An impact-resistant and wear-resistant coating and its preparation method

Abstract

The present invention belongs to the technical field of wear-resistant coatings, and specifically provides an impact-resistant wear-resistant coating and a preparation method thereof. Among them, the impact-resistant wear-resistant coating contains the following components in parts by weight: 70-90 parts of copper alloy, 10-30 parts of urea-formaldehyde microcapsules, 5-10 parts of organic compounds, 0.1-2 parts of silane coupling agent, 60-100 parts of organic solvent, 0.2-2 parts of inhibitor, and 0.3-1 part of photocatalyst. The present invention uses copper alloy and urea-formaldehyde microcapsules for component design, enhancing the impact resistance and wear resistance of the coating. When cracks appear, the urea-formaldehyde microcapsules release the healing agent to achieve self-repair of the coating. The formed superhydrophobic film accelerates the self-repair of the coating and realizes self-cleaning of the coating. Together with the urea-formaldehyde microcapsules, it increases the corrosion resistance of the coating, effectively solving the problem that the coating in the prior art is difficult to simultaneously possess the functions of impact resistance, wear resistance, self-repair, self-cleaning and corrosion resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of wear-resistant coatings, and specifically refers to an impact-resistant wear-resistant coating and a preparation method thereof. Background Art

[0002] With the rapid development of industry and science and technology, the preparation of high-performance wear-resistant coatings on the surface of workpieces has received increasing attention. With the continuous advancement of the modernization process, the working conditions of construction machinery, equipment and components have become increasingly harsh. They have to move and rotate continuously, withstand the impact and wear of different media, and also resist corrosion. Therefore, the preparation of high-performance wear-resistant coatings is of great practical significance for reducing equipment friction and wear, extending service life, saving energy, protecting the environment and saving materials.

[0003] The preparation process and coating materials play a key role in the performance of the coating. The coating materials and the preparation process together form a coating with specific properties. At present, the main process for preparing wear-resistant coatings is that high-temperature heat sources such as lasers and flames directly act on the coating materials and deposit them on the surface of the metal substrate, and the temperature is difficult to control. Under the action of high temperature, the wear-resistant phases in the coating inevitably decompose, burn out and grow, etc., reducing its wear-resistant performance. The bonding strength between the coating and the substrate is relatively low, and the impact resistance is poor.

[0004] The coatings or claddings formed by traditional plating technologies, although having high hardness, are not impact-resistant, have poor toughness, and low impact resistance. Under the action of severe impact and wear, the coatings are prone to cracking, wear and peeling. After long-term use, some small cracks will appear, reducing the service life of the coatings. Even some major losses will be caused due to the generation of small cracks. Most traditional plating technologies are complex in operation, have poor durability, and cannot solve the problems of self-repair and self-cleaning between the coating and the substrate, thus reducing the service life of the coatings. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an impact-resistant and wear-resistant coating and a preparation method thereof in view of the deficiencies of the prior art. The coating can be tightly combined with the substrate. Two layers of coatings are plated on the surface of the substrate by plasma spraying. Plasma spraying realizes the highly uniform distribution of the coating and improves the mechanical strength of the coating. The first layer of coating is formed by using urea-formaldehyde microcapsules and copper alloy. When cracks appear on the surface of the coating, the urea-formaldehyde microcapsules can release the healing agent to achieve self-repair. The urea-formaldehyde microcapsules can also act as an adhesive to bond the copper alloy powder together, making the formed coating more dense and uniform. The second coating is plated on the surface of the metal workpiece to form a superhydrophobic film. The superhydrophobic film is composed of SiO2 and CeO2. The chemical bonding between the two makes them tightly combined, increases the hardness of the coating, improves the toughness of the coating, and through plating the second coating, the substrate surface obtains the properties of self-cleaning, self-repairing and corrosion resistance, effectively solving the problem that in the prior art, it is difficult for the coating to simultaneously possess the functions of impact resistance, wear resistance, self-repairing, self-cleaning and corrosion resistance.

[0006] In order to achieve the above technical purpose, the following technical solutions are adopted:

[0007] The present invention provides an impact-resistant and wear-resistant coating, which comprises a dense coating and a superhydrophobic film from the inside to the outside. The impact-resistant and wear-resistant coating is composed of the following raw materials in parts by weight: 70-90 parts of copper alloy, 10-30 parts of urea-formaldehyde microcapsules, 5-10 parts of organic compounds, 0.1-2 parts of silane coupling agent, 60-100 parts of organic solvent, 0.2-2 parts of inhibitor and 0.3-1 part of photocatalyst.

[0008] Preferably, the mass ratio components of the copper alloy are: Cu 60-90%, Sn 8-30% and Si 2-10%.

[0009] Preferably, the organic compounds are TEOS and PFDS, and the volume ratio of TEOS to PFDS is 2:1.

[0010] Preferably, the silane coupling agent is A151.

[0011] Preferably, the organic solvent is xylene.

[0012] Preferably, the inhibitor is 8-hydroxyquinoline.

[0013] Preferably, the photocatalyst is CeO2.

[0014] Furthermore, the urea-formaldehyde microcapsules are prepared from the following raw materials: urea, formaldehyde, sodium dodecylbenzenesulfonate and a healing agent;

[0015] Furthermore, the preparation of the urea-formaldehyde microcapsules comprises the following steps:

[0016] Y1. Dissolve urea in formaldehyde to form a formaldehyde solution in a beaker. The dosage ratio of urea to formaldehyde is 1 g:2 mL. After complete dissolution, adjust the pH of the formaldehyde solution to 9 with triethanolamine. Place the solution in an 80 °C oil bath and stir for 1 h to obtain a urea-formaldehyde prepolymer.

[0017] Y2. Dissolve sodium dodecylbenzenesulfonate in distilled water to form a solution in a round-bottom flask. After complete dissolution, emulsify the solution in a 50 °C oil bath, and then add a healing agent, which is dicyclopentadiene. The mass ratio of the healing agent to sodium dodecylbenzenesulfonate is 1:0.1. Continuously stir for 1 h until an emulsion is formed.

[0018] Y3. Add the urea-formaldehyde prepolymer obtained in step Y1 to the emulsion obtained in step Y2 and stir for 25 min. The volume ratio of the urea-formaldehyde prepolymer to the emulsion is 1:6 to form a mixed solution. Maintain the pH value of the mixed solution at 2.5 by adding 2 - 3 drops of 1.0 mol / L sulfuric acid.

[0019] Y4. Gradually heat the mixed solution obtained in step Y3 to 70 °C and maintain it at a stirring speed of 900 rpm for 4 h to obtain prefabricated microcapsules. This process uses a sealed beaker to reduce heat loss.

[0020] Y5. Cool the prefabricated microcapsules obtained in step Y4 to room temperature, wash them alternately with deionized water and absolute ethanol 3 times, and dry the prefabricated microcapsules at 40 °C for 18 h to obtain urea-formaldehyde microcapsules.

[0021] The present invention also provides a preparation method for an impact-resistant and wear-resistant coating, which specifically includes the following steps:

[0022] S1. Put the copper alloy into a ball mill for grinding to obtain a copper alloy mixed powder with a particle size of 5 - 8 μm.

[0023] S2. Clean the surface of the metal workpiece substrate. Before use, grind the metal workpiece successively with 600#, 1000#, and 1500# emery papers, and then ultrasonically rinse it with ethanol and deionized water for 5 min respectively to ensure that there are no impurities such as oil stains on the surface of the metal workpiece. Then dry the metal workpiece through a nitrogen gas stream.

[0024] S3. Take 70 - 90 parts of the ball-milled copper alloy mixed powder, 10 - 30 parts of urea-formaldehyde microcapsules, and 0.1 - 2 parts of silane coupling agent and dissolve them together in 60 - 100 parts of an organic solvent. Use a thermostatic stirrer to dissolve to obtain a mixture. The temperature of the thermostatic stirrer is set at 60 - 80 °C, the stirring speed is set at 600 - 1000 rpm, and the stirring time is 1 - 2 h.

[0025] S4. Apply plating to the metal workpiece by spraying. Pour the mixture prepared in step S3 into the hopper of the spray gun and spray it onto the metal workpiece. Then leave the coating overnight at room temperature for preliminary drying, and then cure the coating in an oven at 80 °C for 6 h, thus forming a dense coating on the surface of the metal workpiece.

[0026] S5. Take 5 - 10 parts of the organic compound and dissolve it ultrasonically in 90 parts of absolute ethanol to form solution A. Add 0.2 - 2 parts of the inhibitor and 0.3 - 1 part of the photocatalyst to solution A, stir and heat at 60 °C for 90 min to obtain solution B, and continuously stir solution B at 60 °C for 19 h using a condensing reflux device. Then adjust the pH of solution B to 4 with HAc to obtain a white SiO2 sol and form a superhydrophobic film.

[0027] S6. Use an immersion extraction speed of 600 mm / min to vertically immerse the metal workpiece plated with the dense coating in step S4 into the white SiO2 sol obtained in step S5, perform solvothermal treatment at 80 °C for 8 h, and then anneal the coated metal workpiece at 120 °C for 4 h to cure the coating and remove the unreacted solvent.

[0028] The surface of the urea - formaldehyde microcapsules is tightly combined with the copper alloy powder through physical adsorption, enhancing the mechanical properties of the coating. Moreover, the urea - formaldehyde microcapsules can chemically react with the active groups on the surfaces of SiO2 and CeO2 to form a more stable bond. In addition, the urea - formaldehyde microcapsules can help the filler disperse better in the coating matrix, improving the uniformity of the coating.

[0029] The prepared SiO2 film endows the coating surface with good superhydrophobic properties. The added photocatalyst CeO2 enhances the superhydrophobic properties of the coating. Utilizing the superhydrophobicity of the SiO2 film and the photocatalytic properties of CeO2 enables the coating surface to have dual self - cleaning capabilities. Moreover, CeO2 has excellent weather resistance, and the superhydrophobic coating prepared by combining it with urea - formaldehyde microcapsules and SiO2 is more stable and can better adapt to various environments.

[0030] The beneficial effects achieved by the present invention are as follows:

[0031] The coating prepared by the present invention has a dense structure and strong wear resistance. The inexpensive copper alloy is used, which provides good electrical conductivity and mechanical strength. After mixing the urea - formaldehyde microcapsules and the copper alloy powder, they are plasma - sprayed onto the metal workpiece to deposit a dense coating on the surface of the metal workpiece. Plasma spraying realizes the highly uniform distribution of the coating, improves the mechanical strength of the coating, makes the coating more tough, enhances the impact - resistant and wear - resistant properties of the coating, and minimizes the waste of the coating material, improving the utilization rate of the coating material and the plating efficiency. Moreover, the urea - formaldehyde microcapsules can also act as adhesives to bond the copper alloy powder together, forming a more dense and uniform coating.

[0032] The prepared coating material is plated on the surface of the metal substrate. If cracks occur on the surface of the metal substrate, the microcapsules inside the coating will rupture, releasing the healing agent to repair the cracks. Moreover, dicyclopentadiene can react with substances such as oxides and organic compounds on the surface of the metal substrate, accelerating the self-healing process, restoring the overall performance of the coating. Also, the SiO2 in the superhydrophobic film will release the inhibitor between the skeletons, preventing the generated cracks from further corroding the coating and increasing the service life of the coating;

[0033] A superhydrophobic film is prepared by the sol-gel method. The preparation process is simple, reducing environmental pollution and carried out at low temperature. The prepared superhydrophobic film also adds the photocatalyst CeO2. On the one hand, through chemical bonding with SiO2, the two are closely combined, increasing the hardness of the coating and improving the toughness of the coating. On the other hand, it enhances the self-cleaning effect on the surface of the coating. The water droplets on the superhydrophobic surface formed by SiO2 can roll off quickly, taking away the dust and pollutants on the surface, thus keeping the surface clean. CeO2 endows the coating with photocatalytic activity, which can effectively degrade the surface organic pollutants and strengthen the self-cleaning effect;

[0034] The coating material is plated on the surface of the metal workpiece. The embedding of urea-formaldehyde microcapsules in the coating material enhances the denseness of the coating and improves the barrier performance of the surface of the metal workpiece. The coating doped with urea-formaldehyde microcapsules can effectively block the penetration of corrosive media to the surface of the metal workpiece, delaying the occurrence of corrosion. In addition, the physical barrier of the superhydrophobic surface also effectively postpones the invasion of aggressive species. The superhydrophobic film further prevents the corrosion of the metal workpiece due to 8-hydroxyquinoline in the SiO2 skeleton;

[0035] The microcapsule structure helps to improve the chemical stability and durability of the coating. On the other hand, the superhydrophobic coating shows good stability whether it is washed by rain or irradiated by sunlight, ensuring the long-term effectiveness of the self-cleaning and wear-resistant functions;

[0036] Combining the above beneficial effects, the impact-resistant and wear-resistant coating prepared by the present invention can be closely combined with the substrate to form a dense structure, and has the functions of self-healing, self-cleaning and anti-corrosion. It can reduce the number and cost of maintenance, having good economic benefits. And this kind of coating can be widely applied to many fields such as construction, automobiles, aviation, medical devices, etc., improving the protection performance of the material surface and extending the service life. Description of the Drawings

[0037] Figure 1 It is the model cross-sectional view and partial enlarged schematic diagram of the impact-resistant and wear-resistant coating prepared by the present invention;

[0038] Figure 2It is the main self - repair process diagram of the impact - resistant and wear - resistant coating prepared by the present invention when cracks appear;

[0039] Figure 3 It is the hydrophobic stability diagram of Example 2 of the impact - resistant and wear - resistant coating prepared by the present invention and Comparative Examples 1 - 4 immersed in 3.5 wt% NaCl solution. Specific embodiments

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] Example 1: In this example, an impact - resistant and wear - resistant coating is proposed. The impact - resistant and wear - resistant coating is composed of the following raw materials in parts by weight: 70 parts of copper alloy, 30 parts of urea - formaldehyde microcapsules, 5 parts of organic compound, 0.1 part of silane coupling agent, 60 parts of organic solvent, 0.2 part of inhibitor, and 0.3 part of photocatalyst.

[0042] The urea - formaldehyde microcapsules are prepared from the following raw materials: urea, formaldehyde, sodium dodecylbenzenesulfonate, and healing agent;

[0043] The preparation method of the urea - formaldehyde microcapsules includes the following steps:

[0044] Y1, Dissolve urea in formaldehyde in a beaker to form a solution. The dosage ratio of urea to formaldehyde is 1 g:2 mL. After complete dissolution, adjust the pH of the solution to 9 with triethanolamine. Place the solution in an 80 °C oil bath and stir for 1 h to obtain a urea - formaldehyde prepolymer;

[0045] Y2, Dissolve sodium dodecylbenzenesulfonate in distilled water to form a solution in a round - bottom flask. After complete dissolution, emulsify the solution in a 50 °C oil bath, and then add the healing agent. The healing agent is dicyclopentadiene. The mass ratio of the healing agent to sodium dodecylbenzenesulfonate is 1:0.1. Continuously stir for 1 h until an emulsion is formed;

[0046] Y3, Add the urea - formaldehyde prepolymer obtained in step Y1 to the emulsion obtained in step Y2 and stir for 25 min. The volume ratio of the urea - formaldehyde prepolymer to the emulsion is 1:6 to form a mixed solution. Maintain the pH value of the mixed solution at 2.5 by adding 2 - 3 drops of 1.0 mol / L sulfuric acid;

[0047] Y4. Gradually heat the mixed solution obtained in step Y3 to 70 °C and maintain it at a stirring speed of 900 rpm for 4 h to obtain prefabricated microcapsules. During this process, use the method of sealing the beaker to reduce heat loss;

[0048] Y5. Cool the prefabricated microcapsules obtained in step Y4 to room temperature, wash them alternately with deionized water and absolute ethanol three times, and dry the prefabricated microcapsules at 40 °C for 18 h to obtain urea-formaldehyde microcapsules.

[0049] This embodiment also provides a method for preparing an impact-resistant and wear-resistant coating. The preparation method specifically includes the following steps:

[0050] S1. Put the copper alloy into a ball mill for grinding to obtain a copper alloy mixed powder with a particle size of 5 - 8 μm;

[0051] S2. Clean the surface of the metal workpiece substrate. Before use, grind the metal workpiece successively with 600#, 1000#, and 1500# emery papers, then ultrasonically rinse it with ethanol and deionized water for 5 min respectively to ensure that there are no impurities such as oil stains on the surface of the metal workpiece, and then dry the metal workpiece through a nitrogen gas stream;

[0052] S3. Take 70 parts of the ball-milled copper alloy mixed powder, 30 parts of urea-formaldehyde microcapsules, and 0.1 part of silane coupling agent and dissolve them together in 60 parts of organic solvent. Use a constant-temperature stirrer to dissolve to obtain a mixture. The temperature of the constant-temperature stirrer is set at 60 °C, the stirring speed is set at 600 rpm, the stirring time is 1 h, and then put it into an 80 °C oven and dry for 12 h to obtain a prefabricated coating;

[0053] S4. Carry out coating on the metal workpiece by means of plasma spraying. Pour the prefabricated coating prepared in step S3 into the hopper of the spray gun and spray it onto the metal workpiece cleaned in step S2. Among them, the working voltage of the spraying device is 100 - 200 V, the working current is 200 - 800 mA, the spraying temperature is 120 - 200 °C, the operating pressure is 4 - 40 Kpa, the spraying speed is 50 - 200 m / s, and then leave the sprayed metal workpiece overnight at room temperature for preliminary drying. After that, cure the coating in an 80 °C oven for 6 h to coat the first layer of coating, i.e., the dense coating, on the surface of the metal workpiece;

[0054] S5. Take 5 - 10 parts of the organic compound and ultrasonically dissolve it in 90 parts of absolute ethanol to form Solution A. The ultrasonic dissolution is completed in an ultrasonic cleaner. The power of the ultrasonic wave is set to 240 W and the time is set to 30 min. Add 0.2 part of the inhibitor and 0.3 part of the photocatalyst to Solution A, stir and heat at 60 °C for 90 min to obtain Solution B. Then continuously stir Solution B at 60 °C for 19 h using a condensing reflux device. After that, adjust the pH of Solution B to 4 with HAc to obtain a white SiO₂ sol and form a superhydrophobic film.

[0055] S6. Using an immersion extraction speed of 600 mm / min, vertically immerse the metal workpiece coated with the dense coating in Step S4 into the white SiO₂ sol obtained in Step S5, perform solvothermal treatment at 80 °C for 8 h, and then anneal the coated metal workpiece at 120 °C for 4 h to cure the coating and remove the unreacted solvent.

[0056] Example 2: This example presents an impact - resistant and wear - resistant coating, which is composed of the following raw materials in parts by weight: 80 parts of copper alloy, 20 parts of urea - formaldehyde microcapsule, 8 parts of organic compound, 1.2 parts of silane coupling agent, 80 parts of organic solvent, 1.5 parts of inhibitor, and 0.7 part of photocatalyst.

[0057] The preparation of the urea - formaldehyde microcapsule and the steps are the same as those in Example 1.

[0058] This example also provides a preparation method for the impact - resistant and wear - resistant coating. The specific preparation method includes the following steps:

[0059] S1. Put the copper alloy into a ball mill for grinding to obtain a copper alloy mixed powder with a particle size of 5 - 8 μm.

[0060] S2. Clean the surface of the metal workpiece substrate. Before use, grind the metal workpiece successively with 600#, 1000#, and 1500# emery papers, then ultrasonically rinse it with ethanol and deionized water for 5 min respectively to ensure that there are no impurities such as oil stains on the surface of the metal workpiece, and then dry the metal workpiece through a nitrogen gas stream.

[0061] S3. Take 80 parts of the ball - milled copper alloy mixed powder, 20 parts of urea - formaldehyde microcapsules, and 1.5 parts of silane coupling agent and dissolve them together in 80 parts of organic solvent. Use a constant - temperature stirrer to dissolve to obtain a mixture. The temperature of the constant - temperature stirrer is set to 70 °C, the stirring speed is set to 800 rpm, and the stirring time is 1.5 h.

[0062] S4. Apply plating to the metal workpiece by means of plasma spraying. Pour the prefabricated coating prepared in step S3 into the hopper of the spray gun and spray it onto the metal workpiece cleaned in step S2. Among them, the working voltage of the spraying device is 100 - 200 V, the working current is 200 - 800 mA, the spraying temperature is 120 - 200 °C, the operating pressure is 4 - 40 Kpa, the spraying speed is 50 - 200 m / s. Then leave the sprayed metal workpiece overnight at room temperature for preliminary drying. After that, cure the coating in an oven at 80 °C for 6 h to deposit the first layer of coating, i.e., the dense coating, on the surface of the metal workpiece.

[0063] S5. Take 5 - 10 parts of organic compound and ultrasonically dissolve it in 90 parts of absolute ethanol to form solution A. The ultrasonic dissolution is completed in an ultrasonic cleaner with the ultrasonic power set to 240 W and the time set to 30 min. Add 1.5 parts of inhibitor and 0.7 part of photocatalyst to solution A, stir and heat at 60 °C for 90 min to obtain solution B, and continuously stir solution B at 60 °C for 19 h using a condensing reflux device. Then adjust the pH of solution B to 4 with HAc to obtain a white SiO2 sol and form a superhydrophobic film.

[0064] S6. Use an immersion extraction speed of 600 mm / min to vertically immerse the metal workpiece plated with the dense coating in step S4 into the white SiO2 sol obtained in step S5, perform solvothermal treatment at 80 °C for 8 h, and then anneal the coated metal workpiece at 120 °C for 4 h to cure the coating and remove the unreacted solvent.

[0065] Example 3: This example presents an impact - resistant and wear - resistant coating, which is composed of the following raw materials in parts by weight: 90 parts of copper alloy, 10 parts of urea - formaldehyde microcapsules, 10 parts of organic compound, 2 parts of silane coupling agent, 100 parts of organic solvent, 2 parts of inhibitor, and 1 part of photocatalyst.

[0066] The preparation and steps of the urea - formaldehyde microcapsules are the same as those in Example 1.

[0067] This example also provides a preparation method for the impact - resistant and wear - resistant coating. The preparation method specifically includes the following steps:

[0068] S1. Put the copper alloy into a ball mill for grinding to obtain copper alloy mixed powder with a particle size of 5 - 8 μm.

[0069] S2. Clean the surface of the metal workpiece substrate. Before use, grind the metal workpiece successively with 600#, 1000#, and 1500# emery papers, then ultrasonically rinse it with ethanol and deionized water for 5 min respectively to ensure that there are no impurities such as oil stains on the surface of the metal workpiece. Then dry the metal workpiece through a nitrogen gas stream.

[0070] S3. Take 90 parts of the ball-milled copper alloy mixed powder, 10 parts of urea-formaldehyde microcapsules, and 2 parts of silane coupling agent, dissolve them together in 100 parts of organic solvent, and use a constant-temperature stirrer to obtain a mixture. The temperature of the constant-temperature stirrer is set at 80 °C, the stirring speed is set at 1000 rpm, and the stirring time is 2 h.

[0071] S4. Perform plating on the metal workpiece by plasma spraying. Pour the prefabricated coating prepared in step S3 into the hopper of the spray gun and spray it onto the metal workpiece cleaned in step S2. Among them, the working voltage of the spraying device is 100 - 200 V, the working current is 200 - 800 mA, the spraying temperature is 120 - 200 °C, the operating pressure is 4 - 40 Kpa, the spraying speed is 50 - 200 m / s. Then leave the sprayed metal workpiece overnight at room temperature for preliminary drying, and then cure the coating in an 80 °C oven for 6 h to deposit the first layer of coating, i.e., the dense coating, on the surface of the metal workpiece.

[0072] S5. Take 10 parts of organic compound and ultrasonically dissolve it in 90 parts of absolute ethanol to form solution A. The ultrasonic dissolution is completed in an ultrasonic cleaner. The power of the ultrasonic is set at 240 W and the time is set at 30 min. Add 2 parts of inhibitor and 1 part of photocatalyst to solution A, stir and heat at 60 °C for 90 min to obtain solution B, and continuously stir solution B at 60 °C for 19 h using a condenser reflux device. Then adjust the pH of solution B to 4 with HAc to obtain a white SiO2 sol and form a superhydrophobic film.

[0073] S6. Use an immersion extraction speed of 600 mm / min, vertically immerse the metal workpiece plated with the dense coating in step S4 into the white SiO2 sol obtained in step S5, perform solvothermal treatment at 80 °C for 8 h, and then anneal the coated metal workpiece at 120 °C for 4 h to cure the coating and remove the unreacted solvent.

[0074] Comparative Example 1: Compared with Example 2, the incorporation of urea-formaldehyde microcapsules was cancelled in Comparative Example 1, and the remaining preparation methods and steps were the same as those in Example 2.

[0075] Comparative Example 2: Compared with Example 2, the incorporation of organic compound was cancelled in Comparative Example 2, and the remaining preparation methods and steps were the same as those in Example 2.

[0076] Comparative Example 3: Compared with Example 2, the incorporation of photocatalyst was cancelled in Comparative Example 3, and the remaining preparation methods and steps were the same as those in Example 2.

[0077] Comparative Example 4: Compared with Example 2, the incorporations of organic compound and photocatalyst were cancelled in Comparative Example 4, and the remaining preparation methods were the same as those in Example 2.

[0078] Experimental Example:

[0079] Impact Resistance Performance Test

[0080] Test specimens with standard dimensions of 50 mm × 120 mm × 0.3 mm were prepared respectively using the impact-resistant and wear-resistant coatings of Examples 1 - 3 and Comparative Examples 1 - 4. The impact resistance performance of the specimens was tested according to the national standard GB / T 1732 - 93 for the determination method of film impact resistance. The test was carried out using an impact tester. The coating test specimen was placed flat on the anvil, and the part of the specimen subjected to impact was 20 mm away from the edge. The heavy hammer was fixed at 25 cm of the sliding cylinder by a control device. Press the heavy hammer, and the heavy hammer would freely fall on the punch head. Lift the heavy hammer and take out the specimen. The presence or absence of cracks, wrinkles, and peeling of the impact-resistant and wear-resistant coatings of Examples 1 - 3 and Comparative Examples 1 - 4 were recorded in Table 1.

[0081] Wear Resistance Performance Test

[0082] According to GB / T 23988 - 2009, the abrasive jet erosion method was used to test the wear resistance of the prepared coatings. Two test plates with dimensions of 70 mm × 150 mm were prepared respectively by spraying the coatings for the impact-resistant and wear-resistant coatings of Examples 1 - 3 and Comparative Examples 1 - 4 on metal workpieces. The test was carried out using a wear-resistant abrasive jet erosion experimental device. One circular area was marked on each specimen, with a diameter of about 25 mm. Three test points were required for each circular area, and the average measured value of the coating thickness on each circular area was recorded. The specimen was fixed on the tester, the switch was turned on, and the sand was allowed to pass through the conduit and impact the test plate. The container installed at the bottom of the tester collected the falling sand. The above operation was repeated until the coating was damaged.

[0083] Wear resistance includes the amount of abrasive used and the thickness of the coating. The wear resistance of the test coating was calculated using the formula A = V / T, where A is the wear resistance, V is the amount of abrasive used, and T is the coating thickness. The test results are shown in Table 1.

[0084] Self - Healing Performance Test

[0085] Test specimens were prepared using the materials for the impact-resistant and wear-resistant coatings of Examples 1 - 3 and Comparative Examples 1 - 4, with dimensions of 12 mm × 6 mm × 0.6 mm. Scratches were made on the samples with a new razor, and the depth of the scratches was about 70 μm to ensure that the coating was cut through. To induce the self - healing effect of the coating, the damaged coating was heated in an oven at 50 °C for 12 h. The strain - stress test was carried out by a tensile machine (EZ - LX, SHIMADZU, Japan). The test was carried out at room temperature at a rate of 0.5 N·min -1Apply a ramp force at a certain ratio until the sample is produced. Quantitatively evaluate the self-healing effect through a tensile test. Calculate the healing rate using the formula: Healing rate % = Healing tensile strength / Original tensile strength × 100%, where the original tensile strength and the healing tensile strength are the tensile strengths obtained before and after scratch healing respectively. The calculated healing rates are recorded in Table 1.

[0086] Self-cleaning performance test

[0087] Carry out the photocatalytic self-cleaning performance test on the prepared specimen samples according to GB / T 23764-2009. Cut the materials for the impact-resistant and wear-resistant coatings in Examples 1-3 and Comparative Examples 1-4 respectively according to the standard size of 100 mm ± 2 mm. During the cutting process, pay attention to preventing pollution by organic pollutants such as oil and cross-infection between specimens. Use an ultraviolet light irradiation device to adjust the illuminance on the specimen surface to 2.0 Mw / cm 2 , conduct ultraviolet light irradiation for 25 h, and then use the dipping method to coat oleic acid on the specimen surface, that is, immerse the specimen in the oleic acid n-heptane solution and lift it at a speed of 60 cm / min and dry it at 70 °C for 15 min. Then turn on the power of the black light tube and measure the minimum contact angle of water. The test results are recorded in Table 1.

[0088] Corrosion resistance test

[0089] Test the corrosion resistance of the coating using a salt spray test. Prepare specimens using the materials for the impact-resistant and wear-resistant coatings in Examples 1-3 and Comparative Examples 1-4. Scratch the surface of the prepared coating with a scalpel, let it stand for 24 h, and then place it in a salt spray test chamber to observe the corrosion behavior. During the test, regularly check the corrosion situation on the surface of the coating specimen, and rate it according to the corrosion area specified in the national standard GB / T 6464-2002. The corrosion rating of the metal is calculated according to the percentage of the total area occupied by the corrosion defects using the following formula: Rp = 3×(2 - LogA), where Rp is the corrosion rating number and A is the percentage of the total area occupied by the metal corrosion. The corrosion results are recorded as shown in Table 1.

[0090] Table 1 Performance test results

[0091]

[0092] From the performance test data in the table, it can be known that the impact-resistant and wear-resistant coating provided by this solution has good impact-resistant and wear-resistant performance, self-healing performance, self-cleaning function and corrosion resistance. Using low-cost copper alloy and urea-formaldehyde microcapsules as the main materials, when cracks occur in the coating prepared with the urea-formaldehyde microcapsules, the healing agent inside the capsules can be released for self-healing, healing the cracks, and significantly increasing the service life of the coating. Also, by adding hydrophobic SiO2 and photocatalyst CeO2, a dense silica skeleton is formed, accelerating the inhibition of the corrosion of the coating, and significantly improving the self-cleaning and corrosion resistance of the coating through the surface hydrophobicity and photocatalytic activity, enhancing the stability of the coating in various environments, and enabling the coating to be widely used in various fields.

[0093] Figure 1 It is a cross-sectional view of the impact-resistant and wear-resistant coating model prepared by the present invention and a partial enlarged schematic diagram. It can be seen from the cross-sectional view of the model that the urea-formaldehyde microcapsules are uniformly dispersed in the copper alloy. The urea-formaldehyde microcapsules can be tightly combined with the copper alloy. SiO2 and inhibitor 8-hydroxyquinoline are uniformly adsorbed on the surface of the copper alloy coating, and the materials are tightly combined to form a composite coating. In addition, the partial enlarged view of the urea-formaldehyde microcapsules and the copper alloy can further show that the two are tightly cross-linked together, making the formed coating more dense and uniform, and the materials can achieve synergistic repair when damaged or cracked.

[0094] Figure 2 It is a main self-healing process diagram of the impact-resistant and wear-resistant coating prepared by the present invention when cracks appear. When cracks appear in the coating, it prompts the urea-formaldehyde microcapsules to rupture and release the healing agent dicyclopentadiene, thereby repairing the cracks.

[0095] Figure 3 It is a hydrophobic stability diagram of Example 2 of the impact-resistant and wear-resistant coating prepared by the present invention and Comparative Examples 1-4 immersed in 3.5 wt% NaCl solution. It can be seen from the figure that the stability of Comparative Example 1 decreases compared with that of Example 2, indicating that the added urea-formaldehyde microcapsules enhance the stability of the superhydrophobic coating. As Figure 3 shown, the stability of Comparative Example 3 also decreases compared with that of Example 2, indicating that the superhydrophobic film formed with the assistance of the added photocatalyst has enhanced stability, and the materials interact with each other and act together to enhance the self-cleaning and corrosion resistance of the coating.

[0096] In summary, through the verification of the examples and comparative examples, it can be seen that the present invention prepares an impact-resistant and wear-resistant coating with self-healing, self-cleaning and corrosion-resistant properties by mixing copper alloy and urea-formaldehyde microcapsules and using plasma spraying technology. The incorporated urea-formaldehyde microcapsules and SiO2 in the present invention have an obvious effect of improving the self-healing of the coating, and the photocatalyst CeO2 is incorporated, which can effectively degrade the organic pollutants generated on the surface of the coating, strengthening the self-cleaning effect of the superhydrophobic SiO2 film. Moreover, the present invention also has a good corrosion-resistant effect, enabling the coating of the present invention to be applied in the marine field and some broader fields.

[0097] The above describes the present invention and its implementation manners. The described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. What is shown in the drawings is also only one of the numerous implementation manners of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the present invention claimed, but merely represents the selected embodiments of the present invention. Based on this, other specific implementation manners of the present invention obtained by those skilled in the art without creative labor should fall within the protection scope of the present invention.

Claims

1. A method for preparing an impact-resistant and wear-resistant coating, characterized in that: The impact-resistant and wear-resistant coating includes a dense coating and a super-hydrophobic film from the inside to the outside, wherein the dense coating is prepared from the following components in parts by weight: 70-90 parts of copper alloy, 10-30 parts of urea-formaldehyde microcapsules, 60-100 parts of organic solvents and 0.1-2 parts of silane coupling agents; the super-hydrophobic film is prepared from the following components in parts by weight: 5-10 parts of organic compounds, 0.2-2 parts of inhibitors and 0.3-1 parts of photocatalysts; The organic compound is TEOS and PFDS, the volume ratio of TEOS and PFDS is 2:1, the inhibitor is 8-hydroxyquinoline, the photocatalyst is CeO2, and the urea-formaldehyde microcapsule includes a healing agent, which is dicyclopentadiene; The method specifically comprises the following steps: S1, grinding the copper alloy to obtain a copper alloy mixed powder; S2, cleaning and drying the surface of the metal workpiece substrate; S3, dissolving the copper alloy mixed powder, urea-formaldehyde microcapsules and silane coupling agent in an organic solvent, stirring to obtain a mixture and drying to obtain a mixed coating; S4, coating the metal workpiece by spraying, spraying the mixed coating prepared in step S3 onto the metal workpiece to form a dense coating on the surface of the metal workpiece; S5, dissolving the organic compound in anhydrous ethanol to form solution A, adding an inhibitor and a photocatalyst to solution A, stirring and heating to obtain solution B, adjusting the pH to obtain a white SiO2 sol, and forming a super-hydrophobic film; S6, vertically immersing the metal workpiece coated with the dense coating in step S4 into the white SiO2 sol obtained in step S5, and performing solvent heating and annealing to solidify the coating to form an impact-resistant and wear-resistant coating.

2. The method for preparing an impact-resistant and wear-resistant coating according to claim 1, characterized in that: The urea-formaldehyde microcapsules are prepared from the following raw materials: urea, formaldehyde, sodium dodecylbenzene sulfonate and a healing agent; The preparation of the urea-formaldehyde microcapsules comprises the following steps: Y1, dissolving urea in formaldehyde to form a solution, adjusting the pH, heating and stirring to obtain a urea-formaldehyde prepolymer; Y2, dissolving sodium dodecylbenzene sulfonate in distilled water, stirring and mixing to form a solution, emulsifying the solution after it is completely dissolved, and then adding a healing agent, stirring continuously until an emulsion is formed; Y3, adding the urea-formaldehyde prepolymer obtained in step Y1 to the emulsion obtained in step Y2 and stirring to form a mixed solution, and maintaining the pH value of the mixed solution at 2.5 with sulfuric acid; Y4, heating and stirring the mixed solution obtained in step Y3 to obtain prefabricated microcapsules; Y5, cooling the prefabricated microcapsules obtained in step Y4 to room temperature, washing and drying to obtain urea-formaldehyde microcapsules.

3. The method for preparing an impact-resistant and wear-resistant coating according to claim 1, characterized in that: The chemical components of the copper alloy are as follows: Cu 60-90%, Sn 8-30% and Si 2-10% by weight.

4. The method for preparing an impact-resistant and wear-resistant coating according to claim 1, characterized in that: The organic solvent is xylene, and the silane coupling agent is A151.

5. The method for preparing an impact-resistant and wear-resistant coating according to claim 1, characterized in that: In step S4, the spraying method is plasma spraying, the working voltage of the spraying device is 100-200 V, the working current is 200-800 mA, the spraying temperature is 120-200 ° C, the operating pressure is 4-40 kPa, and the spraying speed is 50-200 m / s.

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