A surface self-textured hard coating composite MoS2 film and its preparation method and application

Abstract

The present invention provides a surface self-texturing hard coating composite MoS2 film and its preparation method and application, which relate to the field of surface treatment and friction and wear protection technology. The present invention sequentially electroplates nickel and chemically plates nickel on the surface of a substrate to form a surface self-texturing nickel-based hard coating on the surface of the substrate; the electroplating solution used for the nickel electroplating includes hard nanoparticles; and electrophoretically deposits a MoS2 film on the surface of the surface self-texturing nickel-based hard coating to obtain a surface self-texturing hard coating composite MoS2 film. The present invention can ensure the integrity of the friction surface while forming a surface micro-texture, greatly improving the friction reduction and wear resistance of the coating composite MoS2 solid lubricating film; moreover, the nickel-based hard coating prepared by electroplating and chemical plating has good bonding strength, and the nickel-based coating has good corrosion resistance and strong wear resistance, which is more conducive to improving the friction reduction and wear resistance of the material; in addition, the present invention can achieve controllable preparation of the degree of surface self-texturing.

Description

Technical Field

[0001] The present invention relates to the technical field of surface treatment and friction and wear protection, and in particular to a surface self-textured hard coating composite MoS2 film, a preparation method thereof, and an application thereof. Background Art

[0002] Motion systems are always accompanied by friction and wear. According to relevant statistics, approximately one-third of the world's disposable energy is consumed by friction, and the resulting wear and tear also causes approximately 60% of equipment damage or failure. Lubrication and surface enhancement technology is one of the effective means to reduce friction and wear. Common application cases include: coating composite lubricants, coating composite solid lubricant films (typically coating composite MoS2 solid lubricant films), nitriding / carbon layer composite lubricant phases, etc. In the application of coating composite solid lubricant films, the strength of the bonding between the lubricating phase and the coating surface directly determines the length of time the solid lubricant film remains in effect on the coating surface, that is, the difference in lubrication life.

[0003] Surface texturing technology can effectively improve the tribological properties of a surface by using mechanical force or subtractive manufacturing processes such as laser etching to produce a lattice of pits or tiny grooves of a certain size and arrangement on the friction surface. The non-smooth surface composite MoS2 solid lubricating film obtained by this technology can improve the bonding strength between MoS2 and the coating, collect and capture the wear particles generated during the friction process, prevent the wear particles from scratching and damaging the friction pair surface during sliding, hinder the removal of the lubricating phase, achieve the slow release of MoS2, extend the friction life, reduce wear, and extend the service life of moving parts. Although surface texturing technology can improve the surface friction performance, the processing of the friction surface is essentially a destruction. Microcracks may be generated during the processing, affecting the integrity of the friction surface and causing premature failure of the coating. Summary of the Invention

[0004] In view of this, the present invention aims to provide a surface self-textured hard coating composite MoS2 film, its preparation method, and application. The preparation method provided by the present invention can form surface microtexture while ensuring the integrity of the friction surface, greatly improving the friction reduction and wear resistance of the coating composite MoS2 solid lubricating film.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a surface self-textured hard coating composite MoS2 film, comprising the following steps:

[0007] Electroplating nickel and chemically plating nickel on the surface of the substrate in sequence to form a surface self-textured nickel-based hard coating on the surface of the substrate; the electroplating solution used in the electroplating nickel includes hard nanoparticles;

[0008] A MoS2 film is electrophoretically deposited on the surface of the surface self-textured nickel-based hard coating to obtain a surface self-textured hard coating composite MoS2 film.

[0009] Preferably, the electroplating solution comprises the following components: 40-50 g / L nickel chloride, 250-300 g / L nickel sulfate, 30-40 g / L boric acid, 1.5-3.5 g / L hard nanoparticles, 0.3-1 g / L surfactant, and water as the solvent; the pH value of the electroplating solution is 4.0-6.0.

[0010] Preferably, the hard nanoparticles include one or more of SiC, Si3N4 and ZrO2; and the particle size of the hard nanoparticles is 10 to 100 nm.

[0011] Preferably, the nickel electroplating temperature is 50-60°C, the electroplating time is less than 10 minutes, and the current density is 2-8A / dm 2 .

[0012] Preferably, the chemical plating solution used for the chemical nickel plating includes the following components: 30-40 g / L of nickel sulfate, 25-30 g / L of sodium hypophosphite, 30-40 g / L of sodium acetate, 11-13 mL / L of lactic acid, 3-5 mg / L of thiourea, and the solvent is water; the pH value of the chemical plating solution is 4.0-6.0.

[0013] Preferably, the electroless nickel plating temperature is 85-90° C., and the plating time is less than 90 minutes.

[0014] Preferably, the electrophoretic deposition solution used in the electrophoretic deposition comprises the following components: MoS2 1-2 g / L, surfactant 0.3-1 g / L, and solvent is water.

[0015] Preferably, the voltage of the electrophoretic deposition is 10-36 V, and the deposition time is less than or equal to 5 minutes.

[0016] The present invention provides a surface self-textured hard coating composite MoS2 film prepared by the preparation method described in the above technical solution.

[0017] The present invention also provides the application of the surface self-textured hard coating composite MoS2 film described in the above technical solution in friction and wear protection.

[0018] The present invention provides a method for preparing a surface self-texturing hard coating composite MoS2 film, comprising the following steps: sequentially electroplating nickel and chemically plating nickel on a substrate surface to form a surface self-texturing nickel-based hard coating on the substrate surface; the electroplating solution used for the nickel electroplating includes hard nanoparticles; and electrophoretically depositing a MoS2 film on the surface of the surface self-texturing nickel-based hard coating to obtain a surface self-texturing hard coating composite MoS2 film. The present invention creates roughness on the substrate surface by electroplating the substrate with an electroplating solution containing hard nanoparticles. Due to the good adaptability of chemical plating, the surface conditions of the electroplated layer can be perfectly reproduced in the chemically plated layer, that is, the roughness is reflected on the friction surface through chemical plating, achieving surface self-texturing without affecting the integrity of the friction surface; obtaining a high-hardness coating through chemical plating; depositing a MoS2 film through electrophoresis to reduce friction, and storing the MoS2 on the textured surface to achieve a long-lasting lubricating effect. The present invention combines electroplating, chemical plating and electrophoretic deposition to prepare a composite film with good texture texture. While forming surface microtexture, it can ensure the integrity of the friction surface, improve the bonding strength of the coating and the MoS2 film, and greatly improve the friction reduction and wear resistance of the coating composite MoS2 solid lubricating film. In addition, the nickel-based hard coating prepared by the electroplating and chemical plating methods has good bonding force, and the nickel-based coating has good corrosion resistance and strong wear resistance, which is more conducive to improving the friction reduction and wear resistance of the material. In addition, the present invention can regulate the surface roughness by regulating the amount of hard nanoparticles added and the electroplating time, thereby achieving controllable preparation of the degree of surface self-texturing, and thus achieving controllable life of the MoS2 lubricating phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the mechanism of action of the surface self-textured hard coating composite MoS2 film prepared in an embodiment of the present invention during the friction process;

[0020] Figure 2 Surface optical microscope images and roughness measurement values ​​of the electroplated nickel layers (Ni-SiC coatings) formed by electroplating in Examples 1 to 4, Figure 2 , (a), (b), (c) and (d) correspond to Example 1, Example 2, Example 3 and Example 4, respectively;

[0021] Figure 3 Surface scanning electron microscope images and roughness measurement values ​​of the multilayer nickel-based hard coatings formed by electroplating and chemical plating in Examples 1 to 4, Figure 3 , (a), (b), (c) and (d) correspond to Example 1, Example 2, Example 3 and Example 4, respectively;

[0022] Figure 4 The thickness 3D image and contour curve of the MoS2 film in Example 1 are shown. Figure 4 (a) is the thickness three-dimensional image, and (b) is the contour curve;

[0023] Figure 5 The friction life curve of the surface self-textured hard coating composite MoS2 film prepared in Examples 1 to 4 is as follows: Figure 5 M1, M2, M3 and M4 correspond to Example 1, Example 2, Example 3 and Example 4 respectively. DETAILED DESCRIPTION

[0024] The present invention provides a method for preparing a surface self-textured hard coating composite MoS2 film, comprising the following steps:

[0025] Electroplating nickel and chemically plating nickel on the surface of the substrate in sequence to form a surface self-textured nickel-based hard coating on the surface of the substrate; the electroplating solution used in the electroplating nickel includes hard nanoparticles;

[0026] A MoS2 film is electrophoretically deposited on the surface of the surface self-textured nickel-based hard coating to obtain a surface self-textured hard coating composite MoS2 film.

[0027] The present invention sequentially performs electroplating of nickel and chemical nickel plating on the surface of the substrate to form a surface self-textured nickel-based hard coating on the surface of the substrate. The present invention has no special requirements for the substrate, and a substrate material familiar to those skilled in the art can be used, such as carbon steel, aluminum alloy, etc. Before electroplating nickel, the present invention preferably pre-treats the substrate; the pre-treatment preferably includes grinding and roughening and ultrasonic cleaning performed in sequence. In the present invention, the grinding and roughening is preferably performed using 800-mesh sandpaper, and the grinding and roughening removes oxides on the metal surface and forms a surface texture, which is beneficial to improving the bonding strength between the substrate surface and the coating; the ultrasonic cleaning preferably includes ultrasonic cleaning in an organic solvent and ultrasonic cleaning in an acidic solution in sequence, the organic solvent is preferably petroleum ether, and the acidic solution is preferably 0.1 mol / L dilute hydrochloric acid, and the ultrasonic cleaning further removes impurities and oxides on the metal surface and fully activates the metal.

[0028] In the present invention, the electroplating solution preferably includes the following components: nickel chloride 40-50 g / L, preferably 45 g / L; nickel sulfate 250-300 g / L, preferably 280 g / L; boric acid 30-40 g / L, preferably 35 g / L; hard nanoparticles 1.5-3.5 g / L, preferably 1.8 g / L; surfactant 0.3-1 g / L, preferably 0.5 g / L; solvent is water; the pH value of the electroplating solution is 4.0-6.0. In the present invention, the nickel chloride and nickel sulfate are the main salts, providing the nickel ions required for the coating; the role of the boric acid is to maintain the pH environment of the electroplating solution stable; the hard nanoparticles preferably include one or more of SiC, Si3N4 and ZrO2, and the particle size of the hard nanoparticles is preferably 10-100 nm; the present invention achieves controllable preparation of the surface texture roughness of the coating by adding hard nanoparticles to the electroplating solution without affecting the integrity of the friction surface. In the present invention, the surfactant preferably includes one or more of cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate (SDBS), and sodium dodecyl sulfate (SDS); the surfactant can effectively disperse the hard nanoparticles and prevent particle agglomeration. In the present invention, the method for preparing the electroplating solution preferably includes the following steps: mixing nickel chloride, nickel sulfate, boric acid, and water, and separating a small portion from the resulting first mixed system; adding the surfactant and hard nanoparticles to the small portion, and sequentially subjecting the resulting second mixed system to ultrasonic vibration dispersion and magnetic stirring dispersion to obtain a pre-dispersed hard nanoparticle system; adding the pre-dispersed hard nanoparticle system to the remaining portion of the first mixed system, and adjusting the pH value to 4.0 to 6.0 after mixing to obtain the electroplating solution. In the present invention, the ultrasonic vibration dispersion time is preferably 60 to 90 minutes, the magnetic stirring dispersion speed is preferably 400 to 600 rpm, and the time is preferably 60 to 90 minutes; the present invention uses the ultrasonic vibration dispersion and magnetic stirring dispersion to enable the hard nanoparticles to be pre-dispersed under the action of a surfactant, thereby facilitating the uniform dispersion of the hard nanoparticles in the entire chemical plating solution; the pH value is preferably adjusted by adding an acid or base reagent, such as sulfuric acid or ammonia water.

[0029] In the present invention, the electroplating temperature of the nickel plating is preferably 50-60°C, more preferably 55°C; the electroplating time is preferably less than 10 minutes, more preferably 1-5 minutes; the current density is preferably 2-8 A / dm 2 , more preferably 5A / dm 2The specific operation of nickel electroplating is as follows: the substrate as the workpiece to be plated is connected to the negative electrode of the power supply as the cathode, the pure nickel plate (i.e., pure nickel is used as the ion supplement source of the electroplating solution) is connected to the positive electrode of the power supply as the anode, the assembled anode and cathode are placed in the electroplating solution at a temperature of 50-60°C, and the power supply current is adjusted to 2-8A / dm 2 The substrate surface is electroplated with nickel at a current density of . After the nickel electroplating, a nickel-based coating containing hard nanoparticles having a surface nodular structure (referred to as a Ni-hard nanoparticle coating) is formed on the substrate surface. Furthermore, the surface roughness can be regulated by adjusting the amount of hard nanoparticles added and the electroplating time, thereby achieving controllable preparation of the degree of surface self-texturing. Specifically, for example, by extending the electroplating time, the roughness of the coating surface increases, thereby enhancing the degree of self-texturing. Increasing or decreasing the amount of hard nanoparticles added affects the content of hard particles deposited in the nickel-based coating, thereby affecting the surface roughness of the coating, thereby achieving controllable preparation of the degree of self-texturing.

[0030] In the present invention, the chemical plating solution used for chemical nickel plating preferably includes the following components: nickel sulfate 30-40g / L, preferably 36g / L; sodium hypophosphite 25-30g / L, preferably 28g / L; sodium acetate 30-40g / L, preferably 34g / L; lactic acid 11-13mL / L, preferably 12.4mL / L, thiourea 3-5mg / L, preferably 4mg / L; the solvent is water; the pH value of the chemical plating solution is preferably 4.0-6.0. In the present invention, the nickel sulfate and sodium hypophosphite are the main salt and the reducing agent, respectively. The former provides nickel ions, and the latter can reduce nickel ions to metallic nickel. The sodium acetate acts as a buffer to stabilize the acid and base, keep the pH value of the system within a certain range, and effectively avoid H during the reaction. +The formation of affects the pH value of the system; the lactic acid acts as a complexing agent to form a relatively stable chelate with the nickel ions in the chemical plating solution, thereby reducing the concentration of free nickel ions in the system. The addition of lactic acid can control the deposition rate to ensure that the coating is uniform and fine and the plating solution is stable; the thiourea acts as a stabilizer to prevent the spontaneous decomposition of the chemical plating solution. The present invention has no special requirements for the preparation method of the chemical plating solution, as long as the components are evenly mixed; the pH value of the chemical plating solution is adjusted by adding acid and alkali reagents, such as sulfuric acid or ammonia water. In the present invention, the plating temperature of the chemical nickel plating is preferably 85-90°C, more preferably 89°C; the plating time is preferably less than 90 minutes, more preferably 15 minutes; the substrate after the nickel plating is immersed in the chemical plating solution to carry out chemical plating. During the electroless plating process, nickel ions in the electroless plating solution are reduced to nickel by sodium hypophosphite, and at the same time, phosphorus element and part of the metallic nickel form a covalent state, thereby forming a wear-resistant and corrosion-resistant nickel-phosphorus alloy coating (denoted as NiP coating) on ​​the coating surface after nickel electroplating, and then forming a surface self-textured nickel-based hard coating on the substrate surface.

[0031] After forming a surface self-texturing nickel-based hard coating on the surface of the substrate, the present invention electrophoretically deposits a MoS2 film on the surface of the surface self-texturing nickel-based hard coating to obtain a surface self-texturing hard coating composite MoS2 film. In the present invention, the electrophoretic deposition liquid used in the electrophoretic deposition preferably includes the following components: MoS2 1-2g / L, preferably 1.5-2g / L; surfactant 0.3-1g / L, preferably 0.5g / L, and the solvent is water; the surfactant is preferably hexadecyltrimethylammonium bromide (CTAB), which can effectively disperse MoS2 and avoid agglomeration. The present invention has no special requirements for the preparation method of the electrophoretic deposition liquid, as long as the components are mixed evenly. In an embodiment of the present invention, the components are mixed evenly by ultrasonic dispersion and stirring to obtain a MoS2 dispersion, i.e., the electrophoretic deposition liquid. In the present invention, the voltage of the electrophoretic deposition is preferably 10-36V, more preferably 25V; the deposition time is preferably less than or equal to 5min, more preferably 2min; and the electrophoretic deposition can be carried out at room temperature. During the electrophoretic deposition process, the chemically nickel-plated substrate is connected to the negative electrode of a power supply, and the positive electrode of the power supply is connected to a graphite electrode. The present invention deposits a MoS2 thin film on the surface of a self-textured nickel-based hard coating using an electrophoretic deposition method. The process is simple and facilitates industrial production. Furthermore, the electrophoretic deposition method can improve the bonding strength and surface hardness of the MoS2 thin film and help reduce the friction coefficient of the film layer.

[0032] This invention combines a hard, wear-resistant nickel-based coating with a MoS2 solid lubricant film. By manipulating the surface morphology and utilizing the microtexture to store wear debris and MoS2, the coating achieves a sustained release of the lubricant phase, thereby controlling and extending the friction life. This method significantly enhances the friction-reducing and wear-resistant properties of the MoS2 solid lubricant film while ensuring the integrity of the friction surface. Furthermore, the invention utilizes mature electroplating and chemical plating techniques, and simple electrophoretic deposition equipment, offering promising prospects for industrial application.

[0033] The present invention provides a surface self-textured hard coating composite MoS2 film prepared by the preparation method described in the above technical solution. The surface self-textured hard coating composite MoS2 film provided by the present invention has excellent friction reduction and wear resistance. During the friction process, the surface self-textured hard coating composite MoS2 film can collect and capture the wear particles generated during the friction process, preventing the wear particles from scratching and damaging the friction pair surface during the sliding process; it can also achieve the slow release of the MoS2 lubricating phase, extend the friction life, reduce wear, and extend the service life of moving parts. In the present invention, the surface self-textured hard coating composite MoS2 film preferably includes a nickel-based coating containing hard nanoparticles, a nickel-phosphorus alloy coating and a MoS2 film sequentially compounded on the surface of the substrate. The mechanism of action of the surface self-textured hard coating composite MoS2 film of the structure during the friction process is as follows: Figure 1 The surface self-textured hard coating composite MoS2 film provided by the present invention can be effectively applied in the field of friction and wear protection.

[0034] The surface self-textured hard coating composite MoS2 film provided by the present invention, its preparation method and application are described in detail below in conjunction with the examples, but they should not be understood as limiting the scope of protection of the present invention.

[0035] Example 1

[0036] The surface self-textured hard coating composite MoS2 film is prepared as follows:

[0037] (1) Surface pretreatment of the substrate: After roughening the substrate surface with 800-grit sandpaper, the substrate was cleaned with deionized water. The substrate was then placed in petroleum ether for ultrasonic cleaning for 5 minutes. The substrate was taken out for cleaning and then placed in a 0.1 mol / L dilute hydrochloric acid solution for ultrasonic cleaning for 5 minutes.

[0038] (2) Electroplating of Ni-SiC coating: The electroplating solution consists of 45g / L nickel chloride, 280g / L nickel sulfate, 35g / L boric acid, 1.8g / L silicon carbide nanoparticles (particle size 50nm), and 0.5g / L hexadecyltrimethylammonium bromide (CTAB). The solvent is deionized water with a pH value of 4.5. The preparation method of the electroplating solution is as follows: the surfactant CTAB and silicon carbide nanoparticles are added to a small amount of electroplating solution, and dispersed by ultrasonic vibration and magnetic stirring at a speed of about 500rpm for 90min each. Then, the obtained pre-dispersed silicon carbide nanoparticle system is added to the entire electroplating solution. The substrate is connected to the negative pole of the power supply as the workpiece to be plated, and the pure nickel plate is connected to the positive pole of the power supply. The substrate is placed in the electroplating solution (temperature 55℃), and the power supply current is adjusted to maintain the current density at 5A / dm 2 , the electroplating time is 1 min to form an electroplated nickel layer.

[0039] (3) Electroless plating coating (nickel-phosphorus alloy coating): The electroless plating solution consists of 36 g / L nickel sulfate, 28 g / L sodium hypophosphite, 34 g / L sodium acetate, 12.4 mL / L lactic acid, and 4 mg / L thiourea. The solvent is deionized water with a pH of 5.1. The electroplated sample is completely immersed in the electroless plating solution (temperature 89°C) for 15 minutes to form an electroless nickel layer. After the above electroplating and electroless plating, a surface self-textured nickel-based hard coating is obtained.

[0040] (4) Electrophoretic deposition of MoS2 thin film: The MoS2 dispersion consists of 2 g / L MoS2 and 0.5 g / L CTAB in deionized water. The MoS2 is evenly dispersed by ultrasonic dispersion and stirring. During electrophoretic deposition, the sample with the self-textured nickel-based hard coating is connected to the negative electrode of the power supply. The positive electrode is a graphite electrode. The voltage is set to 25 V and the electrophoresis time is 2 minutes. The MoS2 thin film is composited on the surface of the self-textured nickel-based hard coating.

[0041] Example 2

[0042] The surface self-textured hard coating composite MoS2 film is prepared as follows:

[0043] (1) Surface pretreatment of the substrate: After roughening the substrate surface with 800-grit sandpaper, the substrate was cleaned with deionized water. The substrate was then placed in petroleum ether for ultrasonic cleaning for 5 minutes. The substrate was taken out for cleaning and then placed in a 0.1 mol / L dilute hydrochloric acid solution for ultrasonic cleaning for 5 minutes.

[0044] (2) Electroplating of Ni-SiC coating: The electroplating solution consists of 45g / L nickel chloride, 280g / L nickel sulfate, 35g / L boric acid, 1.8g / L silicon carbide nanoparticles (particle size 30nm), and 0.5g / L CTAB. The solvent is deionized water with a pH value of 4.6. Preparation method of the electroplating solution: Add the surfactant CTAB and silicon carbide nanoparticles to a small amount of electroplating solution, disperse them by ultrasonic vibration and magnetic stirring at a speed of about 500rpm for 90min each, and then add the obtained pre-dispersed silicon carbide nanoparticle system to the entire electroplating solution. Connect the substrate as the workpiece to be plated to the negative electrode of the power supply, connect the pure nickel plate to the positive electrode of the power supply, and place them in the electroplating solution (temperature 55℃). Adjust the power supply current to maintain the current density at 5A / dm 2 The electroplating time is 2 minutes to form an electroplated nickel layer.

[0045] (3) Electroless nickel coating (nickel-phosphorus alloy coating): The electroless plating solution consists of 36 g / L nickel sulfate, 28 g / L sodium hypophosphite, 34 g / L sodium acetate, 12.4 mL / L lactic acid, and 4 mg / L thiourea. The solvent is deionized water with a pH of 5.0. The electroplated sample is completely immersed in the electroless plating solution (temperature 89°C) for 15 minutes to form an electroless plating layer. After the above electroplating and electroless plating, a surface self-textured nickel-based hard coating is obtained.

[0046] (4) Electrophoretic deposition of MoS2 thin film: The MoS2 dispersion consists of 2 g / L MoS2 and 0.5 g / L CTAB in deionized water. The MoS2 is evenly dispersed by ultrasonic dispersion and stirring. During electrophoretic deposition, the sample with the self-textured nickel-based hard coating is connected to the negative electrode of the power supply. The positive electrode is a graphite electrode. The voltage is set to 25 V and the electrophoresis time is 2 minutes. The MoS2 thin film is composited on the surface of the self-textured nickel-based hard coating.

[0047] Example 3

[0048] The surface self-textured hard coating composite MoS2 film is prepared as follows:

[0049] (1) Surface pretreatment of the substrate: After roughening the substrate surface with 800-grit sandpaper, the substrate was cleaned with deionized water, placed in petroleum ether for ultrasonic cleaning for 5 minutes, taken out and cleaned, and placed in 0.1 mol / L dilute hydrochloric acid solution for ultrasonic cleaning for 5 minutes.

[0050] (2) Electroplating of Ni-SiC coating: The electroplating solution consists of 45g / L nickel chloride, 280g / L nickel sulfate, 35g / L boric acid, 1.8g / L silicon carbide nanoparticles (particle size 60nm), and 0.5g / L CTAB. The solvent is deionized water with a pH value of 4.3. Preparation method of the electroplating solution: Add the surfactant CTAB and silicon carbide nanoparticles to a small amount of electroplating solution, disperse them by ultrasonic vibration and magnetic stirring at a speed of about 500rpm for 90min each, and then add the obtained pre-dispersed silicon carbide nanoparticle system to the entire electroplating solution. Connect the substrate as the workpiece to be plated to the negative electrode of the power supply, connect the pure nickel plate to the positive electrode of the power supply, and place them in the electroplating solution (temperature 55℃). Adjust the power supply current to maintain the current density at 5A / dm 2 The electroplating time is 3 minutes to form an electroplated nickel layer.

[0051] (3) Electroless nickel coating (nickel-phosphorus alloy coating): The electroless plating solution consists of 36 g / L nickel sulfate, 28 g / L sodium hypophosphite, 34 g / L sodium acetate, 12.4 mL / L lactic acid, and 4 mg / L thiourea. The solvent is deionized water with a pH of 4.8. The electroplated sample is completely immersed in the electroless plating solution (temperature 89°C) for 15 minutes to form an electroless plating layer. After the above electroplating and electroless plating, a surface self-textured nickel-based hard coating is obtained.

[0052] (4) Electrophoretic deposition of MoS2 thin film: The MoS2 dispersion consists of 2 g / L MoS2 and 0.5 g / L CTAB in deionized water. The MoS2 is evenly dispersed by ultrasonic dispersion and stirring. During electrophoretic deposition, the sample with the self-textured nickel-based hard coating is connected to the negative electrode of the power supply. The positive electrode is a graphite electrode. The voltage is set to 25 V and the electrophoresis time is 2 minutes. The MoS2 thin film is composited on the surface of the self-textured nickel-based hard coating.

[0053] Example 4

[0054] The surface self-textured hard coating composite MoS2 film is prepared as follows:

[0055] (1) Surface pretreatment of the substrate: After roughening the substrate surface with 800-grit sandpaper, the substrate was cleaned with deionized water. The substrate was then placed in petroleum ether for ultrasonic cleaning for 5 minutes. The substrate was taken out for cleaning and then placed in a 0.1 mol / L dilute hydrochloric acid solution for ultrasonic cleaning for 5 minutes.

[0056] (2) Electroplating of Ni-SiC coating: The electroplating solution consists of 45g / L nickel chloride, 280g / L nickel sulfate, 35g / L boric acid, 1.8g / L silicon carbide nanoparticles (particle size 60nm), and 0.5g / L CTAB. The solvent is deionized water with a pH value of 4.2. The preparation method of the electroplating solution is as follows: the surfactant CTAB and silicon carbide nanoparticles are added to a small amount of electroplating solution, and dispersed by ultrasonic vibration and magnetic stirring at a speed of about 500rpm for 90min each. Then, the obtained pre-dispersed silicon carbide nanoparticle system is added to the entire electroplating solution. The substrate is connected to the negative electrode of the power supply as the workpiece to be plated, and the pure nickel plate is connected to the positive electrode of the power supply. The substrate is placed in the electroplating solution (temperature 55℃), and the power supply current is adjusted to maintain the current density at 5A / dm 2 The electroplating time is 4 minutes to form an electroplated nickel layer.

[0057] (3) Electroless nickel coating (nickel-phosphorus alloy coating): The electroless plating solution consists of 36 g / L nickel sulfate, 28 g / L sodium hypophosphite, 34 g / L sodium acetate, 12.4 mL / L lactic acid, and 4 mg / L thiourea. The solvent is deionized water with a pH of 4.6. The electroplated sample is completely immersed in the electroless plating solution (temperature 89°C) for 15 minutes to form an electroless plating layer. After the above electroplating and electroless plating, a surface self-textured nickel-based hard coating is obtained.

[0058] (4) Electrophoretic deposition of MoS2 thin film: The MoS2 dispersion consists of 2 g / L MoS2 and 0.5 g / L CTAB in deionized water. The MoS2 is evenly dispersed by ultrasonic dispersion and stirring. During electrophoretic deposition, the sample with the self-textured nickel-based hard coating is connected to the negative electrode of the power supply. The positive electrode is a graphite electrode. The voltage is set to 25 V and the electrophoresis time is 2 minutes. The MoS2 thin film is composited on the surface of the self-textured nickel-based hard coating.

[0059] Figure 2 Surface optical microscope images and roughness measurement values ​​of the electroplated nickel layers (Ni-SiC coatings) formed by electroplating in Examples 1 to 4, Figure 2 In the embodiment, (a), (b), (c) and (d) correspond to Example 1, Example 2, Example 3 and Example 4, respectively. Figure 2 The results show that the surface roughness of the coating shows a positive correlation growth trend with the extension of electroplating time.

[0060] Figure 3 Surface scanning electron microscope images and roughness measurement values ​​of the multilayer nickel-based hard coatings formed by electroplating and chemical plating in Examples 1 to 4, Figure 3 In the embodiment, (a), (b), (c) and (d) correspond to Example 1, Example 2, Example 3 and Example 4, respectively. Figure 3The results show that the surface morphology of the multilayer coating reflects the morphological characteristics of the underlying coating well, and the surface roughness of the multilayer coating shows a positively correlated growth trend with the extension of electroplating time.

[0061] Figure 4 The thickness 3D image and contour curve of the MoS2 film in Example 1 are shown. Figure 4 (a) is the thickness three-dimensional image, and (b) is the contour curve. Figure 4 The results show that the thickness of the prepared MoS2 film is uniform.

[0062] Figure 5 The friction life curve of the surface self-textured hard coating composite MoS2 film prepared in Examples 1 to 4 is as follows: Figure 5 M1, M2, M3 and M4 correspond to Example 1, Example 2, Example 3 and Example 4 respectively. The friction test conditions are: rotation radius 5 mm, load 5 N, grinding ball (material 440C) diameter 8 mm, rotation speed 500 r / min. Figure 5 The results show that the present invention can maintain the MoS2 lubricating phase, thereby achieving long-term lubrication.

[0063] The comparative results of the above examples show that introducing hard nanoparticles into nickel-based coatings can form a textured surface. The roughness of the coating surface is provided by the underlying Ni-hard nanoparticle layer, without the need for mechanical processing, and its integrity is necessarily superior to that of subtractive manufacturing processes. The roughness of the Ni-hard nanoparticle layer increases with the extension of the preparation time, and this trend remains after the surface is coated with a nickel-phosphorus alloy. After compounding with a MoS2 solid lubricating film, the textured surface can effectively extend the friction life of MoS2.

[0064] It can be seen from the above embodiments that the present invention combines electroplating, chemical plating and electrophoretic deposition to prepare a composite film with good texture, which can ensure the integrity of the friction surface while forming surface microtexture, and greatly improve the friction reduction and wear resistance of the coating composite MoS2 solid lubricating film.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a surface self-textured hard coating composite MoS2 film, characterized in that: The following steps are involved: Electroplating nickel and chemically plating nickel on the surface of the substrate in sequence to form a surface self-textured nickel-based hard coating on the surface of the substrate; the electroplating solution used in the electroplating nickel includes hard nanoparticles; Electrophoretically depositing a MoS2 film on the surface of the surface self-textured nickel-based hard coating to obtain a surface self-textured hard coating composite MoS2 film; The electroplating solution is composed of the following components: 40-50 g / L nickel chloride, 250-300 g / L nickel sulfate, 30-40 g / L boric acid, 1.8 g / L hard nanoparticles, 0.3-1 g / L surfactant, and water as the solvent; the pH value of the electroplating solution is 4.0-6.0; the particle size of the hard nanoparticles is 10-100 nm; The chemical plating solution used in the chemical nickel plating is composed of the following components: 30-40 g / L nickel sulfate, 25-30 g / L sodium hypophosphite, 30-40 g / L sodium acetate, 11-13 mL / L lactic acid, 3-5 mg / L thiourea, and water as the solvent; the pH value of the chemical plating solution is 4.0-6.0; The electroplating temperature of the nickel plating is 50-60° C., the electroplating time is 4-10 min, and the current density is 2-8 A / dm 2 .

2. The preparation method according to claim 1, characterized in that The hard nanoparticles include one or more of SiC, Si3N4 and ZrO2.

3. The preparation method according to claim 1, characterized in that The electroless nickel plating temperature is 85-90° C., and the plating time is less than 90 minutes.

4. The preparation method according to claim 1, characterized in that The electrophoretic deposition solution used in the electrophoretic deposition includes the following components: MoS2 1-2 g / L, surfactant 0.3-1 g / L, and solvent is water.

5. The preparation method according to claim 1 or 4, characterized in that The voltage of the electrophoretic deposition is 10-36V, and the deposition time is less than or equal to 5 minutes.

6. A surface self-textured hard coating composite MoS2 film prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the surface self-textured hard coating composite MoS2 film according to claim 6 in friction and wear protection.

Images