A sleeve surface treatment process

Abstract

The application relates to the technical field of sleeve surface treatment, and more specifically to a sleeve surface treatment process. The sleeve surface treatment process comprises the following steps: S1 polishing; S2 oil removal; S3 laser rust removal; S4 acid immersion; S5 nickel plating; S6 rust-proof treatment; S7 passivation; and S8 brazing. The sleeve surface treatment process can be used for producing a sleeve used in an automobile engine, and the sleeve has the advantages of better coating and base body bonding strength, corrosion resistance, wear resistance and high-temperature resistance.

Description

Technical Field

[0001] This application relates to the technical field of sleeve surface treatment, and more specifically, to a sleeve surface treatment process. Background Technology

[0002] Automotive engine chains mainly include roller chains, bushing chains, and toothed chains, with bushing chains being the most commonly used. Bushings are made of 304 stainless steel, which is susceptible to corrosion. Therefore, they need to undergo surface treatment before leaving the factory to make the metal parts corrosion-resistant, thereby ensuring the service life of the vehicle.

[0003] Chinese patent CN108716001A discloses a surface treatment process for automotive parts, including the following steps: 1) polishing; 2) spraying; 3) plasma surface treatment; 4) primary coating; 5) secondary coating; 6) glaze application; 7) tertiary coating. The tertiary coating involves applying a PVD coating to the glazed surface of the automotive parts. The treated automotive parts exhibit high surface hardness, corrosion resistance, oxidation resistance, wear resistance, and a long service life.

[0004] Regarding the aforementioned technologies, a stable interfacial bond between the substrate and the coating is a prerequisite for the coating to fully function. Under high-temperature conditions, internal stress is generated at the substrate-coating interface. The higher the bond strength between the substrate and the coating, the less noticeable the coating peeling, and the better the interface stability. However, the sleeve is used in automotive engines, where the operating temperature can reach 500-700℃. The coating prepared using PVD technology will generate high residual stress under high-temperature conditions, affecting the bond strength between the coating and the sleeve, thus causing the coating to peel off. This fails to ensure that the coating can fully function to improve the surface performance and service life of the substrate. Therefore, there is a problem of insufficient bond strength between the coating and the substrate under high-temperature conditions. Summary of the Invention

[0005] To enhance the bonding strength between the coating and the sleeve under high-temperature conditions, this application provides a sleeve surface treatment process.

[0006] The sleeve surface treatment process provided in this application adopts the following technical solution:

[0007] A sleeve surface treatment process includes the following steps:

[0008] S1 Polishing: Grind the sleeve in one direction with sandpaper to polish it, and then wipe the sleeve with a soft cloth with talcum powder to obtain a polished sleeve.

[0009] S2 degreasing: Heat the degreasing agent to 50-60℃, immerse the polished sleeve obtained by S1 polishing in the degreasing agent at a constant temperature for 5-10 minutes, rinse with clean water 1-2 times, and dry to obtain a degreased sleeve.

[0010] S3 Laser Rust Removal: Using a laser rust removal machine, the surface of the degreased sleeve obtained from S2 degreasing is scanned to obtain a rust-removed sleeve;

[0011] S4 pickling: The rust-removed sleeve obtained by S3 laser rust removal is soaked in pickling activator for 5-6 minutes, rinsed with clean water 1-2 times, and dried to obtain the activated sleeve.

[0012] S5 nickel plating: The activated sleeve obtained by S4 acid immersion is placed in a chemical nickel plating solution and immersed for 8-15 minutes at 85-92℃ and pH 4.2-4.6 to obtain a nickel-plated sleeve;

[0013] S6 rust prevention treatment: The nickel-plated sleeve obtained by S5 nickel plating is sealed with rust-preventive sealant at room temperature for 2-4 minutes and the pH is controlled at 7.5-8.5 to obtain a rust-preventive sleeve;

[0014] S7 passivation: The rust-proof sleeve obtained by S6 rust prevention treatment is immersed in 0.7-1.5 vol% dichromate solution, soaked at 80-90℃ for 1-3 minutes, and dried to obtain the passivated sleeve;

[0015] S8 Brazing: The passivated sleeve obtained from S7 passivation and CuMnNi alloy powder are placed in a vacuum furnace, and the furnace is pre-evacuated to 5×10⁻⁶ vacuum in a cold state. -2 Heat to 900℃, fill the furnace with argon gas to maintain the furnace pressure at 2-3Pa, hold for 15 minutes, then heat to 1100-1200℃, hold for 16-20 minutes, cool to below 500℃, air cool, and remove from the furnace to obtain the final product.

[0016] By adopting the above technical solution, the final step involves vacuum brazing to prepare a coating on the sleeve surface, achieving a metallurgical bond between the coating and the substrate. The coating material has a stable structure, excellent bonding strength with the sleeve, and exhibits stability under high-temperature conditions, making it less prone to peeling. This ensures the coating fully functions to improve the surface performance and service life of the substrate. The final sleeve product obtained in this application possesses excellent properties of corrosion resistance, wear resistance, and high-temperature resistance, and is safe and harmless to human health.

[0017] Meanwhile, this application uses laser rust removal for surface treatment, which, compared to chemical cleaning, does not generate rust removal waste liquid. Furthermore, the collection and purification of pollutant particles generated by laser rust removal is simple and can avoid environmental pollution. Chemical nickel plating is used instead of traditional electroplating for surface treatment, which reduces energy consumption and saves energy. Additionally, the chemical nickel plating solution is non-toxic and free of heavy metals, and the solution can be repeatedly replenished, avoiding waste liquid discharge and ensuring safety and environmental protection. Vacuum brazing is used for surface treatment, avoiding the use of flux, making the process environmentally friendly and pollution-free.

[0018] Preferably, the constant temperature soaking and rinsing with clean water in the S2 degreasing step are repeated 2-3 times.

[0019] By adopting the above technical solution, for sleeves heavily soiled with oil, repeated constant temperature soaking and rinsing with clean water can make the oil stains more thoroughly removed, which is beneficial to subsequent processes.

[0020] Preferably, in the S3 laser rust removal step, 2-3 layers of transparent film are covered on the sleeve surface, and 1-2 layers of adhesive film are evenly applied to the sleeve surface at the position where the transparent film contacts the transparent film.

[0021] By adopting the above technical solution, the pollutant particles or fragments washed off adhere to the film, ensuring that the pollutants will not cause pollution to the surrounding environment.

[0022] Preferably, in the S3 laser rust removal step, the incident angle of the laser is controlled to be between 10-20°.

[0023] By adopting the above technical solution, compared with vertical laser beam incidence, oblique incidence can increase the radiation area, further improving the cleaning efficiency and cleaning effect.

[0024] Preferably, the pickling activator in the S4 pickling step comprises the following components in parts by weight:

[0025] Citric acid 5-10 parts;

[0026] Lactic acid 10-20 parts;

[0027] 2-3 parts hydrochloric acid;

[0028] 0.001-0.002 parts of hexamethylenetetramine;

[0029] 3-4 parts sodium acetate;

[0030] 900-960 portions of water.

[0031] By adopting the above technical solution, the sleeve surface can be uniformly activated after acid immersion, which is beneficial for subsequent electroless nickel plating and improves the adhesion between the plating layer and the sleeve surface. Using hexamethylenetetramine as a corrosion inhibitor can, on the one hand, inhibit the dissolution of the metal anolyte, thus preventing corrosion of the sleeve during acid immersion; on the other hand, under the combined action of citric acid, lactic acid, and hydrochloric acid, it can partially decompose into strongly reducing ammonia and formaldehyde, thus preventing rusting of the sleeve during acid immersion. Furthermore, citric acid and lactic acid are safe and non-toxic, while hydrochloric acid and sodium acetate are environmentally friendly, resulting in a non-toxic and environmentally friendly pickling activator.

[0032] Preferably, the electroless nickel plating solution in the S5 nickel plating step comprises the following components in parts by weight:

[0033] 25-35 parts nickel sulfate;

[0034] 5-15 parts of nickel chloride;

[0035] 40-50 parts of sodium hypophosphite;

[0036] 10-20 parts sodium citrate;

[0037] 5-10 parts of sodium thiosulfate;

[0038] 80-90 parts water.

[0039] By adopting the above technical solutions, nickel sulfate and nickel chloride, as the main nickel salts, form a dense layer on the sleeve surface, which can improve the hardness and corrosion resistance of the sleeve. Using sodium thiosulfate instead of traditional thiourea as a stabilizer can avoid the harm to human health and the atmospheric environment caused by hydrogen sulfide formed by the thermal decomposition of thiourea at temperatures above 60°C. This is more environmentally friendly. Sodium citrate is used as a coordinating agent, which can increase the cathodic polarization of the coating. Adding an appropriate amount is beneficial to the smooth progress of nickel plating and can improve the appearance of the coating. Sodium hypophosphite is used as a reducing agent, which can enhance the hardness and wear resistance of the sleeve surface.

[0040] Preferably, the rust-preventive sealant in the S6 rust-preventive treatment comprises the following components in parts by weight:

[0041] 4-5 parts of triethanolamine;

[0042] 1-2 parts boric acid;

[0043] Phytic acid 2-3 parts;

[0044] 1-2 parts polyethylene glycol;

[0045] 1-2 parts of triacetic acid;

[0046] 4-6 parts of lithium silicate;

[0047] 80-87 parts water.

[0048] By adopting the above technical solutions, lithium silicate, as the main film-forming component, is commonly used as an anti-rust coating for surfaces such as steel, effectively sealing the pores of nickel plating, and is safe and non-toxic. Triethylene glycol and phytic acid act as corrosion inhibitors, and phytic acid can also be used in the food industry for preserving fruits and vegetables, and is safe and non-toxic. Nitrogenous triacetic acid is commonly used as a complexing agent in chemical plating, boric acid can prevent rust and corrosion, and polyethylene glycol facilitates the formation of a sealing film and is safe and non-toxic. The anti-rust sealant made from these components is more environmentally friendly.

[0049] Preferably, the CuMnNi alloy powder in the S8 brazing also includes WC particles, and the weight ratio of the CuMnNi alloy powder to the WC particles is 6-8:3.

[0050] By adopting the above technical solution, the coating prepared with CuMnNi alloy powder has good wear resistance. The WC particles have high melting point, high hardness, good wear resistance, stable performance, and good wettability with the sleeve. Adding WC particles to CuMnNi alloy powder is beneficial to improving the bonding performance of welding.

[0051] Preferably, the outer surface of the WC particles is chemically plated with a Ni-P alloy, and the thickness of the Ni-P alloy layer is 2-4 μm.

[0052] By adopting the above technical solution, the wettability between WC particles and CuMnNi alloy powder can be improved, which is conducive to smooth welding.

[0053] In summary, this application has the following beneficial effects:

[0054] 1. This application uses a vacuum brazing process to prepare a coating on the sleeve surface, which results in better bonding strength between the coating and the sleeve and makes the coating less prone to peeling off under high temperature conditions; at the same time, it avoids the use of flux, and the process is environmentally friendly and pollution-free.

[0055] 2. In this application, laser rust removal is used instead of traditional chemical cleaning and rust removal, and a transparent film is covered on the surface of the sleeve, which does not generate rust removal waste liquid. At the same time, the pollutants removed by cleaning are adhered to the film, thus avoiding environmental pollution.

[0056] 3. In this application, chemical nickel plating is used instead of traditional electroplating, which reduces power consumption, saves energy, and avoids waste liquid discharge, making it safe and environmentally friendly;

[0057] 4. The pickling activator, electroless nickel plating solution and rust-preventing sealant used in this application are all environmentally friendly reagents and are environmentally friendly.

[0058] 5. The sleeve obtained by the surface treatment process of this application has excellent properties of rust resistance, wear resistance and high temperature resistance, and the product is safe and harmless to human health. Attached Figure Description

[0059] Figure 1 This is a flowchart of the method provided in this application. Detailed Implementation

[0060] The following is in conjunction with the appendix Figure 1 The present application will be further described in detail with reference to the embodiments.

[0061] In this application, the degreasing agent can be derived from commercially available sources; the talc powder has an average particle size of 1250 mesh; the laser rust removal machine has a maximum power of 1500W; the ratio of Cu, Mn, and Ni elements in the CuMnNi alloy powder is (63-65):(29.5-30.5):(5.5-6.5); the WC particles have an average particle size of 100μm; and the transparent film is transparent to laser light.

[0062] Preparation examples of raw materials and / or intermediates

[0063] Preparation Example 1

[0064] The preparation process of the pickling activator is as follows: Under normal temperature conditions, 8 kg of citric acid, 15 kg of lactic acid, 3 kg of hydrochloric acid, 0.001 kg of corrosion inhibitor, 4 kg of sodium acetate and 920 kg of water are mixed and stirred evenly to obtain the pickling activator.

[0065] Preparation Example 2

[0066] The preparation process of electroless nickel plating solution is as follows: Under 35℃ conditions, 30kg nickel sulfate, 20kg nickel chloride, 40kg sodium hypophosphite, 15kg sodium citrate, 8kg sodium thiosulfate and 87kg water are mixed, stirred evenly, and the pH is adjusted to 8.5-9.5 with ammonia water to obtain electroless nickel plating solution.

[0067] Preparation Example 3

[0068] The preparation process of the rust-preventive sealant is as follows: Under normal temperature conditions, first add 5 kg of lithium silicate and 40 kg of water, stir evenly to obtain mixture one; then mix 4 kg of triethanolamine, 1 kg of boric acid, 2.5 kg of phytic acid, 1.5 kg of polyethylene glycol, 1 kg of triacetic acid, and 25 kg of water evenly to obtain mixture two; then mix mixture one and mixture two with 15 kg of water, stir evenly; finally, let stand and filter to obtain the rust-preventive sealant. Example

[0069] Example 1

[0070] A sleeve surface treatment process includes the following steps:

[0071] S1 Polishing: Grind the sleeve in one direction with sandpaper to polish it, and then wipe the sleeve with a soft cloth with talcum powder to obtain a polished sleeve.

[0072] S2 degreasing: Heat the degreasing agent to 50℃, immerse the polished sleeve obtained by S1 polishing in the degreasing agent at a constant temperature for 10 minutes, rinse once with clean water, and dry to obtain a degreased sleeve.

[0073] S3 laser rust removal: Using a laser rust removal machine, the surface of the degreased sleeve obtained from S2 degreasing is scanned to obtain a rust-removed sleeve;

[0074] S4 pickling: The rust-removed sleeve obtained by S3 laser rust removal is immersed in the pickling activator prepared in Preparation Example 1 for 5 minutes, rinsed once with clean water, and dried to obtain the activated sleeve.

[0075] S5 nickel plating: The activated sleeve obtained by S4 acid immersion is placed in the chemical nickel plating solution prepared in Preparation Example 2 and immersed for 8 minutes at 85°C and pH 4.2 to obtain a nickel-plated sleeve;

[0076] S6 Rust Prevention Treatment: The nickel-plated sleeve obtained by S5 nickel plating was sealed with the rust-preventive sealant prepared in Preparation Example 3 at room temperature for 2 minutes and the pH was controlled at 7.5 to obtain the rust-preventive sleeve;

[0077] S7 passivation: The rust-proof sleeve obtained by S6 rust prevention treatment is immersed in 0.7 vol% dichromate solution, soaked at 80℃ for 3 min, and dried to obtain the passivated sleeve;

[0078] S8 Brazing: The passivated sleeve obtained from S7 passivation and CuMnNi alloy powder are placed in a vacuum furnace, and the furnace is pre-evacuated to 5×10⁻⁶ vacuum in a cold state. -2 The furnace is heated to 900°C, and argon gas is filled into the furnace to maintain the pressure at 2 Pa. The furnace is held for 15 minutes, then heated to 1100°C and held for 16 minutes. The furnace is then cooled to below 500°C, air-cooled, and removed from the furnace to obtain the final product.

[0079] Example 2

[0080] A sleeve surface treatment process includes the following steps:

[0081] S1 Polishing: Grind the sleeve in one direction with sandpaper to polish it, and then wipe the sleeve with a soft cloth with talcum powder to obtain a polished sleeve.

[0082] S2 degreasing: Heat the degreasing agent to 60℃, immerse the polished sleeve obtained by S1 polishing in the degreasing agent at a constant temperature for 5 minutes, rinse twice with clean water, and dry to obtain a degreased sleeve.

[0083] S3 Laser Rust Removal: Using a laser rust removal machine, the surface of the degreased sleeve obtained from S2 degreasing is scanned to obtain a rust-removed sleeve;

[0084] S4 pickling: The rust-removed sleeve obtained by S3 laser rust removal is immersed in the pickling activator prepared in Preparation Example 1 for 6 minutes, rinsed twice with clean water, and dried to obtain the activated sleeve.

[0085] S5 nickel plating: The activated sleeve obtained by S4 acid immersion is placed in the chemical nickel plating solution prepared in Preparation Example 2 and immersed for 15 minutes at 92°C and pH 4.6 to obtain a nickel-plated sleeve.

[0086] S6 Rust Prevention Treatment: The nickel-plated sleeve obtained by S5 nickel plating was sealed with the rust-preventive sealant prepared in Preparation Example 3 at room temperature for 4 minutes and the pH was controlled at 8.5 to obtain the rust-preventive sleeve;

[0087] S7 passivation: The rust-proof sleeve obtained by S6 rust prevention treatment is immersed in 1.5 vol% dichromate solution, soaked at 90℃ for 1 min, and dried to obtain the passivated sleeve;

[0088] S8 Brazing: The passivated sleeve obtained from S7 passivation and CuMnNi alloy powder are placed in a vacuum furnace, and the furnace is pre-evacuated to 5×10⁻⁶ vacuum in a cold state. -2 The furnace is heated to 900°C, and argon gas is filled into the furnace to maintain the pressure at 3 Pa. The furnace is held for 15 minutes, then heated to 1200°C and held for 20 minutes. The furnace is then cooled to below 500°C, air-cooled, and removed from the furnace to obtain the final product.

[0089] Example 3

[0090] A sleeve surface treatment process includes the following steps:

[0091] S1 Polishing: Grind the sleeve in one direction with sandpaper to polish it, and then wipe the sleeve with a soft cloth with talcum powder to obtain a polished sleeve.

[0092] S2 degreasing: Heat the degreasing agent to 55℃, immerse the polished sleeve obtained by S1 polishing in the degreasing agent at a constant temperature for 10 minutes, rinse twice with clean water, and dry to obtain a degreased sleeve.

[0093] S3 Laser Rust Removal: Using a laser rust removal machine, the surface of the degreased sleeve obtained from S2 degreasing is scanned to obtain a rust-removed sleeve;

[0094] S4 pickling: The rust-removed sleeve obtained by S3 laser rust removal is immersed in the pickling activator prepared in Preparation Example 1 for 6 minutes, rinsed twice with clean water, and dried to obtain the activated sleeve.

[0095] S5 nickel plating: The activated sleeve obtained by S4 acid immersion is placed in the chemical nickel plating solution prepared in Preparation Example 2 and immersed for 10 min at 90°C and pH 4.3 to obtain a nickel-plated sleeve;

[0096] S6 Rust Prevention Treatment: The nickel-plated sleeve obtained by S5 nickel plating was sealed with the rust-preventive sealant prepared in Preparation Example 3 at room temperature for 3 minutes and the pH was controlled at 8.0 to obtain the rust-preventive sleeve;

[0097] S7 passivation: The rust-proof sleeve obtained by S6 rust prevention treatment is immersed in a 1.2 vol% dichromate solution, soaked at 85℃ for 3 minutes, and dried to obtain a passivated sleeve;

[0098] S8 Brazing: The passivated sleeve obtained from S7 passivation and CuMnNi alloy powder are placed in a vacuum furnace, and the furnace is pre-evacuated to 5×10⁻⁶ vacuum in a cold state. -2 The furnace is heated to 900°C, and argon gas is filled into the furnace to maintain the pressure at 3 Pa. The furnace is held for 15 minutes, then heated to 1150°C and held for 20 minutes. The furnace is then cooled to below 500°C, air-cooled, and removed from the furnace to obtain the final product.

[0099] Example 4

[0100] The only difference from Example 3 is that the constant temperature soaking and rinsing with clean water in the S1 degreasing step are repeated twice.

[0101] Example 5

[0102] The only difference from Example 4 is that in the S3 laser rust removal step, two layers of transparent film are covered on the sleeve surface, and a layer of adhesive film is evenly applied at the position where the sleeve surface contacts the transparent film, while controlling the incident angle of the laser to be 10°.

[0103] Example 6

[0104] The only difference from Example 4 is that in the S3 laser rust removal step, three layers of transparent film are covered on the sleeve surface, and two layers of adhesive film are evenly applied at the position where the sleeve surface contacts the transparent film, while controlling the incident angle of the laser to be 20°.

[0105] Example 7

[0106] The only difference from Example 6 is that the CuMnNi alloy powder in S8 brazing also includes WC particles, and the weight ratio of CuMnNi alloy powder to WC particles is 2:1.

[0107] Example 8

[0108] The only difference from Example 6 is that the CuMnNi alloy powder in the S8 brazing also includes WC particles, and the weight ratio of CuMnNi alloy powder to WC particles is 8:3.

[0109] Example 9

[0110] The only difference from Example 8 is that the outer surface of the WC particles is chemically plated with a 2μm Ni-P alloy.

[0111] Example 10

[0112] The only difference from Example 8 is that the outer surface of the WC particles is chemically plated with a 4μm Ni-P alloy. Comparative Example

[0113] Comparative Example 1

[0114] The only difference from Example 3 is that the S8 brazing is replaced by a PVD coating process.

[0115] Comparative Example 2

[0116] The only difference from Example 3 is that the sleeve was not subjected to a surface treatment process.

[0117] Performance testing

[0118] The prohibited substance content of the sleeves in Examples 1-10 was tested according to the method described in GB / T 30512-2014 "Requirements for Prohibited Substances in Automobiles". The results are shown in Table 1, where ND indicates that the content is below the method detection limit, i.e., the relevant substance was not detected. The concentration of hexavalent chromium in the coating does not exceed 0.1 μg / cm³. 2 At that time, it was determined to be negative.

[0119] The high-temperature resistance performance of the sleeve coatings of Examples 1-10 and Comparative Example 1 was tested according to the method described in JB / T 10458-2004 "Technical Conditions for High-Temperature Oxidation-Resistant Coatings for Mechanical Equipment". The test temperature was 700℃ and the test time was 20h. The results are shown in Table 2.

[0120] The friction coefficients of the sleeves in Examples 1-3 and Comparative Example 2 were tested according to the method described in GB / T 12444-2006 "Test Methods for Wear of Metallic Materials - Sliding Wear Test of Test Rings and Blocks". The results are shown in Table 3.

[0121] Neutral salt spray (NSS) tests were conducted on Examples 1-3 and Comparative Example 2 according to the method described in GB / T 10125-2021 "Civilization Tests in Artificial Atmospheres - Salt Spray Tests". The tests were conducted at 2h, 6h, 24h, 48h, 96h, 168h, 240h, 480h, 720h, and 1008h to determine whether corrosion occurred. The time when no corrosion occurred was recorded. The results are shown in Table 3.

[0122] Corrosion tests were conducted on Examples 1-3 and Comparative Example 2 according to the methods described in GB / T 6461-2002 "Rating of specimens and test pieces after corrosion testing of metallic and other inorganic coatings on metallic substrates", and protection ratings (R) were performed. P ) and appearance rating (R) A Protection and appearance ratings were divided into 1-10 levels, where 10 represents no defects, 2 represents defects exceeding 10% but not exceeding 25%, and 0 represents defects exceeding 50%. Coating damage types were divided into ten categories (A, J), where B represents darkening caused by difficult-to-see or even invisible coating corrosion, and E represents surface pitting. The subjective evaluation of the degree of coating damage included four levels: vs for very mild, s for mild, m for moderate, and x for severe. The results are shown in Table 3.

[0123] Table 1 Record of Detection Results of Prohibited Substances in Sleeves of Examples 1-10

[0124]

[0125] Table 2 Record of High Temperature Resistance of Sleeve Coatings in Examples 1-10 and Comparative Example 1

[0126]

[0127] Table 3. Record of wear resistance and corrosion resistance of the sleeves in Examples 1-3 and Comparative Example 2

[0128]

[0129] 1. As can be seen from Examples 1-10 and Table 1, after processing the sleeve using the surface treatment process of this application, the content of prohibited substances in the obtained product meets the standards, so it will not cause harm to human health and the environment when used.

[0130] 2. As can be seen from Examples 1-3 and Comparative Example 1 and Table 2, using vacuum brazing to replace the traditional PVD coating process can enhance the bonding strength between the coating and the sleeve under high temperature conditions, thereby preventing the coating from peeling off.

[0131] 3. As can be seen from Examples 1-3 and 4 and Table 2, grease can cause the coating to lose its adhesion in some areas, resulting in blistering. After repeated constant temperature soaking and rinsing with clean water, the grease on the sleeve surface can be removed more thoroughly, thereby alleviating the blistering phenomenon.

[0132] 4. As can be seen from Examples 4 and 5-6, and Table 2, oxides can cause localized loss of adhesion in the coating, leading to blistering. Laser rust removal can improve the smoothness of the sleeve surface and alleviate blistering. Simultaneously, increasing the laser incident angle within a certain range enhances the cleaning effect, making the sleeve surface smoother and facilitating the uniform distribution of subsequent coatings, thereby mitigating bottom leakage.

[0133] 5. As can be seen from Examples 6 and 7-8 and Table 2, the addition of WC particles is beneficial to improving the bonding performance of vacuum brazing, resulting in better adhesion between the coating and the sleeve, thereby further alleviating the blistering phenomenon.

[0134] 6. As can be seen from Examples 8 and 9-10 and Table 2, surface chemical plating of WC particles with Ni-P alloy can improve the wettability of WC particles with CuMnNi alloy powder, which is beneficial to the uniform distribution of the coating and thus further alleviates the bottom leakage phenomenon.

[0135] 7. As can be seen from Examples 1-3 and Comparative Example 2 and Table 3, the friction coefficient of the sleeve after surface treatment is effectively reduced and the corrosion resistance is significantly enhanced. This indicates that the nickel plating layer and CuMnNi coating can improve the wear resistance and corrosion resistance of the sleeve and extend its service life.

[0136] 8. As can be seen from Examples 1-3 and Comparative Example 2, and in conjunction with Table 3, the sleeve without surface treatment process has a protection rating of R. P The lower rating is mainly due to the presence of rust on the sleeve surface after the corrosion test. In contrast, sleeves that underwent surface treatment showed no rust after the corrosion test, achieving a protection rating of R. P It can achieve a defect-free result; however, slight corrosion occurs in the nickel plating layer and the CuMnNi coating.

[0137] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A sleeve surface treatment process characterized by, The method comprises the following steps: S1 polishing: polishing the sleeve in one direction with sandpaper, polishing, and wiping the sleeve with a soft cloth with talcum powder to obtain a polished sleeve; S2 degreasing: heating a degreasing agent to 50-60 DEG C, soaking the polished sleeve obtained in S1 in the degreasing agent for 5-10 min, rinsing with clean water for 1-2 times, and drying to obtain a degreased sleeve; S3 laser rust removal: using a laser rust removal machine to scan the surface of the degreased sleeve obtained in S2 to obtain a rust-removed sleeve; S4 pickling: soaking the rust-removed sleeve obtained in S3 in a pickling activator for 5-6 min, rinsing with clean water for 1-2 times, and drying to obtain an activated sleeve; S5 nickel plating: placing the activated sleeve obtained in S4 in a chemical nickel plating solution, soaking for 8-15 min under the condition of 85-92 DEG C and pH 4.2-4.6, and obtaining a nickel-plated sleeve; S6 rust-proof treatment: sealing the nickel-plated sleeve obtained in S5 with a rust-proof sealing agent at room temperature for 2-4 min and controlling the pH to be 7.5-8.5 to obtain a rust-proof sleeve; S7 passivation: placing the rust-proof sleeve obtained in S6 in a 0.7-1.5 vol% bichromate solution, soaking for 1-3 min under the condition of 80-90 DEG C, and drying to obtain a passivated sleeve; S8 brazing: the passivation sleeve obtained in S7 is put into a vacuum furnace with CuMnNi alloy powder, cold pre-vacuum is performed to 5x10 -2 Pa, heating to 900℃, filling argon into the furnace to keep the pressure in the furnace at 2-3 Pa, keeping for 15 min, heating to 1100-1200℃, keeping for 16-20 min, cooling to below 500℃, air cooling, and discharging from the furnace to obtain the final product; The CuMnNi alloy powder in the S8 brazing further comprises WC particles, and the weight ratio of the CuMnNi alloy powder to the WC particles is 6-8:3; the outer surface of the WC particles is chemically plated with a Ni-P alloy, and the thickness of the Ni-P alloy layer is 2-4 μm.

2. A sleeve surface treatment process according to claim 1, characterised in that: The constant temperature soaking and clean water rinsing in the S2 degreasing step are repeated for 2-3 times.

3. A sleeve surface treatment process according to claim 1, characterized in that: In the S3 laser rust removal step, 2-3 layers of transparent film are covered on the surface of the sleeve, and 1-2 layers of glue film are uniformly applied on the position where the surface of the sleeve contacts the transparent film.

4. A sleeve surface treatment process according to claim 2, wherein: In the S3 laser rust removal step, the incident angle of the laser is controlled to be 10-20 DEG.

5. A sleeve surface treatment process according to claim 1, wherein: The pickling activator in the S4 pickling step comprises the following components in parts by weight: Citric acid 5-10 parts; Lactic acid 10-20 parts; Hydrochloric acid 2-3 parts; Hexamethylenetetramine 0.001-0.002 parts; Sodium acetate 3-4 parts; Water 900-960 parts.

6. A sleeve surface treatment process according to claim 1, characterized in that: The chemical nickel plating solution in the S5 nickel plating step comprises the following components in parts by weight: Nickel sulfate 25-35 parts; Nickel chloride 5-15 parts; Sodium hypophosphite 40-50 parts; Sodium citrate 10-20 parts; Sodium thiosulfate 5-10 parts; Water 80-90 parts.

7. A sleeve surface treatment process according to claim 1, wherein: The rust-proof sealing agent in the S6 rust-proof treatment comprises the following components in parts by weight: Triethanolamine 4-5 parts; Boric acid 1-2 parts; Phytic acid 2-3 parts; Polyethylene glycol 1-2 parts; Nitrilotriacetic acid 1-2 parts; Lithium silicate 4-6 parts; Water 80-87 parts.

Images