Method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating through low-pressure cold spraying and application of Ni-Al2O3-PEEK mixed corrosion-resistant coating

Abstract

The invention provides a method for preparing a Ni-Al2O3-PEEK mixed corrosion-resistant coating through low-pressure cold spraying, and the method comprises the following steps: carrying out surface treatment on a base material, and sequentially carrying out grinding, polishing, cleaning, drying and sand blasting to obtain a base material to be sprayed; the preparation method comprises the following steps: mechanically mixing Ni powder, Al2O3 ceramic particles and polyether-ether-ketone (PEEK) powder to obtain cold spraying prefabricated powder; and the cold spraying prefabricated powder is subjected to low-pressure cold spraying to a to-be-sprayed base material, after the coating is cooled and cured, grinding and correction are conducted, and the Ni-Al2O3-PEEK mixed corrosion-resistant coating is obtained. The prepared coating is good in compactness and uniformity, has good mechanical performance and corrosion resistance, can be applied to the ocean engineering environment and can resist seawater scouring and corrosion.

Description

Technical Field

[0001] The invention belongs to the technical field of surface engineering, and specifically relates to a method for preparing a Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying and an application thereof. Background Art

[0002] In the field of surface additive remanufacturing, the development and application of corrosion-resistant coatings have received widespread attention. This is because corrosion-resistant coatings can effectively protect the substrate, extend its service life, reduce maintenance costs, and improve economic benefits. Among various metal materials, nickel (Ni) metal is widely used in various industrial fields such as chemical, petroleum, and marine industries due to its excellent corrosion resistance. However, there are many problems with the traditional corrosion-resistant coating preparation technology, such as the generation of pores and cracks, and higher spraying problems causing deformation of the metal substrate, phase change, and thermal stress damage. In order to solve this problem, many scholars have studied methods to improve the quality of coatings from different aspects, such as selecting appropriate coating preparation methods and continuously optimizing the process to improve the quality of coatings, and introducing suitable filling materials to seal the pores and defects in the coating to improve the quality of the coating, thereby improving the corrosion resistance. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for preparing a Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying and its application in view of the deficiencies of the above-mentioned prior art. The coating can be applied to marine engineering environments and can resist seawater erosion and corrosion.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying, the method comprising:

[0005] S1. Substrate preparation: The substrate is subjected to surface treatment, and is sequentially ground, polished, cleaned, dried, and sandblasted to obtain a substrate to be sprayed;

[0006] S2, mechanically mixing Ni powder, Al2O3 ceramic particles, and polyetheretherketone (PEEK) powder to obtain cold spray preformed powder;

[0007] S3, cold spraying the cold spray prefabricated powder obtained in S2 onto the substrate to be sprayed obtained in S1 at low pressure, and after the coating is cooled and solidified, grinding and correction are performed to obtain a Ni-Al2O3-PEEK mixed corrosion-resistant coating;

[0008] The process parameters of the low-pressure cold spraying are: the working gas is compressed air, the carrier gas pressure is 0.2-0.6 MPa, the carrier gas temperature is 100-200° C., the nozzle is 10-15 mm away from the substrate, and the spraying speed is 40-60 g / min.

[0009] Preferably, the substrate in S1 is a 316L stainless steel-based material.

[0010] Preferably, the particle size of the Ni powder in S2 is 20 μm to 50 μm, and the purity is ≥99.9%; the particle size of the Al2O3 ceramic particles is 20 μm to 50 μm, and the purity is ≥99.9%; the particle size of the polyetheretherketone PEEK powder is 20 μm to 50 μm, and the purity is ≥99.9%.

[0011] Preferably, the cold spray preformed powder in S2 is composed of the following raw materials in mass fractions: 40% Ni powder, 30% Al2O3 ceramic particles, and the remainder polyetheretherketone PEEK powder.

[0012] Preferably, the mechanical mixing time in S2 is 8 hours.

[0013] Preferably, the average thickness of the Ni-Al2O3-PEEK mixed corrosion-resistant coating in S3 is 500 μm to 2 mm.

[0014] Preferably, the annual average immersion corrosion rate of the Ni-Al2O3-PEEK mixed corrosion-resistant coating in S3 is 0.012-0.014 mm / a, and the annual average erosion corrosion rate is 0.015-0.018 mm / a; the bonding strength between the Ni-Al2O3-PEEK mixed corrosion-resistant coating and the substrate is 18.76-23.56 MPa; the porosity of the Ni-Al2O3-PEEK mixed corrosion-resistant coating is 2.03%-2.14%.

[0015] The present invention also provides the application of the Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared by the above method, and the Ni-Al2O3-PEEK mixed corrosion-resistant coating is used in marine engineering.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared by low-pressure cold spraying in the present invention has good adhesion, low porosity, and excellent corrosion resistance, while avoiding the problem of thermal damage to the substrate that may be caused by traditional high-temperature thermal spraying. The advantages compared with the prior art are mainly the following:

[0018] (1) Improve coating density and uniformity

[0019] The PEEK powder particle size is selected within the range of 20-50μm to ensure the fluidity and deposition efficiency of the powder during the spraying process, thereby forming a uniform and dense coating; spraying is carried out within the optimal temperature range of 100-200℃, which not only ensures the plastic deformation of the Ni metal powder, but also ensures the full melting and filling of the PEEK powder, significantly improving the density and surface smoothness of the coating.

[0020] (2) Enhance the mechanical properties and corrosion resistance of the coating

[0021] The use of PEEK powder with a purity of ≥99.9% ensures the stability and corrosion resistance of the coating in high temperature and marine environments, extending the service life of the coating; by designing a suitable coating material ratio, it not only has good mechanical strength and toughness, but also has excellent wear resistance and impact resistance, and is suitable for a wider range of application scenarios.

[0022] (3) Energy conservation and environmental protection

[0023] Compared with traditional thermal spraying methods, cold spraying technology can achieve efficient coating preparation at lower temperatures, reduce energy consumption, and reduce thermal pollution to the environment and the risk of metal powder oxidation.

[0024] (4) Adapt to various application environments

[0025] The coating formed by using Ni-Al2O3-PEEK mixed material has good comprehensive properties such as seawater corrosion resistance, high temperature resistance, wear resistance and high strength, and is suitable for various application fields such as ocean, aviation, chemical industry, etc. The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a SEM image of the cold-sprayed preformed powder of Ni-Al2O3 mixture according to Example 1 of the present invention.

[0027] Figure 2 This is a physical picture of the polyetheretherketone (PEEK) powder of Example 1 of the present invention.

[0028] Figure 3 This is a pore distribution test diagram of the Ni-Al2O3-PEEK mixed corrosion-resistant coating of Example 1 of the present invention.

[0029] Figure 4 It is a seawater immersion corrosion and erosion corrosion rate diagram of the cold-sprayed Ni single-element coating and the Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared in Example 1 of the present invention.

[0030] Figure 5This is a microscopic image of the Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared in Example 1 of the present invention, wherein (a) is a surface SEM image and (b) is a cross-sectional schematic diagram. DETAILED DESCRIPTION

[0031] Example 1

[0032] The method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying in this embodiment is as follows:

[0033] S1. Substrate preparation: The 316L stainless steel substrate is surface treated by grinding, polishing, cleaning, drying and sandblasting in sequence to obtain the substrate to be sprayed; the preliminary treatment of the substrate can ensure that the substrate surface is clean, dry and roughened, and enhance the adhesion of the coating.

[0034] S2, mechanically mixing Ni powder, Al2O3 ceramic particles and polyetheretherketone (PEEK) powder for 8 hours to obtain cold spray preformed powder;

[0035] After Ni powder and Al2O3 ceramic particles are mixed, the obtained Ni-Al2O3 mixed cold spray preformed powder is as follows Figure 1 As shown; the particle size of the Ni powder is 20μm to 50μm, and the purity is 99.9%; the particle size of the Al2O3 ceramic particles is 20μm to 50μm, and the purity is 99.9%; the particle size of the polyetheretherketone PEEK powder is 20μm to 50μm, and the purity is 99.9% ( Figure 2 ); The cold spray preformed powder is composed of the following raw materials by mass fraction: 40% Ni powder, 30% Al2O3 ceramic particles, and the balance is polyetheretherketone PEEK powder;

[0036] Polyetheretherketone PEEK powder was purchased from Zhongyan Polymer Materials Co., Ltd.

[0037] In this embodiment, the Ni powder undergoes plastic deformation and meshes with the substrate during the cold spraying process. The Al2O3 particles serve as a reinforcing phase composite material to improve the hardness and strength of the coating. The PEEK powder is melted, wetted and cooled to build a sealing layer during the spraying process to fill the pores and defects of the Ni-based coating, thereby enhancing the overall corrosion resistance of the coating. The PEEK powder particle size is selected within the range of 20 to 50 μm to ensure the fluidity and deposition efficiency of the powder during the spraying process, thereby forming a uniform and dense coating; spraying at a low temperature of 200 ° C not only ensures the plastic deformation of the Ni metal powder, but also ensures the full melting and filling of the PEEK powder, significantly improving the density, surface flatness and uniformity of the coating. The purity of PEEK powder is ≥99.9%, which can ensure the stability and corrosion resistance of the coating in high temperature and marine environments, and extend the service life of the coating; by designing a suitable coating material ratio, it not only has good mechanical strength and toughness, but also has excellent wear resistance and impact resistance, and is suitable for a wider range of application scenarios.

[0038] S3. Cold spray the cold spray preformed powder obtained in S2 onto the substrate to be sprayed obtained in S1 at low pressure. After the coating is cooled and solidified, it is polished and corrected to obtain a Ni-Al2O3-PEEK mixed corrosion-resistant coating with an average thickness of 500 μm.

[0039] The process parameters of the low-pressure cold spraying are: the working gas is compressed air, the carrier gas pressure is 0.2 MPa, the carrier gas temperature is 200° C., the nozzle is 15 mm away from the substrate, and the spraying speed is 60 g / min.

[0040] The functions of the raw materials in the coating in this embodiment are as follows:

[0041] Ni element role:

[0042] (1) Ni metal itself has excellent corrosion resistance. Especially in seawater, salt water, acid and alkali environments, it reacts with oxygen, electrolytes, etc. to form a dense oxide film, which can improve the corrosion resistance of the coating and effectively protect the substrate from corrosion.

[0043] (2) Ni metal powder can form a good bond with the substrate surface during the cold spraying process and firmly adhere to the substrate surface through mechanical engagement, thereby improving the bonding strength between the coating and the substrate.

[0044] (3) Ni-based coatings usually have good toughness and are not easily broken when impacted or bent, which is particularly important for the application of coatings under complex stress conditions.

[0045] Al2O3 function:

[0046] (1) It has extremely high hardness. When added into the coating, it can significantly improve the overall hardness and wear resistance of the coating.

[0047] (2) It has excellent chemical stability and can effectively resist the erosion of corrosive media in the marine environment.

[0048] (3) Ceramic particles can fill tiny defects and pores in the coating, increase the density of the coating, and thus improve the overall performance of the coating.

[0049] (3) It has good thermal stability and can maintain its physical and chemical properties in a high temperature environment, thus enhancing the stability of the coating under high temperature conditions.

[0050] PEEK function:

[0051] (1) Acting as a binder and filler in the coating, it can effectively fill the tiny pores and defects in the coating and increase the density of the coating.

[0052] (2) It has excellent chemical corrosion resistance and can effectively resist corrosive media in seawater, especially in seawater environments.

[0053] (3) The high toughness and impact resistance can significantly improve the overall toughness of the coating and reduce cracking and peeling of the coating during use.

[0054] (4) It has high thermal stability and can remain stable in a high temperature environment without decomposition, ensuring the stable performance of the coating under high temperature conditions.

[0055] In order to evaluate the seawater corrosion resistance of the coating, two experimental methods, immersion corrosion and erosion corrosion, were used, and three parallel specimens were used in each experiment. The specimens were polished, ultrasonically cleaned and dried.

[0056] Immersion corrosion test: The sample was immersed in 3.5wt% NaCl solution for 180 hours, and the solution was replaced every 48 hours. Erosion corrosion test: According to GB10124-1988 standard, the sample was immersed in 3.5wt% NaCl and 7.62kg / m 3 The sample was placed in a solution of corundum with a liquid flow rate of 5 m / s and a corrosion time of 180 hours. The test surface of the sample was in full contact with the corrosive medium, and the other surfaces were isolated with epoxy resin. After the experiment, an electronic balance with an accuracy of 0.0001 g was used to measure the weight change of the sample before and after corrosion, and the corrosion rate and depth were calculated.

[0057] At the same time, a Ti single-element coating was sprayed using the same preparation technology and process parameters as a control experiment, and the comparison illustrates the advantages of the Ni-Al2O3-PEEK mixed corrosion-resistant coating.

[0058] The porosity of the Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared in this embodiment is 2.03%, and the pore distribution is as follows: Figure 3 Shown in the red area.

[0059] The Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared in this embodiment has an annual average immersion corrosion rate of 0.012 mm / a, and an annual average erosion corrosion rate of 0.015 mm / a.

[0060] like Figure 4 As shown, the annual average corrosion rate of the Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared in this embodiment is 77.78% lower than that of the Ni-based single substance coating, and the erosion corrosion rate is 72.22%. This shows that adding Al2O3 ceramic particles and polymer PPEK to the Ni-based coating can greatly improve the coating's resistance to seawater corrosion and wear erosion.

[0061] like Figure 5 As shown, Figure 5 (a) is the SEM image of the coating surface. It can be seen that the coating is compact and dense, with high density, no obvious defects and pores, and there are very few defects and holes on the surface. No obvious Al2O3 particles are seen on the surface. The pores are filled with PEEK. From the cross-sectional schematic diagram of Figure (b), it can be seen that a large number of Al2O3 ceramic particles are dispersed inside the coating, which can significantly enhance the overall mechanical properties and toughness. The local cracks and holes inside are filled with PEEK by melting, forming a "bridging" effect, which significantly reduces the porosity of the coating, prevents the further expansion of the cracks, and enhances the toughness of the coating.

[0062] The bonding strength between the Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared in this embodiment and the substrate is 23.56 MPa.

[0063] Compared with the traditional thermal spraying method, the preparation method of this embodiment can achieve efficient coating preparation at a lower temperature by cold spraying process, which reduces energy consumption, thermal pollution to the environment and the risk of metal powder oxidation. The prepared Ni-Al2O3-PEEK hybrid corrosion-resistant coating not only has excellent mechanical strength and corrosion resistance, but also has good thermal stability and toughness, and is suitable for various harsh application environments. It has good comprehensive properties such as seawater corrosion resistance, high temperature resistance, wear resistance and high strength, and is suitable for a variety of application fields such as ocean, aviation, and chemical industry. The coating is resistant to seawater corrosion and performs well in the marine environment. It can effectively resist corrosive media in seawater and is particularly suitable for marine engineering, ships, offshore platforms and other fields.

[0064] In order to illustrate the advantages of the coating raw material selection and dosage in the present invention, coatings with different raw material ratios were prepared using the same preparation technology and process parameters, and their bonding strength was tested for illustration.

[0065] Table 1 Coating properties prepared with different raw material ratios

[0066]

[0067] Example 2

[0068] The method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying in this embodiment is as follows:

[0069] S1. Substrate preparation: Surface treatment of 316L stainless steel substrate is carried out by grinding, polishing, cleaning, drying and sandblasting in sequence to obtain the substrate to be sprayed;

[0070] S2. Mechanically mix Ni powder, Al2O3 ceramic particles and polyetheretherketone (PEEK) powder for 8 hours to obtain cold spray preformed powder; the particle size of the Ni powder is 20μm-50μm, and the purity is 99.95%; the particle size of the Al2O3 ceramic particles is 20μm-50μm, and the purity is 99.95%; the particle size of the polyetheretherketone (PEEK) powder is 20μm-50μm, and the purity is 99.95%; the cold spray preformed powder is composed of the following raw materials in mass fraction: 40% Ni powder, 30% Al2O3 ceramic particles, and the balance is polyetheretherketone (PEEK) powder;

[0071] Polyetheretherketone PEEK powder was purchased from Zhongyan Polymer Materials Co., Ltd.

[0072] S3, cold spraying the cold spray preformed powder obtained in S2 onto the substrate to be sprayed obtained in S1 at low pressure, and after the coating is cooled and solidified, grinding and correction are performed to obtain a Ni-Al2O3-PEEK mixed corrosion-resistant coating with an average thickness of 2 mm;

[0073] The process parameters of the low-pressure cold spraying are: the working gas is compressed air, the carrier gas pressure is 0.6 MPa, the carrier gas temperature is 100° C., the nozzle is 10 mm away from the substrate, and the spraying speed is 40 g / min.

[0074] The annual average immersion corrosion rate of the Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared in this embodiment is 0.014 mm / a, and the annual average erosion corrosion rate is 0.018 mm / a; the bonding strength between the Ni-Al2O3-PEEK mixed corrosion-resistant coating and the substrate is 18.76 MPa, and the porosity of the Ni-Al2O3-PEEK mixed corrosion-resistant coating is 2.14%.

[0075] The Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared in this embodiment can be used in marine engineering.

[0076] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying, characterized in that: The method is: S1. Substrate preparation: The substrate is subjected to surface treatment, and is sequentially ground, polished, cleaned, dried, and sandblasted to obtain a substrate to be sprayed; S2, mechanically mixing Ni powder, Al2O3 ceramic particles, and polyetheretherketone (PEEK) powder to obtain cold spray preformed powder; S3, cold spraying the cold spray prefabricated powder obtained in S2 onto the substrate to be sprayed obtained in S1 at low pressure, and after the coating is cooled and solidified, grinding and correction are performed to obtain a Ni-Al2O3-PEEK mixed corrosion-resistant coating; The process parameters of the low-pressure cold spraying are: the working gas is compressed air, the carrier gas pressure is 0.2-0.6 MPa, the carrier gas temperature is 100-200° C., the nozzle is 10-15 mm away from the substrate, and the spraying speed is 40-60 g / min.

2. The method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying according to claim 1, characterized in that: The substrate described in S1 is a 316L stainless steel-based material.

3. The method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying according to claim 1, characterized in that: The particle size of the Ni powder in S2 is 20 μm to 50 μm, and the purity is ≥99.9%; the particle size of the Al2O3 ceramic particles is 20 μm to 50 μm, and the purity is ≥99.9%; the particle size of the polyetheretherketone PEEK powder is 20 μm to 50 μm, and the purity is ≥99.9%.

4. The method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying according to claim 1, characterized in that: The cold spray preformed powder in S2 is composed of the following raw materials in mass fractions: 40% Ni powder, 30% Al2O3 ceramic particles, and the remainder polyetheretherketone PEEK powder.

5. The method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying according to claim 1, characterized in that: The mechanical mixing time in S2 is 8 hours.

6. The method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying according to claim 1, characterized in that: The average thickness of the Ni-Al2O3-PEEK mixed corrosion-resistant coating in S3 is 500 μm to 2 mm.

7. The method for preparing Ni-Al2O3-PEEK mixed corrosion-resistant coating by low-pressure cold spraying according to claim 1, characterized in that: The annual average immersion corrosion rate of the Ni-Al2O3-PEEK mixed corrosion-resistant coating in S3 is 0.012-0.014 mm / a, and the annual average erosion corrosion rate is 0.015-0.018 mm / a; the bonding strength between the Ni-Al2O3-PEEK mixed corrosion-resistant coating and the substrate is 18.76-23.56 MPa; the porosity of the Ni-Al2O3-PEEK mixed corrosion-resistant coating is 2.03%-2.14%.

8. An application of a Ni-Al2O3-PEEK mixed corrosion-resistant coating prepared by the method according to any one of claims 1 to 7, characterized in that: The Ni-Al2O3-PEEK hybrid corrosion-resistant coating is used in marine engineering.

Images