A method for improving the abrasion resistance of an aluminum material

Abstract

The application discloses a method for improving the anti-abrasion performance of an aluminum material surface. The technical scheme adopted by the application comprises the following steps: preparing a solution system containing first microparticles; performing micro-arc oxidation treatment on the surface of a sample by using the solution system containing the first microparticles to form a composite micro-arc oxidation film; the composite micro-arc oxidation film comprises a micro-arc oxidation film formed on the surface of the sample and the first microparticles dispersed in the micro-arc oxidation film; the first microparticles are selected from microparticles with a particle size slightly larger than the hole diameter of the micro-arc oxidation film and the same composition as the micro-arc oxidation film; laser treatment: presetting second microparticles on the surface of the obtained sample composite micro-arc oxidation film to form a ceramic powder film, and performing laser treatment on the surface of the ceramic powder film. The application improves the micro-arc oxidation film by using targeted laser treatment technology, greatly reduces the holes and cracks of the micro-arc oxidation film, and thus significantly improves the anti-abrasion performance of the aluminum material surface.

Description

Technical Field

[0001] This invention belongs to the field of metal surface treatment technology, specifically a method for improving the abrasion resistance of aluminum surfaces. Background Technology

[0002] The high temperature, high humidity, high chlorine, and strong winds of coastal environments place higher demands on the corrosion resistance of power transmission and transformation equipment. As a primary electrical material, the passivation film on aluminum surfaces rapidly deteriorates in the coastal atmosphere. In the aerospace and automotive industries, aluminum is widely used due to its low density and high strength; however, numerous cases of corrosion failure still occur. Therefore, improving the corrosion resistance of aluminum is of significant practical importance.

[0003] Anodizing and micro-arc oxidation technologies are commonly used to improve the anti-wear properties of aluminum components. However, as described by Su Kaixin et al. (High-cycle fatigue performance and residual stress relaxation mechanism of micro-arc oxidized 6082-T6 aluminum alloy, Acta Metallurgica Sinica, 20223(58): 334-344), anodizing will result in defects such as cracks and low bonding strength between the film and the substrate. Its acidic solution will cause environmental pollution. However, the corrosion resistance and wear resistance of aluminum components after micro-arc oxidation treatment are significantly improved. Chinese patent document CN101845652A discloses a micro-arc oxidation film layer with a metallurgical bond to the substrate with a thickness of up to 300μm and a microhardness of up to 2000HV. The disadvantage is that the outer surface of the layered structure is a loose layer with weak inter-material bonding, more metastable phases, and high porosity.

[0004] Improving the structure and properties of the porous layer on the surface of micro-arc oxidation is key to further enhancing the wear resistance of aluminum materials. Li Zhenwei et al. from Harbin Institute of Technology discovered (Influence of nano-Cr2O3 particles on the structure and wear resistance of 2024-T4 micro-arc oxidation film, Rare Metals Materials and Engineering, 2017, 7(46): 2022-2027) that the addition of nano-Cr2O3 particles can significantly improve the wear resistance of 2024-T4 aluminum alloy. The significant reduction in the number of pores due to the nano-Cr2O3 particles entering the micropores of the film during the reaction process is undoubtedly an important reason. Chinese patent document CN103233258A discloses a method for preparing a dense, reinforced ceramic film based on micro-arc oxidation and laser remelting. This method utilizes laser remelting technology to transform the porous layer dominated by γ-Al2O3 in the micro-arc oxidation film into a dense remelted layer dominated by α-Al2O3 through a phase transformation, thereby improving the wear resistance of the film. Chinese patent document CN107675176A discloses a workpiece surface strengthening treatment method that combines micro-arc oxidation and vacuum cladding. It uses vacuum cladding Ni60A self-fluxing alloy powder to seal the ceramic layer after micro-arc oxidation, which effectively reduces the porosity of the ceramic coating surface. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a method to improve the anti-corrosion performance of aluminum surface. The method utilizes targeted laser processing technology to improve the micro-arc oxide film, significantly reducing the pores and cracks in the micro-arc oxide film, thereby significantly improving the anti-corrosion performance of aluminum surface.

[0006] Therefore, the technical solution adopted by the present invention is: a method for improving the surface corrosion resistance of aluminum materials, comprising:

[0007] Step 1, pretreatment, including pretreatment of aluminum material, first microparticles and second microparticles;

[0008] Step 2, Micro-arc oxidation treatment: The first particles are dispersed by mixing an appropriate amount of dispersant into the pretreated first particles, adding water and stirring, filtering out the first particles, drying them at 80-160℃, and collecting them for later use. Next, a solution system containing the first particles is prepared. Then, the sample surface is subjected to micro-arc oxidation treatment using the solution system containing the first particles to form a composite micro-arc oxidation film. The composite micro-arc oxidation film includes the micro-arc oxidation film formed on the sample surface and the first particles dispersed in the micro-arc oxidation film. The first particles are selected with a particle size slightly larger than the pore diameter of the micro-arc oxidation film and the same composition as the micro-arc oxidation film layer. Finally, the sample is washed with water and then air-dried or blown dry with hot air for later use.

[0009] Step 3, laser treatment: A second microparticle is pre-placed on the surface of the composite micro-arc oxidation film of the sample obtained in step 2 to form a ceramic powder film. The type and particle size of the second microparticle are selected according to the composition of the composite micro-arc oxidation film, the pore size and the powder spreading and feeding method used in the laser treatment. Then, the surface of the ceramic powder film is laser treated, and finally polished or ground.

[0010] The solution system described in this invention can be a phosphate system, a silicate system, or any solution system suitable for micro-arc oxidation treatment. The first microparticle is selected with a particle size slightly larger than the pores of the micro-arc oxidation film, meaning its particle size is sufficient to fill the pores of the micro-arc oxidation film. The dispersant can be anionic surfactants (such as sodium dodecyl sulfonate or sodium dodecyl sulfate), nonionic surfactants (such as OP emulsifier), etc., and its amount is sufficient to disperse the first microparticle.

[0011] Preferably, the composition of the first particles dispersed in the micro-arc oxide film is the same as that of the second particles during laser treatment, i.e., they are the same substance.

[0012] Furthermore, in step one, when performing the pretreatment of aluminum material, the protrusions and burrs on the surface of the aluminum sample are first ground off, and then polished until the surface is clean. Then, the obtained aluminum sample is immersed in anhydrous ethanol and placed in an ultrasonic cleaner for cleaning. When performing the pretreatment of the first or second particles, an appropriate amount of alkali is weighed and mixed with the first or second particles, water is added and stirred, the first or second particles are filtered out, and then placed in an oven to dry, so as to obtain the first or second particles after degreasing.

[0013] Furthermore, in step one, the aluminum material is preferably cast aluminum, 1-series aluminum alloy, 2-series aluminum alloy, 5-series aluminum alloy, 6-series aluminum alloy, or 7-series aluminum alloy, and more preferably Al-Si series cast aluminum or 1-series aluminum alloy.

[0014] Further, in step one, the first and second particles are one or more of Al2O3, ZrO2, TiO2, carbon nanotubes, graphite, graphene, diamond, zircon, boron nitride, silicon carbide, barite, and feldspar powder.

[0015] Furthermore, in step one, the first and second particles are preferably one or more of single-walled carbon nanotubes, 3-5 layers of graphene, graphite, TiO2, and hexagonal boron nitride, and these particles are suitable for reducing the friction on the surface of aluminum materials.

[0016] Furthermore, in step one, the first and second particles are preferably one or more of α-Al2O3, ZrO2, zircon, cubic boron nitride, silicon carbide, barite, and feldspar powder, which are suitable for increasing the friction of the aluminum surface.

[0017] Furthermore, in step one, the first and second particles are preferably one or a mixture of two of α-Al2O3 and single-walled carbon nanotubes and 3-5 layers of graphene. These particles are suitable for aluminum surfaces that require frictionless performance.

[0018] Furthermore, in step two, the solution system containing the first particle is: 10-20 g / L Na₅P₃O₂. 10 The solution consists of 0.2-0.8 g / L NaOH, 1.5-3.0 g / L Na₂WO₃, 1-3 g / L OP-10, and the first microparticle. The concentration of the first microparticle is 0.2-10 g / L when it is in the nanometer range and 1-30 g / L when it is in the micrometer range. This solution system is a phosphate system.

[0019] Further, in step two, the solution system containing the first particle is: 6-12 g / L NaSiO3·9H2O, 1-5 g / L CH3COONa, and 1-5 g / L Na5P3O 10The pH of the solution is 10-11. The concentration of the first particle is 0.2-10 g / L when it is in the nanometer range and 1-30 g / L when it is in the micrometer range. This solution system belongs to the silicate system.

[0020] Furthermore, in step two, the parameters for the micro-arc oxidation treatment are as follows: aluminum material is the positive electrode, the working liquid tank is the negative electrode, and the treatment is carried out in a constant current mode with a positive and negative current density of 6-12 A / dm³. 2 The frequency is 400-1100Hz, the duty cycle is 50-80%, and the processing time is 40-80 minutes (adjusted according to the required film thickness). During processing, mechanical stirring or ultrasonic stirring is used to enhance mass transfer and improve the dispersibility of the first particles. When using mechanical stirring, the speed is selected as 100-2000r / min (adjusted according to the size of the tank). At the same time, a circulating cooling system is used to keep the temperature of the tank solution below 40℃.

[0021] Furthermore, in step three, a binder is used to uniformly coat the second microparticles onto the surface of the composite micro-arc oxidation film; the binder is a water glass solution, and the mass ratio of water glass to water is 1:(1-3).

[0022] Further, in step two, the particle size of the first particle is 50 nanometers to 60 micrometers; in step three, the particle size of the second particle is 10 nanometers to 300 micrometers. When using the powder spreading method, the particle size of the second particle is 50 nanometers to 200 micrometers, preferably 10 micrometers to 40 micrometers; when using the coaxial powder feeding method, the particle size of the second particle is 100 micrometers to 200 micrometers. When using the powder spreading method, the second particle powder is first pre-placed on the surface of the sample to be treated with an adhesive, and then scanned with a laser. The laser energy is partially absorbed by the micro-arc oxide film layer on the surface of the particle and the substrate, and then conducted to the aluminum substrate, resulting in a significant reduction in heat. Therefore, the particle size is smaller than that of the coaxial powder feeding method. However, since the high-energy laser beam will cause partial melting and shrinkage of the particle surface, the particle size of the particle is preferably slightly larger than the pore size in the micro-arc oxide film layer when using the powder spreading method. Coaxial powder feeding involves directly delivering the fine powder to the same axis position as the laser head nozzle through a powder feeding pipe, and then blowing the powder directly into the molten pool through a carrier gas flow. Therefore, when using coaxial powder feeding, the fine powder is already in a semi-molten state due to laser irradiation before it has fully entered the molten pool, which requires a larger particle size than the powder spreading method.

[0023] Furthermore, in step three, the laser processing parameters are preferably: laser power of 1-5KW, scanning speed of 5-16mm / s, laser spot diameter of 1-6mm, and overlap rate of 30-50%; more preferably, the laser processing parameters are: laser power of 1-3KW, scanning speed of 6-10mm / s, laser spot diameter of 2-4mm, and overlap rate of 50%; the parameters are adjusted according to the particle size for the same type of particles, and adjusted according to the melting point and the absorption rate of laser for different types of particles.

[0024] Furthermore, during the laser processing, air or argon is used as a protective gas to protect the laser lens, with a gas flow rate of 6-10 L / min, preferably 6-8 L / min.

[0025] The present invention has the following beneficial effects:

[0026] 1. By adding first microparticles with a particle size slightly larger than the pore size of the membrane and the same composition as the second phase during the micro-arc oxidation process, the pore sealing effect is achieved, thereby improving the compactness of the composite micro-arc oxidation membrane.

[0027] 2. Based on the composition, pore size, and powder feeding method of the composite micro-arc oxidation film, select the type and particle size of the second particle during laser treatment, and further seal the pores on the surface of the composite micro-arc oxidation film.

[0028] 3. The laser processing parameters are specifically designed to take into account the composition of the composite micro-arc oxidation film, the melting point of the added microparticles, and their absorption rate of the laser. This not only meets the conditions for the phase transformation from γ-Al2O3 to α-Al2O3 in conventional laser remelting (1000-1200℃), but also makes the laser-targeted treatment significantly better than laser remelting by pre-placing a second microparticle on the composite micro-arc oxidation film for sealing. Furthermore, it avoids the formation of brittle layers and brittle phases such as new interface compounds after laser alloying and laser cladding.

[0029] 4. When laser processing, it is preferable to use a second microparticle with the same composition as the composite micro-arc oxidation film as the additive phase, which can eliminate stress defects caused by the mismatch of the thermal expansion coefficients between the film and the additive phase.

[0030] 5. The addition of linear phases such as carbon nanotubes and graphene can improve the toughness of the composite micro-arc oxidation film to a certain extent, alleviate the decline in fatigue performance of aluminum components during service, and reduce the friction coefficient of the composite micro-arc oxidation film when combined with solid lubricants such as hexagonal boron nitride.

[0031] 6. The process of this invention is simple, environmentally friendly, adjustable and controllable, and suitable for industrial production. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Comparative Example 1

[0034] This comparative example provides a micro-arc oxidation treatment method for aluminum surface, for comparison with the embodiments. The steps are as follows:

[0035] Step 1, aluminum material pretreatment. Select an Al-Si cast aluminum alloy with dimensions of 20×20×2. First, use 180# sandpaper to grind away the protrusions and burrs on the surface of the aluminum sample. Then, use 400#, 600#, 800#, and 1000# sandpaper in sequence to polish until the surface is clean. Then, immerse the prepared sample in anhydrous ethanol and place it in an ultrasonic cleaner for 30 minutes.

[0036] Step two, micro-arc oxidation treatment. First, prepare the solution system: 10-20 g / L Na₅P₃O₃. 10 The solution consists of 0.2-0.8 g / L NaOH, 1.5-3.0 g / L Na₂WO₃, and 1 g / L sodium dodecyl sulfate. Then, the operating parameters are selected: aluminum is the positive electrode, the working fluid tank is the negative electrode, and a constant current method is used, with positive and negative current densities of 6-12 A / dm³. 2 The frequency is 400-1100Hz, the duty cycle is 50-80%, and the processing time is 40-80 minutes. During processing, mechanical or ultrasonic stirring is used to enhance mass transfer, while a circulating cooling system is used to keep the bath temperature below 40℃. Finally, the solution is rinsed clean in water at 40-60℃ and then air-dried for later use.

[0037] The spare sample was subjected to a neutral salt spray test according to GB / T10125-2012. Corrosion marks were visible after 1200 hours. The tribological properties of the treated sample were tested according to GB / T12444-2006 and GB / T11378-2005. The friction pair consisted of Φ6mm SUS304 balls, with a loading force of 520g and a rotation diameter of 3.84×10⁻⁶ mm. -3 m, rotation speed 120 rpm, 3600 rotations, the measured wear volume was 7.92 × 10 m. -11 -9.20×10 -11 m 3 The average friction coefficient ranges from 0.65 to 0.77.

[0038] Comparative Example 2

[0039] This embodiment provides a method for composite micro-arc oxidation treatment of aluminum surfaces, the steps of which are as follows:

[0040] Step 1, pretreatment, includes aluminum material pretreatment and first particle pretreatment. For aluminum material pretreatment, firstly, select an Al-Si cast aluminum alloy with dimensions of 20×20×2 mm. Use 180# sandpaper to grind away any protrusions and burrs on the surface of the aluminum sample. Then, successively use 400#, 600#, 800#, and 1000# sandpaper to polish until the surface is clean. Next, immerse the prepared sample in anhydrous ethanol and place it in an ultrasonic cleaner for 30 minutes. When performing the pretreatment of the first microparticle, considering the characteristics of the film composition and the fact that the microparticles will become smaller during spark discharge, α-Al2O3 microparticles with a particle size of 25-35μm (slightly larger than the pore size of the film) were selected as the first microparticle. The first microparticle was mixed with 1% NaOH by mass, and 250mL (relative to the amount of 10g of the first microparticle) of deionized water was added and stirred for 10min. The first microparticle was filtered out using analytical filter paper or other methods, and then placed in an oven and dried at 120℃ for 1h to obtain the pretreated first microparticle.

[0041] Step two, composite micro-arc oxidation treatment. First, prepare a solution system containing the first microparticle: 10-20 g / L Na₅P₃O₃. 10 The following solutions were used: 0.2-0.8 g / L NaOH, 1.5-3.0 g / L Na₂WO₃, 1 g / L sodium dodecyl sulfate, and 30 g / L α-Al₂O₃. Then, the operating parameters were selected: aluminum as the positive electrode, the working fluid tank as the negative electrode, and constant current treatment was employed, with positive and negative current densities of 6-10 A / dm³. 2 The frequency is 400-800Hz, the duty cycle is 50-80%, and the processing time is 40-80 minutes. During processing, mechanical or ultrasonic stirring is used to enhance mass transfer, while a circulating cooling system is used to keep the bath temperature below 40℃. Finally, the solution is rinsed clean in water at 40-60℃ and then air-dried for later use.

[0042] The spare sample was subjected to a neutral salt spray test according to GB / T10125-2012. No obvious corrosion was observed after 1440 hours. The tribological properties of the treated sample were tested according to GB / T12444-2006 and GB / T11378-2005. The friction pair consisted of Φ6mm SUS304 balls, with a loading force of 520g and a rotation diameter of 3.84×10⁻⁶ mm. -3 m, rotation speed 120 rpm, rotation number 3600 times, the measured wear volume is 2.06 × 10 m. -11 -2.85×10 -11 m 3 The average friction coefficient ranges from 0.82 to 0.86.

[0043] Example 1

[0044] This embodiment provides a method for improving the surface corrosion resistance of aluminum materials, the steps of which are as follows:

[0045] Step 1, pretreatment, includes pretreatment of the aluminum material, the first microparticle, and the second microparticle. For aluminum material pretreatment, firstly, select an Al-Si cast aluminum alloy with dimensions of 20×20×2 mm. Use 180# sandpaper to grind away any protrusions and burrs on the surface of the aluminum sample. Then, successively use 400#, 600#, 800#, and 1000# sandpaper to polish until the surface is clean. Next, immerse the prepared sample in anhydrous ethanol and place it in an ultrasonic cleaner for 30 minutes. For the pretreatment of the first and second particles, α-Al2O3 particles with a particle size of 25-35 μm (slightly larger than the pore size of the membrane layer) and 35-40 μm were selected as the first particles for composite micro-arc oxidation treatment and the second particles for laser treatment, respectively. Both were mixed with 1% NaOH by mass. First, 1% NaOH by mass of the particles was weighed and mixed with the first or second particles respectively. After adding 250 mL of deionized water (relative to the amount of 10 g particles), the mixture was stirred for 10 min. The first and second particles were filtered out using analytical filter paper or other methods. The mixture was then placed in an oven and dried at 120℃ for 1 h to obtain the pretreated first and second particles.

[0046] Step two, composite micro-arc oxidation treatment. First, the first microparticles are dispersed. An appropriate amount of dispersant is mixed into the pretreated first microparticles, water is added and stirred, the first microparticles are filtered out, and dried at 80-160℃. The first microparticles are then collected for later use. Second, a solution system containing the first microparticles is prepared: 10-20 g / L Na₂P₃O₃. 10 The following solutions were used: 0.2-0.8 g / L NaOH, 1.5-3.0 g / L Na₂WO₃, 1 g / L sodium dodecyl sulfate, and 30 g / L α-Al₂O₃. Then, the operating parameters were selected: aluminum as the positive electrode, the working fluid tank as the negative electrode, and constant current treatment was employed, with positive and negative current densities of 6-10 A / dm³. 2 The frequency is 400-800Hz, the duty cycle is 50-80%, and the processing time is 40-80 minutes. During processing, mechanical or ultrasonic stirring is used to enhance mass transfer, while a circulating cooling system is used to keep the bath temperature below 40℃. Finally, the solution is rinsed clean in water at 40-60℃ and then air-dried for later use.

[0047] Step 3, Laser Treatment. First, microparticles are pre-placed on the surface of the composite micro-arc oxidation film of the aluminum sample obtained in Step 2: A second microparticle is uniformly coated onto the surface of the composite micro-arc oxidation film using a binder, which is a water glass solution with a water-to-water mass ratio of 1:(1-3). Based on the composition of the composite micro-arc oxidation film, the pore size, and the powder feeding method used for laser treatment, 35-40 μm α-Al₂O₃ microparticles are selected for laser treatment. Then, the operating parameters are adjusted for laser treatment: laser power is 1-2 kW, scanning speed is 5-10 mm / s, laser spot diameter is 1-6 mm, and overlap rate is 30-50%. Air or argon is used as a protective gas for the lens, with a gas flow rate of 6-8 L / min. Finally, the sample is polished or ground.

[0048] The spare samples were subjected to a neutral salt spray test according to GB / T10125-2012, and no obvious corrosion was observed after 1680 hours. The tribological properties of the treated samples were tested according to GB / T12444-2006 and GB / T11378-2005. The friction pair consisted of Φ6mm SUS304 balls, with a loading force of 520g and a rotation diameter of 3.84×10⁻⁶ mm. -3 m, rotation speed 120 rpm, rotation number 3600 times, the measured wear volume is 1.28 × 10 m. -11 -1.47×10 -11 m 3 The average friction coefficient ranges from 0.88 to 0.94.

[0049] Example 2

[0050] This embodiment provides a method for improving the surface corrosion resistance of aluminum materials, the steps of which are as follows:

[0051] Step 1, pretreatment, includes pretreatment of the aluminum material, the first microparticle, and the second microparticle. For aluminum material pretreatment, firstly, select an Al-Si cast aluminum alloy with dimensions of 20×20×2 mm. Use 180# sandpaper to grind away any protrusions and burrs on the surface of the aluminum sample. Then, successively use 400#, 600#, 800#, and 1000# sandpaper to polish until the surface is clean. Next, immerse the prepared sample in anhydrous ethanol and place it in an ultrasonic cleaner for 30 minutes. For the pretreatment of the first and second particles, hexagonal boron nitride particles with a particle size of 20-30 μm (slightly larger than the pore size of the membrane layer) and 25-35 μm were selected as the first particles for composite micro-arc oxidation treatment and the second particles for laser treatment, respectively. Both were mixed with 1% NaOH by mass. First, 1% NaOH by mass of the particles was weighed and mixed with the first and second particles, respectively. After adding 250 mL of deionized water (relative to the amount of 10 g particles), the mixture was stirred for 10 min. The first and second particles were filtered out using analytical filter paper or other methods, and then placed in an oven and dried at 120℃ for 1 h to obtain the pretreated first and second particles.

[0052] Step two, composite micro-arc oxidation treatment. First, the first microparticles are dispersed. An appropriate amount of dispersant is mixed into the pretreated first microparticles, water is added and stirred, the first microparticles are filtered out, and dried at 80-160℃. The first microparticles are then collected for later use. Second, a solution system containing the first microparticles is prepared: 10-20 g / L Na₂P₃O₃. 10 The following solutions were used: 0.2-0.8 g / L NaOH, 1.5-3.0 g / L Na₂WO₃, 1 g / L sodium dodecyl sulfate, and 30 g / L hexagonal boron nitride. Then, the operating parameters were selected: aluminum as the positive electrode, the working fluid tank as the negative electrode, and constant current treatment was employed, with positive and negative current densities of 10⁻¹² A / dm³. 2 The frequency is 900Hz-1100Hz, the duty cycle is 50%-80%, and the processing time is 40-80 minutes. During processing, mechanical or ultrasonic stirring is used to enhance mass transfer, while a circulating cooling system is used to keep the bath temperature below 40℃. Finally, the solution is rinsed clean in water at 40-60℃ and then air-dried for later use.

[0053] Step 3, Laser Treatment. First, microparticles are pre-placed on the surface of the composite micro-arc oxidation film obtained in Step 2: A second microparticle is uniformly coated onto the surface of the composite micro-arc oxidation film using a binder, specifically a water glass solution with a water-to-water mass ratio of 1:(1-3). Based on the composition of the composite micro-arc oxidation film, pore size, and the powder feeding method used for laser treatment, 25-35 μm hexagonal boron nitride microparticles are selected for laser treatment. Then, the operating parameters are adjusted for laser treatment: laser power is 5 kW, scanning speed is 12-16 mm / s, laser spot diameter is 1-6 mm, and overlap rate is 30-50%. Air or argon is used as a protective gas for the lens, with a gas flow rate of 6-8 L / min. Finally, the sample is polished or ground.

[0054] Hexagonal boron nitride has a higher melting point than α-Al2O3, and its particle size changes relatively less during melting. Therefore, the particle size of the hexagonal boron nitride used is slightly smaller, and other operating parameters can also be adjusted accordingly, such as the laser power being slightly higher.

[0055] The spare sample was subjected to a neutral salt spray test according to GB / T10125-2012. No obvious corrosion was observed after 1440 hours. The tribological properties of the treated sample were tested according to GB / T12444-2006 and GB / T11378-2005. The friction pair consisted of Φ6mm SUS304 balls, with a loading force of 520g and a rotation diameter of 3.84×10⁻⁶ mm. -3 m, rotation speed 120 rpm, rotation number 3600 times, the measured wear volume is 1.02 × 10 m. -11 -1.12×10 -11 m 3 The average friction coefficient ranges from 0.15 to 0.27.

[0056] Example 3

[0057] This embodiment provides a method for improving the surface corrosion resistance of aluminum materials, the steps of which are as follows:

[0058] Step 1, pretreatment, includes pretreatment of the aluminum material, the first microparticle, and the second microparticle. For aluminum material pretreatment, firstly, select an Al-Si cast aluminum alloy with dimensions of 20×20×2 mm. Use 180# sandpaper to grind away any protrusions and burrs on the surface of the aluminum sample. Then, successively use 400#, 600#, 800#, and 1000# sandpaper to polish until the surface is clean. Next, immerse the prepared sample in anhydrous ethanol and place it in an ultrasonic cleaner for 30 minutes. For the pretreatment of the first and second particles, firstly, a mixture of α-Al2O3 particles with a particle size of 25-35 μm (slightly larger than the pore size of the membrane layer) and 3-5 layers of graphene is selected as the first particle for composite micro-arc oxidation treatment, and a mixture of α-Al2O3 particles with a particle size of 35-40 μm and 3-5 layers of graphene is selected as the second particle for laser treatment. Both are mixed with 1% NaOH by mass. First, 1% NaOH by mass of the particles is weighed and mixed with the first and second particles respectively. After adding 250 mL of deionized water (relative to the amount of 10 g particles), the mixture is stirred for 10 min. The first and second particles are filtered out using analytical filter paper or other methods, and then placed in an oven and dried at 120℃ for 1 h to obtain the pretreated first and second particles.

[0059] Step two, composite micro-arc oxidation treatment. First, the first microparticles are dispersed. An appropriate amount of dispersant is mixed into the pretreated first microparticles, water is added and stirred, the first microparticles are filtered out, and dried at 80-160℃. The first microparticles are then collected for later use. Second, a solution system containing the first microparticles is prepared: 10-20 g / L Na₂P₃O₃. 10 The following components are selected: 0.2-0.8 g / L NaOH, 1.5-3.0 g / L Na₂WO₃, 1 g / L sodium dodecyl sulfate, 30 g / L α-Al₂O₃, and 0.5 g / L 3-5 layer graphene. Then, the operating parameters are selected: aluminum is used as the positive electrode, the working fluid tank is used as the negative electrode, and a constant current method is employed, with positive and negative current densities of 6-10 A / dm³. 2 The frequency is 400-800Hz, the duty cycle is 50-80%, and the processing time is 40-80 minutes. During processing, mechanical or ultrasonic stirring is used to enhance mass transfer, while a circulating cooling system is used to keep the bath temperature below 40℃. Finally, the solution is rinsed clean in water at 40-60℃ and then air-dried for later use.

[0060] Step 3, Laser Treatment. First, microparticles are pre-placed on the surface of the composite micro-arc oxidation film obtained in Step 2: a second microparticle is uniformly coated onto the surface of the composite micro-arc oxidation film using a binder, which is a water glass solution with a water-to-water mass ratio of 1:(1-3). Based on the composition of the composite micro-arc oxidation film, pore size, and the powder feeding method used in laser treatment, a mixture of 35-40 μm α-Al₂O₃ microparticles and 3-5 layers of graphene is selected as the microparticles for laser treatment. Then, the operating parameters are adjusted for laser treatment: laser power is 1-2 kW, scanning speed is 5-10 mm / s, laser spot diameter is 1-6 mm, and overlap rate is 30-50%. Air or argon is used as a protective gas for the lens, with a gas flow rate of 6-8 L / min. Finally, the sample is polished or ground.

[0061] The spare sample was subjected to a neutral salt spray test according to GB / T10125-2012. No obvious corrosion was observed after 1440 hours. The tribological properties of the treated sample were tested according to GB / T12444-2006 and GB / T11378-2005. The friction pair consisted of Φ6mm SUS304 balls, with a loading force of 520g and a rotation diameter of 3.84×10⁻⁶ mm. -3 m, rotation speed 120 rpm, rotation number 3600 times, the measured wear volume is 1.11 × 10 m. -11 -1.22×10 -11 m 3 The average friction coefficient is 0.46-0.61.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for improving the surface corrosion resistance of aluminum materials, characterized in that, include: Step 1, pretreatment, including pretreatment of aluminum material, first microparticles and second microparticles; Step 2, micro-arc oxidation treatment: Disperse the first particles. Take an appropriate amount of dispersant and mix it into the pretreated first particles. Add water and stir. Filter out the first particles and dry them at a temperature of 80-160℃. Collect the first particles for later use. Secondly, a solution system containing the first particle is prepared, wherein the solution system is a phosphate system or a silicate system; Then, the sample surface is subjected to micro-arc oxidation treatment using a solution system containing the first microparticle to form a composite micro-arc oxidation film. The composite micro-arc oxidation film includes the micro-arc oxidation film formed on the sample surface and the first microparticle dispersed in the micro-arc oxidation film. The first microparticle is selected as a microparticle with a particle size larger than the pore diameter of the micro-arc oxidation film. The first microparticle is α-Al2O3. Finally, the sample is washed with water and then air-dried or blown dry with hot air for later use. Step 3, laser treatment: First, a second microparticle is pre-placed on the surface of the composite micro-arc oxidation film of the sample obtained in step 2 to form a ceramic powder film. The type and particle size of the second microparticle are selected according to the composition of the composite micro-arc oxidation film, the pore size and the powder feeding method used for laser treatment. Then, the surface of the ceramic powder film is laser-treated, and finally polished or ground. In step three, the parameters of the laser processing are: laser power of 1-5KW, scanning speed of 5-16mm / s, laser spot diameter of 1-6mm, and overlap rate of 30-50%; during the laser processing, air or argon is used as a protective gas to protect the laser lens, and the gas flow rate is 6-10L / min. In step one, the second particle is a mixture of Al2O3, boron nitride, or α-Al2O3 with 3-5 layers of graphene.

2. The method for improving the surface corrosion resistance of aluminum materials according to claim 1, characterized in that, In step one, when the aluminum surface needs to reduce friction, the second particle is hexagonal boron nitride; when the aluminum surface needs to increase friction, the second particle is α-Al2O3; when the aluminum surface does not require friction, the second particle is a mixture of α-Al2O3 and 3-5 layers of graphene.

3. The method for improving the surface corrosion resistance of aluminum materials according to claim 1, characterized in that, In step two, the particle size of the first particle is 20 to 60 micrometers; in step three, the particle size of the second particle is 10 nanometers to 300 micrometers.

4. The method for improving the surface corrosion resistance of aluminum materials according to claim 3, characterized in that, In step three, when using the powder spreading method, the particle size of the second microparticle is 10 nanometers to 60 micrometers.

5. The method for improving the surface corrosion resistance of aluminum materials according to claim 3, characterized in that, In step three, when using a coaxial powder feeding method, the particle size of the second microparticle is 80 micrometers to 200 micrometers.

6. The method for improving the surface corrosion resistance of aluminum materials according to claim 1, characterized in that, In step two, the phosphate system containing the first particle is: 10-20 g / L Na₅P₃O₂. 10 0.2-0.8 g / L of NaOH, 1.5-3.0 g / L of Na2WO3, 1-3 g / L of OP-10 and the first microparticle, the first microparticle having a particle size of micrometers and a concentration of 1-30 g / L.

7. The method for improving the surface corrosion resistance of aluminum materials according to claim 1, characterized in that, In step two, the silicate system containing the first microparticle is: 6-12 g / L Na₂SiO₃·9H₂O, 1-5 g / L CH₃COONa, and 1-5 g / L Na₅P₃O₂. 10 The solution has a pH of 10-11 and the first particle has a particle size of micrometers and a concentration of 1-30 g / L.

8. The method for improving the surface corrosion resistance of aluminum materials according to claim 1, characterized in that, In step two, the parameters for the micro-arc oxidation treatment are as follows: aluminum material is the positive electrode, the working liquid tank is the negative electrode, and the treatment is carried out in a constant current mode with a positive and negative current density of 6-12 A / dm³. 2 The frequency is 400-1100Hz, the duty cycle is 50-80%, and the processing time is 40-80 minutes. During the processing, mechanical stirring or ultrasonic stirring is used to enhance mass transfer, and a circulating cooling system is used to keep the temperature of the tank solution below 40℃.

9. The method for improving the surface corrosion resistance of aluminum materials according to claim 1, characterized in that, In step three, a binder is used to uniformly pre-place the second microparticles on the surface of the composite micro-arc oxidation film; the binder is a water glass solution, and the mass ratio of water glass to water is 1:(1-3).