Preparation method of CrFeNiAlTi-Cu high-entropy alloy coating

Abstract

The present invention relates to a preparation method of a CrFeNiAlTi-Cu high-entropy alloy coating, and the method comprises the following steps: (1) cleaning a metal substrate first, then performing roughening treatment, and then performing ultrasonic cleaning to obtain a treated metal substrate; (2) mixing 10-30 wt.% of spherical Cu powder and the balance of spherical CrFeNiAl 0.3 Ti 0.3 powders evenly in a planetary ball mill to obtain a sprayed composite powder; (3) adopting an explosion spraying technique, first spraying NiCrAlY powder on the surface of the treated metal substrate to obtain a NiCrAlY transition layer; then spraying the sprayed composite powder on the surface of the NiCrAlY transition layer to obtain a CrFeNiAl 0.3 Ti 0.3 -Cu high-entropy alloy coating. The present invention is simple and easy to operate, the process is controllable, and the cost is low. The prepared CrFeNiAl 0.3 Ti 0.3 -Cu high-entropy alloy coating has good performance and is applicable to key mechanical systems in a marine environment, such as moving transmission components like bearings, bushings, rotating shafts, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of marine wear-resistant coating materials, and particularly to a preparation method of a CrFeNiAlTi-Cu high-entropy alloy coating. Background Art

[0002] High-end marine engineering equipment is a key means for humans to explore and develop marine resources. Marine new materials are the material basis for the innovative development of marine engineering equipment. In a marine environment, many key moving and transmission components of engineering equipment, such as pumps, bearings, valves, propellers, gears, seals, etc., often face the interactive damage of wear and corrosion, which has a great impact on the service safety and life of the equipment. Therefore, developing advanced surface coating materials and technologies is one of the most effective ways to solve the problems of wear and corrosion of moving and transmission components in a marine environment.

[0003] High bonding strength, low porosity, and excellent lubrication, wear resistance, and corrosion resistance are the key performance indicators for evaluating the quality of coatings used in a marine environment. Therefore, how to obtain high-quality coatings from two aspects of component design and spraying process optimization is a technical difficulty in this field. In recent years, novel high-entropy alloys (HEAs) have brought new opportunities for designing and preparing high-performance coating materials for a marine environment due to their new alloying design concept and broad composition and microstructure regulation space, which have achieved the improvement of comprehensive properties such as the mechanical and tribological properties of materials.

[0004] Research shows that by introducing alloying elements such as Al, Ti, Cu, etc. into the CrFeNi or CoCrNi high-entropy alloy system to regulate heterogeneous components / structures such as BCC phase, FCC phase, and nano-precipitates, the strength, hardness, and wear and corrosion resistance of materials can be significantly improved. Patent CN 105463443B discloses a CrFeNiAlMn / Zn corrosion-resistant coating that can be used for an offshore drilling platform. Patent CN 115418595B discloses a supersonic sprayed AlCrCoNi high-entropy alloy coating, which shows excellent cavitation-corrosion resistance performance in a seawater medium environment, superior to ZG06Cr13Ni4Mo stainless steel. Patent CN117488161A discloses a laser cladded CrFeAlTi (0.05~1) high-entropy alloy coating, which generates a B2 second phase by adding Ti element to the BCC-structured CrFeAl, and endows the alloy with excellent mechanical and corrosion resistance through grain refinement strengthening and solid solution. Patent CN 117802383A discloses a laser cladded (CrFeCuNi) 60% (AlTi) 40%Lightweight high-entropy alloy coating. The volumetric wear of this coating is reduced by half compared to the substrate Q235 steel, and the self-corrosion current density is reduced by two orders of magnitude compared to Q325 steel, being at the same order of magnitude as that of 304 stainless steel with good corrosion resistance, but its wear resistance is improved compared to 304 stainless steel. The literature (Materials Science and Engineering: A. 2020;771:138566) designed and prepared a CrFeNiAl with a near-equi-volume fraction of FCC-BCC-L21 coupled phases by regulating Al and Ti elements x Ti y alloy, and the compressive fracture strength of the alloy reaches 3 GPa and the plasticity reaches 39.8%. Therefore, on the basis of the high-strength and high-plasticity CrFeNiAl x Ti y alloy, adding Cu elements with both lubricating and corrosion-resistant properties is expected to obtain a high-quality wear-resistant and corrosion-resistant coating for marine environments.

[0005] In terms of preparation processes, currently, laser cladding is mostly used for high-entropy alloy coatings. However, this process requires controlling many process parameters, the coating is prone to porosity and segregation, and it causes significant thermal damage to the substrate. In contrast, the detonation spraying technology mainly uses and controls the deflagration of combustible gases to heat metal, ceramic and other powders to a molten or semi-molten state and accelerate them to bombard the substrate surface to obtain various functional coatings. This technology has many advantages: high particle velocity, high density and bonding strength of the prepared coating, and low oxidation degree; it uses a pulsed operation, resulting in little thermal damage to the substrate.

[0006] Therefore, the present invention aims to obtain a CrFeNiAlTi-Cu high-entropy alloy coating material to achieve high bonding strength between the coating and the substrate and excellent tribological properties, providing a reliable material solution for solving the lubrication and wear problems of mechanical components in marine environments. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a preparation method for a CrFeNiAlTi-Cu high-entropy alloy coating that is simple and easy to operate, has controllable processes, and low costs.

[0008] To solve the above problems, a preparation method for a CrFeNiAlTi-Cu high-entropy alloy coating according to the present invention includes the following steps:

[0009] ⑴ First, put the metal substrate into anhydrous ethanol for cleaning, then use a sandblaster to roughen the surface of the metal substrate, and then put the sandblasted metal substrate into an anhydrous ethanol solution for ultrasonic cleaning to obtain the treated metal substrate;

[0010] ⑵ By mass fraction, 10 - 30 wt. % of spherical Cu powder and the balance of spherical CrFeNiAl 0.3 Ti 0.3 powders are mixed evenly in a planetary ball mill to obtain the sprayed composite powder;

[0011] ⑶ Using the detonation spraying technique, first spray NiCrAlY powder on the surface of the treated metal substrate to obtain the NiCrAlY transition layer: Then spray the sprayed composite powder on the surface of the NiCrAlY transition layer to obtain the CrFeNiAl 0.3 Ti 0.3 -Cu high-entropy alloy coating.

[0012] In the step ⑴, the metal substrate is one of SUS304 stainless steel, TC4 titanium alloy, Inconel 718 alloy, and Inconel 625 alloy.

[0013] In the step ⑴, during the sandblasting process, Al with a particle size of 60 - 100 μm is used 2 O 3 and its pressure is 0.55 - 0.80 MPa.

[0014] In the step ⑵, the particle size of the spherical Cu powder is 15 - 45 μm and the purity is 99.99 %; the particle size of the spherical CrFeNiAl 0.3 Ti 0.3 powder is 15 - 53 μm.

[0015] In the step ⑵, the conditions of ball milling refer to a ball-to-material ratio of 1:1 - 1:2, the medium is tungsten carbide balls, the rotation speed is 200 - 300 r / min, and the mixing time is 6 - 8 hours.

[0016] In the step ⑶, the NiCrAlY powder is spherical with a particle size of 13 - 45 μm.

[0017] In the step ⑶, the conditions of detonation spraying refer to an oxygen-carbon ratio of the detonation gas mixture of 1 - 1.27:1, the fuel gas components are acetylene and propane, the gas filling amount is 42 % - 56 %, using a pulsed powder feeding and ignition method, the spraying frequency is 2 - 6 Hz, the spraying distance is 150 - 200 mm, and nitrogen is used as the powder feeding carrier gas and protective gas.

[0018] In the step ⑶, the thickness of the NiCrAlY transition layer is 20 - 80 μm, and the thickness of the CrFeNiAl 0.3 Ti 0.3 -Cu high-entropy alloy coating is between 150 - 400 μm.

[0019] A CrFeNiAl prepared by the method as described above0.3 Ti 0.3 -Cu high entropy alloy coating.

[0020] A CrFeNiAl as described above 0.3 Ti 0.3 -Cu high entropy alloy coating, characterized in that: the friction coefficient of the coating in seawater is 0.113 - 0.13, and the wear rate is 8.08×10 -8 mm 3 / Nm - 1.94×10 -7 mm 3 / Nm, and the corrosion current is 2.59×10 -7 A / cm 2 ~1.26×10 -6 A / cm 2 .

[0021] The present invention has the following advantages compared with the prior art:

[0022] 1. The present invention uses the detonation spraying process to prepare the coating, which has the advantages of small thermal damage to the workpiece, high hardness of the prepared coating, easy control of the thickness and high bonding strength.

[0023] 2. The present invention is simple and easy to operate, the process is controllable, the cost is low, and it is easy to carry out mass production.

[0024] 3. The CrFeNiAl 0.3 Ti 0.3 -Cu high entropy alloy coating prepared by the present invention is dense (porosity is less than 1%), and the thickness is between 150 - 400 μm. The bonding strength between the coating and the metal matrix is high (greater than 67 MPa); the friction coefficient of the coating in seawater reaches as low as 0.113; the wear rate reaches as low as 8.08×10 -8 mm 3 / Nm, and the corrosion current density in the seawater environment can be reduced by up to 250 times compared with SUS304 stainless steel, and it is applicable to key mechanical systems in the marine environment such as moving transmission components such as bearings, bushings, and rotating shafts. Description of the Drawings

[0025] The following further details the specific embodiments of the present invention with reference to the drawings.

[0026] Figure 1 This is the cross-sectional electron microscope picture of the CrFeNiAl 0.3 Ti 0.3 -Cu high entropy alloy coating prepared in Example 1 of the present invention. Among them: a is the electron microscope scanning picture; b is the Cr element distribution map; c is the Fe element distribution map; d is the Al element distribution map; e is the Ti element distribution map; f is the Ni element distribution map; g is the Cu element distribution map.

[0027] Figure 2 For the CrFeNiAl of the present invention 0.3 Ti 0.3 -Cu high-entropy alloy coating in seawater environment. Friction coefficient diagram

[0028] Figure 3 For the CrFeNiAl of the present invention 0.3 Ti 0.3 -Cu high-entropy alloy coating in seawater. Wear rate diagram Detailed implementation manners

[0029] A preparation method of a CrFeNiAlTi-Cu high-entropy alloy coating, comprising the following steps:

[0030] ⑴ First, put the metal substrate into absolute ethanol for cleaning to remove the oil stains and contaminant particles on its surface; then use Al with a particle size of 60-100 μm 2 O 3 , use a sandblasting machine to roughen the surface of the metal substrate under the condition of a pressure of 0.55-0.80 MPa, and then put the sandblasted metal substrate into an absolute ethanol solution for ultrasonic cleaning to remove the surface contaminants, thus obtaining the treated metal substrate.

[0031] Wherein: the metal substrate is one of SUS304 stainless steel, TC4 titanium alloy, Inconel 718 alloy and Inconel 625 alloy.

[0032] ⑵ By mass fraction (g), mix 10-30 wt.% of spherical Cu powder and the remaining spherical CrFeNiAl 0.3 Ti 0.3 powder in a planetary ball mill, with a ball-to-material ratio (g / g) of 1:1-1:2, the medium being tungsten carbide balls, the rotation speed being 200-300 r / min, and the mixing time being 6-8 hours. After mixing evenly, the sprayed composite powder is obtained.

[0033] Wherein: the particle size of the spherical Cu powder is 15-45 μm and the purity is 99.99%; the particle size of the spherical CrFeNiAl 0.3 Ti 0.3 powder is 15-53 μm.

[0034] ⑶ Under the conditions that the explosion gas mixing oxygen-carbon (oxygen / fuel) ratio (mL / mL) is 1 to 1.27:1, the fuel gas components are acetylene and propane, the gas filling amount is 42% to 56%, the pulse powder feeding and ignition method is adopted, the spraying frequency is 2 to 6 Hz, the spraying distance is 150 to 200 mm, and nitrogen is used as the powder feeding carrier gas and protective gas, the explosion spraying technology is used. First, spherical NiCrAlY powder with a particle size of 13 to 45 μm is sprayed on the surface of the treated metal substrate to obtain a NiCrAlY transition layer with a thickness of 20 to 80 μm; then the sprayed composite powder is sprayed on the surface of the NiCrAlY transition layer to obtain a CrFeNiAl 0.3 Ti 0.3 -Cu high-entropy alloy coating.

[0035] The friction coefficient of this coating in seawater is 0.113 to 0.13, and the wear rate is 8.08×10 -8 mm 3 / Nm to 1.94×10 -7 mm 3 / Nm, and the corrosion current is 2.59×10 -7 A / cm 2 ~1.26×10 -6 A / cm 2 .

[0036] Example 1 A preparation method of a CrFeNiAl 0.3 Ti 0.3 -10 wt.%Cu high-entropy alloy coating, comprising the following steps:

[0037] ⑴ First, put the 304 stainless steel substrate into anhydrous ethanol for cleaning to remove the oil stains and contaminant particles on its surface; then use Al with a particle size of 60 to 100 μm 2 O 3 , and use a sandblasting machine to roughen the surface of the metal substrate under the condition of a pressure of 0.55 to 0.80 MPa, and then put the sandblasted metal substrate into an anhydrous ethanol solution for ultrasonic cleaning to remove the surface contaminants, thus obtaining the treated metal substrate.

[0038] ⑵ Mix 90 g of CrFeNiAl 0.3 Ti 0.3 and 10 g of Cu powder in a planetary ball mill for 7 hours, with a ball-to-material ratio (g / g) of 1:1, the medium being tungsten carbide balls and the rotation speed being 200 r / min, to prepare a CrFeNiAl 0.3 Ti 0.3 -Cu sprayed composite powder.

[0039] ⑶ Use a CCDS-2000 explosion spraying equipment to spray NiCrAlY powder on the surface of the treated metal substrate, obtaining a NiCrAlY transition layer with a thickness of 50 μm. Then spray the sprayed composite powder on the surface of the NiCrAlY transition layer, obtaining a CrFeNiAl 0.3 Ti 0.3 -10 wt.% Cu high-entropy alloy coating. During explosion spraying, the mixed oxygen-fuel ratio (mL / mL) is 1:1.170, the gas filling amount is 54%, the spraying frequency is 5 Hz, and the spraying distance is 155 mm.

[0040] The micro-Vickers hardness (HV) of the obtained coating is 560.21.

[0041] Characterize the morphology characteristics and element distribution state of the coating cross-section of the obtained coating by using a scanning electron microscope (SEM) and an energy dispersive spectrometer (EDS). The results are as Figure 1 shown. It can be seen from the figure that: CrFeNiAl 0.3 Ti 0.3 -10 wt.% Cu coating has a dense structure, and the elements Cr, Fe, Ni, Al, Ti, and Cu are evenly distributed, indicating that the powder is evenly sprayed on the substrate surface.

[0042] Test the bonding strength between the coating and the substrate according to the ASTM C633 standard. The bonding strength of this coating is 79.43 MPa.

[0043] Conduct tribological performance tests on the obtained coating in a seawater environment by using an HSR-2M type high-speed reciprocating friction testing machine. The mating pair is a SiC ball with a diameter of 6 mm, the sliding speed is 0.05 m / s, the load is 60 N, and the test time is 30 min; the friction coefficient is automatically recorded by the instrument, and the wear volume on the coating surface is measured by a MicroXAM-800 non-contact surface profiler, and the wear rate is calculated accordingly. The results are as Figures 2 - 3 , Table 1 shows. The friction coefficient and wear rate in the seawater environment are 0.13 and 1.94×10 -7 mm 3 / Nm respectively; the corrosion current in the seawater environment is 1.26×10 -6 A / cm 2 , which is 51 times lower than that of SUS304 stainless steel.

[0044] Example 2 A preparation method of a CrFeNiAl 0.3 Ti 0.3 -20 wt.% Cu high-entropy alloy coating, including the following steps:

[0045] ⑴ The treated metal substrate is the same as that in Example 1.

[0046] ⑵ Mix 80 g of CrFeNiAl 0.3 Ti 0.3 and 20 g of Cu powder in a planetary ball mill for 8 hours. The ball-to-material ratio (g / g) is 1:1, the medium is tungsten carbide balls, and the rotation speed is 250 r / min to obtain CrFeNiAl 0.3 Ti 0.3 -Cu sprayed composite powder.

[0047] ⑶ Spray NiCrAlY powder on the surface of the treated metal substrate using a CCDS-2000 explosion spraying device to obtain a NiCrAlY transition layer with a thickness of 75 μm. Then spray the sprayed composite powder on the surface of the NiCrAlY transition layer to obtain a CrFeNiAl 0.3 Ti 0.3 -20 wt.%Cu high-entropy alloy coating. During explosion spraying, the mixed oxygen-fuel ratio (mL / mL) is 1:1.170, the gas filling amount is 54%, the spraying frequency is 5 Hz, and the spraying distance is 155 mm.

[0048] The micro-Vickers hardness (HV) of the obtained coating is 523.33.

[0049] Test the bonding strength between the coating and the substrate according to the ASTM C633 standard. The bonding strength of this coating is 74.40 MPa.

[0050] Perform tribological property tests on the obtained coating in a seawater environment using an HSR-2M type high-speed reciprocating friction testing machine. The method is the same as in Example 1. The results are as Figures 2 - 3 shown in Table 1. The friction coefficient and wear rate in the seawater environment are 0.126 and 1.48×10 -7 mm 3 / Nm respectively; the corrosion current in the seawater environment is 0.88×10 -6 A / cm 2 which is 74 times lower than that of SUS304 stainless steel.

[0051] Example 3 A preparation method of a CrFeNiAl 0.3 Ti 0.3 -30 wt.%Cu high-entropy alloy coating, comprising the following steps: ⑴

[0052] The treated metal substrate of Example 1.

[0053] ⑵ Mix 70 g of CrFeNiAl 0.3 Ti 0.3The powders of [metal] and 30 g of Cu were mixed in a planetary ball mill for 8 hours. The ball-to-powder ratio (g / g) was 1:1, the medium was tungsten carbide balls, and the rotation speed was 250 r / min to obtain the CrFeNiAl 0.3 Ti 0.3 -Cu sprayed composite powder.

[0054] ⑶ The NiCrAlY powder was sprayed on the surface of the treated metal substrate using a CCDS-2000 explosion spraying equipment to obtain a NiCrAlY transition layer with a thickness of 60 μm. Then the sprayed composite powder was sprayed on the surface of the NiCrAlY transition layer to obtain a CrFeNiAl 0.3 Ti 0.3 -30 wt.%Cu high-entropy alloy coating. During explosion spraying, the mixed oxygen-fuel ratio (mL / mL) was 1:1.170, the gas charging amount was 54%, the spraying frequency was 5 Hz, and the spraying distance was 200 mm.

[0055] The micro-Vickers hardness (HV) of the obtained coating was 496.74.

[0056] The bonding strength between the coating and the substrate was tested according to the ASTM C633 standard, and the bonding strength of this coating was 67.83 MPa.

[0057] The tribological properties of the obtained coating in a seawater environment were tested using an HSR-2M high-speed reciprocating friction testing machine, and the method was the same as that in Example 1. The results are as Figures 2 - 3 shown in Table 1. The friction coefficient and wear rate in the seawater environment were 0.113 and 8.08×10 -8 mm 3 / Nm respectively; the corrosion current in the seawater environment was 2.59×10 -7 A / cm 2 , which was 250 times lower than that of SUS304 stainless steel.

[0058] Table 1 Corrosion current density of the CrFeNiAl 0.3 Ti 0.3 -Cu coating of the present invention in a seawater environment

[0059]

Claims

1. A method for preparing a CrFeNiAlTi-Cu high entropy alloy coating, comprising the following steps: (1) The metal substrate is first placed in anhydrous ethanol for cleaning, and then the surface of the metal substrate is roughened by a sandblasting machine, and then the metal substrate after sandblasting is placed in anhydrous ethanol solution for ultrasonic cleaning to obtain the treated metal substrate; ⑵ According to the mass fraction, 10~30 wt.% of spherical Cu powder and the rest of spherical CrFeNiAl 0.3 Ti 0.3 The powders are mixed evenly in a planetary ball mill to obtain a spray composite powder; the particle size of the spherical Cu powder is 15-45 μm and the purity is 99.99%; the spherical CrFeNiAl 0.3 Ti 0.3 The particle size of the powder is 15-53 μm; the ball milling conditions are that the ball-to-material ratio is 1:1-1:2, the medium is a tungsten steel ball, the rotation speed is 200-300 r / min, and the mixing time is 6-8 hours; ⑶ Using explosion spraying technology, first spray NiCrAlY powder on the surface of the treated metal substrate to obtain a NiCrAlY transition layer; then spray the spray composite powder on the surface of the NiCrAlY transition layer to obtain CrFeNiAl 0.3 Ti 0.3 -Cu high entropy alloy coating; the thickness of the NiCrAlY transition layer is 20~80 μm, CrFeNiAl 0.3 Ti 0.3 The thickness of the Cu-HEA coating is between 150 and 400 μm.

2. The method for preparing a CrFeNiAlTi-Cu high entropy alloy coating according to claim 1, characterized in that: In the step (1), the metal matrix is ​​one of SUS304 stainless steel, TC4 titanium alloy, Inconel 718 alloy and Inconel 625 alloy.

3. The method for preparing a CrFeNiAlTi-Cu high entropy alloy coating according to claim 1, characterized in that: In the sandblasting process in step (1), Al2O3 with a particle size of 60-100 μm is used, and the pressure is 0.55-0.80 MPa.

4. The method for preparing a CrFeNiAlTi-Cu high entropy alloy coating according to claim 1, characterized in that: In step (3), the NiCrAlY powder is spherical and has a particle size of 13-45 μm.

5. The method for preparing a CrFeNiAlTi-Cu high entropy alloy coating according to claim 1, characterized in that: The conditions for explosion spraying in step (3) refer to that the oxygen-carbon ratio of the explosion gas mixture is 1-1.27:1, the fuel gas components are acetylene and propane, the inflation volume is 42%-56%, pulse powder feeding and ignition are adopted, the spraying frequency is 2-6 Hz, the spraying distance is 150-200 mm, and nitrogen is used as the powder feeding carrier gas and protective gas.

6. A CrFeNiAl prepared by the method according to any one of claims 1 to 5 0.3 Ti 0.3 -Cu high entropy alloy coating.

7. A CrFeNiAl as claimed in claim 6 0.3 Ti 0.3 -Cu high entropy alloy coating, characterized by: The friction coefficient of the coating in seawater is 0.113~0.13, and the wear rate is 8.08×10 -8 mm 3 / Nm~1.94×10 -7 mm 3 / Nm, the corrosion current is 2.59×10 -7 A / cm 2 ~1.26×10 -6 A / cm 2 .

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