A high entropy alloy friction-reducing and wear-resistant coating prepared by arc cladding and a method thereof

Abstract

The invention discloses a method for preparing a high entropy alloy anti-friction and wear-resistant coating by arc cladding, characterized in that the method comprises the following steps: step 1, mixing high entropy alloy powder with ethanol solution to obtain a suspension; step 2, grinding and cleaning the surface of the substrate; step 3, applying the suspension on the surface of the substrate multiple times to form a coating; step 4, preheating the substrate by electric arc; step 5, arc cladding the substrate under an inert protective atmosphere; step 6, repeating steps 3 to 5 multiple times; the invention also discloses a high entropy alloy anti-friction and wear-resistant coating. The method of the invention adopts a high entropy alloy powder suspension as a coating material, realizes the combination of the coating and the substrate by arc cladding, and adjusts the thickness and improves the bonding strength by adjusting the number of cladding times, so as to obtain a high entropy alloy anti-friction and wear-resistant coating with a low friction coefficient and excellent wear resistance under long-term service conditions, which is suitable for the field of surface modification and coating technology.

Description

Technical Field

[0001] The invention belongs to the technical field of surface modification and coating, and in particular relates to a high entropy alloy friction-reducing and wear-resistant coating prepared by arc cladding and a method thereof. Background Art

[0002] Titanium and titanium alloys are widely used in aviation, aerospace, navigation, biomedicine and other fields due to their low density, high strength and excellent corrosion resistance. However, titanium and titanium alloys have low hardness and high friction coefficient. Due to the particularity of their use environment, the surface of titanium and titanium alloys is easily affected by friction and wear, resulting in reduced dimensional accuracy, which in turn affects their service life and performance.

[0003] High entropy alloy is a new type of alloy material obtained in recent years by introducing "chemical disorder" through the mixing of multiple main elements. It is composed of multiple equal or approximately equal elements as the main components to form a material different from traditional alloys. This diversity not only gives high entropy alloys the characteristics of high strength and high hardness, but also makes them excellent in wear resistance, and is expected to become a wear-resistant coating material for titanium and titanium alloys.

[0004] In the prior art, conventional surface coating processes such as vapor deposition, coating, and ion implantation are generally used to improve the surface properties of titanium and titanium alloys by increasing the surface hardness. However, the uniformity of the coating cannot be guaranteed, the coating is easy to fall off during use, and it is difficult to maintain the wear resistance of titanium and titanium alloys for a long time. Therefore, it is urgent to develop a method for preparing a high entropy alloy coating that maintains wear resistance and has an excellent friction coefficient under service conditions. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and provide a method for preparing a high-entropy alloy anti-friction and wear-resistant coating by arc cladding. The preparation method can be evenly distributed on the surface of a substrate by using a suspension of high-entropy alloy powder as a coating material, and the metallurgical bonding of the coating and the substrate is achieved by using an arc cladding method. At the same time, by adjusting the number of arc cladding times, the thickness of the high-entropy alloy anti-friction and wear-resistant coating is adjusted and the bonding strength between the high-entropy alloy anti-friction and wear-resistant coating and the substrate is improved, which solves the problem that the prior art cannot ensure the uniformity of the coating on the substrate surface, and it is difficult to maintain the wear resistance and friction coefficient of the coating under service conditions for a long time.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a high entropy alloy friction-reducing and wear-resistant coating by arc cladding, characterized in that the preparation method comprises the following steps:

[0007] Step 1: Evenly mix the high entropy alloy powder and the ethanol solution to obtain a suspension;

[0008] Step 2: Grinding and cleaning the surface of the substrate; the surface roughness of the substrate after grinding is not greater than Ra1.6;

[0009] Step 3, applying the suspension obtained in step 1 evenly on the surface of the substrate cleaned in step 2 for multiple times to form a coating;

[0010] Step 4: preheating the substrate after the coating is formed in step 3 by using an electric arc;

[0011] Step 5: arc cladding the substrate preheated in step 4 under an inert protective atmosphere;

[0012] Step 6: Repeat steps 3 to 5 multiple times to obtain a high entropy alloy friction-reducing and wear-resistant coating.

[0013] The present invention controls the surface roughness of the substrate to be no greater than Ra1.6, and the smooth substrate surface can improve the uniformity and density of the coating after adhesion; by mixing high entropy alloy powder with ethanol solution and then coating the mixture on the substrate surface, it avoids direct arc cladding to cause powder scattering and polluting the environment, and at the same time, ethanol is completely volatilized before arc cladding, which will not affect the performance of the substrate itself.

[0014] The above-mentioned method for preparing a high-entropy alloy friction-reducing and wear-resistant coating by arc cladding is characterized in that the particle size of the high-entropy alloy powder in step one is not greater than 100µm.

[0015] The above-mentioned method for preparing a high-entropy alloy friction-reducing and wear-resistant coating by arc cladding is characterized in that the volume concentration of the ethanol solution in step one is 60%~95%.

[0016] The above-mentioned method for preparing a high-entropy alloy friction-reducing and wear-resistant coating by arc cladding is characterized in that the coating thickness in step three is 0.1 mm to 1.2 mm.

[0017] The present invention adjusts the thickness of a single coating by adjusting the concentration of the ethanol solution and the number of times the suspension is coated. The higher the concentration of the ethanol solution, the greater the thickness of the coating in a single coating.

[0018] The above-mentioned method for preparing a high-entropy alloy friction-reducing and wear-resistant coating by arc cladding is characterized in that the preheating temperature in step 4 is 100°C~500°C, and the preheating time is 5s~30s.

[0019] The present invention preheats the titanium and titanium alloy substrate coated with the coating to allow ethanol to evaporate quickly and increase the substrate temperature, thereby avoiding the problem that the coating has a high liquid content due to excessive cooling of the substrate, and can flow freely on the substrate surface, resulting in insufficient and uneven adhesion of the coating on the substrate surface.

[0020] The above-mentioned method for preparing a high-entropy alloy friction-reducing and wear-resistant coating by arc cladding is characterized in that the inert protective atmosphere in step five is argon.

[0021] The above-mentioned method for preparing a high-entropy alloy friction-reducing and wear-resistant coating by arc cladding is characterized in that the parameters of the arc cladding in step five are: power 1800kW~3400kW, scanning speed 40mm / min~200mm / min.

[0022] In addition, the present invention also discloses a high entropy alloy friction-reducing and wear-resistant coating prepared by arc cladding, characterized in that it is obtained by the preparation method of the above claims.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The present invention adopts a suspension of high entropy alloy powder as a coating material, so that the high entropy alloy powder can be evenly distributed on the surface of the substrate. The high entropy alloy powder in the coating completely covers the surface of the substrate by coating for multiple times. An arc cladding method is used to achieve metallurgical bonding between the coating and the substrate. The thickness of the high entropy alloy anti-friction and wear-resistant coating is adjusted by adjusting the number of arc cladding times. Multiple arc claddings help to make the high entropy alloy anti-friction and wear-resistant coating more firmly bonded to the substrate, so that the high entropy alloy anti-friction and wear-resistant coating does not fall off under long-term service conditions.

[0025] 2. The present invention adopts high-hardness, wear-resistant high-entropy alloy as the coating material for titanium and titanium alloys, so as to obtain a smooth high-entropy alloy anti-friction and wear-resistant coating, thereby reducing the friction coefficient of titanium and titanium alloys. The high-entropy alloy anti-friction and wear-resistant coating also has corrosion resistance, thereby improving the service life of titanium and titanium alloys.

[0026] 3. The present invention prepares a high entropy alloy powder suspension by using an ethanol solution, and arc cladding is performed after the suspension is coated and the substrate is preheated, thereby avoiding the high entropy alloy powder from scattering, causing material loss and environmental pollution. At the same time, the ethanol is completely volatilized after preheating and will not affect the performance of the substrate itself.

[0027] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a test result diagram of the friction coefficient of the substrate in Example 1 of the present invention.

[0029] Figure 2 This is a graph showing the test results of the friction coefficient of the high entropy alloy anti-friction and wear-resistant coating prepared in Example 1 of the present invention.

[0030] Figure 3This is a graph showing the test results of the friction coefficient of the substrate in Example 2 of the present invention.

[0031] Figure 4 This is a graph showing the test results of the friction coefficient of the high entropy alloy anti-friction and wear-resistant coating prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0032] Example 1

[0033] The preparation method of this embodiment comprises the following steps:

[0034] Step 1: Evenly mix FeCr0.5NiCu0.5Co0.5 powder and 60% ethanol solution to obtain a suspension;

[0035] Step 2: Grind and clean the surface of the TC4 substrate; the surface roughness of the substrate after grinding is not greater than Ra1.6;

[0036] Step 3: spray the suspension obtained in step 1 evenly twice on the surface of the TC4 substrate washed in step 2 to form a coating with a thickness of 0.1 mm;

[0037] Step 4: preheating the TC4 substrate after the coating is formed in step 3 at 100° C. for 30 seconds using an electric arc;

[0038] Step 5: arc cladding the TC4 substrate preheated in step 4 under an argon atmosphere; the parameters of the arc cladding are: power 1800 kW, scanning speed 40 mm / min;

[0039] Step 6: Repeat steps 3 to 5 to obtain a high-entropy alloy anti-friction and wear-resistant coating with a thickness of 0.2 mm.

[0040] The friction coefficient of the TC4 substrate and the high entropy alloy anti-friction and wear-resistant coating prepared in this embodiment were tested respectively. The results are as follows: Figure 1 and Figure 2 As shown, the friction coefficient of the TC4 substrate is much greater than that of the high entropy alloy anti-friction and wear-resistant coating and has a strong volatility, indicating that the high entropy alloy anti-friction and wear-resistant coating prepared in this embodiment can effectively reduce the friction coefficient and surface roughness of the substrate.

[0041] After testing, it is found that the high-entropy alloy anti-friction and wear-resistant coating prepared in this embodiment has good interface bonding with the substrate, and the wear resistance is improved by 50% after the high-entropy alloy anti-friction and wear-resistant coating is attached.

[0042] The high entropy alloy anti-friction and wear-resistant coating prepared in this embodiment was electrochemically tested in a NaCl solution with a mass concentration of 3.5%. The results showed that the corrosion current density was less than 5.271×10 -8 mA / cm 2, corrosion resistance is better than 316L stainless steel.

[0043] Example 2

[0044] The difference between this embodiment and embodiment 1 is that the FeCrNiCu0.5 powder is evenly mixed with an ethanol solution having a volume concentration of 60% to obtain a suspension.

[0045] The friction coefficient of the TC4 substrate and the high entropy alloy anti-friction and wear-resistant coating prepared in this embodiment were tested respectively. The results are as follows: Figure 3 and Figure 4 As shown, the friction coefficient of the TC4 substrate is much greater than that of the high entropy alloy anti-friction and wear-resistant coating and has a strong volatility, indicating that the high entropy alloy anti-friction and wear-resistant coating prepared in this embodiment can effectively reduce the friction coefficient of the substrate.

[0046] After testing, it is found that the high-entropy alloy anti-friction and wear-resistant coating prepared in this embodiment has good interface bonding with the substrate, and the wear resistance is improved by 80% after the high-entropy alloy anti-friction and wear-resistant coating is attached.

[0047] The high entropy alloy anti-friction and wear-resistant coating prepared in this embodiment was electrochemically tested in a NaCl solution with a mass concentration of 3.5%. The results showed that the corrosion current density was less than 5.271×10 -8 mA / cm 2 , corrosion resistance is better than 316L stainless steel.

[0048] Example 3

[0049] The difference between this embodiment and embodiment 1 is that the preheating temperature in step 4 is 500° C. and the preheating time is 5 s.

[0050] After testing, the high-entropy alloy anti-friction and wear-resistant coating prepared in this embodiment has good interface bonding with the substrate, and the friction coefficient after the high-entropy alloy anti-friction and wear-resistant coating is attached is 0.38, and the wear resistance is improved by 70%.

[0051] The high entropy alloy anti-friction and wear-resistant coating prepared in this embodiment was electrochemically tested in a NaCl solution with a mass concentration of 3.5%. The results showed that the corrosion current density was less than 5.271×10 -8 mA / cm 2 , corrosion resistance is better than 316L stainless steel.

[0052] Example 4

[0053] The difference between this embodiment and embodiment 1 is that in step 5, the arc cladding power is 3400 kW and the scanning speed is 200 mm / min.

[0054] After testing, the high-entropy alloy anti-friction and wear-resistant coating prepared in this embodiment has good interface bonding with the substrate, and the friction coefficient after the high-entropy alloy anti-friction and wear-resistant coating is attached is 0.37, and the wear resistance is improved by 50%.

[0055] The high entropy alloy anti-friction and wear-resistant coating prepared in this embodiment was electrochemically tested in a NaCl solution with a mass concentration of 3.5%. The results showed that the corrosion current density was less than 5.271×10 -8 mA / cm 2 , corrosion resistance is better than 316L stainless steel.

[0056] Example 5

[0057] The difference between this embodiment and embodiment 1 is that: in step 1, the FeCr0.5NiCu0.5Co0.5 powder is evenly mixed with an ethanol solution with a volume concentration of 95%; in step 3, the coating is applied by brushing, and the coating is applied multiple times to obtain a coating with a thickness of 1.2 mm.

[0058] After testing, the high-entropy alloy anti-friction and wear-resistant coating prepared in this embodiment has good interface bonding with the substrate, and the friction coefficient after the high-entropy alloy anti-friction and wear-resistant coating is attached is 0.37, and the wear resistance is improved by 50%.

[0059] The high entropy alloy anti-friction and wear-resistant coating prepared in this embodiment was electrochemically tested in a NaCl solution with a mass concentration of 3.5%. The results showed that the corrosion current density was less than 5.271×10 -8 mA / cm 2 , corrosion resistance is better than 316L stainless steel.

[0060] Example 6

[0061] The preparation method of this embodiment comprises the following steps:

[0062] Step 1: Evenly mix FeCr0.5NiCu0.5Co0.5 powder and 75% ethanol solution to obtain a suspension;

[0063] Step 2: Grind and clean the surface of the TC4 substrate; the surface roughness of the substrate after grinding is not greater than Ra1.6;

[0064] Step 3: spray the suspension obtained in step 1 evenly twice on the surface of the TC4 substrate washed in step 2 to form a coating with a thickness of 0.6 mm;

[0065] Step 4: preheating the TC4 substrate after the coating is formed in step 3 at 350° C. for 25 seconds using an electric arc;

[0066] Step 5: arc cladding the TC4 substrate preheated in step 4 under an argon atmosphere; the parameters of the arc cladding are: power 2800 kW, scanning speed 100 mm / min;

[0067] Step 6: Repeat steps 3 to 5 to obtain a high-entropy alloy anti-friction and wear-resistant coating with a thickness of 1.2 mm.

[0068] After testing, the high-entropy alloy anti-friction and wear-resistant coating prepared in this embodiment has good interface bonding with the substrate, and the friction coefficient after the high-entropy alloy anti-friction and wear-resistant coating is attached is 0.39, and the wear resistance is improved by 60%.

[0069] The high entropy alloy anti-friction and wear-resistant coating prepared in this embodiment was electrochemically tested in a NaCl solution with a mass concentration of 3.5%. The results showed that the corrosion current density was less than 5.271×10 -8 mA / cm 2 , corrosion resistance is better than 316L stainless steel.

[0070] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a high entropy alloy friction-reducing and wear-resistant coating by arc cladding, characterized in that: The method comprises the following steps: Step 1, uniformly mixing high entropy alloy powder and ethanol solution to obtain a suspension; the high entropy alloy powder is FeCr0.5NiCu0.5Co0.5 powder or FeCrNiCu0.5 powder; Step 2: Grinding and cleaning the surface of the substrate; the surface roughness of the substrate after grinding is not greater than Ra1.6; the substrate is titanium or titanium alloy; Step 3, the suspension obtained in step 1 is uniformly coated on the surface of the substrate cleaned in step 2 for multiple times to form a coating; the coating thickness is 0.1 mm to 1.2 mm; Step 4: preheating the substrate after the coating is formed in step 3 by using an electric arc; Step 5: arc cladding the substrate preheated in step 4 under an inert protective atmosphere; Step 6: Repeat steps 3 to 5 multiple times to obtain a high entropy alloy friction-reducing and wear-resistant coating.

2. The method for preparing a high entropy alloy friction-reducing and wear-resistant coating by arc cladding according to claim 1, characterized in that: The particle size of the high entropy alloy powder in step 1 is not greater than 100 μm.

3. The method for preparing a high entropy alloy friction-reducing and wear-resistant coating by arc cladding according to claim 1, characterized in that: The volume concentration of the ethanol solution in step 1 is 60% to 95%.

4. The method for preparing a high entropy alloy friction-reducing and wear-resistant coating by arc cladding according to claim 1, characterized in that: The preheating temperature in step 4 is 100° C. to 500° C., and the preheating time is 5s to 30s.

5. The method for preparing a high entropy alloy friction-reducing and wear-resistant coating by arc cladding according to claim 1, characterized in that: The inert protective atmosphere in step 5 is argon.

6. The method for preparing a high entropy alloy friction-reducing and wear-resistant coating by arc cladding according to claim 1, characterized in that: The parameters of the arc cladding in step five are: power 1800kW~3400kW, scanning speed 40mm / min~200mm / min.

7. A high entropy alloy friction-reducing and wear-resistant coating prepared by arc cladding, characterized in that: Obtained by the method described in any one of claims 1 to 6.

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