A bright corrosion-resistant aluminum profile and a method for manufacturing the same

Abstract

The application discloses a preparation method of bright corrosion-resistant aluminum profile and relates to the technical field of aluminum profile processing, which comprises the following processes: mixing and smelting raw materials, pouring, homogenizing treatment, forming ingot; extruding, heat treatment, forming aluminum profile; surface treatment, obtaining the bright corrosion-resistant aluminum profile; the surface treatment comprises electrolytic oxidation, electrophoretic painting and sealing hole. The rare earth elements play the roles of purifying the matrix, refining modification and micro-alloying in the aluminum alloy, refine the aluminum alloy structure, can show better compactness and integrity after oxidation, improve the protection performance of the aluminum profile, and improve the corrosion resistance and brightness of the aluminum profile. The anode plasma electrolytic oxidation is used for pretreating the aluminum profile and oxidizing the surface of the aluminum profile; then the cathode plasma electrolytic deposition is used, direct contact of the cathode aluminum profile with the electrolyte is avoided, the pores of the barrier layer are sealed, a more compact oxide layer is obtained, and the brightness and corrosion resistance are improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum profile processing technology, specifically a bright and corrosion-resistant aluminum profile and its preparation method. Background Technology

[0002] Aluminum and aluminum alloys possess numerous advantages and are widely used in machinery manufacturing, construction and decoration, aerospace, and electrical and electronic fields. Electroplating, electroless plating, anodizing, and vapor deposition can improve the surface hardness, wear resistance, and corrosion resistance of aluminum and aluminum alloys. Micro-arc oxidation can form an oxide layer on the surface of aluminum and aluminum alloys. Compared with other technologies, the oxide layer has a higher growth rate, stronger adhesion to the aluminum alloy substrate, and better wear resistance and corrosion resistance. However, micro-arc oxidation is an anodic reaction, which leads to anodic dissolution and the formation of a passivation film, resulting in a porous oxide layer surface that affects the corrosion resistance and surface gloss of the aluminum profile. Therefore, we propose a bright, corrosion-resistant aluminum profile and its preparation method. Summary of the Invention

[0003] The purpose of this invention is to provide a bright and corrosion-resistant aluminum profile and its preparation method, so as to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a bright and corrosion-resistant aluminum profile, comprising the following processes:

[0005] The raw materials are mixed, smelted, cast, and homogenized to form ingots;

[0006] Extrusion and heat treatment are used to form aluminum profiles;

[0007] Surface treatment yields bright, corrosion-resistant aluminum profiles.

[0008] Furthermore, the aluminum profile comprises the following components by mass: Si (silicon): 0.2%–0.6%, Mg (magnesium): 0.35%–0.90%, Fe (iron): ≤0.05%, Cu (copper): ≤0.10%, Mn (manganese): ≤0.10%, Cr (chromium): ≤0.10%, Ti (titanium): ≤0.10%, Zn (zinc): ≤0.10%, RE (rare earth elements): 0.1%–0.4%, with the balance being Al (aluminum).

[0009] Furthermore, RE (rare earth elements) is one or more of Y (yttrium), Ce (cerium), and La (lanthanum).

[0010] Furthermore, the homogenization process conditions are as follows: heating to 520-530℃ and holding for 1.0-1.5h; heating to 530-550℃ and holding for 6.5-8.0h; cooling in a cooling furnace to below 100℃, removing and air-cooling to room temperature.

[0011] Furthermore, the extrusion process conditions are as follows: ingot preheating to 455-465°C, die heating temperature 450-460°C, extrusion ratio 12-17, extrusion speed 2.5-4.0 m / min; air cooling to room temperature.

[0012] Furthermore, heat treatment includes solution treatment and aging;

[0013] The solution treatment process is as follows: hold at 500-550℃ for 6-8 hours, and then quench in water at 25-40℃.

[0014] The aging process is as follows: heating temperature 160-180℃, holding time 4-6h; air cooling to room temperature.

[0015] In the above technical solution, adding rare earth elements to aluminum alloys can purify the matrix, refine the altered structure, and microalloy the alloy, thus contributing to the refinement of the aluminum alloy microstructure and the improvement of its mechanical properties and extrusion processing performance. The Si and Fe phases can be uniformly distributed in the aluminum alloy matrix, forming a network distribution on the grain boundary surface, hindering grain growth at the grain boundaries, thereby refining the microstructure and improving the corrosion resistance and gloss of the aluminum alloy. During the extrusion molding process, the microstructure of the aluminum alloy can be further refined. Aluminum profiles with refined microstructure exhibit better density and integrity after oxidation, further enhancing their protective performance, corrosion resistance, and gloss.

[0016] Further surface treatments include electrolytic oxidation, electrophoretic coating, and pore sealing;

[0017] Electrolytic oxidation includes anodic plasma electrolytic oxidation and cathodic plasma electrolytic deposition;

[0018] Electrophoretic coating is performed using cathodic electrophoresis.

[0019] Among the aforementioned technical solutions, there are many technologies for protecting the surface of aluminum and its alloys, including electroplating, spraying, electroless plating, anodizing, micro-arc oxidation, and vapor deposition. Micro-arc oxidation (plasma electrolytic oxidation) forms an oxide layer on the aluminum alloy surface. Compared to other technologies, this oxide layer has a higher growth rate, stronger adhesion to the aluminum alloy substrate, and better wear and corrosion resistance. However, micro-arc oxidation is an anodic reaction, which leads to anodic dissolution and the formation of a passivation film, resulting in a porous oxide layer surface that affects the corrosion resistance of the aluminum profile. Therefore, this application adds cathodic plasma electrolytic deposition after the anodic plasma electrolytic oxidation process.

[0020] Anodizing coating often encounters problems during use, such as anodic dissolution and discoloration of the paint film due to oxygen generated during electrolysis, leading to corrosion on the profile surface and a reduction in the corrosion resistance of the aluminum profile. Therefore, this application employs cathodic electrophoresis for coating aluminum profiles.

[0021] Furthermore, the anodic plasma electrolytic oxidation includes the following process steps:

[0022] Using aluminum profiles as the anode, anodic plasma electrolytic oxidation is performed in a sodium silicate mixture to form a barrier layer.

[0023] Furthermore, the sodium silicate mixture comprises 25–35 g / L sodium silicate and 13–22 g / L sodium phosphate, and the pH is adjusted to 7.5–8.5 using sodium hydroxide;

[0024] The process conditions for anodic plasma electrolytic oxidation are: frequency 500–600 Hz, duty cycle 20%–30%, and current density 10–15 A / dm³. 2 The duration is 2.5 to 3.0 minutes.

[0025] Furthermore, the cathode plasma electrolytic deposition includes the following process steps:

[0026] Using the aluminum profile obtained in the previous step as the cathode and platinum as the anode, cathode plasma electrolytic deposition is performed in the electrolyte to form an oxide layer.

[0027] Furthermore, in the electrolyte, the immersion area of ​​the anode is ≥ twice the immersion area of ​​the aluminum profile; to ensure that the plasma reaction occurs on the cathode; the distance between the anode and the aluminum profile is about 5cm.

[0028] Furthermore, the process conditions for cathode plasma electrolytic deposition are: voltage 150–200V, frequency 500–600Hz, duty cycle 50%–60%, and oxidation time 10–30min.

[0029] Furthermore, the electrolyte comprises the following components: 100–300 g / L aluminum nitrate, 10–50 g / L yttrium nitrate, 10–50 mL / L glycerol, and 15–25 g / L polyethylene glycol.

[0030] Furthermore, in the electrolyte, the mass ratio of aluminum nitrate to yttrium nitrate is (5.2–5.6):1.

[0031] In the above technical solution, the aluminum profile is pretreated by anodic plasma electrolytic oxidation to oxidize its surface, which is referred to as a barrier layer. In the initial stage of the cathode plasma electrolytic deposition reaction, the surface of the aluminum profile is covered by water vapor, glycerol vapor, and hydrogen gas generated from water electrolysis. When the inter-electrode voltage is sufficiently high, the gas film layer is broken down by discharge, glycerol decomposes, and further decomposes into active carbon and active oxygen. The plasma sheath layer is located at the cathode surface and the gas-liquid interface. The aluminum profile is continuously heated, its surface temperature rises, and a large number of active aluminum atoms are generated. These atoms combine with active oxygen to form aluminum oxide, which grows rapidly. Carbon can exist in the alumina lattice in the form of oxygen substitution, increasing the conductivity of the oxide layer and contributing to the densification and surface smoothness of the oxide layer produced by electrolytic oxidation. In subsequent high-temperature treatment, carbon diffuses and reacts, and is removed. If the glycerol content is too high, it will leave residues in the oxide layer, forming defects and hindering the maximization of the oxide layer's performance.

[0032] By using cathodic plasma electrolytic deposition technology, direct contact between the cathode aluminum profile and the electrolyte is avoided, the pores of the barrier layer obtained in the previous step are sealed, and a denser oxide layer is obtained, which improves the surface gloss and corrosion resistance.

[0033] Yttrium nitrate is added to the electrolyte, which dissolves in the generated alumina lattice during electrolytic oxidation, improving the surface conductivity of the aluminum profile. The generated yttrium oxide forms yttrium aluminum oxide with alumina, further enhancing the surface conductivity of the oxide layer. This results in a denser and smoother oxide layer with increased specular reflection, thereby improving the corrosion resistance and gloss of the aluminum profile. Furthermore, yttrium has a lower atomic radius compared to other rare earth elements, leading to better solid solution performance in alumina.

[0034] The addition of polyethylene glycol to the electrolyte can restrict the morphology of the aforementioned gas film layer, which helps to reduce the cathode current density and thus improve the uniformity of the oxide layer.

[0035] Furthermore, the electrophoretic coating includes the following processes:

[0036] The aluminum profile obtained in the previous step is used as the cathode. It is placed in an electrophoretic solution and electrophoretically coated to obtain a sealing layer.

[0037] Furthermore, the process conditions for electrophoretic coating are: electrophoretic solution temperature 20-30℃, electrophoresis time 1-3 min, and electrophoresis voltage 160-220V.

[0038] Furthermore, the electrophoresis solution is 100–150 g / L aqueous cation exchange resin;

[0039] Adjust the pH of the solution to 5.0–6.0 using lactic acid.

[0040] In the above technical solution, the aqueous cationic resin in the electrophoretic solution has cations and therefore carries a positive charge. Under the action of an external electric field, it moves towards the cathode, forming a uniform and dense film on the surface of the aluminum profile (oxide layer). It has excellent adhesion and corrosion resistance and is referred to as the sealing layer.

[0041] Furthermore, the waterborne cationic resin is one or more of the following: cationic waterborne epoxy resin, cationic waterborne acrylic resin, and cationic waterborne polyurethane resin.

[0042] Furthermore, the aqueous cationic resin is prepared by the following process:

[0043] Mix 1 / 4 of the emulsifier and deionized water, and stir at 40-45°C and 650-750 r / min. Add methyl methacrylate, styrene, butyl acrylate, unsaturated epoxy resin, vinyltriisopropoxysilane, dimethylaminoethyl methacrylate, and hexafluorobutyl methacrylate, and stir for 30-40 min to obtain a pre-emulsion.

[0044] Mix 1 / 4 of the component mass of the initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat to 65-75℃, add 1 / 4 of the initiator, and stir at 200-300 r / min for 30-40 min; slowly add the remaining pre-emulsion, and add the remaining initiator every 30 min, until the addition is complete in 4 h, and continue to keep the temperature and react for 60-75 min; add diethanolamine, and react for 100-150 min;

[0045] Cool to 50-60℃, add glacial acetic acid, stir and react for 150-180 min; cool to obtain aqueous cationic resin.

[0046] Furthermore, the aqueous cationic resin comprises the following components by weight: 10-15 parts methyl methacrylate, 4.5-10 parts styrene, 9-19 parts butyl acrylate, 27-36 parts unsaturated epoxy resin, 5-10 parts vinyltriisopropoxysilane, 3-7 parts dimethylaminoethyl methacrylate, 4-12 parts hexafluorobutyl methacrylate, 0.8-1.2 parts initiator, 0.5-1.0 parts emulsifier, 10-20 parts diethanolamine, and 3.2-5.7 parts glacial acetic acid;

[0047] The solid content of the waterborne cationic resin is 60%.

[0048] In the above technical solution, the waterborne cationic resin is an epoxy resin-acrylate resin. Based on the properties of epoxy resin, the resulting sealing layer has excellent gloss and hardness. The epoxy resin introduces alkenyl groups through reaction with alkenyl acids; utilizing its unsaturated bonds, it copolymerizes with acrylate monomers to prepare an emulsion, giving the sealing layer excellent comprehensive performance. The unsaturated epoxy resin is obtained by reacting epoxy resin with octadecenoic acid under the action of a catalyst. Its long alkyl chains have good flexibility, making it easier to fill the pores of the oxide layer and exhibiting good film-forming properties. This facilitates the sealing and film formation of the waterborne cationic resin on the aluminum profile surface, giving the sealing layer good density and water and corrosion resistance.

[0049] In the above technical solution, methyl methacrylate and styrene are hard monomers, which can improve the hardness, water resistance, and gloss of the sealing layer. Butyl acrylate is a soft monomer with good flexibility, which can promote the film formation of waterborne cationic resin on the surface of aluminum profiles. The introduction of vinyltriisopropoxysilane, through hydrolysis, generates active -Si(OH) groups that condense, which can increase the crosslinking density of the system, thereby increasing the rigidity and hydrophobicity of the molecular chains. In the polymer system of the sealing layer, it is difficult for water molecules to penetrate and swell between the molecular chains, effectively improving the water resistance of the sealing layer; and it can also improve the bonding strength between the sealing layer and the oxide layer. The addition of hexafluorobutyl methacrylate allows the fluorinated segments to migrate to the film surface under thermodynamic action, which significantly reduces the surface energy of the film, increases the water contact angle, and decreases the water absorption rate, which helps to improve the water resistance of the sealing layer. Corrosive media are blocked, further improving the corrosion resistance of the aluminum profile. Dimethylaminoethyl methacrylate is a functional monomer, which, after acidification, is used to realize the cationic properties of the resin.

[0050] Furthermore, the unsaturated epoxy resin is prepared by the following process:

[0051] The epoxy resin, 4-(4-hydroxyphenyl)-1(2H)-one and catalyst were mixed and heated to 65-75°C under nitrogen atmosphere and reacted at a constant temperature for 5-7 hours; the mixture was washed and dried to obtain the azanaphthalene epoxy resin.

[0052] Azanaphthalene epoxy resin, 6-thiooleic acid, catalyst and polymerization inhibitor are mixed, heated to 60-80℃, and reacted in the dark for 3-5 hours; washed and dried to obtain unsaturated epoxy resin.

[0053] Furthermore, the mass ratio of epoxy resin to 4-(4-hydroxyphenyl)-1(2H)-one (CAS No: 152594-70-2) is 10:(2.3~3.0);

[0054] The catalyst is triphenylphosphine, and its dosage is 1.5% to 2.5% of the epoxy resin.

[0055] Furthermore, the mass ratio of azirand epoxy resin to 6-thiooleic acid (CAS No: 102838-90-4) is 10:(1.8~3.6);

[0056] The catalyst is triphenylphosphine, and its dosage is 1.5% to 2.5% of the azinon epoxy resin;

[0057] The polymerization inhibitor is 4-methoxyphenol, and its dosage is 0.8% to 1.2% of the epoxy resin.

[0058] In the above technical solution, the unsaturated resin is obtained by reacting epoxy resin, 4-(4-hydroxyphenyl)-o-phthalazine-1(2H)-one, and 6-thiooleic acid. The reaction of epoxy resin with active groups such as amine, hydroxyl, and mercapto groups introduces sulfur and azirnaphthalene, which helps to increase the refractive index of the sealing layer and improve its gloss. Furthermore, based on the steric hindrance effect, it can hinder the penetration of corrosive media, thus improving the corrosion resistance of the sealing layer.

[0059] Furthermore, after electrophoretic coating, the product is washed with water and baked at 140–160°C for 20–30 minutes.

[0060] In the above technical solution, high-temperature baking effectively removes moisture from the film layer and further cross-links the active groups, thereby obtaining a more robust, reliable, and high-quality sealing layer. Detailed Implementation

[0061] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0062] In the following specific implementation,

[0063] Epoxy resin: E-44, sourced from Qingdao Yousuo Chemical Technology Co., Ltd.;

[0064] The emulsifier is a mixture of nonionic OP-10 and ionic emulsifier 31524 in a mass ratio of 1:3; the initiator is V50, which is sourced from Sinopharm Chemical Reagent Co., Ltd.

[0065] The catalyst is triphenylphosphine, and the polymerization inhibitor is 4-methoxyphenol;

[0066] In Examples 1-3, step 1, mixing and melting the raw materials, casting, and homogenizing the process, is as follows: heating to 525°C and holding for 75 hours; heating to 540°C and holding for 7 hours; placing in a cooling furnace to cool to below 100°C, removing, and air-cooling to room temperature to form an ingot;

[0067] Step 2, extrusion, the process is as follows: preheat the ingot to 460℃, the die heating temperature is 455℃, the extrusion ratio is 15, and the extrusion speed is 3.2m / min; air cool to room temperature; heat treatment, the heat treatment includes solution treatment and aging; the solution treatment process is: hold at 525℃ for 7h, and quench in water at 25℃; the aging process is: heating temperature is 170℃, holding time is 5h; air cool to room temperature to form aluminum profile; the aluminum profile includes the following components by mass: Si: 0.41%, Mg: 0.57%, Fe: 0.04%, Cu: 0.01%, Mn: 0.01%, Cr: 0.3%, Ti: 0.01%, Zn: 0.1%, Y: 0.3%, with the balance being Al.

[0068] Example 1: A method for preparing a bright and corrosion-resistant aluminum profile, comprising the following processes:

[0069] Step 3, Surface Treatment:

[0070] (1) Using aluminum profiles as the anode, anodic plasma electrolytic oxidation is performed in a sodium silicate mixture to form a barrier layer; the sodium silicate mixture includes 25 g / L sodium silicate and 13 g / L sodium phosphate, and the pH is adjusted to 7.5 using sodium hydroxide; the process conditions for anodic plasma electrolytic oxidation are: frequency 600 Hz, duty cycle 20%, current density 15 A / dm³. 2 Duration: 3.0 minutes;

[0071] (2) Using the aluminum profile obtained in the previous step as the cathode and platinum as the anode, cathode plasma electrolytic deposition is performed in the electrolyte to form an oxide layer; the process conditions are: voltage 200V, frequency 600Hz, duty cycle 50%, oxidation time 30min; the electrolyte includes the following components: 100g / L aluminum nitrate, 19.2g / L yttrium nitrate, 10mL / L glycerol and 15g / L polyethylene glycol;

[0072] (3) Epoxy resin, 4-(4-hydroxyphenyl)-1-(2H)-one and 1.5% catalyst were mixed and heated to 65°C under nitrogen atmosphere and reacted at a constant temperature for 5 h; washed and dried to obtain azinaphthalene epoxy resin; the mass ratio of epoxy resin to 4-(4-hydroxyphenyl)-1-(2H)-one was 10:2.3; azinaphthalene epoxy resin, 6-thiooleic acid, 1.5% catalyst and 0.8% polymerization inhibitor were mixed and heated to 60°C and reacted in the dark for 5 h; washed and dried to obtain unsaturated epoxy resin; the mass ratio of azinaphthalene epoxy resin to 6-thiooleic acid was 10:3.6;

[0073] Mix 1 / 4 of the emulsifier and deionized water, and stir at 650 rpm at 40°C. Add methyl methacrylate, styrene, butyl acrylate, unsaturated epoxy resin, vinyltriisopropoxysilane, dimethylaminoethyl methacrylate, and hexafluorobutyl methacrylate, and stir for 30 min to obtain a pre-emulsion. Mix 1 / 4 of the initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat to 75°C, add 1 / 4 of the initiator, and stir at 200 rpm for 30 min. Slowly add the remaining pre-emulsion, and add every 30 minutes. Add the remaining initiator over 4 hours, and continue the reaction at this temperature for 60 minutes. Add diethanolamine and react for 100 minutes. Cool to 50°C, add glacial acetic acid, and stir for 150 minutes. Cool to obtain an aqueous cationic resin with a solid content of 60%. The aqueous cationic resin comprises the following components by weight: 15 parts methyl methacrylate, 10 parts styrene, 19 parts butyl acrylate, 27 parts unsaturated epoxy resin, 10 parts vinyltriisopropoxysilane, 7 parts dimethylaminoethyl methacrylate, 12 parts hexafluorobutyl methacrylate, 1.0 part initiator, 0.8 parts emulsifier, 15 parts diethanolamine, and 5 parts glacial acetic acid.

[0074] The aluminum profile obtained in the previous step is used as the cathode. It is placed in the electrophoretic solution for electrophoretic coating. After electrophoretic coating, it is washed with water and baked at 140℃ for 30 minutes to obtain the sealing layer. The process conditions for electrophoretic coating are: electrophoretic solution temperature 30℃, electrophoresis time 3 minutes, electrophoresis voltage 220V; the electrophoretic solution is 100g / L water-based cationic resin, and the pH of the solution is adjusted to 6.0 using lactic acid to obtain a bright and corrosion-resistant aluminum profile.

[0075] Example 2: A method for preparing a bright and corrosion-resistant aluminum profile, comprising the following processes:

[0076] Step 3, Surface Treatment:

[0077] (1) Using aluminum profiles as the anode, anodic plasma electrolytic oxidation is performed in a sodium silicate mixture to form a barrier layer; the sodium silicate mixture includes 30 g / L sodium silicate and 15 g / L sodium phosphate, and the pH is adjusted to 8 using sodium hydroxide; the process conditions for anodic plasma electrolytic oxidation are: frequency 550 Hz, duty cycle 25%, current density 12 A / dm³. 2 Duration: 2.8 minutes;

[0078] (2) Take the aluminum profile obtained in the previous step as the cathode and platinum as the anode, and perform cathode plasma electrolytic deposition in the electrolyte to form an oxide layer; the process conditions for cathode plasma electrolytic deposition are: voltage 170V, frequency 550Hz, duty cycle 50%, oxidation time 20min; the electrolyte includes the following components: 200g / L aluminum nitrate, 37g / L yttrium nitrate, 20mL / L glycerol and 20g / L polyethylene glycol;

[0079] (3) The epoxy resin, 4-(4-hydroxyphenyl)-1(2H)-one and 2% catalyst were mixed and heated to 70°C under nitrogen atmosphere and reacted at a constant temperature for 5 h; washed and dried to obtain azinaphthalene epoxy resin; the mass ratio of epoxy resin to 4-(4-hydroxyphenyl)-1(2H)-one was 10:2.6.

[0080] Azanaphthalene epoxy resin, 6-thiooleic acid, 2% catalyst and 1% polymerization inhibitor were mixed, heated to 70°C and reacted in the dark for 4 hours; washed and dried to obtain unsaturated epoxy resin; the mass ratio of azanaphthalene epoxy resin to 6-thiooleic acid was 10:2.7.

[0081] Mix 1 / 4 of the emulsifier and deionized water, and stir at 700 rpm at 42°C. Add methyl methacrylate, styrene, butyl acrylate, unsaturated epoxy resin, vinyltriisopropoxysilane, dimethylaminoethyl methacrylate, and hexafluorobutyl methacrylate, and stir for 35 min to obtain a pre-emulsion. Mix 1 / 4 of the initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat to 78°C, add 1 / 4 of the initiator, and stir at 250 rpm for 35 min. Slowly add the remaining pre-emulsion, and add every... Add the remaining initiator after 30 minutes, and complete the addition over 4 hours. Continue the reaction at this temperature for 68 minutes. Add diethanolamine and react for 120 minutes. Cool to 55°C, add glacial acetic acid, and stir for 165 minutes. Cool to obtain an aqueous cationic resin with a solid content of 60%. The aqueous cationic resin comprises the following components by weight: 12 parts methyl methacrylate, 7 parts styrene, 14 parts butyl acrylate, 32 parts unsaturated epoxy resin, 7 parts vinyltriisopropoxysilane, 5 parts dimethylaminoethyl methacrylate, 8 parts hexafluorobutyl methacrylate, 1 part initiator, 0.8 parts emulsifier, 15 parts diethanolamine, and 5 parts glacial acetic acid.

[0082] The aluminum profile obtained in the previous step is used as the cathode. It is placed in the electrophoretic solution for electrophoretic coating. After electrophoretic coating, it is washed with water and baked at 150℃ for 25 minutes to obtain the sealing layer. The process conditions for electrophoretic coating are: electrophoretic solution temperature 25℃, electrophoresis time 2 minutes, electrophoresis voltage 190V; the electrophoretic solution is 120g / L water-based cationic resin, and the pH of the solution is adjusted to 5.5 using lactic acid to obtain a bright and corrosion-resistant aluminum profile.

[0083] Example 3: A method for preparing a bright and corrosion-resistant aluminum profile, comprising the following processes:

[0084] Step 3, Surface Treatment:

[0085] (1) Using aluminum profiles as the anode, anodic plasma electrolytic oxidation is performed in a sodium silicate mixture to form a barrier layer; the sodium silicate mixture includes 35 g / L sodium silicate and 22 g / L sodium phosphate, and the pH is adjusted to 8.5 using sodium hydroxide; the process conditions for anodic plasma electrolytic oxidation are: frequency 500 Hz, duty cycle 30%, current density 10 A / dm³. 2 Duration: 2.5 minutes;

[0086] (2) Take the aluminum profile obtained in the previous step as the cathode and platinum as the anode, and perform cathode plasma electrolytic deposition in the electrolyte to form an oxide layer; the process conditions for cathode plasma electrolytic deposition are: voltage 150V, frequency 500Hz, duty cycle 60%, oxidation time 10min; the electrolyte includes the following components: 280g / L aluminum nitrate, 50g / L yttrium nitrate, 50mL / L glycerol and 25g / L polyethylene glycol;

[0087] (3) Epoxy resin, 4-(4-hydroxyphenyl)-1-(2H)-one and 2.5% catalyst were mixed and heated to 75°C under nitrogen atmosphere and reacted at a constant temperature for 7 hours; washed and dried to obtain azinaphthalene epoxy resin; the mass ratio of epoxy resin to 4-(4-hydroxyphenyl)-1-(2H)-one was 10:3; azinaphthalene epoxy resin, 6-thiooleic acid, 2.5% catalyst and 1.2% polymerization inhibitor were mixed and heated to 80°C and reacted in the dark for 3 hours; washed and dried to obtain unsaturated epoxy resin; the mass ratio of azinaphthalene epoxy resin to 6-thiooleic acid was 10:1.8;

[0088] Mix 1 / 4 of the emulsifier and deionized water, and stir at 750 rpm at 45°C. Add methyl methacrylate, styrene, butyl acrylate, unsaturated epoxy resin, vinyltriisopropoxysilane, dimethylaminoethyl methacrylate, and hexafluorobutyl methacrylate, and stir for 40 min to obtain a pre-emulsion. Mix 1 / 4 of the initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat to 80°C, add 1 / 4 of the initiator, and stir at 300 rpm for 40 min. Slowly add the remaining pre-emulsion, and add every 30 minutes. Add the remaining initiator over 4 hours, and continue the reaction at this temperature for 75 minutes. Add diethanolamine and react for 150 minutes. Cool to 60°C, add glacial acetic acid, and stir for 180 minutes. Cool to obtain an aqueous cationic resin with a solid content of 60%. The aqueous cationic resin comprises the following components by weight: 10 parts methyl methacrylate, 4.5 parts styrene, 9 parts butyl acrylate, 36 parts unsaturated epoxy resin, 5 parts vinyltriisopropoxysilane, 3 parts dimethylaminoethyl methacrylate, 4 parts hexafluorobutyl methacrylate, 1 part initiator, 0.8 parts emulsifier, 15 parts diethanolamine 105, and 5 parts glacial acetic acid.

[0089] The aluminum profile obtained in the previous step is used as the cathode. It is placed in the electrophoretic solution for electrophoretic coating. After electrophoretic coating, it is washed with water and baked at 160℃ for 20 minutes to obtain the sealing layer. The process conditions for electrophoretic coating are: electrophoretic solution temperature 20℃, electrophoresis time 1 minute, electrophoresis voltage 160V; the electrophoretic solution is 150g / L water-based cationic resin; the pH of the solution is adjusted to 5.0 using lactic acid to obtain a bright and corrosion-resistant aluminum profile.

[0090] Comparative Example 1: A method for preparing a bright and corrosion-resistant aluminum profile, comprising the following processes:

[0091] Step 3, Surface treatment: Replace the water-based cationic resin in step (3) with water-based cationic epoxy resin, and the other processes are the same as in Example 1 to obtain a bright and corrosion-resistant aluminum profile;

[0092] The waterborne cationic epoxy resin is prepared by the following process: epoxy resin and ethylene glycol monobutyl ether are mixed, diethanolamine is added, the mixture is heated to 100°C and reacted for 120 min; the mixture is cooled to 50°C, glacial acetic acid and deionized water are added, and the mixture is stirred and reacted for 150 min; the mixture is cooled and deionized water is added to obtain a waterborne cationic resin with a solid content of 60%. The mass ratio of epoxy resin, diethanolamine and glacial acetic acid is 100:15:5; the ratio of epoxy resin to ethylene glycol monobutyl ether is 30 g / 10 mL.

[0093] Comparative Example 2: A method for preparing a bright and corrosion-resistant aluminum profile, comprising the following processes:

[0094] Step 3, Surface Treatment:

[0095] (1) Take the aluminum profile obtained in the previous step as the cathode and platinum as the anode, and perform cathode plasma electrolytic deposition in the electrolyte to form an oxide layer; the process conditions are: voltage 200V, frequency 600Hz, duty cycle 50%, oxidation time 30min; the electrolyte includes the following components: 100g / L aluminum nitrate, 10mL / L glycerol and 15g / L polyethylene glycol;

[0096] (2) Mix 1 / 4 of the emulsifier and deionized water, stir at 750 r / min at 45°C, and add methyl methacrylate, styrene, butyl acrylate, vinyltriisopropoxysilane, acrylic acid, and hexafluorobutyl methacrylate. Stir for 40 min to obtain a pre-emulsion. Mix 1 / 4 of the initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat to 80°C, add 1 / 4 of the initiator, and stir at 300 r / min. The mixture was stirred at a speed of n for 40 minutes; the remaining pre-emulsion was slowly added, and the remaining initiator was added every 30 minutes until the addition was completed in 4 hours. The reaction was then continued at a constant temperature for 75 minutes, followed by cooling to obtain an aqueous acrylic resin with a solid content of 60%. The aqueous cationic resin contained the following components by weight: 10 parts methyl methacrylate, 4.5 parts acrylic acid, 9 parts butyl acrylate, 5 parts vinyltriisopropoxysilane, 3 parts hydroxyethyl acrylate, 4 parts hexafluorobutyl methacrylate, 0.8 parts initiator, and 0.5 parts emulsifier.

[0097] The aluminum profile obtained in the previous step is used as the anode. It is placed in an electrophoretic solution for electrophoretic coating. After electrophoretic coating, it is washed with water and baked at 160℃ for 20 minutes to obtain a sealing layer. The process conditions for electrophoretic coating are: electrophoretic solution temperature 20℃, electrophoresis time 1 minute, and electrophoresis voltage 160V. The electrophoretic solution contains the following components: 8% water-based acrylic resin, 0.25% dimethylaminoethanol, 2% isopropanol, 1% ethylene glycol butyl ether, and pH 8.0. A bright and corrosion-resistant aluminum profile is obtained.

[0098] Comparative Example 3: A method for preparing a bright and corrosion-resistant aluminum profile, comprising the following processes:

[0099] Step 3, Surface Treatment:

[0100] (1) Using aluminum profiles as the anode, anodic plasma electrolytic oxidation is performed in a sodium silicate mixture to form an oxide layer; the sodium silicate mixture includes 25 g / L sodium silicate and 13 g / L sodium phosphate, and the pH is adjusted to 7.5 using sodium hydroxide; the process conditions for anodic plasma electrolytic oxidation are: frequency 600 Hz, duty cycle 20%, current density 15 A / dm³. 2, duration 10min; (2) same as (2) in Comparative Example 2, forming a sealing layer to obtain a bright and corrosion-resistant aluminum profile.

[0101] Comparative Example 4: A method for preparing a bright and corrosion-resistant aluminum profile, comprising the following processes:

[0102] Step 3, Surface Treatment:

[0103] Using aluminum profiles as the anode, anodic plasma electrolytic oxidation is performed in a sodium silicate mixture to form an oxide layer. The sodium silicate mixture consists of 25 g / L sodium silicate and 13 g / L sodium phosphate, with the pH adjusted to 7.5 using sodium hydroxide. The process conditions for anodic plasma electrolytic oxidation are: frequency 600 Hz, duty cycle 20%, and current density 15 A / dm³. 2 Duration: 10 minutes;

[0104] Take the aluminum profile obtained in the previous step and immerse it in a 5wt% KH-560 hydrolysis solution (90v% ethanol solution and KH-560 hydrolyzed at 60℃ for 12h, pH 4) for 10min; take it out, blow it dry with nitrogen, and bake it at 100℃ for 120min to form a sealing layer, thus obtaining a bright and corrosion-resistant aluminum profile.

[0105] Comparative Example 5: A method for preparing a bright and corrosion-resistant aluminum profile, comprising the following processes:

[0106] Step 1: Mix and melt the raw materials, cast them, and homogenize them. The process is as follows: heat to 525℃ and hold for 75 hours; heat to 540℃ and hold for 7 hours; place in a cooling furnace to cool to below 100℃, take it out, and air cool to room temperature to form an ingot.

[0107] Step 2, extrusion: The process is as follows: preheat the ingot to 460℃, heat the die to 455℃, extrusion ratio 15, extrusion speed 3.2m / min; air cool to room temperature; heat treatment, including solution treatment and aging; solution treatment: hold at 525℃ for 7h, quench in water at 25℃; aging treatment: heat at 170℃ for 5h; air cool to room temperature to form aluminum profile; the aluminum profile includes the following components by mass: Si: 0.43%, Mg: 0.56%, Fe: 0.06%, Cu: 0.04%, Mn: 0.07%, Cr: 0.3%, Ti: 0.05%, Zn: 0.5%, balance Al;

[0108] Step 3: The surface treatment is the same as in Comparative Example 4, resulting in a bright and corrosion-resistant aluminum profile.

[0109] Experiment: Bright and corrosion-resistant aluminum profiles obtained in Examples 1-3 and Comparative Examples 1-5 were used to prepare samples. Their properties were tested and the test results were recorded.

[0110] Gloss test: Using ASTM D523 as the reference standard, a gloss meter was used to test the gloss of the sample. The test angle was 20°, and the test was performed 5 times. The arithmetic mean was taken.

[0111] Corrosion resistance test: The corrosion resistance of the sample was tested by three-electrode electrochemical corrosion. The sample was the test electrode, graphite was the auxiliary electrode, and saturated calomel was the reference electrode. The sample test area was 10mm×10mm. The medium was 3.5wt% sodium chloride aqueous solution (pH 7). The sample was soaked for 30min before the experiment. The scanning range was -2 to 2V and the rate was 120mV / s.

[0112] gloss <![CDATA[Corrosion current density (A / cm 2 )]]> Example 1 158 <![CDATA[2.9×10 -9 ]]> Example 2 160 <![CDATA[2.1×10 -9 ]]> Example 3 172 <![CDATA[1.0×10 -9 ]]> Comparative Example 1 142 <![CDATA[5.1×10 -9 ]]> Comparative Example 2 96 <![CDATA[2.2×10 -8 ]]> Comparative Example 3 84 <![CDATA[7.8×10 -8 ]]> Comparative Example 4 67 <![CDATA[1.7×10 -7 ]]> Comparative Example 5 56 <![CDATA[8.3×10 -7 ]]>

[0113] Based on the data in the table above, the following conclusions can be clearly drawn:

[0114] The bright, corrosion-resistant aluminum profiles obtained in Examples 1-3 are compared with those obtained in Comparative Examples 1-5. The test results show that...

[0115] Compared to the comparative examples, the bright and corrosion-resistant aluminum profiles obtained in Examples 1-3 exhibit higher gloss levels and lower corrosion current densities measured in three-electrode electrochemical corrosion detection. This clearly demonstrates that the present invention improves the surface gloss characteristics and corrosion resistance of aluminum profiles.

[0116] Compared to Example 1, the cathodic electrophoresis (sealing) process in Comparative Example 1 used an aqueous cationic epoxy resin as the electrophoresis solution; the surface treatment in Comparative Example 2 consisted of cathodic plasma electrolytic deposition and anodic electrophoresis; the surface treatment in Comparative Example 3 consisted of anodic plasma electrolytic oxidation and anodic electrophoresis; the surface treatment in Comparative Example 4 consisted of anodic plasma electrolytic oxidation and silane hydrolysis sealing; and compared to Comparative Example 4, the aluminum profile in Comparative Example 5 did not contain rare earth elements. The bright, corrosion-resistant aluminum profiles obtained in Comparative Examples 1-5 exhibited deteriorated gloss and corrosion current density. It is evident that the preparation of aluminum profiles, surface treatment processes, and the selection of components used in this application can promote improvements in their surface gloss characteristics and corrosion resistance.

[0117] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing a bright, corrosion-resistant aluminum profile, characterized in that: Including the following processes: The raw materials are mixed, smelted, cast, and homogenized to form ingots; extruded and heat-treated to form aluminum profiles; and surface-treated to obtain bright and corrosion-resistant aluminum profiles. Surface treatment includes electrolytic oxidation, electrophoretic coating, and pore sealing; The electrolytic oxidation includes anodic plasma electrolytic oxidation and cathodic plasma electrolytic deposition; The anodic plasma electrolytic oxidation uses an aluminum profile as the anode and is carried out in a sodium silicate mixture to form a barrier layer. The cathode plasma electrolytic deposition uses the aluminum profile obtained in the previous step as the cathode and platinum as the anode, and performs cathode plasma electrolytic deposition in an electrolyte to form an oxide layer. The process conditions for cathode plasma electrolytic deposition are: voltage 150-200V, frequency 500-600Hz, duty cycle 50%-60%, and oxidation time 10-30min. The electrolyte comprises the following components: 100–300 g / L aluminum nitrate, 10–50 g / L yttrium nitrate, 10–50 mL / L glycerol, and 15–25 g / L polyethylene glycol; the mass ratio of aluminum nitrate to yttrium nitrate is (5.2–5.6):

1. The electrophoretic coating process is as follows: the aluminum profile obtained in the previous step is used as the cathode, and electrophoretic coating is performed in the electrophoretic solution to obtain a sealing layer; the electrophoretic solution is 100-150g / L water-based cationic resin.

2. The method for preparing a bright, corrosion-resistant aluminum profile according to claim 1, characterized in that: The aluminum profile comprises the following components by mass: Si: 0.2%–0.6%, Mg: 0.35%–0.90%, Fe: ≤0.05%, Cu: ≤0.10%, Mn: ≤0.10%, Cr: ≤0.10%, Ti: ≤0.10%, Zn: ≤0.10%, RE: 0.1%–0.4%, with the balance being Al.

3. The method for preparing a bright, corrosion-resistant aluminum profile according to claim 1, characterized in that: The aqueous cationic resin is prepared by the following process: Mix 1 / 4 of the emulsifier and deionized water, and stir at 40-45°C and 650-750 r / min. Add methyl methacrylate, styrene, butyl acrylate, unsaturated epoxy resin, vinyltriisopropoxysilane, dimethylaminoethyl methacrylate, and hexafluorobutyl methacrylate, and stir for 30-40 min to obtain a pre-emulsion. Mix 1 / 4 of the component mass of the initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat to 65-75℃, add 1 / 4 of the initiator, and stir at 200-300 r / min for 30-40 min; slowly add the remaining pre-emulsion, and add the remaining initiator every 30 min, until the addition is complete in 4 h, and continue to keep the temperature and react for 60-75 min; add diethanolamine, and react for 100-150 min; Cool to 50-60℃, add glacial acetic acid, stir and react for 150-180 min; cool to obtain aqueous cationic resin.

4. The method for preparing a bright, corrosion-resistant aluminum profile according to claim 3, characterized in that: The unsaturated epoxy resin is obtained by the following process: Epoxy resin, 4-(4-hydroxyphenyl)-1(2H)-one and catalyst were mixed and heated to 65-75°C under nitrogen atmosphere and reacted at a constant temperature for 5-7 hours to obtain azinaphthalene epoxy resin. Azanaphthalene epoxy resin, 6-thiooleic acid, catalyst and polymerization inhibitor are mixed, heated to 60-80℃, and reacted in the dark for 3-5 hours to obtain unsaturated epoxy resin.

5. The method for preparing a bright, corrosion-resistant aluminum profile according to claim 3, characterized in that: The aqueous cationic resin comprises the following components by weight: 10-15 parts methyl methacrylate, 4.5-10 parts styrene, 9-19 parts butyl acrylate, 27-36 parts unsaturated epoxy resin, 5-10 parts vinyltriisopropoxysilane, 3-7 parts dimethylaminoethyl methacrylate, 4-12 parts hexafluorobutyl methacrylate, 0.8-1.2 parts initiator, 0.5-1.0 parts emulsifier, 10-20 parts diethanolamine, and 3.2-5.7 parts glacial acetic acid.

6. A bright, corrosion-resistant aluminum profile prepared by the preparation method according to any one of claims 1-5.