Preparation method of wear-resistant protective coating for metal sealing surface wide temperature range and coating

Abstract

The application belongs to the field of coating, and particularly relates to a preparation method of a wear-resistant protective coating for a metal sealing surface in a wide temperature range and the coating. 2+ The coating is prepared by electroplating in a plating solution with a concentration of 125g / L-155g / L, ceramic particle concentration of 5g / L-15g / L including chromium carbide particles and / or chromium oxide particles, and hBN particle concentration of 1g / L-10g / L, under ultrasonic waves, wherein the Dv50 values of the ceramic particles and the hBN particles are 2-8um and 3-15um respectively; the composite electroplating is divided into three stages, and the ultrasonic frequencies of the three stages are 28-32KHZ, 38-42KHZ and 38-42KHZ respectively, and the current densities are 0.5-2A / dm 2 , 1.5-3A / dm 2 and 3-4A / dm 2 respectively. The coating has significantly improved wear resistance and reduced surface roughness.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coating, and particularly relates to a preparation method of a wear-resistant protective coating for a metal sealing surface in a wide temperature range and the coating. BACKGROUND

[0002] To improve the service life and working temperature of multiple types of hot end components in engines such as gas turbines and aero-engines, wear-resistant and high-temperature-resistant coatings have attracted great attention. Thin-walled metal sealing elements with strong resilience are widely used in high-pressure compressors and high-pressure turbines of engines to improve the air path sealing performance of the elements, but the thin-walled metal sealing elements are prone to fretting wear during service, which may cause wear-out of the elements and reduction of air tightness. It has been proposed to use thermal spraying technology to prepare a CoCr-based coating on the surface of the thin-walled metal sealing element, but the coating has the problems of poor sealing performance due to large surface roughness and easy peeling and wear-out of the elements due to limited wear resistance.

[0003] It should be noted that this part of the present application only provides background related to the present application, and does not necessarily constitute prior art or common knowledge. SUMMARY

[0004] The present application aims to overcome the defects of the coating on the surface of the thin-walled metal sealing element in the prior art, such as large surface roughness, limited wear resistance, easy peeling of the coating, wear-out of the element and poor sealing performance, and to provide a preparation method of a wear-resistant protective coating for a metal sealing surface in a wide temperature range and the coating. The coating has significantly improved wear resistance and reduced surface roughness.

[0005] To achieve the above-mentioned purpose, in a first aspect, the present application provides a preparation method of a wear-resistant protective coating for a metal sealing surface in a wide temperature range, comprising the following steps:

[0006] The substrate is placed in a pre-plating solution for pre-plating treatment to obtain a pre-plating layer. The substrate after pre-plating treatment is placed in a composite plating solution for composite electroplating to obtain the wear-resistant protective coating. The composite plating solution contains Co 2+ , ceramic particles and hBN particles. The ceramic particles include chromium carbide particles and / or chromium oxide particles. The particle size distribution of the ceramic particles has a Dv50 value of 2-8 μm. The particle size distribution of the hBN particles has a Dv50 value of 3-15 μm. The concentration of Co 2+ in the composite plating solution is 125-155 g / L, the concentration of ceramic particles is 5-15 g / L, and the concentration of hBN particles is 1-10 g / L.

[0007] The composite electroplating is performed under ultrasonic waves, and the composite electroplating comprises sequentially performed first composite electroplating, second composite electroplating and third composite electroplating, the ultrasonic wave frequency and current density of the first composite electroplating are respectively 28KHZ-32KHZ and 0.5A / dm 2 ~2A / dm 2 , the ultrasonic wave frequency and current density of the second composite electroplating are respectively 38KHZ-42KHZ and 1.5A / dm 2 ~3A / dm 2 , the ultrasonic wave frequency and current density of the third composite electroplating are respectively 38KHZ-42KHZ and 3A / dm 2 ~4A / dm 2 .

[0008] In some preferred embodiments, the electroplating time of the first composite electroplating, the second composite electroplating and the third composite electroplating is respectively 1h-1.5h, 1h-1.5h and 0.5h-1h.

[0009] In some preferred embodiments, the temperature of the composite plating solution is 50℃-60℃.

[0010] In some preferred embodiments, the composite plating solution further contains NaCl, H3BO3 and a first surfactant, the concentration of NaCl in the composite plating solution is 30g / L-50g / L, the concentration of H3BO3 is 20g / L-50g / L, and the concentration of the first surfactant is 0.01g / L-0.2g / L, and the first surfactant is sodium dodecyl sulfonate.

[0011] In some preferred embodiments, the initial hBN particles are ultrasonically dispersed in anhydrous ethanol, centrifuged and separated to obtain an hBN particle precursor, and the hBN particle precursor is ultrasonically dispersed in an aqueous solution of a second surfactant, centrifuged and separated to obtain the hBN particles, and the second surfactant is sodium dodecyl sulfonate.

[0012] And / or, the initial ceramic particles are ultrasonically dispersed in anhydrous ethanol, centrifuged and separated to obtain a ceramic particle precursor, and the ceramic particle precursor is ultrasonically dispersed in water, centrifuged and separated to obtain the ceramic particles.

[0013] Preferably, the concentration of the aqueous solution of the second surfactant is 0.1g / L-0.5g / L.

[0014] In some preferred embodiments, the ceramic particles comprise chromium carbide particles; and / or, after the composite electroplating, heat treatment is performed to obtain the wear-resistant protective coating, and the temperature of the heat treatment is 400℃-500℃.

[0015] In some preferred embodiments, the pre-plating solution is a nickel-based plating solution, the concentration of Ni 2+ is 45 g / L to 60 g / L, the pH of the pre-plating solution is 2 to 3.8, and the temperature of the pre-plating solution is 20℃ to 40℃.

[0016] The current density of the pre-plating treatment is 3 A / dm 2 to 9 A / dm 2 , and the time is 4 min to 10 min.

[0017] In a second aspect, the present application provides a wear-resistant protective coating for a metal sealing surface in a wide temperature range, which is prepared by the preparation method of the first aspect, and the wear-resistant protective coating comprises a Co matrix component and ceramic particles and hBN particles dispersedly distributed in the Co matrix component, wherein the ceramic particles comprise chromium carbide particles and / or chromium oxide particles.

[0018] In some preferred embodiments, the roughness of the wear-resistant protective coating is ≤1.2 μm.

[0019] The preparation method of the wear-resistant protective coating of the present application comprises the following steps: placing the substrate after the pre-plating treatment into a composite plating solution containing Co 2+ , chromium carbide ceramic particles and / or chromium oxide ceramic particles, and hBN particles to perform composite electroplating, so that the prepared coating comprises a Co matrix component and ceramic particles and hBN particles dispersedly distributed in the Co matrix component.

[0020] The present application can reduce the possibility of surface wear or adhesion of the coating to the debris of the friction pair by utilizing the good lubricity of the h-BN particles themselves, can reduce the surface friction of the coating, and can improve the wear resistance. 2+The concentration is 125g / L-155g / L, the ceramic particle concentration is 5g / L-15g / L, the hBN particle concentration is 1g / L-10g / L, the ceramic particle size distribution is Dv50 value of 2-8um, the hBN particle size distribution is Dv50 value of 3-15um, the composite electroplating is carried out under ultrasonic wave, the cavitation effect of ultrasonic wave can make the ceramic particles and hBN particles in the plating solution uniformly dispersed, and the composite electroplating is further carried out in stages, the ultrasonic frequency and current density of the first stage are respectively 28KHZ-32KHZ, 0.5A / dm 2 -2A / dm 2 , the lower ultrasonic frequency is used to improve the wettability of the ceramic particles and hBN particles, the uniform dispersion of the ceramic particles and hBN particles in the plating solution is realized, and the lower current density is used to carry out the preliminary co-deposition of the ceramic particles, hBN particles and the matrix metal Co, so that the matrix metal is coated with a composite coating with low particle content, and the adhesion between the composite coating and the substrate is improved; the ultrasonic frequency and current density of the second stage are respectively 38KHZ-42KHZ, 1.5A / dm 2 -3A / dm 2 , the higher ultrasonic frequency is used to further promote the uniform dispersion of the ceramic particles and hBN particles, the uniform distribution of the coating is improved, the current density is increased to promote the transmission speed of the ceramic particles and hBN particles to the substrate, the content of the ceramic particles and hBN particles in the coating is increased, the chromium carbide ceramic particles and / or chromium oxide ceramic particles are fully utilized, and the effect of promoting the crystallization refinement of the matrix metal is achieved; the ultrasonic frequency and current density of the third stage are respectively 38KHZ-42KHZ, 3A / dm 2 -4A / dm 2 , the dispersion degree of the ceramic particles and hBN particles in the plating solution is maintained, the current density is increased to further improve the transmission speed of the particles and increase the content of the ceramic particles and hBN particles in the coating, the hBN particles are fully utilized to reduce the possibility of adhesion or adhesion of the coating surface to the abrasive debris, the Co matrix component and Cr element form an enamel layer to improve the lubricity and wear resistance of the coating, and the chromium carbide ceramic particles and / or chromium oxide ceramic particles promote the crystallization refinement of the matrix metal. The three-stage composite electroplating under ultrasonic wave maximizes the effects of the three aspects to reduce the roughness of the coating and improve the wear resistance of the coating. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0022] Figure 1 A schematic diagram of the cross-sectional structure of the wear-resistant protective coating of the metal sealing surface of the present application in a wide temperature range.

[0023] Figure 2 A scanning electron microscope photo of the surface morphology of the wear-resistant protective coating of Example 1 of the present application.

[0024] Figure 3 A photo of the appearance of the coating of Example 1 of the present application after the fretting wear test at 400℃.

[0025] Figure 4 A photo of the appearance of the coating of Comparative Example 4 of the present application after the fretting wear test at 400℃.

[0026] Figure 5 A photo of the appearance of the coating of Example 1 of the present application after the fretting wear test at 500℃.

[0027] Figure 6 A photo of the appearance of the coating of Comparative Example 4 of the present application after the fretting wear test at 500℃. DETAILED DESCRIPTION

[0028] The endpoints of the ranges and any values claimed herein are not to be understood as being limited to the exact values recited as implicitly included within the range. Ranges can be expressed as from about one particular value to about another particular value. When such a range is expressed, the range is intended to include all values and sub-ranges between the specific values stated.

[0029] The inventors of the present application have found that the existing coating on the surface of the thin-walled metal sealing member has a large surface roughness and limited wear resistance, which can easily lead to peeling of the coating, wear of the part and affect the sealing performance.

[0030] For this first aspect, the present application provides a method for preparing a wear-resistant protective coating of a metal sealing surface in a wide temperature range, comprising the following steps:

[0031] The substrate is placed in a pre-plating solution for pre-plating treatment to obtain a pre-plating layer; the substrate after pre-plating treatment is placed in a composite plating solution for composite electroplating to obtain the wear-resistant protective coating, the composite plating solution contains Co 2+ , ceramic particles and hBN particles, the ceramic particles include chromium carbide particles and / or chromium oxide particles, the particle size distribution of the ceramic particles has a Dv50 value of 2 μm to 8 μm, the particle size distribution of the hBN particles has a Dv50 value of 3 μm to 15 μm, the concentration of Co 2+ in the composite plating solution is 125 g / L to 155 g / L, the concentration of ceramic particles is 5 g / L to 15 g / L, and the concentration of hBN particles is 1 g / L to 10 g / L.

[0032] The composite electroplating is carried out under ultrasonic waves, and the composite electroplating comprises sequentially carried out first composite electroplating, second composite electroplating and third composite electroplating, the ultrasonic wave frequency and current density of the first composite electroplating are respectively 28KHZ-32KHZ and 0.5A / dm 2 ~2A / dm 2 , the ultrasonic wave frequency and current density of the second composite electroplating are respectively 38KHZ-42KHZ and 1.5A / dm 2 ~3A / dm 2 , and the ultrasonic wave frequency and current density of the third composite electroplating are respectively 38KHZ-42KHZ and 3A / dm 2 ~4A / dm 2 .

[0033] The preparation method of the wear-resistant protective coating of the present application comprises the following steps: placing a pre-plated substrate into a composite plating solution containing Co 2+ , chromium carbide ceramic particles and / or chromium oxide ceramic particles and hBN particles to carry out composite electroplating, and the prepared coating comprises a Co matrix component and ceramic particles and hBN particles dispersedly distributed in the Co matrix component. The first aspect is that the good lubricity of h-BN particles can reduce the possibility of surface wear or adhesion of the coating to the debris of the opposite grinding pair, and also can reduce the surface friction of the coating and improve the wear resistance. The second aspect is that when shearing at high temperature, the Co matrix component and Cr elements form an enamel layer to improve the lubricity and wear resistance of the coating. The third aspect is that the strong pinning effect of a large number of chromium carbide ceramic particles and / or chromium oxide ceramic particles has the effect of refining the crystallization of the coating matrix metal, and increases the hardness of the coating. Through the mutual cooperation of the above three aspects, the coating can maintain a low surface roughness and high wear resistance in a wide temperature range of-10℃ to 600℃, effectively resist fretting wear, prevent the thin-walled metal sealing element from being worn through, maintain excellent sealing performance, and improve the service life of the part.

[0034] In the composite plating solution of the present application, Co 2+The concentration of the ceramic particles is not less than 5 g / L, which can improve the composite amount of the ceramic particles in the coating, fully play the role of the chromium element in forming the enamel layer and the ceramic particles in promoting the crystallization refinement of the matrix metal, and is not more than 15 g / L, which can prevent the accumulation of the ceramic particles on the surface of the substrate and affect the mass transfer of the cobalt ions of the matrix metal; the Dv50 value of the ceramic particles is not less than 2 μm, which can prevent the agglomeration of the ceramic particles and affect the compactness and uniformity of the coating, and can fully play the pinning effect of the ceramic particles, and is not more than 8 μm, which can ensure the composite amount of the ceramic particles in the coating and improve the wear resistance of the coating; the concentration of the hBN particles is not less than 1 g / L, which can improve the composite amount of the hBN particles in the coating and fully play the role of the hBN particles in reducing the possibility of the adhesion of the coating surface to the attrition debris, and is not more than 10 g / L, which can prevent the accumulation of the hBN particles on the surface of the substrate and affect the mass transfer of the cobalt ions of the matrix metal, and can prevent the composite of the ceramic particles from being affected and the composite amount of the ceramic particles from being reduced, thereby affecting the final wear resistance; the Dv50 value of the hBN particles is not less than 3 μm, which can prevent the agglomeration of the hBN particles and affect the compactness and uniformity of the coating, and is not more than 15 μm, which can ensure the composite amount of the hBN particles in the coating and prevent the problems such as the increase of the surface roughness of the coating and the appearance of holes in the coating. In the composite plating solution, Co 2+ When the concentration of the ceramic particles is 5 g / L to 15 g / L, the concentration of the hBN particles is 1 g / L to 10 g / L, the particle size distribution of the ceramic particles has a Dv50 value of 2 μm to 8 μm, and the particle size distribution of the hBN particles has a Dv50 value of 3 μm to 15 μm, the composite electroplating is carried out under ultrasonic waves, which will not cause directional flow of the plating solution compared with magnetic stirring and other methods, and the cavitation effect of the ultrasonic waves can uniformly disperse the ceramic particles and the hBN particles in the plating solution, and the ceramic particles and the hBN particles can be separated. Further, the composite electroplating is carried out in stages, the ultrasonic frequency and the current density in the first stage are 28 KHZ to 32 KHZ and 0.5 A / dm 2 2 A / dm 2 , respectively, the lower ultrasonic frequency is used to improve the wettability of the ceramic particles and the hBN particles, the uniform dispersion of the ceramic particles and the hBN particles in the plating solution is realized, and the lower current density is used to preliminarily co-deposit the ceramic particles, the hBN particles and the matrix metal Co, so as to obtain a matrix metal base composite coating with a low particle composite amount; the ultrasonic frequency and the current density in the second stage are 38 KHZ to 42 KHZ and 1.5 A / dm 2 3 A / dm 2, the higher ultrasonic frequency is used to further promote the uniform dispersion of ceramic particles and hBN particles, improve the uniform distribution of the coating, increase the current density to promote the transmission speed of ceramic particles and hBN particles to the substrate, increase the composite amount of ceramic particles and hBN particles in the coating, fully exert the effect of chromium carbide ceramic particles and / or chromium oxide ceramic particles, and promote the crystallization refinement of the matrix metal; the ultrasonic frequency and current density of the third stage are 38KHZ-42KHZ and 3A / dm 2 -4A / dm 2 , maintain the dispersion degree of ceramic particles and hBN particles in the plating solution, increase the current density to further improve the transmission speed of the particles and increase the composite amount of ceramic particles and hBN particles in the coating, fully exert the effect of hBN particles to reduce the possibility of wear or adhesion of the coating surface to the abrasive debris, chromium element to form enamel layer, and chromium carbide ceramic particles and / or chromium oxide ceramic particles to promote the crystallization refinement of the matrix metal. The three stages of composite electroplating under ultrasonic waves make the three aspects of the foregoing mutually cooperate to maximize the reduction of coating roughness and improve the wear resistance of the coating.

[0035] If the ultrasonic frequency of the first stage is lower than 28KHZ, it will affect the uniform dispersion of ceramic particles and hBN particles in the plating solution, and if it is higher than 32KHZ, the composite amount of ceramic particles and hBN particles will be too high, affecting the connection between the composite coating and the substrate and the bonding force between the composite coating and the substrate. If the current density is lower than 0.5A / dm 2 , it will affect the mass transfer rate of cobalt ions in the matrix metal, leading to slow growth of the coating matrix metal and affecting the coating quality. If it is higher than 2A / dm 2 , the composite amount of ceramic particles and hBN particles will be too high, affecting the bonding force between the composite coating and the substrate; if the ultrasonic frequency of the second stage is lower than 38KHZ, it will affect the full dispersion of ceramic particles and hBN particles in the plating solution and the embedding of ceramic particles and hBN particles by the matrix metal deposition, and if it is higher than 42KHZ, it will easily increase the bubbles in the plating solution, leading to defects such as holes in the coating. If the current density is lower than 1.5A / dm 2 , the mass transfer rate of the matrix metal ions will be too low to catch up with the deposition rate of the matrix metal ions, which will reduce the composite amount of ceramic particles and hBN particles in the coating and affect the wear resistance of the coating. If the current density is higher than 3A / dm 2 , the mass transfer rate of the matrix metal ions will be too fast, which is not conducive to the stable embedding deposition of ceramic particles and hBN particles and the stable growth of the plating layer. If the ultrasonic frequency of the third stage is lower than 38KHZ, it will affect the composite amount of ceramic particles and hBN particles in the composite coating and the uniform distribution of ceramic particles and hBN particles in the plating layer. If it is higher than 42KHZ, it will easily increase the bubbles in the plating solution, leading to defects such as holes in the coating. If the current density is lower than 3A / dm 2, affect the composite amount of ceramic particles and hBN particles in the composite coating, and is not conducive to obtaining a high powder composite amount of the coating in a short time. 2 If only the first stage of smaller current and smaller ultrasonic frequency electroplating is used, the composite amount of ceramic powder and hBN particles in the coating tends to be close to zero, and the wear resistance of the coating is insufficient. If only the second stage of current and ultrasonic frequency electroplating is used, the adhesion of the composite coating to the substrate is easily affected, resulting in a decrease in the wear resistance of the coating. If only the third stage of larger current and larger ultrasonic frequency electroplating is used, the coating is easily roughened. If only the first stage of current and ultrasonic frequency electroplating and the second stage of current and ultrasonic frequency electroplating are used in sequence, the overall composite amount of the coating is easily low, reducing the wear resistance of the coating. If only the second stage of current and ultrasonic frequency electroplating and the third stage of current and ultrasonic frequency electroplating are used in sequence, the adhesion of the coating to the substrate is easily low, affecting the wear resistance of the coating. If only the first stage of current and ultrasonic frequency electroplating and the third stage of current and ultrasonic frequency electroplating are used in sequence, the coating is easily roughened, affecting the sealing of the part.

[0036] The pre-plating treatment of the substrate in the pre-plating solution of the present application can improve the adhesion of the coating to the substrate and prevent the coating from peeling off.

[0037] The Dv50 value of the ceramic particles may, for example, be 2, 4, 6 and 8 μm, the Dv50 value of the hBN particles may, for example, be 3, 6, 9, 12 and 15 μm, the Co 2+ concentration in the composite plating solution may, for example, be 125, 130, 135, 140, 145, 150 and 155 g / L, the ceramic particle concentration may, for example, be 5, 7, 9, 11, 13 and 15 g / L, the hBN particle concentration may, for example, be 1, 3, 5, 7, 9 and 10 g / L, the ultrasonic frequency of the first composite electroplating may, for example, be 28, 29, 30, 31 and 32 KHZ, and the current density may, for example, be 0.5, 1, 1.5 and 2 A / dm 2 , the ultrasonic frequency of the second composite electroplating may, for example, be 38, 39, 40, 41 and 42 KHZ, and the current density may, for example, be 1.5, 2, 2.5 and 3 A / dm 2 , the ultrasonic frequency of the third composite electroplating may, for example, be 38, 39, 40, 41 and 42 KHZ, and the current density may, for example, be 3, 3.2, 3.4, 3.6, 3.8 and 4 A / dm 2 .

[0038] In some preferred embodiments, the plating time of the first composite electroplating, the second composite electroplating and the third composite electroplating is 1h-1.5h, 1h-1.5h and 0.5h-1h, respectively. Under this preferred scheme, the plating time of the first composite electroplating is not less than 1h, which is more conducive to promoting the growth of the coating and obtaining a coating with high bonding force, and is not more than 1.5h, which is more conducive to the subsequent growth of the coating with high particle composite amount. The plating time may be, for example, 1h, 1.1h, 1.2h, 1.3h, 1.4h and 1.5h. The plating time of the second composite electroplating is not less than 1h, which is more conducive to obtaining a coating with a better particle composite amount and facilitating the exertion of the wear resistance of the third composite electroplating layer, and is not more than 1.5h, which is more conducive to avoiding a large deviation in the powder composite amount between the three stages affecting the uniformity of the overall composition of the coating. The plating time may be, for example, 1h, 1.1h, 1.2h, 1.3h, 1.4h and 1.5h. The plating time of the third composite electroplating is not less than 0.5h, which is more conducive to obtaining a coating with a high particle composite amount and a certain thickness, and is not more than 1h, which is more conducive to avoiding the roughness and powder accumulation of the coating affecting the wear resistance and the powder composite amount of the coating, and improving the denseness of the coating. The plating time may be, for example, 0.5h, 0.6h, 0.7h, 0.8h, 0.9h and 1h.

[0039] In some preferred embodiments, the temperature of the composite plating solution is 50℃-60℃. Under this preferred scheme, the temperature of the composite plating solution is not less than 50℃, which is more conducive to promoting the transmission of ions in the plating solution, and is not more than 60℃, which is more conducive to the stable preparation of the coating and reducing the roughness of the coating. The temperature of the composite plating solution may be, for example, 50℃, 52℃, 54℃, 56℃, 58℃ and 60℃.

[0040] In some preferred embodiments, the composite plating solution further contains NaCl, H3BO3 and a first surfactant, the concentration of NaCl in the composite plating solution is 30-50 g / L, the concentration of H3BO3 is 20-50 g / L, and the concentration of the first surfactant is 0.01-0.2 g / L, and the first surfactant is sodium dodecyl sulfonate. In this preferred solution, the presence of NaCl improves the conductivity of the plating solution, which is conducive to the deposition of the matrix metal cobalt ions and the smooth progress of the electrodeposition process. The presence of H3BO3 can buffer the pH value of the plating solution, which is conducive to preventing the sharp decrease of the pH value after the hydrogen evolution of the plating solution. The presence of the surfactant is conducive to the sufficient wetting of the ceramic particles and the hBN particles with the plating solution, which promotes the dispersibility of the ceramic particles and the hBN particles in the plating solution and ensures the smooth progress of the electrodeposition process. Furthermore, the concentration of NaCl is not less than 30 g / L, which is conducive to improving the conductivity of the plating solution and promoting the deposition of the matrix metal cobalt ions. The concentration of NaCl is not more than 50 g / L, which is conducive to improving the uniformity of the current distribution, refining the coating crystals and improving the coating quality. The concentration of H3BO3 is 20-50 g / L, which is conducive to enhancing the pH buffering effect and improving the coating quality. The concentration of the surfactant is not less than 0.01 g / L, which is conducive to improving the wetting of the ceramic particles and the hBN particles with the plating solution, preventing the agglomeration of the ceramic particles and the hBN particles and affecting the deposition of the ceramic particles and the hBN particles. The concentration of the surfactant is not more than 0.2 g / L, which is conducive to avoiding the turbidity of the plating solution, improving the stability of the plating solution and reducing the roughness of the coating.

[0041] In some preferred embodiments, the initial hBN particles are ultrasonically dispersed in anhydrous ethanol, centrifuged and separated to obtain an hBN particle precursor, and the hBN particle precursor is ultrasonically dispersed in an aqueous solution of a second surfactant, centrifuged and separated to obtain the hBN particles, and the second surfactant is sodium dodecyl sulfonate.

[0042] And / or, the initial ceramic particles are ultrasonically dispersed in anhydrous ethanol, centrifuged and separated to obtain a ceramic particle precursor, and the ceramic particle precursor is ultrasonically dispersed in water, centrifuged and separated to obtain the ceramic particles.

[0043] Under this preferred scheme, after the initial hBN particles are separated by ultrasonic dispersion in anhydrous ethanol, the hBN particles are ultrasonically dispersed in an aqueous surfactant solution, which is more conducive to improving the wettability of the hBN particles, so that the hBN particles are fully dispersed in the composite plating solution, and are uniformly distributed in the plating layer after composite electroplating, thereby improving the compactness of the plating layer. The second surfactant is sodium dodecyl sulfonate, which is more conducive to improving the wettability of the hBN particles, and is consistent with the first surfactant in the plating solution. No other surfactant is introduced into the plating solution, thereby improving the stability of the plating solution. After the initial ceramic particles are separated by ultrasonic dispersion in anhydrous ethanol, the ceramic particles are ultrasonically dispersed in water, which is more conducive to improving the wettability of the ceramic particles, so that the ceramic particles are fully dispersed in the composite plating solution, and are uniformly distributed in the plating layer after composite electroplating, thereby improving the compactness of the plating layer.

[0044] Preferably, the concentration of the second aqueous surfactant solution is 0.1 g / L to 0.5 g / L. Under this preferred scheme, the wettability of the hBN particles is improved, and the agglomeration of the hBN particles is prevented. For example, the concentration of the second aqueous surfactant solution can be 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L, or 0.5 g / L.

[0045] In some preferred embodiments, the ceramic particles include chromium carbide particles; and / or, after the composite electroplating, heat treatment is performed to obtain the wear-resistant protective coating, and the temperature of the heat treatment is 400°C to 500°C. Under this preferred scheme, the ceramic particles include chromium carbide particles, which have a higher hardness than chromium oxide, so that the coating has high hardness and is more conducive to enhancing the wear resistance of the coating.

[0046] In some preferred embodiments, the pre-plating solution is a nickel-based plating solution, and the concentration of Ni 2+ in the pre-plating solution is 45 g / L to 60 g / L, the pH of the pre-plating solution is 2 to 3.8, and the temperature of the pre-plating solution is 20°C to 40°C.

[0047] The current density of the pre-plating treatment is 3 A / dm 2 to 9 A / dm 2 , and the time is 4 min to 10 min.

[0048] Under this preferred scheme, the pre-plating solution is a nickel-based plating solution, and the pre-plating layer is a nickel-based plating layer, which is more conducive to improving the adhesion between the coating and the substrate and improving the service life of the coating. The concentration of Ni 2+A concentration of not less than 45 g / L is more conducive to improving current efficiency and promoting the smooth progress of the electrodeposition process; a concentration not exceeding 60 g / L is more conducive to avoiding excessively rapid nickel ion deposition, which could increase coating roughness. The pH of the pre-plating solution should not be less than 2 to avoid the increased hydrogen evolution reaction affecting nickel ion deposition; a pH not exceeding 3.8 is more conducive to improving the current efficiency and stability of the plating solution. The temperature of the pre-plating solution should not be less than 20℃ to facilitate nickel ion transport and ensure the smooth progress of the electrodeposition process; a temperature not exceeding 40℃ is more conducive to controlling the ion reaction rate and reducing coating roughness. Based on the aforementioned pre-plating solutions, the current density of the pre-plating treatment should not be less than 3 A / dm³. 2 This facilitates rapid deposition of nickel plating, with a maximum value not exceeding 9A / dm. 2 This is more conducive to reducing coating roughness. Furthermore, a pre-plating time of not less than 4 minutes is more conducive to the growth of nickel underlayer, and not more than 10 minutes is more conducive to leaving a larger growth space for the cobalt-based composite coating. The Ni in the pre-plating solution 2+ The concentration can be, for example, 45, 48, 51, 54, 57, and 60 g / L; the pH of the pre-plating solution can be, for example, 2, 2.3, 2.6, 2.9, 3.2, 3.6, and 3.8; the temperature of the pre-plating solution can be, for example, 20, 25, 30, 35, and 40°C; and the current density of the pre-plating treatment can be, for example, 3, 4, 5, 6, 7, 8, and 9 A / dm³. 2 The time can be, for example, 4, 5, 6, 7, 8, 9, and 10 minutes.

[0049] Secondly, this invention provides a wear-resistant protective coating for a wide temperature range on a metal sealing surface, prepared by the method described in the first aspect. The wear-resistant protective coating comprises a Co matrix component and ceramic particles and hBN particles dispersed within the Co matrix component. The ceramic particles include chromium carbide particles and / or chromium oxide particles. The h-BN particles in the coating possess good lubricity. The Co matrix component and Cr elements in the coating form a glaze layer during high-temperature grinding and shearing. The chromium carbide ceramic particles and / or chromium oxide ceramic particles increase the hardness of the coating, resulting in significantly improved wear resistance and reduced surface roughness. The cross-sectional structure of the wear-resistant protective coating of this invention is shown in the figure. Figure 1 .

[0050] In some preferred embodiments, the roughness of the wear-resistant protective coating is ≤1.2μm.

[0051] The present invention will be further described in detail below with reference to specific embodiments.

[0052] Example 1

[0053] A method for preparing a wear-resistant protective coating with a wide temperature range on a metal sealing surface, comprising the following steps:

[0054] Step one: centrifugal separation after ultrasonic dispersion of the initial hBN particles in anhydrous ethanol for 3 min to obtain hBN particle precursors, centrifugal separation after ultrasonic dispersion of the hBN particle precursors in a sodium dodecyl sulfonate aqueous solution (second surfactant aqueous solution) for 3 min, and repeating the process of centrifugal separation after ultrasonic dispersion in the sodium dodecyl sulfonate aqueous solution for 3 times to obtain hBN particles, which are ready for use, the concentration of the sodium dodecyl sulfonate aqueous solution is 0.3 g / L, and the Dv50 value of the hBN particles is 10 μm; centrifugal separation after ultrasonic dispersion of the initial chromium carbide ceramic particles in anhydrous ethanol for 3 min to obtain chromium carbide ceramic particle precursors, centrifugal separation after ultrasonic dispersion of the chromium carbide ceramic particle precursors in water for 3 min, and repeating the process of centrifugal separation after ultrasonic dispersion in water for 3 times to obtain chromium carbide ceramic particles, which are ready for use, and the Dv50 value of the chromium carbide ceramic particles is 6 μm;

[0055] Step two: pre-plating treatment of the substrate in a nickel-based pre-plating solution using a nickel anode to obtain a pre-plating layer, the concentration of Ni 2+ in the pre-plating solution is 50 g / L, the temperature of the pre-plating solution is 25℃, the pH of the pre-plating solution is 2.5, the current density is 6 A / dm 2 , and the pre-plating time is 8 min;

[0056] Step three: composite electroplating of the substrate with the pre-plating layer after the pre-plating treatment in a composite plating solution using a cobalt plate to obtain a wear-resistant protective coating, the composition of the composite plating solution is Co 2+ : 140 g / L, NaCl: 45 g / L, H3BO3: 35 g / L, sodium dodecyl sulfonate (first surfactant): 0.1 g / L, the chromium carbide ceramic particles obtained in step one: 10 g / L, and the hBN particles obtained in step one: 5 g / L, the temperature of the composite plating solution is 55℃, the composite electroplating is carried out under ultrasonic waves, and the composite electroplating is sequentially carried out in a first composite electroplating, a second composite electroplating, and a third composite electroplating, the ultrasonic wave frequency of the first composite electroplating is 30 KHZ, the current density is 0.5 A / dm 2 , the electroplating time is 1 h, the ultrasonic wave frequency of the second composite electroplating is 40 KHZ, the current density is 2 A / dm 2 , the electroplating time is 1.5 h, the ultrasonic wave frequency of the third composite electroplating is 40 KHZ, the current density is 3 A / dm 2 , and the electroplating time is 0.5 h.

[0057] A wear-resistant protective coating prepared by the aforementioned preparation method, the surface morphology of the coating is shown in Figure 2 , and the Co matrix component uniformly disperses the dispersed chromium carbide ceramic particles and hBN particles.

[0058] Example 2

[0059] Referring to the preparation method of Example 1, except that in step three, the plating time of the third composite electroplating is 1.5 h. The prepared wear-resistant protective coating has chromium carbide ceramic particles and hBN particles dispersed in the Co matrix component.

[0060] Example 3

[0061] Referring to the preparation method of Example 1, except that in step three, the temperature of the composite plating solution is 45°C. The prepared wear-resistant protective coating has chromium carbide ceramic particles and hBN particles dispersed in the Co matrix component.

[0062] Example 4

[0063] Referring to the preparation method of Example 1, except that in step three, there is no sodium dodecyl sulfonate in the composite plating solution, and no first surfactant is used. The prepared wear-resistant protective coating has chromium carbide ceramic particles and hBN particles dispersed in the Co matrix component, and the hBN particles have agglomeration phenomenon.

[0064] Example 5

[0065] Referring to the preparation method of Example 1, except that in step three, the concentration of NaCl in the composite plating solution is 60 g / L. The prepared wear-resistant protective coating has chromium carbide ceramic particles and hBN particles dispersed in the Co matrix component, and the Co matrix metal grains in the coating are coarse.

[0066] Example 6

[0067] Referring to the preparation method of Example 1, except that in step three, the concentration of NaCl in the composite plating solution is 20 g / L. The prepared wear-resistant protective coating has chromium carbide ceramic particles and hBN particles dispersed in the Co matrix component.

[0068] Example 7

[0069] Referring to the preparation method of Example 1, except that chromium oxide ceramic particles are used instead of chromium carbide ceramic particles. The prepared wear-resistant protective coating has chromium oxide ceramic particles and hBN particles dispersed in the Co matrix component.

[0070] Comparative Example 1

[0071] Referring to the preparation method of Example 1, except that in step three, only the first composite electroplating is performed, and the plating time of the first composite electroplating is 3.5 h. The prepared wear-resistant protective coating has chromium carbide ceramic particles and hBN particles distributed in the Co matrix component.

[0072] Comparative Example 2

[0073] Referring to the preparation method of Example 1, except that in step three, only the third composite electroplating is performed, and the time of the third composite electroplating is 3.5 h. The prepared wear-resistant protective coating is rough, and the Co matrix component is distributed with chromium carbide ceramic particles and hBN particles.

[0074] Comparative Example 3

[0075] Referring to the preparation method of Example 1, except that in step three, only the first composite electroplating and the third composite electroplating are performed, and the time of the first composite electroplating is 1.5 h, and the time of the third composite electroplating is 2 h. The prepared wear-resistant protective coating is rough, and the Co matrix component is distributed with chromium carbide ceramic particles and hBN particles.

[0076] Comparative Example 4

[0077] Referring to the preparation method of Example 1, except that in step three, the order of the first composite electroplating, the second composite electroplating and the third composite electroplating is different, and the first composite electroplating, the third composite electroplating and the second composite electroplating are performed in turn. The prepared wear-resistant protective coating is rough, and the Co matrix component is distributed with chromium carbide ceramic particles and hBN particles.

[0078] The coatings of the examples and the comparative examples are respectively detected for surface roughness (GB / T 1031) by using an SJ-210 type surface roughness meter, the roughness is the average value of the roughness of at least three different positions, and the detection results are shown in Table 1. The coatings of the examples and the comparative examples are respectively tested for micro-oscillation wear performance at 400°C and 500°C by using a step load method, the detection parameters are shown in Table 2, and the detection results are shown in Table 1, wherein the value of the wear amount is detected by using a white light interferometer. The appearance photos of the coating of Example 1 after the micro-oscillation wear test at 400°C are shown in Figure 3 , and the appearance photos after the micro-oscillation wear test at 500°C are shown in Figure 5 , the appearance photos of the coating of Comparative Example 4 after the micro-oscillation wear test at 400°C are shown in Figure 4 , and the appearance photos after the micro-oscillation wear test at 500°C are shown in Figure 6 .

[0079] Table 1

[0080]

[0081] Table 2

[0082] Serial number Temperature / °C Frequency / Hz Load / N Time / s 1 400 / 500 5 10 1001 2 400 / 500 5 20 1001 3 400 / 500 5 30 1001 4 400 / 500 5 40 1001 5 400 / 500 5 50 1001 6 400 / 500 5 60 1001 7 400 / 500 5 70 1001 8 400 / 500 5 80 1001 9 400 / 500 5 90 1001 10 400 / 500 5 100 1001

[0083] Compared with Comparative Example 1 and Example 1, compared with only using the process parameters of the first composite electroplating, sequentially performing the first composite electroplating, the second composite electroplating and the third composite electroplating can improve the composite amount of the chromium carbide ceramic particles and the hBN particles, improve the wear resistance of the coating, compared with Comparative Example 2 and Example 1, compared with only using the process parameters of the third composite electroplating, sequentially performing the first composite electroplating, the second composite electroplating and the third composite electroplating can reduce the roughness of the coating and improve the wear resistance of the coating, compared with Comparative Example 3 and Example 1, compared with only sequentially using the process parameters of the first composite electroplating and the third composite electroplating, sequentially performing the first composite electroplating, the second composite electroplating and the third composite electroplating can reduce the roughness of the coating and improve the wear resistance of the coating, compared with Comparative Example 4 and Example 1, compared with first using the process parameters of the first composite electroplating, then using the process parameters of the third composite electroplating, and then using the process parameters of the second composite electroplating, sequentially performing the first composite electroplating, the second composite electroplating and the third composite electroplating can improve the wear resistance of the coating and reduce the roughness of the coating.

[0084] Compared with Comparative Example 1 and Example 2, the time of the third composite electroplating is not more than 1h, which is more conducive to reducing the roughness of the coating and improving the wear resistance of the coating, compared with Comparative Example 1 and Example 3, the temperature of the composite plating solution is not less than 50℃, which is more conducive to reducing the roughness of the coating and improving the wear resistance of the coating, compared with Comparative Example 1 and Example 4, the composite plating solution contains a surfactant, which is more conducive to reducing the roughness of the coating, improving the composite amount of the chromium carbide ceramic particles and the hBN particles, and improving the wear resistance of the coating, compared with Comparative Example 1 and Example 5, the concentration of NaCl in the composite plating solution is not higher than 50g / L, which is more conducive to refining the substrate metal crystals of the coating, reducing the roughness of the coating, and improving the wear resistance of the coating, compared with Comparative Example 1 and Example 6, the concentration of NaCl in the composite plating solution is not less than 30g / L, which is more conducive to improving the composite amount of the chromium carbide ceramic particles and the hBN particles, improving the wear resistance of the coating, and reducing the roughness of the coating, compared with Comparative Example 1 and Example 7, the chromium carbide ceramic particles are used, which is more conducive to improving the wear resistance of the coating.

[0085] The above describes the preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method for preparing a wear-resistant protective coating with a wide temperature range on a metal sealing surface, characterized in that, Includes the following steps: The substrate is immersed in a pre-plating solution for pre-plating treatment to obtain a pre-plating layer; the pre-plated substrate is then immersed in a composite plating solution for composite electroplating to obtain the wear-resistant protective coating, wherein the composite plating solution contains Co. 2+ The composite plating solution contains ceramic particles and hBN particles, wherein the ceramic particles include chromium carbide particles and / or chromium oxide particles, the particle size distribution of the ceramic particles is 2μm to 8μm with a Dv50 value, and the particle size distribution of the hBN particles is 3μm to 15μm with a Dv50 value. 2+ The concentration is 125 g / L to 155 g / L, the ceramic particle concentration is 5 g / L to 15 g / L, and the hBN particle concentration is 1 g / L to 10 g / L; The composite electroplating is performed under ultrasonic waves and includes a first composite electroplating, a second composite electroplating, and a third composite electroplating performed sequentially. The ultrasonic frequency and current density of the first composite electroplating are 28kHz to 32kHz and 0.5A / dm, respectively. 2 ~2A / dm 2 The ultrasonic frequency and current density of the second composite electroplating are 38kHz~42kHz and 1.5A / dm, respectively. 2 ~3A / dm 2 The ultrasonic frequency and current density of the third composite electroplating are 38kHz~42kHz and 3A / dm, respectively. 2 ~4A / dm 2 .

2. The preparation method according to claim 1, characterized in that, The electroplating times for the first composite electroplating, the second composite electroplating, and the third composite electroplating are 1h to 1.5h, 1h to 1.5h, and 0.5h to 1h, respectively.

3. The preparation method according to claim 1, characterized in that, The temperature of the composite plating solution is 50℃~60℃.

4. The preparation method according to claim 1, characterized in that, The composite plating solution also contains NaCl, H3BO3 and a first surfactant. The concentration of NaCl in the composite plating solution is 30g / L-50g / L, the concentration of H3BO3 is 20g / L-50g / L, and the concentration of the first surfactant is 0.01g / L-0.2g / L. The first surfactant is sodium dodecyl sulfonate.

5. The preparation method according to claim 1, characterized in that, The initial hBN particles were ultrasonically dispersed in anhydrous ethanol and then centrifuged to obtain the hBN particle precursor. The hBN particle precursor was ultrasonically dispersed in an aqueous solution of a second surfactant and then centrifuged to obtain the hBN particles. The second surfactant was sodium dodecyl sulfonate. And / or, the initial ceramic particles are ultrasonically dispersed in anhydrous ethanol and then centrifuged to obtain a ceramic particle precursor, and the ceramic particle precursor is ultrasonically dispersed in water and then centrifuged to obtain the ceramic particles.

6. The preparation method according to claim 5, characterized in that, The concentration of the second surfactant aqueous solution is 0.1 g / L-0.5 g / L.

7. The preparation method according to claim 1, characterized in that, The ceramic particles include chromium carbide particles; and / or, after the composite electroplating, heat treatment is performed to obtain the wear-resistant protective coating, wherein the heat treatment temperature is 400℃~500℃.

8. The preparation method according to claim 1, characterized in that, The pre-plating solution is a nickel-based plating solution, in which Ni... 2+ The concentration is 45 g / L to 60 g / L, the pH of the pre-plating solution is 2 to 3.8, and the temperature of the pre-plating solution is 20℃ to 40℃; The current density of the pre-plating treatment is 3A / dm. 2 ~9A / dm 2 The time is 4 to 10 minutes.

9. A wear-resistant protective coating for a wide temperature range on a metal sealing surface, prepared by the preparation method according to any one of claims 1 to 8, characterized in that, The wear-resistant protective coating comprises a Co matrix component and ceramic particles and hBN particles dispersed in the Co matrix component, wherein the ceramic particles include chromium carbide particles and / or chromium oxide particles.

10. The wear-resistant protective coating according to claim 9, characterized in that, The roughness of the wear-resistant protective coating is ≤1.2μm.

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