosphide; wherein the forming raw materials of the multi-element alloy coating comprise multi-element metal powder and a phosphorus-containing compound, and the metal phosphide is endogenous through reaction of the multi-element metal powder and the phosphorus-containing compound in the laser cladding process. The preparation method comprises the following steps: uniformly coating mixed multi-component alloy powder on the surface of a metal matrix by adopting a preset powder method, and carrying out laser cladding by using continuous laser by adopting the preset powder method, so as to finally prepare the phosphide reinforced multi-component alloy composite coating with four layers. The method is simple to operate and high in powder utilization rate, the friction coefficient of the prepared coating is remarkably reduced and the wear resistance is remarkably improved due to enhancement of phosphide, so that the service life of the reinforced coating is effectively prolonged, and the method is suitable for being used in severe environments such as corrosion and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of surface modification, and in particular relates to an endogenous phosphide-reinforced friction-reducing and wear-resistant multi-element alloy coating and a preparation method thereof. Background Art

[0002] In recent years, high entropy alloys, as a new metal material design concept, have attracted widespread attention in the field of materials research due to their excellent comprehensive performance. High entropy alloys based on transition metals and their coatings have shown high strength, toughness, excellent wear resistance and corrosion resistance through the synergistic effect of multiple principal elements, and have become one of the important research directions of high-performance structural materials. This type of alloy has potential application value under extreme environmental conditions, especially in marine engineering and other harsh service environments. However, existing studies have shown that the wear resistance of this type of high entropy alloy is still significantly insufficient under the coupling of corrosion and wear, which is manifested in a higher friction coefficient and a larger wear rate, which seriously limits its application in practical engineering.

[0003] As an advanced surface modification technology, laser cladding technology has many significant advantages. It can form a dense and strong bonding coating on the surface of the base material by rapidly melting the alloy powder with a high energy density laser beam. Moreover, the rapid solidification process helps to refine the grains and optimize the microstructure of the coating, which is expected to obtain excellent material properties. However, the laser cladding process, such as cladding process, laser process parameters, coating method, etc., has a great influence on the performance of the coating. Improper control can easily cause a series of problems such as insufficient interface bonding, coating cracks or pores, internal unevenness of the coating, and component segregation.

[0004] In view of the above problems, it is urgent to further optimize the composition design of alloy materials and laser cladding process conditions to reduce the friction coefficient of alloy materials, improve their wear resistance, and thus effectively extend the service life of alloy coatings, which has important guiding significance for the design of wear-resistant materials serving in harsh environments such as corrosion. Summary of the invention

[0005] The present invention aims to overcome the defects of the prior art and provide an endogenous phosphide-reinforced friction-reducing and wear-resistant multi-element alloy coating and a preparation method thereof. During the laser cladding process, the friction coefficient of the multi-element alloy coating is significantly reduced and the wear resistance is significantly improved due to the enhancement of endogenous metal phosphides, which can effectively extend the service life of the alloy coating and is suitable for use in harsh environments such as corrosion.

[0006] In order to solve the above technical problems, the first aspect of the present invention provides a multi-component alloy coating, which is composed of an FCC phase, a BCC phase and a metal phosphide. The raw material components of the multi-component alloy coating include multi-component metal powder and a phosphorus-containing compound. The metal phosphide is endogenously generated by the reaction of the multi-component metal powder and the phosphorus-containing compound during the laser cladding process.

[0007] Specifically, multi-component alloys have shown potential application value in extreme environments due to their excellent mechanical properties, wear resistance and corrosion resistance, but their application in friction parts still has problems such as high friction and high wear. Under the coupling of corrosion and wear, multi-component alloys often show a high friction coefficient and a large wear rate, which greatly limits their wide application in marine engineering, mechanical equipment and other harsh environments. Studies have found that introducing phosphorus into the multi-component alloy system is an effective modification method. The addition of phosphorus can not only significantly improve the hardness of the base material, reduce the friction coefficient and wear rate, but also give the material excellent corrosion resistance in the marine environment. This makes the phosphide-reinforced multi-component alloy coating show more excellent comprehensive performance under the conditions of corrosion and wear coupling, further broadening its application prospects in harsh environments.

[0008] Therefore, the present invention uses multi-component metal powder as the main raw material, adds a certain amount of phosphide, and adopts laser cladding technology to obtain an endogenous metal phosphide reinforced multi-component alloy coating, which has a multiphase structure composed of FCC phase, BCC phase and metal phosphide, and exhibits excellent wear resistance and friction reduction properties due to the enhancement of endogenous metal phosphide. On the one hand, the metal phosphide in the coating is endogenous due to the reaction during the laser cladding process, the interface between the two is clean, and the bonding strength between the endogenous metal phosphide and the metal matrix is ​​high, which is not only beneficial to improve the mechanical properties, but also beneficial to improve the corrosion resistance. On the other hand, the metal phosphide formed in the multi-component alloy coating can effectively reduce the friction coefficient of the coating, improve the wear resistance and corrosion resistance in a corrosive environment, and is beneficial to be applied in marine engineering, mechanical equipment and energy fields.

[0009] In some embodiments of the present invention, the multi-metal powder is selected from at least two of Al, Co, Cr, Fe, Ni, Ti, Mo, Nb, Zr, and W.

[0010] Specifically, the present invention selects the multi-element metal powder based on the following: it has a strong phosphide-forming ability and can chemically react with phosphorus-containing compounds during the laser cladding process to form endogenous metal phosphides, thereby achieving improved tribological properties.

[0011] In some embodiments of the present invention, the multi-metal powder is Al, Co, Cr, Fe, Ni, and Ti in equimolar proportions, namely, AlCoCrFeNiTi.

[0012] In some embodiments of the present invention, the particle size of the multi-element metal powder is 10-150 μm.

[0013] Specifically, too high laser power can easily cause cracking of the coating. By controlling the particle size of the multi-element metal powder, the laser power can be effectively controlled and the heat input can be reduced. At the same time, selecting multi-element metal powder with a relatively small particle size is conducive to the role of fine grain strengthening, thereby improving the hardness and wear resistance of the material.

[0014] In some embodiments of the present invention, the purity of the multi-metal powder is ≥99.9%.

[0015] In some embodiments of the present invention, the phosphorus-containing compound is selected from at least one of Fe2P, Fe3P, Ni3P, VP, V3P, Co2P, CoP, WP, and W2P.

[0016] Specifically, the phosphorus-containing compound of the present invention exists in the coating in the form of intermediate alloy powder. During the laser cladding process, it will form endogenous metal phosphide with the multi-metal powder, thereby significantly improving the microhardness of the coating, reducing the friction coefficient, and enhancing the corrosion resistance.

[0017] In some embodiments of the present invention, the ratio of the total mole number of the multi-element metal powder to the mole number of phosphorus in the phosphorus-containing compound is (50-99): (1-50).

[0018] In some embodiments of the present invention, the ratio of the total mole number of the multi-element metal powder to the mole number of phosphorus in the phosphorus-containing compound is (75-95): (5-25).

[0019] In some embodiments of the present invention, the ratio of the total molar number of the multi-element metal powder to the molar number of phosphorus in the phosphorus-containing compound is (77-92): (8-23).

[0020] Specifically, the present invention optimizes the amount of phosphorus-containing compounds and precisely controls the generation of strengthening phases, which is not only beneficial for improving the hardness and wear resistance of the coating, but also can enhance the corrosion resistance of the coating through densification and passivation, making it suitable for corrosion and wear scenarios in marine environments.

[0021] In some embodiments of the present invention, the thickness of the multi-element alloy coating is 0.1-2 mm.

[0022] In some embodiments of the present invention, the thickness of the multi-element alloy coating is 0.5-1.5 mm.

[0023] A second aspect of the present invention provides a method for preparing the above-mentioned multi-element alloy coating, comprising the following steps:

[0024] (1) mixing multi-element metal powder and phosphorus-containing compound, and ball milling to obtain multi-element alloy powder;

[0025] (2) coating the multi-component alloy powder on the surface of a metal substrate and drying it; and then performing laser cladding to form the multi-component alloy coating.

[0026] Specifically, the present invention combines the characteristics of multi-element alloy powder, improves the coating process, and adopts the pre-set powder method to ensure that the mixed alloy powder is evenly distributed during the cladding process, avoiding local component segregation, thereby improving the wear resistance and friction reduction performance of the coating; at the same time, it is conducive to accurately controlling the diffusion effect of phosphorus, so that the coating shows higher uniformity in microhardness and corrosion resistance. In addition, the pre-set powder method laser cladding multi-element alloy coating can form a dense, uniform and excellent performance coating by quickly melting the pre-set powder through a high-energy density laser and realizing metallurgical bonding with the substrate on the basis of meeting the high powder utilization rate, significantly improving the hardness, wear resistance and corrosion resistance of the material, so that it can show excellent performance in complex wear, corrosion and high temperature environments.

[0027] In some embodiments of the present invention, in step (2), the multi-component alloy powder further comprises a step of mixing with a binder before coating, the binder comprises polyvinyl alcohol, and the amount of polyvinyl alcohol added is 3-6wt% of the multi-component alloy powder.

[0028] In some embodiments of the present invention, in step (2), the process parameters of the laser cladding are: laser power 800-2000 W, scanning speed 5-40 mm / s, spot diameter 1-6 mm, protective gas is argon or nitrogen, and flow rate is 6-15 L / min.

[0029] Studies have found that high energy input and fast scanning can easily lead to defects such as cracks or pores in the coating, and the dilution rate between the coating and the substrate is high, which affects the consistency of the coating performance. The present invention uses lower laser power and slower scanning speed, and optimizes the spot diameter and protective gas flow rate, thereby reducing heat input, reducing the size of the heat-affected zone, and effectively inhibiting coating cracking and stress concentration. At the same time, the density of the coating is improved, microscopic defects such as pores and cracks are reduced; the surface flatness and thickness uniformity of the cladding layer are improved to facilitate subsequent processing performance.

[0030] In some embodiments of the present invention, in step (2), the laser cladding adopts a multi-layer repeated cladding process, and the number of repetitions is 3-5 times.

[0031] Research has found that although single-layer laser cladding can achieve a coating with higher hardness, the performance gradient between the coating and the substrate is large due to the limitation of the thickness of the cladding layer and the dilution effect during the cladding process, which may cause problems such as insufficient interface bonding or uneven internal coating. The present invention adopts a multi-layer cladding process, that is, after each layer of cladding is completed, the powder is re-coated and laser cladding is performed again, and the cladding is repeated many times to finally form a multi-layer multi-element alloy composite coating, which ensures the uniformity and accuracy of the chemical composition, can significantly reduce the dilution rate, and ensure that the composition of each layer of coating is closer to the designed ratio. At the same time, through multi-layer stacking, the coating thickness reaches an ideal level, and the internal density and uniformity are higher; and the metallurgical bonding between the coating and the substrate is more firm, which is beneficial to improving the overall wear resistance and fatigue resistance of the coating.

[0032] The third aspect of the present invention provides the application of the above multi-component alloy coating in the field of wear.

[0033] In some embodiments of the present invention, the wear field includes marine engineering field, mechanical equipment field or energy field.

[0034] Compared with the prior art, the above technical solution of the present invention has at least the following technical effects or advantages:

[0035] (1) The present invention uses multi-element metal powder as the main raw material, adds a certain amount of phosphide, and adopts laser cladding technology to obtain an endogenous metal phosphide reinforced multi-element alloy coating. The coating has a multiphase structure composed of FCC phase, BCC phase and metal phosphide, and exhibits excellent wear resistance and friction reduction properties due to the reinforcement of endogenous metal phosphide.

[0036] (2) The present invention adopts the pre-set powder method to ensure that the mixed alloy powder is evenly distributed during the cladding process, avoiding local component segregation, thereby improving the wear resistance and friction reduction performance of the coating; at the same time, the pre-set powder method laser cladding multi-element alloy coating can quickly melt the pre-set powder through high energy density laser and achieve metallurgical bonding with the substrate on the basis of meeting the high powder utilization rate, forming a dense, uniform and high-performance coating, significantly improving the hardness, wear resistance and corrosion resistance of the material, so that it can show excellent performance in complex wear, corrosion and high temperature environments. In addition, this technology has the characteristics of low heat input, small heat-affected zone, strong coating adhesion, and can accurately control the alloy composition, which is suitable for surface strengthening and repair of complex-shaped workpieces.

[0037] (3) The preparation process of the multi-element alloy coating of the present invention has the advantages of simple operation, high efficiency, wide application range, high material utilization rate and low process cost. During the laser cladding process, by optimizing the laser power and scanning speed, the generation of defects such as cracks and pores on the coating surface is reduced, thereby further improving the density and overall performance of the coating. This preparation method effectively improves the mechanical properties and wear and corrosion resistance of the multi-element alloy coating, and provides reliable technical support for its application in complex service environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A flow chart for preparing a multi-element alloy coating according to the present invention;

[0039] Figure 2 X-ray diffraction (XRD) spectra of the multi-element alloy coatings prepared in Example 1 of the present invention and Comparative Example 1;

[0040] Figure 3 The microstructure scanning electron microscope (SEM) photograph (a) and the corresponding element distribution energy spectrum (bd) of the multi-element alloy coating prepared in Example 1 of the present invention;

[0041] Figure 4 Polarization curves of the multi-element alloy coatings prepared in Example 1 of the present invention and Comparative Example 1 measured during sliding friction under a load of 20N in a 3.5% NaCl solution;

[0042] Figure 5 The friction coefficient curves of the multi-element alloy coatings prepared in Example 2 of the present invention and Comparative Example 1 under a load of 10N in a 3.5% NaCl solution;

[0043] Figure 6 The graph of the corrosion potential of the multi-element alloy coating prepared in Example 2 of the present invention and Comparative Example 1 before and after the start of sliding friction under a load of 10N in a 3.5% NaCl solution is a graph of the corrosion potential of the multi-element alloy coating prepared in Example 2 of the present invention and Comparative Example 1 with time;

[0044] Figure 7 This is a comparison chart of the average friction coefficient and average wear rate of the multi-element alloy coating prepared in Example 2 of the present invention and in Comparative Example 1 after sliding friction in a 3.5% NaCl solution under a load of 10N for 100 minutes. DETAILED DESCRIPTION

[0045] The present invention is described in detail below in conjunction with the examples, so that the technical personnel of the relevant technical field can understand the present invention. It is necessary to point out here that the examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. The non-essential improvements and adjustments made to the present invention by the skilled person in the relevant field according to the above invention content should still belong to the scope of protection of the present invention. At the same time, the raw materials mentioned below that are not described in detail are all commercially available products; the process steps or preparation methods that are not mentioned in detail are all process steps or preparation methods known to those skilled in the art.

[0046] Example 1

[0047] A multi-component alloy coating, the raw materials for forming the multi-component alloy coating include multi-component metal powder and phosphorus-containing compound, wherein: the multi-component metal powder includes Al, Co, Cr, Fe, Ni, and Ti in equal molar ratios, and the particle size of the multi-component metal powder is 10-150μm, and the purity is ≥99.9%; the phosphorus-containing compound is a phosphorus-iron intermediate alloy whose main component is Fe2P; the molar ratio of Al, Co, Cr, Fe, Ni, Ti and P is 14:14:14:14:14:14:16.

[0048] The preparation method of the multi-element alloy coating is as follows: Figure 1 As shown, the following steps are included:

[0049] (1) Al, Co, Cr, Fe, Ni, Ti and a phosphorus-containing compound were weighed in molar ratio and poured into a stainless steel ball milling jar, and an appropriate amount of ceramic balls (the weight of which is 10 times that of the alloy powder) were added into the jar; the mixture was mixed using a ball mill, and the specific ball milling parameters were as follows: mixing for 2 minutes, followed by a pause of 13 minutes, a total time of 156 hours, and a frequency of 11 Hz, to obtain a multi-element alloy powder;

[0050] (2) The multi-element alloy powder obtained in step (1) was mixed with a binder polyvinyl alcohol (added in an amount of 4.5 wt % of the multi-element alloy powder) and then uniformly coated on the surface of a Q235 steel substrate with a coating layer thickness of 1 mm by a pre-set powder method, and then placed in a drying oven for drying for 1-4 hours; then laser cladding was performed using a JM-RG3000 laser; the cladding parameters were as follows: laser power 1200 W, scanning speed 10 mm / s, spot diameter 5 mm, protective gas argon, flow rate 11 L / min; in order to reduce the effect of dilution, a multi-layer cladding process was adopted; that is, after each layer of cladding was completed, the multi-element alloy powder was re-coated and the cladding was repeated four times; finally, a four-layer AlCoCrFeNiTi multi-element alloy coating containing 16 at % phosphorus with a thickness of 1.5 mm was obtained, which was recorded as HEA-P16%.

[0051] Example 2

[0052] A multi-component alloy coating, the raw materials for forming the multi-component alloy coating include multi-component metal powder and phosphorus-containing compound, wherein: the multi-component metal powder includes Al, Co, Cr, Fe, Ni, and Ti in equal molar ratios, and the particle size of the multi-component metal powder is 10-150μm, and the purity is ≥99.9%; the phosphorus-containing compound is a phosphorus-iron intermediate alloy whose main component is Fe2P; the molar ratio of Al, Co, Cr, Fe, Ni, Ti and P is 12.83:12.83:12.83:12.83:12.83:12.83:23.

[0053] The method for preparing the multi-element alloy coating comprises the following steps:

[0054] (1) Al, Co, Cr, Fe, Ni, Ti and a phosphorus-containing compound were weighed in molar ratio and poured into a stainless steel ball milling jar, and an appropriate amount of ceramic balls (the weight of which is 10 times that of the alloy powder) were added into the jar; the mixture was mixed using a ball mill, and the specific ball milling parameters were as follows: mixing for 2 minutes, followed by a pause of 13 minutes, a total time of 156 hours, and a frequency of 11 Hz, to obtain a multi-element alloy powder;

[0055] (2) The multi-element alloy powder obtained in step (1) was mixed with a binder polyvinyl alcohol (the amount added was 4.5 wt% of the multi-element alloy powder) and then uniformly coated on the surface of a Q235 steel substrate with a coating layer thickness of 1 mm by a pre-set powder method, and placed in a drying oven for drying for 1-4 hours; then laser cladding was performed using a JM-RG3000 laser; the cladding parameters were as follows: laser power 1400 W, scanning speed 10 mm / s, spot diameter 5 mm, protective gas argon, flow rate 11 L / min; in order to reduce the dilution effect, a multi-layer cladding process was adopted; that is, after each layer of cladding was completed, the multi-element alloy powder was re-coated, and the cladding was repeated four times to finally obtain a four-layer AlCoCrFeNiTi multi-element alloy coating containing 23 at% phosphorus with a thickness of 1.5 mm, which was recorded as HEA-P23%.

[0056] Example 3

[0057] A multi-component alloy coating, the raw materials for forming the multi-component alloy coating include multi-component metal powder and phosphorus-containing compound, wherein: the multi-component metal powder includes Al, Co, Cr, Fe, Ni, and Ti in equal molar ratios, and the particle size of the multi-component metal powder is 10-150μm, and the purity is ≥99.9%; the phosphorus-containing compound is a phosphorus-iron intermediate alloy whose main component is Fe2P; the molar ratio of Al, Co, Cr, Fe, Ni, Ti and P is 15.3:15.3:15.3:15.3:15.3:15.3:8.

[0058] The method for preparing the multi-element alloy coating comprises the following steps:

[0059] (1) Al, Co, Cr, Fe, Ni, Ti and a phosphorus-containing compound were weighed in molar ratio and poured into a stainless steel ball milling jar, and an appropriate amount of ceramic balls (the weight of which is 10 times that of the alloy powder) were added into the jar; the mixture was mixed using a ball mill, and the specific ball milling parameters were as follows: mixing for 2 minutes, followed by a pause of 13 minutes, a total time of 156 hours, and a frequency of 11 Hz, to obtain a multi-element alloy powder;

[0060] (2) The multi-element alloy powder obtained in step (1) was mixed with a binder polyvinyl alcohol (added in an amount of 4.5 wt % of the multi-element alloy powder) and then uniformly coated on the surface of a Q235 steel substrate with a coating layer thickness of 1 mm using a pre-set powder method, and then placed in a drying oven for drying for 1-4 hours; then laser cladding was performed using a JM-RG3000 laser; the cladding parameters were as follows: laser power 800 W, scanning speed 10 mm / s, spot diameter 5 mm, protective gas argon, flow rate 11 L / min; in order to reduce the effect of dilution, a multi-layer cladding process was adopted; that is, after each layer of cladding was completed, the multi-element alloy powder was re-coated, and the cladding was repeated four times to finally obtain a four-layer AlCoCrFeNiTi multi-element alloy coating containing 8 at % phosphorus with a thickness of 1.5 mm, which was recorded as HEA-P8%.

[0061] Comparative Example 1

[0062] A multi-component alloy coating, the raw materials for forming the multi-component alloy coating include multi-component metal powder, and the multi-component metal powder includes Al, Co, Cr, Fe, Ni and Ti in equal molar ratios, the particle size of the multi-component metal powder is 10-150 μm, and the purity is ≥99.9%.

[0063] The method for preparing the multi-element alloy coating comprises the following steps:

[0064] (1) Al, Co, Cr, Fe, Ni, and Ti were weighed in molar ratio and poured into a stainless steel ball mill jar, and an appropriate amount of ceramic balls (the weight of which was 10 times that of the alloy powder) were added into the jar; the mixture was mixed using a ball mill, and the specific ball milling parameters were: mixing for 2 min, followed by a pause of 13 min, a total time of 156 h, and a frequency of 11 Hz, to obtain a multi-element alloy powder;

[0065] (2) The multi-component alloy powder obtained in step (1) was mixed with a binder polyvinyl alcohol (the amount added was 4.5 wt% of the multi-component alloy powder) and then uniformly coated on the surface of a Q235 steel substrate with a coating layer thickness of 1 mm by a pre-set powder method, and placed in a drying oven for drying for 1-4 hours; then laser cladding was performed using a JM-RG3000 laser; the cladding parameters were as follows: laser power 800 W, scanning speed 10 mm / s, spot diameter 5 mm, protective gas argon, flow rate 11 L / min; in order to reduce the effect of dilution, a multi-layer cladding process was adopted; that is, after each layer of cladding was completed, the multi-component alloy powder was re-coated, and the cladding was repeated four times to finally obtain a four-layer AlCoCrFeNiTi multi-component alloy coating with a thickness of 1.5 mm, which was recorded as HEA.

[0066] Compared with Example 1, the raw materials for forming the multi-element alloy coating of Comparative Example 1 do not contain phosphorus-containing compounds.

[0067] Performance Testing

[0068] 1. Crystalline phase composition and microstructure

[0069] Figure 2 The X-ray diffraction (XRD) spectra of the multi-element alloy coatings prepared in Example 1 and Comparative Example 1 are shown in FIG. Figure 2 The horizontal axis 2θ represents the diffraction angle, and the vertical axis Intensity represents the intensity of the diffraction peak. Figure 2 It can be seen that after adding 16at% phosphorus, the AlCoCrFeNiTi multi-component alloy coating transforms from a single FCC phase to a multiphase structure composed of FCC phase, BCC phase and metal phosphide mainly composed of Ti-P.

[0070] Figure 3 The SEM image of the multi-element alloy coating prepared in Example 1 of the present invention and the corresponding element distribution spectrum are shown in FIG. Figure 3 It can be seen that the internal structure of the coating is uniform and dense, without obvious defects such as pores and cracks, and the phosphorus, titanium and chromium elements are evenly distributed.

[0071] 2. Microhardness

[0072] The average Vickers hardness of the surfaces of the multi-element alloy coatings prepared in Examples 1-3 and Comparative Example 1 was tested using a Vickers hardness tester. The results are shown in Table 1.

[0073] Table 1:

[0074]

[0075]

[0076] It can be seen from Table 2 that, compared with Comparative Example 1, the microhardness of the multi-element alloy coatings prepared in Examples 1-3 is significantly improved due to the formation of endogenous metal phosphides.

[0077] 3. Friction and wear

[0078] In the friction and wear test, the multi-element alloy coating sample prepared above was first cut into 10mm×10mm×10mm cubes by an electric spark wire cutting machine, and then the surface oxide scale was removed by a grinding wheel machine, and then it was polished step by step with sandpaper of 100 to 1500 mesh, and then polished for use.

[0079] The reciprocating friction test was carried out using a CFT-I friction and wear test system. The friction pair was a Si3N4 ceramic ball with a diameter of 6 mm. The test was carried out in an air environment at room temperature or in a 3.5% NaCl solution, with loads of 5N, 10N and 20N, a sliding speed of 7.67mm / s, a reciprocating length of 5mm, and a sliding time of 100 minutes. For each load, the test was repeated three times. A probe profilometer was used to scan the wear track to obtain the wear volume.

[0080] Figure 4 The polarization curves of the multi-element alloy coatings prepared in Example 1 and Comparative Example 1 were measured during the sliding friction process in a 3.5% NaCl solution under a load of 20N. Figure 4 It can be seen that the addition of 16 at% phosphorus significantly improves the corrosion resistance of the AlCoCrFeNiTi multi-element alloy coating under sliding conditions. Under a sliding load of 20 N, the corrosion current density increases from 2.86×10 -5 A / cm 2 Reduced to 1.57×10 -6 A / cm 2 , the corrosion rate is reduced by about one order of magnitude. At the same time, under a sliding load of 20N, the friction coefficient is reduced from 0.560 to 0.365, and the wear rate is reduced from 12.2 to 5.7×10-6mm 3 / N·m. Therefore, the addition of 16at% phosphorus significantly improves the tribological properties of the AlCoCrFeNiTi multi-element alloy coating, which is particularly suitable for surface strengthening of friction parts in marine environments.

[0081] Figure 5-7The friction coefficient curve of the multi-element alloy coating prepared in Example 2 and Comparative Example 1 under a load of 10N in 3.5% NaCl solution (Sliding under 10N In 3.5% NaCl), the change of the corrosion potential (OCP) with time (Sliding time) before and after the start of sliding friction, and the comparison of the average friction coefficient and average wear rate (Wear rate) measured after 100 minutes of sliding friction. Figure 5-7 It can be seen that in a 3.5% NaCl solution simulating a seawater environment, under a sliding load of 10N, the AlCoCrFeNiTi multi-element alloy coating with 23at% phosphorus added exhibits excellent tribological properties. Compared with the multi-element alloy coating without P added, its friction coefficient is reduced from 0.690 to 0.270, and the corrosion wear rate is reduced from 21.6 to 5.3×10-6mm 3 / N·m. This shows that the introduction of phosphorus promotes the formation of metal phosphides and BCC phases, which helps to improve the stability and corrosion resistance of the multi-element alloy coating in a corrosion-wear coupling environment, thereby effectively improving the surface friction characteristics of the coating, significantly reducing friction resistance, and reducing the amount of wear on the coating. Phosphide-reinforced multi-element alloy coatings that exhibit excellent tribological properties in seawater environments have broad application prospects in the field of marine engineering equipment.

[0082] For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, without having to go through creative labor. Therefore, simple improvements made to the present invention by those skilled in the art based on the disclosure of the present invention should be within the protection scope of the present invention. The above embodiments are preferred embodiments of the present invention, and all processes similar to the present invention and equivalent changes made should belong to the protection scope of the present invention.

Claims

1. A multi-element alloy coating, characterized in that: The multi-component alloy coating consists of an FCC phase, a BCC phase and a metal phosphide. The raw material components of the multi-component alloy coating include multi-component metal powder and a phosphorus-containing compound. The metal phosphide is endogenously generated by the reaction of the multi-component metal powder and the phosphorus-containing compound during the laser cladding process.

2. The multi-element alloy coating according to claim 1, characterized in that: The multi-metal powder is selected from at least two of Al, Co, Cr, Fe, Ni, Ti, Mo, Nb, Zr, and W; and / or the particle size of the multi-metal powder is 10-150 μm; and / or the purity of the multi-metal powder is ≥99.9%.

3. The multi-element alloy coating according to claim 1, characterized in that: The phosphorus-containing compound is selected from at least one of Fe2P, Fe3P, Ni3P, VP, V3P, Co2P, CoP, WP, and W2P.

4. The multi-element alloy coating according to claim 1, characterized in that: The ratio of the total mole number of the multi-element metal powder to the mole number of phosphorus in the phosphorus-containing compound is (50-99): (1-50).

5. The multi-element alloy coating according to claim 1, characterized in that: The thickness of the multi-element alloy coating is 0.1-2 mm.

6. A method for preparing a multi-element alloy coating according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) mixing multi-element metal powder and phosphorus-containing compound, and ball milling to obtain multi-element alloy powder; (2) coating the multi-component alloy powder on the surface of a metal substrate and drying it; and then performing laser cladding to form the multi-component alloy coating.

7. The method for preparing a multi-element alloy coating according to claim 6, characterized in that: In step (2), the multi-component alloy powder further includes a step of mixing with a binder before coating, wherein the binder includes polyvinyl alcohol, and the amount of polyvinyl alcohol added is 3-6wt% of the multi-component alloy powder.

8. The method for preparing a multi-element alloy coating according to claim 6, characterized in that: In step (2), the process parameters of the laser cladding are: laser power 800-2000W, scanning speed 5-40mm / s, spot diameter 1-6mm, protective gas is argon or nitrogen, and flow rate is 6-15L / min.

9. The method for preparing a multi-element alloy coating according to claim 6, characterized in that: In step (2), the laser cladding adopts a multi-layer repeated cladding process, and the number of repetitions is 3-5 times.

10. Use of the multi-element alloy coating according to any one of claims 1 to 5 in the field of wear.

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