Antifriction, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating as well as preparation method and application thereof

Abstract

The invention discloses an anti-friction, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating and a preparation method and application thereof.The preparation method comprises the steps that firstly, an impact nickel film is deposited on a stainless steel base body through an electrochemical deposition method to increase the binding force of the coating and the base body, and then a strengthening phase is doped in electroplating liquid to continue electroplating to form a doped composite coating; and finally, carrying out reduction treatment on the surface of the doped composite coating by utilizing a chemical plating method, so as to obtain the composite coating of which the surface is of a spore-shaped structure with a lubricating effect and the coating interface is flat and compact. The amorphous nickel-phosphorus coating provided by the invention can meet the performance requirements of friction reduction, wear resistance and corrosion resistance in extremely severe working conditions. The good chemical stability of the amorphous nickel-phosphorus coating cooperates with the anti-friction and wear-resistant effects of the doped components, corrosion media are prevented from entering, the friction coefficient is reduced, the hardness of the coating is improved, and then the wear resistance and corrosion resistance of the 316H stainless steel plate in the extreme working environment are improved.

Description

Technical Field

[0001] The invention belongs to the metal material surface treatment technology, and specifically relates to a friction-reducing, wear-resistant and corrosion-resistant integrated coating prepared on the surface of 316H stainless steel for use in high-temperature and extremely harsh environments. Background Art

[0002] 316H stainless steel is a high-carbon austenitic heat-resistant stainless steel. Its characteristics include good corrosion resistance, high temperature resistance and processing performance. It has a wide range of uses. However, 316H without surface treatment cannot meet the working conditions of extremely harsh environments, such as in the aerospace environment of vacuum, high temperature and high-speed friction. Continuous contact with the outside world will cause wear or damage to the workpiece. With the development of CVD technology, there are also various methods for material surface modification, such as preparing Ni coating by electrochemical deposition, chemical nickel-phosphorus coating and plasma cladding nickel-based coating. Nickel-based coating can improve the hardness of the material and enhance wear resistance. The nickel oxide film generated by nickel oxidation also improves the corrosion resistance of the material. However, the pure nickel coating has weak surface bonding with 316H, low hardness, thin thickness, and no good thermal insulation performance. The coating heats up rapidly under high-speed friction, resulting in easy expansion at the interface with the substrate. Nickel hydroxide is easily generated at high temperature to destroy the coating, so it is very easy to break and fall off during wear. Chemical nickel-phosphorus coating has high hardness, smooth surface and metallic luster, and the preparation method is simpler and safer, but it has poor bonding with the 316H surface and is easy to fall off. Plasma cladding nickel-based coating has certain requirements for the shape and specifications of the substrate. It is difficult to prepare coatings for irregular-shaped substrates using plasma cladding technology, which is relatively less convenient than electrochemical deposition.

[0003] Doping particles of different properties in the plating solution can achieve the desired functional coating. For example, adding MoS2 and WS2 with self-lubricating properties can greatly reduce the friction coefficient of the coating and reduce the degree of wear; adding WC with higher hardness can increase the hardness of the coating and play a role in wear resistance. Co-doping WS2 with lubricating effect and WC with high hardness in the corrosion-resistant Ni-P coating can prepare a composite coating with integrated friction reduction, wear resistance and corrosion resistance. However, it is not easy to obtain Ni-P coating on the surface of 316H stainless steel by electrochemical deposition, which hinders the use of 316H stainless steel materials under harsh working conditions such as vacuum, high temperature and high-speed friction.

[0004] Chinese patent authorization announcement number CN102859250B discloses a coated sleeve oil and gas well production device, which uses electroplating technology to prepare a coating on the surface of the inner sleeve, the surface of the outer sleeve or a combination thereof, wherein the coating is selected from amorphous alloys, heat-treated non-electroplated or electroplated nickel-phosphorus composite materials (wherein the phosphorus content is greater than 12wt%), graphite, MoS2, WS2, fullerene-based composite materials, boride-based metal ceramics, quasi-crystalline materials, diamond-based materials, diamond-like carbon (DLC), boron nitride and the above combination. The method is used to reduce friction, wear, corrosion, erosion and deposition in oil and gas well production operations. Although the technology discloses the use of electroplating to prepare the coating, the coating prepared by it is only used in general situations, and no detailed research is conducted on high temperature environments. Based on high temperature and harsh environments such as aerospace, by doping with microparticles with lubricating and friction-reducing effects, the coating and the substrate can be better protected. Summary of the invention

[0005] In order to meet the application of 316H in extremely harsh environments, the present invention provides a doped friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating, which achieves the effect of friction-reducing, wear-resistant and corrosion-resistant composite functions by preparing a Ni-WS2 (WC) / Ni-P composite structure coating.

[0006] The invention also provides a preparation method and application of the coating.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A doped friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating, characterized in that it is composed of a bottom Ni-(WS2 and / or WC) layer and an upper amorphous Ni-P layer, the two of which work together to achieve friction reduction, wear resistance and corrosion resistance, wherein the WS2 or WC exists in the coating in a lamellar scaly structure.

[0009] The above-mentioned doped friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating can be prepared by the following method, and the method steps are as follows:

[0010] Step 1: Pre-treat the 316H stainless steel substrate;

[0011] Step 2: Pre-plating a layer of impact nickel film on the substrate

[0012] The pretreated stainless steel substrate is placed in an acidic nickel-containing electroplating solution and deposited by pulse current chemical deposition. The entire process should follow the principle of short time and high current density, so as to form a (0.1-0.5μm) thick impact nickel film on the surface of the stainless steel substrate to ensure the bonding strength of the subsequent coating;

[0013] Step 3: Continue electroplating to form a doped composite coating

[0014] The stainless steel substrate pre-plated with an impact nickel film is continuously subjected to pulse current chemical deposition in an acidic nickel-containing composite electroplating solution containing a doping component, thereby forming a doped composite coating on the surface of the stainless steel substrate; the doping component refers to WS2 or WC or a combination of the two; the preparation method of the acidic nickel-containing composite electroplating solution containing the doping component is:

[0015] Firstly, nickel sulfate, nickel chloride and boric acid are placed in a constant temperature electroplating tank and stirred until a transparent solution is obtained, and then the pH value is adjusted to 3.8-4.3 with concentrated sulfuric acid or ammonia water to prepare a nickel-containing main salt solvent;

[0016] Adding a tank opening agent, a leveling agent, a wetting agent and a supplement into a nickel-containing main salt solvent and stirring until the solution is completely dissolved to obtain an undoped composite electroplating solution;

[0017] The doping component is dissolved in a cetyltrimethylammonium bromide (CTAB) solvent, and then added into an undoped composite electroplating solution and uniformly dispersed by ultrasonication;

[0018] Step 4: Reduction treatment of the doped composite coating

[0019] The substrate plated with the doped composite coating is placed in an alkaline nickel-phosphorus plating solution for chemical plating to obtain a Ni-P@(WS2 and / or WC) composite coating with a bottom doping and an amorphous surface.

[0020] Furthermore, the nickel-containing electroplating solution in step 2 is composed of nickel chloride and hydrochloric acid, wherein the concentration of nickel chloride is 200 g / L, and the concentration of hydrochloric acid is 100 mL / L.

[0021] Furthermore, in step 2 and step 3, the nickel plate is used as the anode.

[0022] Further, the pulse current chemical deposition parameters in step 3 are: current density 2-3A / dm 2 , plating solution temperature 50-60℃, plating solution PH value 3.0-4.5, plating time 50-60min.

[0023] Furthermore, the chemical plating parameters in step 4 are: chemical plating temperature 85-100° C., plating solution pH 4.6-5.2, and chemical plating time 60 min.

[0024] Furthermore, the chemical nickel-phosphorus plating solution in step 4 is composed of a phosphorus-containing solution, a phosphorus-containing solution and an alkaline solution, wherein the concentration of the nickel-containing solution is 50-60 mL / L, and the concentration of the phosphorus-containing solution is 130-150 mL / L; the alkaline solution is used to adjust the pH value.

[0025] Furthermore, in step 2, the pretreatment process of the stainless steel substrate includes mechanical grinding, degreasing and oil removal, and activation treatment.

[0026] Further, in step three, the concentrations of the components of the composite electroplating solution are: nickel sulfate 270-320 g / L, nickel chloride 35-45 g / L, boric acid 38-45 g / L, cylinder opener 9-12 g / L, leveler 0.3-1.0 g / L, wetting agent 2.0-5.0 g / L, supplementer 0.1-0.25 g / L, doping component WS2 5-20 g / L, doping component WC 4-10 g / L.

[0027] Furthermore, the friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating of the present invention is mainly used in vacuum, high-temperature and high-speed friction environments, such as aerospace environments.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The electrochemical deposition method adopted in the present invention has the advantages of simple process, low cost, and can be used to prepare modified coatings on large-area and complex-shaped substrates. The prepared coating is dense and uniform, has high bonding strength with the substrate, has high purity, electrochemical stability and conductivity, can effectively reduce the manufacturing cost of the plate coating, is suitable for mass production, and can meet the performance requirements of friction reduction, wear resistance and corrosion resistance in extremely harsh working conditions.

[0030] 3. The present invention first dissolves and disperses WS2 and / or WC in a CTAB solvent uniformly, and then mixes the mixture with a nickel electroplating solution to obtain a doped composite electroplating solution. The doped composite electroplating solution provides active sites for the deposition of a Ni-(WS2 and / or WC) composite coating. In this way, reduction at the cathode under the action of an electric field can complete the reduction and film-forming steps on a stainless steel substrate in one step (reduction refers to the reduction of charged particles in the plating solution, and film-forming refers to the deposition of charged particles on the substrate surface to form a thin film coating after reduction), and cross-linking grows into a continuous nickel-WS2 / WC coating.

[0031] 4. The amorphous nickel-phosphorus coating of the present invention is used as a corrosion-resistant coating to provide corrosion protection for stainless steel plates in extremely harsh working environments such as high-temperature vacuum environments in aerospace. The nickel-phosphorus-WS2 / WC coating has good conductivity and can effectively reduce the contact resistance of the system to meet the requirements of the plate for low contact resistance. At the same time, the two-dimensional layer structure of WS2 / WC in the composite coating can be used as a physical barrier layer. The good chemical stability of the amorphous nickel-phosphorus coating cooperates with the physical barrier layer of the WS2 / WC layer to prevent the entry of corrosive media, extend the corrosion channel, and improve the corrosion resistance and service stability of 316H stainless steel plates in extreme working environments.

[0032] 5. In the preparation of the acidic nickel-containing composite electroplating solution containing doping components, the present invention adds additives to the nickel-containing main salt solvent. In order to ensure the surface tension of the nickel composite electroplating solution before electroplating, an opener is added, which can maintain the excellent ductility and leveling force of the coating. The leveling agent is mainly used to obtain the leveling force of the coating, but if too much is added, the coating will lose its ductility, so it should be added in small amounts and multiple times. The supplementer is used in combination with the leveling agent to produce a uniform semi-bright coating within a wide current density range. The wetting agent can reduce the surface tension of the solution and prevent the generation of pinholes, thereby ensuring that the coating has excellent electrochemical stability and conductivity, as well as excellent mechanical strength and adhesion, and can fully utilize the synergistic effect of the composite coating.

[0033] 6. The present invention combines electrochemical deposition and chemical plating to obtain a doped nickel-phosphorus coating on a 316H stainless steel substrate. The doped component WS2 has a self-lubricating effect, generates a lubricating transfer film through friction, generates friction heat during friction and wear, forms a nickel oxide protective film on the surface of the coating, and reduces the friction coefficient. The doped component WC has an extremely high hardness advantage. In addition to being a hard doped particle, its own corrosion resistance also adds additional corrosion resistance to the coating. This is because the exogenous doped particles themselves can be used as a dispersion strengthening phase. The strong antioxidant properties of the particles themselves will reduce the ability of the Ni crystals around the particles to absorb oxygen, thereby delaying the occurrence of corrosion. The added P element combines with Ni in the coating to form polymers of different valence states, and produces single substance P, which has an effect on improving the corrosion resistance of the coating; in addition, in a high-temperature wear environment, as the temperature rises, Ni-P is oxidized to Ni3P, the hardness of the coating increases, and the wear resistance is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0035] Figure 1 X-ray diffraction patterns of Ni-P@WS2 composite coatings at different doping concentrations prepared in Example 1 of the present invention.

[0036] Figure 2 X-ray diffraction patterns of Ni-P@WC composite coatings at different doping concentrations prepared in Example 2 of the present invention.

[0037] Figure 3 X-ray diffraction patterns of Ni-P@WS2@WC composite coatings at different doping concentrations prepared in Example 3 of the present invention.

[0038] Figure 4Microhardness diagram of the Ni-P@WS2 composite coating at different doping concentrations prepared in Example 1 of the present invention, wherein a, b, c, and d represent doping concentrations of 5 g / L, 10 g / L, 15 g / L, and 20 g / L, respectively.

[0039] Figure 5 This is a curve diagram of the friction coefficient at room temperature of the Ni-P@WS2 composite coating at different doping concentrations prepared in Example 1 of the present invention.

[0040] Figure 6 The high temperature friction coefficient curves of the Ni-P@WS2 composite coating with a doping concentration of 15 g / L prepared in Example 1 of the present invention at high temperatures of 300°C and 500°C respectively.

[0041] Figure 7 Wear volume diagram of the Ni-P@WS2 composite coating with a doping concentration of 15 g / L prepared in Example 1 of the present invention at high temperatures of 300°C and 500°C, respectively, where a represents 300°C and b represents 500°C.

[0042] Figure 8 This is the electrochemical impedance Nyquist plot of the Ni-P@WS2 composite coating at different doping concentrations prepared in Example 1 of the present invention.

[0043] Fig. 9 The surface and interface micromorphology of the Ni-P@WS2@WC composite coating prepared in Example 3 of the present invention; wherein picture (a) is the surface micromorphology of the composite coating, and picture (b) is the interface micromorphology. DETAILED DESCRIPTION

[0044] In order to clearly express the purpose and specific implementation scheme of the present invention, the technical scheme in the embodiment of the present invention is described clearly and completely below by taking 316H stainless steel plate as a substrate. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0046] Example 1: Taking the preparation of Ni-P@WS2 coating on the surface of 316H stainless steel plate as an example, the steps are as follows:

[0047] Step 1: Pre-treat 316H stainless steel plate

[0048] The 316H stainless steel plate was polished with sandpaper of model 400#, 800# and 1200# in turn to remove the surface oxide film and defects, rinsed with deionized water, placed in an alkaline solution composed of 60g / L NaOH, 20g / L Na2 CO3, 30g / L NaPO4·12H2 O and 10g / L NaSiO3·9H2 O, and ultrasonically vibrated for 40min at room temperature for degreasing treatment, rinsed with deionized water, and then immersed in a 10% mass concentration hydrochloric acid solution for 40s for surface activation to remove the oxide scale, and finally ultrasonically cleaned with deionized water for use;

[0049] Step 2: Pre-plating a layer of impact nickel film on the pre-treated 316H stainless steel plate

[0050] 2.1: Weigh 200 g / L nickel chloride (that is, 200 g per liter of pre-nickel electroplating solution), 100 mL / L concentrated hydrochloric acid, add deionized water and stir to dissolve into a transparent solution to prepare a pre-nickel electroplating solution; the concentration of concentrated hydrochloric acid is 12 mol / L;

[0051] 2.2: Rinse the two nickel plates in deionized water to remove surface contaminants, then place them in an alkaline cleaning solution for ultrasonic cleaning for 40 minutes to remove grease, and finally rinse them with deionized water for later use;

[0052] 2.3: Connect the 316H stainless steel plate pretreated in step 1 to the negative electrode of the pulse power supply as a cathode, connect the two nickel plates treated in step 2.2 to the positive electrode of the pulse electroplating power supply as a double anode, place the cathode and double anode in the pre-nickel plating solution prepared in step 2.1, and use constant current deposition method with a deposition current density of 6A / cm 2 , the electroplating solution is placed in a constant temperature water bath at room temperature, the deposition time is 5 minutes, the rotation speed is 400r / min, and the impact nickel coating is obtained on the surface of the stainless steel plate. The cathode and anode are taken out and rinsed with deionized water for use (the cathode refers to a 316H stainless steel plate with a layer of nickel film, and the anode refers to two nickel plates);

[0053] Step 3: Continue electroplating to form Ni@WS2 composite coating

[0054] 3.1: Weigh 300 g / L nickel sulfate, 40 g / L nickel chloride, and 42 g / L boric acid, add deionized water, place in a constant temperature water bath, and stir until a transparent solution is obtained. The stirring temperature is room temperature. Use ammonia water or concentrated sulfuric acid to adjust the pH value to 3.8-4.3 to prepare a nickel-containing main salt solvent for use;

[0055] 3.2: Weigh 10g / L of opening agent, 0.5g / L of leveling agent, 2.5g / L of wetting agent, and 0.15g / L of supplement. Add them into the nickel-containing main salt solvent and stir until completely dissolved at room temperature to prepare the electroplating nickel coating solution;

[0056] The cylinder opening agent, leveling agent, wetting agent and supplementing agent are commonly used additives in this field and will not be described in detail here;

[0057] 3.3: Weigh 10 g / L WS2 and 20 mg / g CTAB of WS2 and add them to the plating solution obtained in step 3.2, stir for 60 min, and ultrasonicate for 20 min. Repeat three times until WS2 is completely dispersed and there is no obvious agglomeration, to obtain a WS2 composite electroplating solution;

[0058] 3.4: Connect the 316H stainless steel plate pre-nickel-plated in step 2 to the negative electrode of the pulse power supply as the cathode, connect the two nickel plates treated in step 2.3 to the positive electrode of the pulse electroplating power supply as double anodes, place the cathode and double anodes in the WS2 composite electroplating solution prepared in step 3.3, and use constant current deposition method with a deposition current density of 2A / cm 2 The electroplating solution was placed in a constant temperature water bath at 57°C, the deposition time was 60 min, the rotation speed was 400 r / min, and a Ni@WS2 composite coating was obtained on the surface of the stainless steel plate; the cathode and anode were taken out and rinsed with deionized water for later use;

[0059] The g / L in the above steps 3.1-3.3 refers to the concentration of the component in the WS2 composite electroplating solution;

[0060] Step 4: Chemical plating of the Ni@WS2 composite coating to form a Ni-P@WS2 composite coating

[0061] 4.1: Weigh 60 g / L of nickel-containing solution and 150 g / L of phosphorus-containing solution, add deionized water and stir to dissolve into a transparent solution, adjust the pH value to 4.6-5.2 with ammonia water, and prepare a chemical nickel-phosphorus plating solution;

[0062] The mL / L here refers to the volume concentration of the component in the chemical nickel phosphorus plating solution;

[0063] In the embodiment, the nickel-containing solution is NiSO4·6H2O solution, and the phosphorus-containing solution is NiSO4·6H2O solution;

[0064] In order to maintain the stability of the chemical nickel-phosphorus plating solution, the chemical nickel-phosphorus plating solution in the embodiment further adds C6H8O7·H2O, CH3COONa and Na2MoO4·2H2O. These are well-known technologies in the art and will not be described in detail here;

[0065] 4.2: Place the 316H stainless steel plate with Ni@WS2 composite coating in step 3.4 in the chemical nickel-phosphorus plating solution prepared in step 4.1. The plating solution is kept in a constant temperature water bath at 88°C, the deposition time is 60 minutes, and the rotation speed is 400r / min, thereby obtaining a bright and smooth chemical nickel-phosphorus coating.

[0066] Example 2: Taking the preparation of Ni-P@WC coating on the surface of 316H stainless steel plate as an example

[0067] The difference between Example 2 and Example 1 is that the doping component 10 g / L WS2 in step 3.3 is replaced by 8 g / L WC, and correspondingly, the solvent CTAB is replaced from the original 20 mg / g WS2 to 20 mg / g WC. The other parameters remain unchanged.

[0068] Example 3: Taking the preparation of Ni-P@WS2@WC coating on the surface of 316H stainless steel plate as an example

[0069] The difference between Example 3 and Example 1 is that the doping component 10g / L WS2 in step 3.3 is replaced by a combination of 10g / L WS2 and 8g / L WC. Correspondingly, the solvent CTAB is replaced by 20mg / g (WS2+WC) from the original 20mg / g WS2 (that is, 20mg CTAB solvent is required for every 1g WS2 and WC combination), and the other parameters remain unchanged. The surface and interface micromorphology of the Ni-P@WS2@WC composite coating prepared in Example 3 is shown in FIG. Fig. 9 .from Fig. 9 As can be seen from (a), the surface of the composite coating presents a spore-like structure with lubricating effect, and from 9(b), it can be seen that the interface of the composite coating is flat and dense.

[0070] The X-ray diffraction patterns of the composite coatings prepared in the above three embodiments are shown in Figure 1 , Figure 2 and Figure 3 From the XRD results of the three figures, it can be seen that the peak positions of the coatings obtained under different doping concentrations are basically the same. The peak intensity does not increase continuously with the increase of doping concentration, but has a trend of first increasing and then weakening, indicating that the agglomeration state of doping is different with the increase of content. When the doping content is high, the particle agglomeration effect is aggravated, resulting in a sudden decrease in the Ni peak intensity, indicating that further increasing the doping content will not improve the distribution uniformity of the material, so in actual operation, the doping concentration in the electroplating solution must be strictly controlled. In addition, from the spectrum, it can be seen that P does not appear near the main peak or on the main peak, which indicates that P exists in an amorphous state.

[0071] In order to verify the mechanical properties of the composite coating of the present invention, the hardness of the Ni-P@WS2 composite coating with different doping concentrations prepared in Example 1 was tested. The test results are shown in Figure 4 ,from Figure 4It can be seen that the Ni-P@WS2-15 coating has the highest microhardness, which can reach 660.6HV0.1. The lowest hardness is the Ni-P@WS2-20 coating, with a hardness value of 420.1HV0.1. As the concentration of WS2 increases, the deposition rate on the substrate surface increases, and the WS2 particles occupy more binding sites, resulting in changes in the content of Ni and P. The thickness of the Ni-P@WS2 coating also changes accordingly, causing the microhardness of the coating to first increase and then decrease. This is because the addition of WS2 reduces the grain size, resulting in grain boundary strengthening. WS2 particles provide more attachment surface area at the mosaic sites, and their own conductivity efficiency is higher than the conductivity of the material itself, which greatly promotes the ion adsorption effect in the solution and increases the nucleation rate of the coating. Figure 5 The friction coefficient at room temperature also shows that the Ni-P@WS2-15 coating has the lowest friction coefficient and the best friction reduction property.

[0072] In order to prove the high temperature friction reduction and wear resistance of the composite coating of the present invention, the friction coefficient and wear volume of the Ni-P@WS2-15 coating prepared in Example 1 were tested at 300°C and 500°C respectively. The test results are shown in Figure 6-7 As can be seen from the figure, when the friction temperature is 300℃ and 500℃, the friction coefficient of the composite coating tends to decrease with increasing temperature, and the wear quality also decreases with increasing temperature.

[0073] In order to verify the corrosion resistance of the composite coating of the present invention, the electrochemical corrosion of the Ni-P@WS2 composite coating with different doping concentrations prepared in Example 1 was tested, and the results were as follows: Figure 8 As can be seen from the electrochemical impedance Nyquist diagram, the curve is arc-shaped, indicating a charge transfer mechanism. The larger the radius of the arc curve, the higher the transfer resistance, the more difficult it is for the coating to transfer electrons, and the more difficult it is for electrochemical corrosion to occur on the surface, thereby further improving the corrosion resistance of the material.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating, characterized in that: It is composed of a bottom Ni-(WS2 and / or WC) layer and an upper amorphous Ni-P layer, which work together to achieve friction reduction, wear resistance and corrosion resistance. The WS2 or WC exists in the coating in a lamellar scaly structure.

2. A method for preparing the friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating according to claim 1, characterized in that: The steps are as follows: Step 1: pre-treat the stainless steel substrate; Step 2: Pre-plating a layer of impact nickel film on the substrate The pretreated stainless steel substrate is placed in an acidic nickel-containing electroplating solution and deposited by pulse current chemical deposition. The entire process should follow the principle of short time and high current density, so as to form a (0.1-0.5μm) thick impact nickel film on the surface of the stainless steel substrate to ensure the bonding strength of the subsequent coating; Step 3: Continue electroplating to form a doped composite coating The stainless steel substrate pre-plated with an impact nickel film is continuously subjected to pulse current chemical deposition in an acidic nickel-containing composite electroplating solution containing a doping component, thereby forming a doped composite coating on the surface of the stainless steel substrate; the doping component refers to WS2 or WC or a combination of the two; the preparation method of the acidic nickel-containing composite electroplating solution containing the doping component is: Firstly, nickel sulfate, nickel chloride and boric acid are placed in a constant temperature electroplating tank and stirred until a transparent solution is obtained, and then the pH value is adjusted to 3.8-4.3 with concentrated sulfuric acid or ammonia water to prepare a nickel-containing main salt solvent; Adding a tank opening agent, a leveling agent, a wetting agent and a supplement into a nickel-containing main salt solvent and stirring until the solution is completely dissolved to obtain an undoped composite electroplating solution; The doping component is dissolved in a cetyltrimethylammonium bromide (CTAB) solvent, and then added into an undoped composite electroplating solution and uniformly dispersed by ultrasonication; Step 4: Reduction treatment of the doped composite coating The substrate plated with the doped composite coating is placed in an alkaline nickel-phosphorus plating solution for chemical plating to obtain a Ni-P@(WS2 and / or WC) composite coating with a bottom doping and an amorphous surface.

3. The method for preparing the friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating according to claim 2, characterized in that: The nickel-containing electroplating solution in step 2 is composed of nickel chloride and hydrochloric acid, wherein the concentration of nickel chloride is 200 g / L, and the concentration of hydrochloric acid is 100 mL / L.

4. The method for preparing the friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating according to claim 2, characterized in that: In both step 2 and step 3, the nickel plate is used as the anode.

5. The method for preparing the friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating according to claim 4, characterized in that: The pulse current chemical deposition parameters in step 3 are: current density 2-3A / dm 2 , electroplating solution temperature 50-60℃, electroplating solution PH value 3.0-4.5, electroplating time 50-60min.

6. The method for preparing the friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating according to claim 2, characterized in that: The chemical plating parameters in step 4 are: chemical plating temperature 85-100° C., plating solution pH 4.6-5.2, and chemical plating time 60 min.

7. The method for preparing the friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating according to claim 2, characterized in that: The chemical nickel-phosphorus plating solution in step 4 is composed of a phosphorus-containing solution, a phosphorus-containing solution and an alkali solution, wherein the concentration of the nickel-containing solution is 50-60 mL / L, and the concentration of the phosphorus-containing solution is 130-150 mL / L; the alkali solution is used to adjust the pH value.

8. The method for preparing the friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating according to claim 2, characterized in that: In step 2, the pretreatment process of the stainless steel substrate includes mechanical grinding, degreasing and oil removal, and activation treatment.

9. The method for preparing the friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating according to claim 5, characterized in that: In step three, the concentrations of the components of the composite electroplating solution are: nickel sulfate 270-320 g / L, nickel chloride 35-45 g / L, boric acid 38-45 g / L, cylinder opener 9-12 g / L, leveler 0.3-1.0 g / L, wetting agent 2.0-5.0 g / L, supplementer 0.1-0.25 g / L, doping component WS 25-20 g / L, doping component WC 4-10 g / L.

10. Use of the friction-reducing, wear-resistant and corrosion-resistant integrated nickel-phosphorus coating as claimed in claim 1 in a vacuum, high temperature and high-speed friction environment.

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