Nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of surface engineering protective coatings, and discloses a nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating as well as a preparation method and application thereof. The preparation method comprises the following steps that firstly, a magnetron sputtering technology is adopted, a CoCrFeMnNi target serves as a cathode target material, and a corrosion-resistant high-entropy alloy coating is obtained through deposition on the surface of a base body; and then, in a three-electrode system, the corrosion-resistant high-entropy alloy coating is placed in an electrolyte containing a nitrogen heterocyclic onium salt compound to be subjected to electro-deposition, and the nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating is prepared. The corrosion-resistant inorganic-organic hybrid coating prepared by the invention has excellent corrosion resistance, can keep high stability and durability in a complex corrosion environment, and has relatively high corrosion potential and relatively low corrosion current density. The coating can remarkably prolong the service life of a structural base material, is suitable for various harsh working conditions, and provides an efficient and reliable protection solution for industrial application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surface engineering protective coating, in particular to a nitrogen heterocyclic compound modified corrosion resistant high-entropy alloy coating and a preparation method and application thereof. BACKGROUND

[0002] In marine engineering or water conservancy engineering environments, complex physical, chemical and biological coupling effects are usually involved, which puts high requirements on the comprehensive corrosion resistance of the coating. The high temperature, high humidity, high salt and high radiation in the marine environment can accelerate the electrochemical corrosion of metal materials, especially the penetration of Cl - , which easily causes local damage such as pitting corrosion and crevice corrosion; for example, the corrosion rate of traditional materials such as carbon steel and stainless steel for marine engineering transmission components such as hydraulic motors and drilling pump valve bodies on islands is significantly increased, so the coating needs to have a wide passivation range and low corrosion current density characteristics. In a sand-laden water flow or high-speed fluid environment, mechanical wear and cavitation erosion work together to cause rapid abrasion failure of the material surface, such as fish-scale pits and honeycomb damage caused by high-frequency impact force and sand cutting action after accelerated collapse of cavitation bubbles on water turbine blades, which reduces equipment efficiency and increases maintenance costs, so the coating needs to have corrosion resistance and wear resistance to resist the synergistic effect of cavitation erosion and wear. In the marine engineering or water conservancy engineering environment with multiple factors coupling, the coating is required to have certain composition and organizational uniformity, and even a single-phase structure to resist the occurrence or aggravation of pitting corrosion, intergranular corrosion and galvanic corrosion. High-entropy alloys usually have a single-phase solid solution structure and excellent mechanical and corrosion resistance properties, but the traditional arc melting or powder metallurgy preparation of bulk high-entropy alloys has the problem of high cost due to complex and difficult preparation process, which limits its further application. The coating prepared by magnetron sputtering technology has the characteristics of compactness, uniformity and strong film-substrate adhesion, and the low-temperature deposition can reduce the damage to the substrate and accurately control the composition of the coating. At the same time, the mechanical properties of the coating can be further improved by optimizing the multi-layer interface and introducing reinforcing phases through reactive sputtering, so as to meet the long-term protection needs of engineering equipment under complex working conditions.

[0003] Chinese Patent Application No. CN113981395A discloses a preparation method of a deep-sea environment corrosion-resistant coating. The coating is a chromium / chromium nitride / amorphous carbon multilayer iterative coating obtained by sequentially depositing on the surface of the substrate using a direct current magnetron sputtering method. The coating has a corrosion current density of less than 10 -6 A / cm 2 under simulated 3000m deep-sea environment, and the coating has a low porosity. However, the corrosion resistance of the coating needs to be further improved.

[0004] The Chinese patent application with the publication number CN111074224A discloses a preparation method of a corrosion-resistant high-entropy alloy nitride coating. The coating is a (VAlTiCrMo)N composition coating deposited by a magnetron sputtering technology, has a self-corrosion current density lower than 5*10 - 5 A·cm -2 and a thickness of 900-1000 nm. However, the corrosion resistance of the coating in the invention still needs to be further improved.

[0005] How to fully exert the advantages of organic coatings and alloy coatings and improve the comprehensive protective performance of the coatings through the synergistic effect between the two is a problem to be solved by those skilled in the art. SUMMARY

[0006] The present application aims to provide a nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating, a preparation method and application thereof, and solve the problem that the corrosion resistance of the existing coating still cannot meet the needs of harsh working conditions such as marine engineering or water conservancy engineering environment.

[0007] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0008] The present application provides a preparation method of a nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating, comprising the following steps:

[0009] (1) using a magnetron sputtering method, taking a CoCrFeMnNi target as a cathode target material, and depositing a corrosion-resistant high-entropy alloy coating on the surface of a substrate;

[0010] (2) in a three-electrode system, carrying out electrodeposition of the corrosion-resistant high-entropy alloy coating in an electrolyte containing a nitrogen heterocyclic onium salt compound to obtain a nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating.

[0011] Preferably, in the preparation method, in step (1), the Co, Cr, Fe, Mn and Ni in the CoCrFeMnNi target are in an equimolar atomic ratio.

[0012] The CoCrFeMnNi target is prepared by an arc melting technology and has a diameter of 50.8 mm and a thickness of 3 mm.

[0013] Preferably, in the preparation method, in step (1), the conditions of the magnetron sputtering include: a sputtering power of 100-150 W, a substrate bias voltage of -70 to -100 V, argon as the working gas, a working gas flow rate of 20-30 sccm, a gate valve opening degree of 11-15%, a working gas pressure resistance gauge of 0.4-0.7 Pa, a thin film gauge of 1.5-2.0 Pa, a substrate rotation speed of 14-18 rpm, and a deposition time of 50-70 min.

[0014] Preferably, in the preparation method, in step (1), the target-substrate distance between the cathode target and the substrate is 10-15 cm, and the target tilt angle of the cathode target is 30-35°.

[0015] Preferably, in the preparation method, in step (1), the substrate includes silicon or steel.

[0016] Preferably, in the preparation method, in step (2), in the three-electrode system, the working electrode is a corrosion-resistant high-entropy alloy coating, the counter electrode is platinum, and the reference electrode is Ag / AgCl.

[0017] Preferably, in the preparation method, in step (2), the electrolyte of the nitrogen-containing heterocyclic onyx salt compound includes the nitrogen-containing heterocyclic onyx salt compound, an organic solvent, and water;

[0018] The nitrogen-containing heterocyclic onium salts include one or more of imidazole salts, triazole salts, thiazole salts, oxazole salts, and pyrazine salts;

[0019] The imidazole salt includes 1-ethyl-3-methylimidazolium tetrafluoroborate;

[0020] The triazole salts include 1,2,4-triazolium hexafluorophosphate and 1-benzyl-3-methyltriazolium bis(trifluoromethanesulfonyl)imide;

[0021] The thiazolium salts include 3-methylbenzothiazolium tetrafluoroborate and N-methylthiazolium trifluoromethanesulfonate;

[0022] The oxazolium salts include N-methyloxazolium tetrafluoroborate and 2-phenyloxazolium perchlorate;

[0023] The pyrazine salts include N-methylpyrazineonium bis(fluorosulfonyl)imine salt and 1,4-dimethylpyrazineonium iodide;

[0024] The organic solvent includes one or more of acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide and acetone;

[0025] The concentration of the nitrogen-containing heterocyclic onium salt in the electrolyte is 0.05–0.3 mol / mL;

[0026] The volume ratio of the organic solvent to water is 100 mL: 2 mL.

[0027] Preferably, in the preparation method, in step (2), the electrodeposition potential is -1.8 to -0.5V, and the electrodeposition time is 10 to 30 minutes.

[0028] The application also provides a nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating.

[0029] The application also provides application of the nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating in a marine engineering environment or a water conservancy engineering environment.

[0030] Compared with the prior art, the application has the following beneficial effects:

[0031] The CoCrFeMnNi high-entropy alloy (Cantor alloy) has excellent mechanical properties such as high strength and plasticity and corrosion resistance, and has great application prospects in marine and water conservancy engineering. The high fracture toughness and ductility of the CoCrFeMnNi high-entropy alloy enable it to maintain good performance in low-temperature environments, and it is suitable for complex application scenarios such as extreme marine engineering and water conservancy engineering. The high-entropy effect in thermodynamics, the delayed diffusion effect in kinetics, the lattice distortion effect in structure, and the "cocktail" effect in performance of the high-entropy alloy make the CoCrFeMnNi high-entropy alloy usually a single-phase solid solution with a face-centered cubic structure. The corrosion-resistant elements Co, Cr, and Ni contained in the CoCrFeMnNi high-entropy alloy enable the alloy to have strong passivation ability in a corrosive environment. The CoCrFeMnNi amorphous coating does not have dislocations and grain boundaries, so that the corrosion medium is difficult to penetrate into the interior of the material through these channels, thereby significantly improving the corrosion resistance of the coating. The short-range order and long-range disorder of the amorphous structure make the coating more uniform at the microscale, and local corrosion can be avoided. The magnetron sputtering is realized through high-energy particle bombardment and rapid cooling, and has the characteristics of non-equilibrium deposition, which can inhibit crystal growth and make the deposited coating tend to form an amorphous structure.

[0032] 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) has good stability and can effectively slow down the corrosion rate of metal materials. The CoCrFeMnNi organic-inorganic hybrid coating with imidazole functional groups is obtained by electrochemically depositing EMIMBF4 on the CoCrFeMnNi high-entropy alloy coating, which can further improve the corrosion resistance and stability of the coating. At the same time, the organic-inorganic hybrid composite coating has the flexibility and processing performance of the organic material EMIMBF4, and the high strength and corrosion resistance of the inorganic material CoCrFeMnNi high-entropy alloy, and has a more extensive application prospect in the field of corrosion resistance, such as marine engineering, aerospace, petrochemical industry, and nuclear power engineering.

[0033] The application utilizes the combination of magnetron sputtering and electrochemical deposition to deposit a CoCrFeMnNi high-entropy amorphous coating on a substrate by magnetron sputtering direct current deposition, and then deposit a 2-methyl imidazole coating on the deposited CoCrFeMnNi coating by electrochemical deposition, to obtain a corrosion-resistant inorganic-organic hybrid CoCrFeMnNi / C4H6N2 coating, which has excellent corrosion resistance, a corrosion potential as high as 0.04-0.1 V, and a corrosion current density of 5*10 -8 ~5*10 -7 A / cm 2 , and can effectively protect the 304 stainless steel substrate. The coating can maintain good stability and durability in complex corrosion environments, significantly extending the service life of the structural substrate. In addition, the CoCrFeMnNi coating itself has good comprehensive mechanical properties such as high strength, high plasticity and toughness, and fracture toughness, and the imidazole functionalized organic-inorganic hybrid coating formed thereby can adapt to various harsh working conditions, providing an efficient and reliable protection solution for industrial applications. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description.

[0035] Figure 1 Typical cyclic potentiodynamic polarization curves of the imidazole ligand modified corrosion-resistant high-entropy alloy coating prepared in Example 1, the CoCrFeMnNi coating without deposition of 1-ethyl-3-methyl imidazolium tetrafluoroborate on the surface, and the 304 stainless steel substrate (304ss);

[0036] Figure 2 XPS characterization graph of the imidazole modified corrosion-resistant high-entropy alloy coating of Example 3. DETAILED DESCRIPTION

[0037] The application provides a preparation method of a nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating, comprising the following steps:

[0038] (1) using a magnetron sputtering method, a CoCrFeMnNi target as a cathode target material, depositing a corrosion-resistant high-entropy alloy coating on the surface of a substrate;

[0039] (2) in a three-electrode system, electrodepositing the corrosion-resistant high-entropy alloy coating in an electrolyte containing a nitrogen heterocyclic onium salt compound to obtain a nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating.

[0040] In the application, in step (1), the substrate is preferably pretreated before deposition, and the pretreatment preferably comprises the following steps:

[0041] The surface of the substrate is polished; the polished substrate is sequentially cleaned in acetone, anhydrous ethanol and water by ultrasonic cleaning to remove grease and impurities on the surface of the substrate.

[0042] In the present application, the time of the ultrasonic cleaning is independently preferably 10-20 min, further preferably 15-18 min, and more preferably 18 min.

[0043] In the present application, in step (1), the chamber for magnetron sputtering is preferably vacuumed before magnetron sputtering.

[0044] In the present application, the vacuum degree of the vacuuming is preferably 1×10 -5 -5×10 -4 Pa, further preferably 1×10 -5 -1×10 -4 Pa, and more preferably 5×10 -5 Pa.

[0045] In the present application, in step (1), the Co, Cr, Fe, Mn and Ni in the CoCrFeMnNi target are preferably in equimolar atomic ratio.

[0046] In the present application, in step (1), the CoCrFeMnNi target is prepared by arc melting technology, with a diameter of 50.8 mm and a thickness of 3 mm.

[0047] In the present application, in step (1), the target-substrate distance between the cathode target material and the substrate is preferably 10-15 cm, further preferably 13-15 cm, and more preferably 14 cm.

[0048] In the present application, in step (1), the target inclination angle of the cathode target material is preferably 30-35°, further preferably 32-35°, and more preferably 35°.

[0049] In the present application, in step (1), pre-sputtering is preferably performed before deposition on the surface of the substrate, with the purpose of removing surface impurities of the cathode target material.

[0050] In the present application, the time of the pre-sputtering is preferably 5-10 min, further preferably 6-10 min, and more preferably 10 min.

[0051] In the present application, in step (1), the conditions of the magnetron sputtering include: the sputtering power is preferably 100-150 W, further preferably 120-150 W, and more preferably 140 W; the bias voltage of the substrate is preferably -70 to -100 V, further preferably -80 to -100 V, and more preferably -90 V; the working gas is preferably argon; the flow rate of the working gas is preferably 20-30 sccm, further preferably 25-30 sccm, and more preferably 30 sccm; the gate valve opening is preferably 11-15%, further preferably 11-13%, and more preferably 12%; the working gas pressure resistance gauge is preferably 0.4-0.7 Pa, further preferably 0.4-0.6 Pa, and more preferably 0.5 Pa; the thin film gauge is preferably 1.5-2.0 Pa, further preferably 1.6-2.0 Pa, and more preferably 1.8 Pa; the rotation speed of the substrate is preferably 14-18 rpm, further preferably 15-17 rpm, and more preferably 16 rpm; and the deposition time is preferably 50-70 min, further preferably 50-60 min, and more preferably 55 min.

[0052] In the present application, in step (1), the substrate preferably includes silicon material or steel material, and the steel material is selected from carbon steel, stainless steel, weathering steel and low-alloy high-strength structural steel, and is further preferably stainless steel.

[0053] In the present application, in step (1), after obtaining the corrosion-resistant high-entropy alloy coating, the cavity is preferably cooled to room temperature.

[0054] In the present application, in step (1), the thickness of the obtained corrosion-resistant high-entropy alloy coating is 500-1500 nm, preferably 700-1200 nm, and further preferably 900-1000 nm.

[0055] In the present application, in step (2), in the three-electrode system, the working electrode is preferably a corrosion-resistant high-entropy alloy coating, the counter electrode is preferably platinum, and the reference electrode is preferably Ag / AgCl.

[0056] In the present application, in step (2), the electrolyte containing nitrogen heterocyclic onium salt compounds includes nitrogen heterocyclic onium salt compounds, organic solvents and water.

[0057] In the present application, the nitrogen heterocyclic onium salt compounds include one or more of imidazole salts, triazole salts, thiazole salts, oxazole salts and pyrazine salts.

[0058] In the present application, the imidazole salt includes 1-ethyl-3-methylimidazolium tetrafluoroborate.

[0059] In the present application, the triazole salt includes 1,2,4-triazolium hexafluorophosphate, 1-benzyl-3-methyltriazolium bis(trifluoromethylsulfonyl) imide.

[0060] In the present application, the thiazole salt includes 3-methylbenzothiazolium tetrafluoroborate, N-methylthiazolium triflate.

[0061] In the present application, the oxazole salt includes N-methyloxazolium tetrafluoroborate, 2-phenyloxazolium perchlorate.

[0062] In the present application, the pyrazine salt includes N-methylpyrazolium bis (fluorosulfonyl) imide, 1,4-dimethylpyrazolium iodide.

[0063] In the present application, the organic solvent includes one or more of acetonitrile, dimethyl sulfoxide, N, N-dimethylformamide and acetone.

[0064] In the present application, the concentration of the nitrogen-containing heterocyclic onium salt compound in the electrolyte of the nitrogen-containing heterocyclic onium salt compound is 0.05-0.3 mol / mL, preferably 0.08-0.25 mol / mL, further preferably 0.1-0.2 mol / mL, and more preferably 0.12-0.18 mol / mL.

[0065] In the present application, the volume ratio of the organic solvent to water is 100 mL:2 mL.

[0066] In the present application, in step (2), the preparation method of the electrolyte of the nitrogen-containing heterocyclic onium salt compound includes the following steps: dissolving the nitrogen-containing heterocyclic onium salt compound in the organic solvent, and then adding water to mix.

[0067] In the present application, the conditions for mixing are not limited, and the mixing is uniform.

[0068] In the present application, in step (2), the potential for electrodeposition is preferably -1.8 to -0.5 V, further preferably -1.5 to -0.8 V, and more preferably -1 V; and the time for electrodeposition is preferably 10-30 min, further preferably 20-30 min, and more preferably 30 min.

[0069] In the present application, in step (2), the nitrogen-containing heterocyclic compound modified corrosion-resistant high-entropy alloy coating is also preferably dried.

[0070] In the present application, the auxiliary gas for drying is preferably nitrogen.

[0071] The present application also provides a nitrogen-containing heterocyclic compound modified corrosion-resistant high-entropy alloy coating.

[0072] The application also provides application of the nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating in a marine engineering environment or a water conservancy engineering environment.

[0073] In the application, the method for the application is not limited, and a scheme well known by those skilled in the art can be adopted.

[0074] The technical solutions in the embodiments of the application will be clearly and completely described below. Apparently, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0075] Embodiment 1

[0076] The embodiment provides a preparation method of an imidazole modified corrosion-resistant high-entropy alloy coating, comprising the following steps:

[0077] (1) ultrasonic cleaning Si wafer polished on one side, 304 stainless steel substrate polished by sandpaper and polished in acetone, anhydrous ethanol and deionized water for 15 min respectively to remove grease and impurities on the surface of the substrate caused by processing; then fixing the two substrates on the sample plate respectively and placing them into the magnetron sputtering cavity;

[0078] (2) installing an equimolar atomic ratio CoCrFeMnNi target material on the target position in the magnetron sputtering cavity, setting the target-substrate distance to 13 cm and the target tilt angle to 30°, and vacuumizing to a target vacuum degree of 5x10 -4 Pa; introducing Ar gas, setting the gas flow to 30 sccm, opening the resistance gauge and thin film gauge protection valves, adjusting the gate valve opening degree to 12%, so that the working gas pressure resistance gauge displays 0.5 Pa and the thin film gauge displays 1.6 Pa; connecting the target material to the direct current power supply and opening the direct current power supply switch, setting the CoCrFeMnNi target sputtering power to 120 W and the substrate bias to -80 V; closing the target and sample plate shutter, setting the sample plate autorotation to 16 rpm, and pre-sputtering the target material for 5 min to remove impurities on the surface of the target material; then opening the CoCrFeMnNi target shutter and sputtering for 60 min; after sputtering, closing the power supply and Ar gas valve, closing the thin film gauge protection valve, taking out the sample after the cavity cools to room temperature, and obtaining the corrosion-resistant high-entropy alloy coating;

[0079] (3) Take 5 mmol of the to-be-deposited 1-ethyl-3-methylimidazolium tetrafluoroborate, dissolve it in 100 mL of acetonitrile, add 2 mL of deionized water, and stir it at room temperature with a stirrer for 2 min to make the solution fully mixed and uniform, obtaining an imidazole salt electrolyte; prepare a three-electrode system, including Ag / AgCl as a reference electrode, a platinum sheet as a counter electrode, and a platinum sheet electrode clamp, and install the magnetron sputtered corrosion-resistant high-entropy alloy coating sample in the working electrode position; select the CV test mode in the workstation, set the potential scanning interval to -1.5V~+1.5V, observe whether polarization occurs in the sample in this voltage interval, and determine the voltage parameters for electrochemical deposition; select the chronoamperometry test mode in the electrochemical workstation, and electrolyze for 20 min at -1V to obtain an electrochemically deposited 2-methylimidazole coating; after the electrochemical deposition is completed, the sample is taken out and dried in an N2 flow, and the sample is taken out to obtain an imidazole-modified corrosion-resistant high-entropy alloy coating.

[0080] Example 2

[0081] The present embodiment provides a preparation method of an imidazole-modified corrosion-resistant high-entropy alloy coating, comprising the following steps:

[0082] (1) The single-side polished Si sheet and the 304 stainless steel substrate polished with sandpaper are respectively ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 10 min to remove grease and impurities on the surface of the substrate caused by processing; then the two substrates are respectively fixed on a sample plate and placed in a magnetron sputtering cavity;

[0083] (2) An equimolar atomic ratio CoCrFeMnNi target is installed on the target position in the magnetron sputtering cavity, the target-substrate distance is set to 14 cm, the target tilt angle is set to 32°, and the vacuum is pumped to a target vacuum degree of 1×10 -4 Pa; Ar gas is introduced, the gas flow is set to 25 sccm, the resistance gauge and film gauge protection valves are opened, the gate valve opening degree is adjusted to 11%, the working gas pressure resistance gauge displays 0.6 Pa, and the film gauge displays 1.8 Pa; the target is connected to a direct current power supply, the direct current power supply switch is turned on, the CoCrFeMnNi target sputtering power is set to 100 W, and the substrate bias is set to -100 V; the target and sample plate shutter is closed, the sample plate is set to rotate at 15 rpm, and the target is pre-sputtered for 6 min to remove impurities on the surface of the target; then the CoCrFeMnNi target shutter is opened, and sputtering is performed for 70 min; after sputtering is completed, the power supply and Ar gas valve are turned off, the film gauge protection valve is closed, the sample is taken out after the cavity cools to room temperature, and a corrosion-resistant high-entropy alloy coating is obtained;

[0084] (3) Take 5 mmol of the to-be-deposited 1-ethyl-3-methylimidazolium tetrafluoroborate, dissolve it in 100 mL of acetonitrile, add 2 mL of deionized water, and stir it at room temperature with a stirrer for 2 min to make the solution fully mixed and uniform, obtaining an electrolyte containing a nitrogen-containing heterocyclic onium salt compound; prepare a three-electrode system, including Ag / AgCl as a reference electrode, a platinum sheet as a counter electrode, and a platinum sheet electrode clamp, and install the magnetron sputtered corrosion-resistant high-entropy alloy coating sample at the position of the working electrode; select the CV test mode in the workstation, set the potential scanning interval to -1.5V~+1.5V, and observe whether polarization occurs in the sample in this voltage interval to determine the voltage parameters for electrochemical deposition; select the chronoamperometry test mode in the electrochemical workstation, and electrolyze for 10 min at -1V to obtain an electrochemically deposited 2-methylimidazole coating; after the electrochemical deposition is completed, the sample is taken out and dried in an N2 flow, and the sample is taken out to obtain an imidazole-modified corrosion-resistant high-entropy alloy coating.

[0085] Example 3

[0086] The present embodiment provides a preparation method of an imidazole-modified corrosion-resistant high-entropy alloy coating, comprising the following steps:

[0087] (1) The single-side polished Si sheet and the 304 stainless steel substrate polished with sandpaper are respectively ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 18 min to remove grease and impurities on the surface of the substrate caused by processing; then the two substrates are respectively fixed on a sample plate and placed in a magnetron sputtering cavity;

[0088] (2) An equimolar atomic ratio CoCrFeMnNi target is installed on the target position in the magnetron sputtering cavity, the target-substrate distance is set to 15 cm, the target tilt angle is set to 35°, and the cavity is vacuumized to a target vacuum degree of 5x10 -5 Pa; Ar gas is introduced, the gas flow is set to 30 sccm, the resistance gauge and the film gauge protection valves are opened, the gate valve opening degree is adjusted to 13%, the working gas pressure resistance gauge displays 0.4 Pa, and the film gauge displays 1.5 Pa; the target is connected to a direct current power supply, the direct current power supply switch is turned on, the CoCrFeMnNi target sputtering power is set to 140 W, and the substrate bias is set to -90 V; the target and the sample plate shutter are closed, the sample plate autorotation is set to 18 rpm, and the target is pre-sputtered for 10 min to remove impurities on the surface of the target; then the CoCrFeMnNi target shutter is opened, and sputtering is performed for 55 min; after sputtering is completed, the power supply and the Ar gas valve are turned off, the film gauge protection valve is closed, and the cavity is cooled to room temperature to obtain a corrosion-resistant high-entropy alloy coating;

[0089] (3) Take 5 mmol of the to-be-deposited 1-ethyl-3-methylimidazolium tetrafluoroborate, dissolve it in 100 mL of acetonitrile, add 2 mL of deionized water, and stir it with a stirrer at room temperature for 2 min to make the solution fully mixed and uniform, obtaining an imidazole salt electrolyte; prepare a three-electrode system, including Ag / AgCl as a reference electrode, a platinum sheet as a counter electrode, and a platinum sheet electrode clamp, and install the magnetron sputtering deposited corrosion-resistant high-entropy alloy coating sample at the position of the working electrode; select the CV test mode in the workstation, set the potential scanning range to -1.5V~+1.5V, observe whether polarization occurs in the sample in this voltage range, and determine the voltage parameters for electrochemical deposition; select the chronoamperometry test mode in the electrochemical workstation, and electrolyze for 30 min at -1V to obtain an electrochemically deposited 2-methylimidazole coating; after the electrochemical deposition is completed, remove the sample and dry it in a N2 flow, and obtain the imidazole-modified corrosion-resistant high-entropy alloy coating.

[0090] Figure 1 Typical cyclic potentiodynamic polarization curves of the imidazole-based ligand-modified corrosion-resistant high-entropy alloy coating prepared in Example 1, the CoCrFeMnNi coating without 1-ethyl-3-methylimidazolium tetrafluoroborate deposited on the surface, and a 304 stainless steel substrate (304ss) are shown in Figure 1. Figure 1 As can be seen from the comparison, the imidazole-modified CoCrFeMnNi high-entropy alloy organic-inorganic hybrid composite coating has a corrosion potential of 0.05V and a corrosion current density of 1×10 -7 A / cm 2 , and has the best corrosion resistance.

[0091] The corrosion resistance (corrosion potential and corrosion current density) of the imidazole-modified corrosion-resistant high-entropy alloy coatings prepared in Examples 1-3 was tested, and the test method and test results are as follows:

[0092] The cyclic potentiodynamic polarization test was performed on the coating samples prepared in Examples 1-3 under the conditions of a voltage range of -0.5~1.5V OCP and a scanning rate of 1mV / s, and when the working electrode current was higher than 0.005A, the reverse retrace was started.

[0093] The imidazole-modified corrosion-resistant high-entropy alloy coating prepared in Example 1 has a corrosion potential of 0.05V and a corrosion current density of 1×10 -7 A / cm 2 .

[0094] The imidazole-modified corrosion-resistant high-entropy alloy coating prepared in Example 2 has a corrosion potential of 0.07V and a corrosion current density of 8×10 -8 A / cm 2 .

[0095] The imidazole-modified corrosion-resistant high-entropy alloy coating prepared in Example 3 has a corrosion potential of 0.1 V and a corrosion current density of 1 x 10 -8 A / cm 2 .

[0096] To demonstrate the effectiveness of introducing imidazole functional groups in the process of electrochemically depositing 1-ethyl-3-methylimidazolium tetrafluoroborate on the magnetron sputtered CoCrFeMnNi coating, the imidazole-modified corrosion-resistant high-entropy alloy coating obtained in Example 3 was characterized by X-ray photoelectron spectroscopy (XPS), and the results are shown in Figure 2 Figure 2 The results show that the appearance of Me-N peak formed between metal and N on one hand proves the existence of imidazole on the surface of the CoCrFeMnNi coating, and on the other hand confirms that a chemical bond is formed between the magnetron sputtered CoCrFeMnNi layer and the electrochemically deposited imidazole functional groups, realizing the organic-inorganic hybridization between the coatings.

[0097] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.​

Claims

1. A method for preparing a nitrogen heterocyclic compound-modified corrosion-resistant high-entropy alloy coating, characterized in that, Includes the following steps: (1) A corrosion-resistant high-entropy alloy coating was deposited on the substrate surface by using a CoCrFeMnNi target as the cathode target through magnetron sputtering. (2) In a three-electrode system, a corrosion-resistant high-entropy alloy coating is electrodeposited in an electrolyte containing nitrogen heterocyclic onium salts to obtain a nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating.

2. The preparation method according to claim 1, characterized in that, In step (1), in the CoCrFeMnNi target, Co, Cr, Fe, Mn and Ni are in equimolar atomic ratio; The CoCrFeMnNi target was prepared by arc melting technology, with a diameter of 50.8 mm and a thickness of 3 mm.

3. The preparation method according to claim 1 or 2, characterized in that, In step (1), the conditions for magnetron sputtering include: sputtering power of 100-150W, substrate bias voltage of -70-100V, working gas of argon, working gas flow rate of 20-30sccm, gate valve opening of 11-15%, working gas pressure resistance gauge of 0.4-0.7Pa, thin film gauge of 1.5-2.0Pa, substrate rotation speed of 14-18rpm, and deposition time of 50-70min.

4. The preparation method according to claim 3, characterized in that, In step (1), the target-substrate distance between the cathode target and the substrate is 10-15 cm, and the target tilt angle of the cathode target is 30-35°.

5. The preparation method according to claim 1, characterized in that, In step (1), the substrate includes silicon or steel.

6. The preparation method according to claim 1, characterized in that, In step (2), in the three-electrode system, the working electrode is a corrosion-resistant high-entropy alloy coating, the counter electrode is platinum, and the reference electrode is Ag / AgCl.

7. The preparation method according to claim 1 or 6, characterized in that, In step (2), the electrolyte containing the nitrogen-containing heterocyclic onium salt compound includes the nitrogen-containing heterocyclic onium salt compound, an organic solvent, and water; The nitrogen-containing heterocyclic onium salts include one or more of imidazole salts, triazole salts, thiazole salts, oxazole salts, and pyrazine salts; The imidazole salt includes 1-ethyl-3-methylimidazolium tetrafluoroborate; The triazole salts include 1,2,4-triazolium hexafluorophosphate and 1-benzyl-3-methyltriazolium bis(trifluoromethanesulfonyl)imide; The thiazolium salts include 3-methylbenzothiazolium tetrafluoroborate and N-methylthiazolium trifluoromethanesulfonate; The oxazolium salts include N-methyloxazolium tetrafluoroborate and 2-phenyloxazolium perchlorate; The pyrazine salts include N-methylpyrazineonium bis(fluorosulfonyl)imine salt and 1,4-dimethylpyrazineonium iodide; The organic solvent includes one or more of acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide and acetone; The concentration of the nitrogen-containing heterocyclic onium salt in the electrolyte is 0.05–0.3 mol / mL; The volume ratio of the organic solvent to water is 100 mL: 2 mL.

8. The preparation method according to claim 7, characterized in that, In step (2), the electrodeposition potential is -1.8 to -0.5V, and the electrodeposition time is 10 to 30 minutes.

9. A nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the nitrogen heterocyclic compound modified corrosion-resistant high-entropy alloy coating of claim 9 in marine engineering or hydraulic engineering environments.

Images