Preparation method of seawater wear and corrosion resistant high-entropy alloy coating

Abstract

The invention relates to a preparation method of a seawater wear and corrosion resistant high-entropy alloy coating, and belongs to the technical field of coating preparation and treatment. The preparation method comprises the steps that matching calculation is conducted according to the chemical formula FeCrCoMnSix of the high-entropy alloy, Fe, Cr, Co, Si and Mn-Fe alloy powder are weighed, and x is equal to 0.1-1; the weighed powder is mixed and then subjected to ball milling, and a mixture is obtained; mixing the mixture with an adhesive, coating the mixture on a substrate to form a plurality of prefabricated layers, distributing the prefabricated layers on the substrate in parallel, and then drying the coated substrate; under the protection atmosphere of inert gas, the dried base body coated with the prefabricated layer is subjected to multi-channel laser cladding; and then annealing treatment is conducted, and the high-entropy alloy coating is obtained. According to the method, the seawater corrosion resistance and wear resistance of the high-entropy alloy coating are improved by adjusting the content of the Si element, utilizing the laser cladding technology and further performing annealing treatment.

Description

Technical Field

[0001] The present application relates to the technical field of high entropy alloys, and in particular to a method for preparing a high entropy alloy coating resistant to seawater wear and corrosion. Background Art

[0002] FeCrCoMn-based high-entropy alloys have similar atomic radius and electronegativity among their constituent elements, and the mixing enthalpy between atoms of different elements is small. High-entropy alloys composed of these elements can easily form a simple solid solution structure, giving them good plasticity. Therefore, high-entropy alloys of this system have become one of the research hotspots in the field of materials in recent years.

[0003] Although the high entropy alloy coating improves the overall performance of the substrate, the study found that the friction coefficient of FeCrCoMn high entropy alloy coating is mostly above 0.4, CoCrFeMnNiSi 1.6 The friction coefficient of the high entropy alloy coating is 0.65, CoCrFeMnTi 0.2 The friction coefficient of the high entropy alloy coating is about 0.42, which limits the friction reduction and wear resistance of the coating to a certain extent. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the embodiments of the present application includes providing a method for preparing a high-entropy alloy coating resistant to seawater wear and corrosion, so as to improve the seawater corrosion resistance of the high-entropy alloy.

[0005] The embodiment of the present application is implemented as follows:

[0006] In a first aspect, the present invention provides a method for preparing a high entropy alloy coating resistant to seawater wear and corrosion, comprising: x The method comprises the following steps: performing a ratio calculation, weighing Fe, Cr, Co, Si and Mn-Fe alloy powders, wherein x is 0.1-1; mixing the weighed powders and then ball milling them to obtain a mixture; mixing the mixture with a binder and then coating the mixture on a substrate to form a plurality of prefabricated layers, wherein the plurality of prefabricated layers are arranged in parallel on the substrate, and then drying the coated substrate; in an inert gas protective atmosphere, performing a multi-pass laser cladding on the dried substrate coated with the prefabricated layers using a laser with a power greater than 2 kW to form a cladding layer on the surface of the substrate; and then performing an annealing treatment to obtain a high entropy alloy coating.

[0007] The present invention prepares FeCrCoMnSi on the substrate by adjusting the content of Si element and using laser cladding technology. xHigh-entropy alloy coating, and the seawater corrosion resistance and wear resistance of the high-entropy alloy coating are improved through further annealing treatment; wherein, on the one hand, annealing treatment reduces defects such as pores, microcracks and segregation, improves the densification of the structure and the stability of the interface, and reduces the surface roughness of the coating; on the other hand, it improves the diffusion efficiency between elemental atoms, thereby enhancing the solid solubility of the solid solution, resulting in an increase in the diffraction peak intensity of the BCC phase. Moreover, there is a relatively negative mixing entropy between Si element and Mn, Cr elements, which has a strong attraction, which makes more metal elements combine with Si to form silicides; at the same time, due to the sufficient diffusion between elemental atoms, a part of Si atoms with smaller atomic radii are dissolved in the solid solution as interstitial atoms, enhancing the lattice distortion effect and producing significant solid solution strengthening; while another part of Si atoms easily form hard metal silicides with other metal atoms, playing a second-phase strengthening effect. Under the synergistic action of the two, the hardness of the coating is increased, the ability of the coating to resist deformation is increased, thereby reducing the friction coefficient and wear rate of the coating, and improving the oxidation resistance of the coating; in addition, annealing treatment releases the residual stress inside the coating, reduces stress concentration, and at the same time promotes the uniformity of the coating microstructure, further increasing the resistance to the diffusion of conductive ions in the coating, increasing the resistance of the coating, and making the capacitance characteristics more stable, thereby improving the seawater corrosion resistance of the coating.

[0008] In some embodiments of the present application, the chemical formula of the high-entropy alloy is FeCrCoMnSi x , where x = 0.1 - 0.6.

[0009] By adjusting the content of Si element within the above range, it is more beneficial to improve the corrosion resistance and wear resistance of the high-entropy alloy coating.

[0010] In some embodiments of the present application, the annealing temperature is 500 - 650 °C, and the annealing time is 0.5 - 2 h.

[0011] By controlling the annealing temperature within the range of 500 - 650 °C and the time within the range of 0.5 - 2 h, defects such as pores, microcracks and segregation in the coating can be effectively reduced; at the same time, through annealing treatment, the surface roughness of the coating will also be improved. The reduced surface roughness not only reduces friction and wear, but also improves the wear resistance of the coating. In addition, the annealing process can also improve the densification of the coating, enhance the stability of the interface, reduce the permeability of the coating, thereby enhancing the corrosion resistance; at the same time, as the annealing treatment progresses, the resistance of the coating will also increase, and the capacitance characteristics become more stable, thereby improving the seawater corrosion resistance of the coating.

[0012] In some embodiments of the present application, the size of the prefabricated layer is: width 8 - 18 mm, length 50 - 70 mm, and height 2 - 4 mm.

[0013] This application uses laser cladding technology to prepare the coating. Therefore, the size of the prefabricated layer is limited to: width 8 - 18 mm, length 50 - 70 mm, and height 2 - 4 mm. This can enable the laser beam to evenly cover the surface of the prefabricated layer during cladding, reduce the non-uniformity of the coating, and further improve the density and adhesion of the coating, thereby enhancing the wear resistance and corrosion resistance of the coating.

[0014] In some embodiments of this application, the substrate includes 45 steel or 316 stainless steel.

[0015] In some embodiments of this application, the drying temperature is 60 - 120 °C and the drying time is 30 - 70 min.

[0016] Within the temperature range of 60 - 120 °C, it can effectively remove the moisture in the mixture and the binder, and further reduce the possible bubbles or defects during the subsequent laser cladding process, improving the density of the coating.

[0017] In some embodiments of this application, the conditions of laser cladding include: laser power 1.2 - 2.4 kW, scanning speed 5 - 12 mm / s, spot diameter 3 - 5 mm, and overlap rate 30 - 70%.

[0018] Setting the laser power within the range of 1.2 - 2.4 kW can accelerate the melting speed, form a denser cladding layer, and also help reduce pores and cracks during the cladding process, improving the overall density of the coating. Setting the scanning speed at 5 - 12 mm / s can make the thickness of the cladding layer within the ideal range and improve the uniformity of the finally prepared coating. Setting the spot diameter at 3 - 5 mm can provide a moderate heat affected zone, improving the uniformity and strength of the cladding layer. Setting the overlap rate at 30 - 70% can effectively promote the good combination between the cladding layers, reduce local defects, enhance the continuity and overall strength of the coating, reduce the casting defects of the coating, and improve the wear and corrosion resistance.

[0019] In some embodiments of this application, the binder includes anhydrous ethanol and / or acetone.

[0020] These two solvents can improve the adhesion between the substrate and the prefabricated layer, enabling the coating to firmly adhere to the substrate during the subsequent laser cladding process and reducing the risk of coating peeling or falling off. In addition, both anhydrous ethanol and acetone are volatile solvents and can evaporate quickly. This characteristic helps to rapidly remove the excess solvent during the drying stage, reducing the defects in the coating during the drying process, such as bubbles or holes, and improving the density and uniformity of the coating.

[0021] In some embodiments of this application, the ball milling speed is 80 - 150 r / min and the ball milling time is 70 - 150 min.

[0022] Setting the ball milling speed to 80 - 150 r / min and the ball milling time to 70 - 150 min can effectively refine particles, mix them evenly, reduce agglomeration, improve fluidity, and control the thermal effect, thereby enhancing the quality and performance of the high - entropy alloy coating.

[0023] In some embodiments of the present application, during ball milling, the mass ratio of the grinding balls to the powder is (2 - 5):1.

[0024] By defining the mass ratio of the grinding balls to the powder as (2 - 5):1, the grinding efficiency can be effectively improved, wear can be controlled, the particle shape can be optimized, agglomeration can be reduced, the mixing uniformity can be improved, and the mechanical properties of the coating can be enhanced.

[0025] In some embodiments of the present application, the particle size of the powder is 45 - 80 μm.

[0026] Setting the particle size of the powder to 45 - 80 μm can effectively improve the fluidity, density, and thermal conductivity of the coating, reduce agglomeration, and enhance the mechanical properties of the coating. Brief Description of the Drawings

[0027] To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0028] Figure 1 XRD pattern of the FeCrCoMnSi x high - entropy alloy coating provided by the present application;

[0029] Figure 2 Friction coefficient change curve of the FeCrCoMnSi x high - entropy alloy coating provided by the present application under a simulated seawater environment;

[0030] Figure 3 Wear scar morphology of the FeCrCoMnSi x high - entropy alloy coating provided by the present application after annealing under a simulated seawater environment, where (a) Si0; (b) Si 0.3 ; (c) Si 0.6 ; (d) Si 0.9 ; (e) Si 1.0 ;

[0031] Figure 4SEM images of the surface morphology of FeCrCoMnSix before and after annealing: Among them, (a) FeCrCoMn; (b) FeCrCoMn annealed at 600 °C for 1 h; (c) FeCrCoMnSi 0.6 ; (d) FeCrCoMnSi 0.6 annealed at 600 °C for 1 h. Specific implementation manners

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. For those not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0033] A preparation method of a high-entropy alloy coating resistant to seawater wear and corrosion in the embodiments of this application will be specifically described below.

[0034] The embodiments of this application provide a preparation method of a high-entropy alloy coating resistant to seawater wear and corrosion, including the following steps:

[0035] Step S1: According to the chemical formula of the high-entropy alloy FeCrCoMnSi x , where x = 0.1 - 1, perform proportion calculation, and weigh elemental Fe powder, Cr powder, Co powder, Si powder, and Mn-Fe alloy powder with a purity of 99.99%; put the weighed powders into a planetary ball mill for uniform mixing and ball milling to obtain a mixture.

[0036] In this application, the chemical formula of the high-entropy alloy is FeCrCoMnSi x , where x = 0.1 - 1; as an example, the values of x include but are not limited to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0.

[0037] Among them, the particle size of the raw material powder is 45 - 80 μm.

[0038] Among them, the grinding balls are zirconia ceramic balls with a diameter of 3 mm, the mass ratio of the grinding balls to the powder is (2 - 5):1, the ball milling speed is 80 - 150 r / min, and the ball milling time is 70 - 150 min.

[0039] Step S2: Mix the mixture with an adhesive and then coat it on the substrate to form a plurality of prefabricated layers. The plurality of prefabricated layers are arranged side by side on the substrate, and then the coated substrate is dried.

[0040] Among them, the adhesive includes but is not limited to absolute ethanol and / or acetone.

[0041] Among them, the substrate includes but is not limited to 45 steel or 316 stainless steel.

[0042] In this application, the surface of the substrate needs to be polished smoothly and then put into absolute ethanol for ultrasonic cleaning to remove surface impurities.

[0043] Among them, the size of the prefabricated layer is: width 7 - 18 mm, length 50 - 70 mm, and height 2 - 4 mm. Exemplarily, the size of the prefabricated layer is a rectangle with a width of 15 mm × a length of 70 mm × a height of 2 mm. Among them, the width of the prefabricated layer includes but is not limited to 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm.

[0044] Set the width of the prefabricated layer to 7 - 18 mm and the length to 50 - 70 mm, so that the prefabricated layer is easier to control during the coating process, enabling the laser beam to evenly cover the surface of the prefabricated layer during cladding, improving the uniformity, density, and adhesion of the coating, and further improving the wear resistance and corrosion resistance of the coating. Set the height of the prefabricated layer to 2 - 4 mm, which can enable the laser energy to effectively penetrate and melt the prefabricated layer, thereby achieving better mutual combination and increasing the strength and stability of the coating.

[0045] Among them, the drying temperature is 60 - 120 °C, and the drying time is 30 - 70 min.

[0046] Under the conditions of a drying temperature of 60 - 120 °C and a drying time of 30 - 70 min, it can effectively remove moisture, maintain the adhesive properties, improve the uniformity of the prefabricated layer, reduce thermal stress, and enhance the quality and performance of the coating.

[0047] Step S3: Under an inert gas protection atmosphere, use a laser with a power greater than 2 kW to perform multi-pass laser cladding on the dried substrate coated with the prefabricated layer, forming a cladding layer on the surface of the substrate.

[0048] Exemplarily, use a fiber laser (ROFIN-FL020) for multi-pass overlapping cladding.

[0049] Among them, the laser cladding process parameters are: laser power 1.2 - 2.4 kW, scanning speed 5 - 12 mm / s, spot diameter 3 - 5 mm, and overlapping rate 30 - 70%. The inert gas includes but is not limited to argon with a purity of 99.99%.

[0050] Step S4: Anneal the substrate with the cladding layer in step S3 to obtain a high-entropy alloy coating.

[0051] Among them, use a box-type resistance furnace (SX3-1-7) to anneal the alloy specimen.

[0052] Among them, the annealing temperature is 500 - 650 °C, and the annealing time is 0.5 - 2 h.

[0053] Exemplarily, the annealing temperature includes but is not limited to 500 °C, 520 °C, 550 °C, 600 °C, 620 °C, 650 °C; the annealing time includes but is not limited to 0.5 h, 1 h, 1.5 h, 2 h.

[0054] By controlling the annealing temperature within the range of 500 - 650 °C and the time within the range of 0.5 - 2 h, the material atoms can obtain sufficient energy to promote their migration, thereby filling defects and reducing the inhomogeneity of the phase interface, and effectively reducing defects such as pores, microcracks, and segregation in the coating. Moreover, annealing can also improve the densification of the coating, enhance the stability of the interface, reduce the permeability of the coating, and thus improve the corrosion resistance. During the annealing process, the surface roughness of the coating will also be improved. The reduced surface roughness not only reduces friction and wear but also improves the wear resistance of the coating. At the same time, by controlling the annealing temperature and time within the above range, the diffusion efficiency between elemental atoms can be significantly improved, the content of solid solution can be enhanced, the diffraction peak intensity of the BCC phase increases, and thus the mechanical properties of the coating are improved. In addition, annealing can also release the residual stress inside the coating, reduce stress concentration, and promote the uniformity of the microstructure. As the annealing process progresses, the resistance of the coating will also increase, and the capacitance characteristics become more stable, thereby improving the seawater corrosion resistance of the coating.

[0055] The features and properties of the present application will be further described in detail below in conjunction with the embodiments.

[0056] Example 1

[0057] This example provides a high-entropy alloy coating resistant to seawater wear and corrosion, and its preparation method includes the following steps:

[0058] S1. According to the chemical formula of the high-entropy alloy FeCrCoMnSi x , with x = 0.6, perform proportion calculation, and use an electronic balance (JJ1000Y, accuracy 0.01 g) to weigh elemental Fe powder, Cr powder, Co powder, Si powder, and Mn-Fe alloy powder with a purity of 99.99% and a particle size of 70 μm; put the prepared powder into a planetary ball mill for uniform mixing. The grinding balls are zirconia ceramic balls with a diameter of 3 mm, the ball-powder ratio is 3:1, the rotational speed of the ball mill is 120 r / min, and the ball milling time is 140 min to obtain a mixture.

[0059] S2. The selected substrate is 45 steel. The substrate is cut into specimens with dimensions of 70×30×8 mm using wire cutting (DK7745), and the surface of the substrate is polished smooth with sandpaper. Subsequently, it is placed in absolute ethanol and ultrasonically cleaned to remove surface impurities. The mixture in step S1 is mixed with absolute ethanol and then coated on the 45-steel specimen to form multiple prefabricated layers. The multiple prefabricated layers are distributed side by side on the 45-steel specimen, and the formed prefabricated layer is a rectangle with a width of 15 mm × a length of 70 mm × a height of 2 mm. Subsequently, the coated substrate is dried at 120 °C for 180 min.

[0060] S3. Under an argon atmosphere, the dried 45-steel specimen coated with prefabricated layers in step S2 is subjected to multi-pass overlapping cladding using a fiber laser (ROFIN-FL020) to form a cladding layer on the surface of the 45-steel specimen. Among them, the laser process parameters are: laser power is 1600 W, scanning speed is 10 mm / s, spot diameter is 4 mm, and overlapping rate is 45%.

[0061] S4. The 45-steel specimen with the cladding layer in step S3 is annealed at 600 °C for 1 h using a fully fiber energy-saving box-type resistance furnace (SX3-1-7) to obtain a high-entropy alloy coating resistant to seawater wear and corrosion.

[0062] Example 2

[0063] This example is basically the same as Example 1, except that the annealing time is 0.5 h.

[0064] Example 3

[0065] This example is basically the same as Example 1, except that the annealing time is 2 h.

[0066] Example 4

[0067] This example is basically the same as Example 1, except that the annealing temperature is 400 °C.

[0068] Example 5

[0069] This example is basically the same as Example 1, except that the annealing temperature is 500 °C.

[0070] Example 6

[0071] This example is basically the same as Example 1, except that the annealing temperature is 700 °C.

[0072] Example 7

[0073] This example is basically the same as Example 1, except that the width of each coated prefabricated layer is 7 mm.

[0074] Example 8

[0075] This embodiment is basically the same as Embodiment 1, except that: the width of each prefabricated layer coated is 10 mm.

[0076] Embodiment 9

[0077] This embodiment is basically the same as Embodiment 1, except that: the width of each prefabricated layer coated is 20 mm.

[0078] Embodiment 10

[0079] This embodiment is basically the same as Embodiment 1, except that: in step S1, according to the chemical formula of the high-entropy alloy FeCrCoMnSi x , x = 0.3, perform proportioning calculation, weigh elemental Fe powder, Cr powder, Co powder, Si powder with a purity of 99.99%, and Mn-Fe alloy powder; put the weighed powders into a planetary ball mill for uniform mixing and ball milling to obtain a mixture.

[0080] Embodiment 11

[0081] This embodiment is basically the same as Embodiment 1, except that: in step S1, according to the chemical formula of the high-entropy alloy FeCrCoMnSi x , x = 0.9, perform proportioning calculation, weigh elemental Fe powder, Cr powder, Co powder, Si powder with a purity of 99.99%, and Mn-Fe alloy powder; put the weighed powders into a planetary ball mill for uniform mixing and ball milling to obtain a mixture.

[0082] Embodiment 12

[0083] This embodiment is basically the same as Embodiment 1, except that: in step S1, according to the chemical formula of the high-entropy alloy FeCrCoMnSi x , x = 1.0, perform proportioning calculation, weigh elemental Fe powder, Cr powder, Co powder, Si powder with a purity of 99.99%, and Mn-Fe alloy powder; put the weighed powders into a planetary ball mill for uniform mixing and ball milling to obtain a mixture.

[0084] Comparative Example 1

[0085] This comparative example is basically the same as Embodiment 1, except that: in step S1, according to the chemical formula of the high-entropy alloy FeCrCoMn, perform proportioning calculation, weigh elemental Fe powder, Cr powder, Co powder, Si powder with a purity of 99.99%, and Mn-Fe alloy powder; put the weighed powders into a planetary ball mill for uniform mixing and ball milling to obtain a mixture.

[0086] Comparative Example 2

[0087] This comparative example is basically the same as Example 1, except that: annealing treatment is not carried out.

[0088] This comparative example provides a high-entropy alloy coating resistant to seawater erosion-corrosion, and its preparation method includes the following steps:

[0089] S1. According to the chemical formula of the high-entropy alloy FeCrCoMnSi x , x = 0.6, perform proportioning calculations, and use an electronic balance (JJ1000Y, with a precision of 0.01 g) to weigh elemental Fe powder, Cr powder, Co powder, Si powder, and Mn-Fe alloy powder with a purity of 99.99% and a particle size of 70 μm; put the prepared powder into a planetary ball mill for uniform mixing, the grinding balls are zirconia ceramic balls with a diameter of 3 mm, the ball-to-powder ratio is 3:1, the rotation speed of the ball mill is 120 r / min, and the ball milling time is 140 min to obtain a mixed material.

[0090] S2. The selected substrate is 45 steel. Use wire cutting (DK7745) to cut the substrate into specimens with dimensions of 70×30×8 mm, and polish the surface of the substrate with sandpaper until smooth. Then put it into absolute ethanol for ultrasonic cleaning to remove surface impurities; mix the mixed material in step S1 with absolute ethanol and then coat it on the 45 steel specimen to form multiple prefabricated layers. The multiple prefabricated layers are arranged side by side on the 45 steel specimen, and the formed prefabricated layer is a rectangle with a width of 15 mm×a length of 70 mm×a height of 2 mm; then dry the coated substrate at 120 °C for 180 min.

[0091] S3. Under an argon atmosphere, use a fiber laser (ROFIN-FL020) to perform multi-pass overlapping cladding on the dried 45 steel specimen coated with the prefabricated layer in step S2 to obtain a high-entropy alloy coating resistant to seawater erosion-corrosion; among them, the laser process parameters are: laser power is 1600 W, scanning speed is 10 mm / s, spot diameter is 4 mm, and overlapping rate is 45%.

[0092] For the partial parameters of the above examples and comparative examples, please refer to Table 1 for details.

[0093] Table 1

[0094]

[0095]

[0096] Test Example 1

[0097] This test example tested the grain size and hardness of the high-entropy alloy coatings prepared in Examples 1-6, and the test result data are shown in Table 2.

[0098] Table 2

[0099] Group Annealing Treatment Conditions Average Hardness (HV) Grain Size (μm) Example 1 600℃ / 1h 314.20 8.30 Example 2 600°C / 30 min 306.48 8.57 Example 3 600℃ / 2h 308.27 11.30 Example 4 400℃ / 1h 295.85 9.46 Example 5 500℃ / 1h 296.38 9.33 Example 6 700℃ / 1h 294.63 11.17

[0100] As can be seen from Table 2, the grains of the coating prepared within the annealing temperature range of 500 - 650 °C and annealing time of 0.5 - 2 h defined in this application are finer and the hardness is higher; in particular, the finest grains and the highest hardness are obtained under the conditions of an annealing temperature of 600 °C and an annealing time of 1 h.

[0101] Test Example 2

[0102] In this test example, the hardness, wear resistance and corrosion resistance of the high-entropy alloy coatings prepared in Examples 1, 7 - 9 were studied and analyzed, including average hardness, friction coefficient, wear rate, electrode potential E and current density I corr , and the above test results are shown in Table 3.

[0103] Table 3

[0104]

[0105] It can be seen from the data in Table 3 that the coatings prepared within the prefabricated layer width range of 8 - 18 mm defined in this application have better corrosion resistance.

[0106] Test Example 3

[0107] I. The crystal phase structure of the high-entropy alloy coatings prepared in Examples 1, 10 - 12 and Comparative Example 1 was detected. The XRD patterns of the FeCrCoMnSi x high-entropy alloy coatings provided by this application are as Figure 1 shown.

[0108] As can be seen from Figure 1 , no new phase precipitation was found in the phase structure of the coating after annealing treatment at different Si contents, and the crystal orientation did not change. At the same time, in Figure 1 , it was observed that after annealing treatment, the diffraction intensities of the BCC phase and the hard metal silicide phase in the coating with the addition of Si element increased significantly. It is analyzed that firstly, the heat treatment improved the diffusion efficiency between elemental atoms, thus enhancing the content of the solid solution and resulting in an increase in the diffraction peak intensity of the BCC phase; in addition, there is a relatively negative mixing entropy between Si element and Mn, Cr elements, which has a strong attraction, causing more metal elements to combine with Si to form silicides, thus enhancing the diffraction peak intensity of the hard metal silicide.

[0109] II. The hardness of the FeCrCoMnSi x (x = 0, 0.3, 0.6, 0.9, 1.0) high-entropy alloy coatings provided by this application was measured. The hardness of the coatings prepared by two processes of annealing treatment and non-annealing treatment was tested respectively, and the hardness test results of the above coatings are shown in Table 4.

[0110] Table 4

[0111]

[0112] Note: The room temperature in Table 4 is the average hardness of the high-entropy alloy coating prepared under the condition of not performing annealing treatment.

[0113] As can be seen from Table 4, after annealing treatment, the hardness change trend of the coating is still to increase first and then decrease with the increase of Si element. When Si 0.6 is present, the coating has the highest hardness, which is 551.3 HV. However, by comparing the data before and after heat treatment in Table 4, it can be clearly seen that annealing treatment overall increases the hardness of the coating, and the hardness of the Si-containing coatings all increases significantly after annealing treatment. Among them, when Si 0.3 is present, the hardness change is the most obvious, and the hardness is increased by 36.723% compared with the coating without heat treatment. Since heat treatment promotes the full diffusion of elemental atoms, a part of the Si atoms with smaller atomic radii are dissolved as interstitial atoms in the solid solution, enhancing the lattice distortion effect and producing significant solid solution strengthening; while another part of the Si atoms are easy to form hard metal silicides with other metal atoms, playing a second-phase strengthening effect. Under the synergistic action of the two, the hardness of the coating is improved.

[0114] III. The corrosion resistance of the FeCrCoMnSi x (x = 0, 0.3, 0.6, 0.9, 1.0) high-entropy alloy coatings prepared by annealing treatment and without annealing treatment in a simulated seawater environment, including the friction coefficient and wear rate, are tested. The test results are shown in Table 5. Figure 2 This is the friction coefficient change curve of the FeCrCoMnSi x high-entropy alloy coating provided by this application in a simulated seawater environment.

[0115] Table 5

[0116]

[0117] Note: The room temperature in Table 5 is the test result of the high-entropy alloy coating prepared under the condition of not performing annealing treatment.

[0118] As can be seen from Table 5, in this environment, the friction coefficient and wear rate of the coating after annealing treatment decrease more significantly. When Si 0.6 is present, the coating still has the lowest friction coefficient and wear rate, which are 0.1524 and 2.2268×10 5 mm 3 / N·m respectively. Compared with the coating without heat treatment, the two are reduced by 24.592% and 45.151% respectively. This is because first, annealing treatment reduces defects such as pores, microcracks and segregation (such asFigure 4 As shown in the figure, it improves the compactness of the tissue and the stability of the interface, and reduces the surface roughness of the coating. Secondly, the hardness of the coating increases significantly after heat treatment, enhancing the coating's ability to resist deformation, thereby reducing the friction coefficient and wear rate of the coating. In addition, from Figure 2 it can be seen that the friction coefficient of the coating shows large fluctuations at Si 0.9 and Si 1.0 . This may be due to the chemical corrosion of the coating in 3.5% NaCl solution, resulting in the formation of irregular corrosion pits on the coating surface, which in turn affects the stability of the friction coefficient.

[0119] Figure 3 This is the wear scar morphology of the FeCrCoMnSi x high-entropy alloy coating under the simulated seawater environment after annealing provided by this application, where: (a) Si0; (b) Si 0.3 ; (c) Si 0.6 ; (d) Si 0.9 ; (e) Si 1.0 ; First, from Figure 3 (a), it can be seen that there are deep and numerous plough grooves on the worn surface of Si0, and there are also a small number of corrosion pits. At this time, the wear mechanism is mainly abrasive wear and corrosive oxidation wear. Figure 3 From (b)-(e), it can be seen that after adding Si element, the number of plough grooves on the worn surface of the coating decreases significantly. Among them, when Si 0.6 , there are only shallow plough grooves and slight corrosion pits on the worn surface, showing excellent corrosion and wear resistance. In addition, when Si 0.9 and Si 1.0 , a large amount of oxide accumulation and a large number of corrosion pits are found on the worn surface of the coating, and there are cracks in the wear scar area, which is also one of the important reasons for the fluctuation of the friction coefficient; moreover, the oxidation phenomenon on the worn surface of Si 1.0 is significantly reduced compared with the unheat-treated coating, which further indicates that the antioxidant ability of the coating after annealing is greatly improved.

[0120] The specific corrosion kinetic parameters and impedance spectrum parameters of the FeCrCoMnSi x (x = 0, 0.3, 0.6, 0.9, 1.0) high-entropy alloy coating prepared by annealing provided by this application are shown in Table 6.

[0121] Table 6

[0122]

[0123] It can be seen from the data in Table 6 that after annealing treatment, the corrosion potential of the coatings with different Si contents increases, and the corrosion current density decreases significantly. This indicates that after annealing treatment, the corrosion tendency of the coatings becomes weaker, the corrosion rate slows down, and the corrosion resistance is improved. This may be because annealing treatment releases the residual stress inside the coatings, reduces stress concentration, and thus reduces the possibility of corrosion of the coatings. It is also observed from Table 6 that when Si 0.6 is present, the self-corrosion current density of the coating decreases by one order of magnitude compared with the coating without heat treatment (1.1484×10 -6 A·cm 2 ), indicating that the coating has good electrochemical corrosion resistance at this time. This means that the surface activity of the Si 0.6 coating after annealing treatment is low, and the corrosion resistance is the best.

[0124] In addition, it can be observed from the impedance spectrum data that after annealing treatment, the radius of the capacitive reactance arc, the phase angle CPE-P in the low-frequency region, and the impedance modulus value of the coating are all improved. This is because annealing treatment promotes the uniformity of the coating microstructure. From an electrochemical perspective, a uniform microstructure will increase the resistance to ion diffusion in the coating, increase the resistance of the coating, and make the capacitance characteristics more stable, thus improving the corrosion resistance of the coating. It can be seen from the resistance impedance fitting data in Table 6 that the Si 0.6 coating has a high charge transfer resistance R p and the lowest CPE value, which further indicates that the S i0.6 coating after annealing treatment has excellent electrochemical characteristics.

[0125] Table 7 shows the corrosion protection efficiency of FeCrCoMnSi x (x = 0, 0.3, 0.6, 0.9, 1.0) high-entropy alloy coatings before and after annealing treatment.

[0126] Table 7

[0127]

[0128] Note: The room temperature in Table 7 is the test result of the high-entropy alloy coating prepared under the condition of not performing annealing treatment.

[0129] It can be seen from the data in Table 7 that the FeCrCoMnSi x high-entropy alloy coating provided by this application has a high corrosion protection efficiency. After annealing treatment, the overall protection efficiency increases, and it reaches 94.17% when Si 0.6 is present, which can effectively play a role in corrosion protection.

[0130] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of this application claimed, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.

Claims

1. A method for preparing a high entropy alloy coating resistant to seawater wear and corrosion, characterized in that: include: According to the chemical formula of high entropy alloy FeCrCoMnSi x Perform ratio calculation and weigh Fe, Cr, Co, Si and Mn-Fe alloy powders, x = 0.1-1; The weighed powders are mixed and ball-milled to obtain a mixture; The mixed material is mixed with a binder and then coated on a substrate to form a plurality of prefabricated layers, wherein the plurality of prefabricated layers are arranged in parallel on the substrate, and then the coated substrate is dried; In an inert gas protective atmosphere, the dried substrate coated with the prefabricated layer is subjected to multiple laser cladding using a laser with a power greater than 2 kW to form a cladding layer on the surface of the substrate; Then, an annealing treatment is performed to obtain the high entropy alloy coating.

2. The preparation method according to claim 1, characterized in that: The chemical formula of the high entropy alloy is FeCrCoMnSi x , where x = 0.1-0.

6.

3. The preparation method according to claim 1, characterized in that: The temperature of the annealing treatment is 500-650° C., and the time of the annealing treatment is 0.5-2 h.

4. The preparation method according to any one of claims 1 to 3, characterized in that The dimensions of the prefabricated layer are: 8-18 mm in width, 50-70 mm in length and 2-4 mm in height.

5. The preparation method according to any one of claims 1 to 3, characterized in that: The substrate includes 45 steel or 316 stainless steel.

6. The preparation method according to any one of claims 1 to 3, characterized in that: The drying temperature is 60-120° C., and the drying time is 30-70 min.

7. The preparation method according to any one of claims 1 to 3, characterized in that: The conditions of the laser cladding include: The laser power is 1.2-2.4 kW, the scanning speed is 5-12 mm / s, the spot diameter is 3-5 mm and the overlap rate is 30-70%.

8. The preparation method according to any one of claims 1 to 3, characterized in that: The adhesive comprises anhydrous ethanol and / or acetone.

9. The preparation method according to any one of claims 1 to 3, characterized in that: The ball milling speed is 80-150 r / min, and the ball milling time is 70-150 min.

10. The preparation method according to claim 9, characterized in that: In the ball mill, the mass ratio of grinding balls to powder is (2-5):1; Optionally, the powder has a particle size of 45-80 μm.

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