A corrosion-resistant electrophoretic coating and its preparation process

Abstract

The application provides a kind of corrosion-resistant electrophoretic painting and preparation process, by the synthesis of electrophoretic painting of arabic gum, deionized water, polyethylene acrylic acid emulsion and octanoic acid ammonium, the corrosion resistance of aluminum alloy profile is greatly improved by the electrophoretic painting synthesized by the method, and the synthesis process is simple, and other additives are not needed.

Description

Technical Field

[0001] This invention relates to the field of electrophoretic coating technology, and more particularly to a corrosion-resistant electrophoretic coating and its preparation process. Background Technology

[0002] Aluminum profiles, due to their excellent thermal ductility and ease of processing, are widely used in emerging fields such as aerospace, construction, and solar energy. When heat-treated aluminum profiles are placed in air, a dense aluminum oxide film forms on their surface with oxygen, providing a certain degree of corrosion resistance. However, because the protective layer formed in the natural environment is too thin and its corrosion resistance is insufficient, it cannot meet the corrosion resistance requirements of some aluminum alloys that need to be used in long-term high-temperature, high-salinity environments. Therefore, surface treatment of aluminum alloys is necessary to improve their corrosion resistance. Anodizing is a method that uses an acidic electrolyte such as sulfuric acid as the anode, a platinum or lead plate as the cathode, and applies direct current, causing a protective film to form on the surface of the aluminum alloy anode, thus providing corrosion resistance.

[0003] As a surface treatment method, aluminum profile electrophoresis involves placing the aluminum profile in an electrophoresis tank and applying direct current to it, forming a dense resin film on the surface. Electrophoretic coating began to be used as a surface treatment for aluminum profiles abroad in the 1960s. After anodizing and electrophoretic treatment, the aluminum alloy has a composite coating of anodic oxide and electrophoretic coating. This is equivalent to adding an extra layer of electrophoretic organic coating on top of the aluminum alloy oxide film, thereby enhancing the aluminum alloy's corrosion resistance, weather resistance, and other properties.

[0004] When aluminum alloy profiles are used as solar panel supports and frames, the profiles need to have high corrosion resistance because most new energy devices are installed in areas with variable climates and harsh environments. The corrosion resistance of conventional electrophoretic paints is insufficient for current requirements. Therefore, this patent proposes a corrosion-resistant electrophoretic coating and preparation process. The treated aluminum alloy profiles exhibit high corrosion resistance, extending their shelf life even in harsh climates and corrosive environments. Summary of the Invention

[0005] The purpose of this invention is to overcome the fact that existing corrosion resistance cannot meet current usage requirements. This invention provides a corrosion-resistant electrophoretic coating and preparation process. The treated aluminum alloy profiles have high corrosion resistance and can be stored for longer periods under harsh climates and corrosive conditions.

[0006] The specific plan is as follows:

[0007] An electrophoretic coating comprises the following components in parts by weight: 1-5 parts gum arabic; 5-20 parts deionized water; 100-150 parts polyethylene acrylic emulsion; and 0.5-5 parts ammonium octanoate.

[0008] Furthermore, the electrophoretic coating comprises the following components by weight: 1-3 parts gum arabic; 5-10 parts deionized water; 100-110 parts polyethylene acrylic emulsion; and 0.5-1 parts ammonium octanoate.

[0009] Furthermore, the preparation method of the polyethylene acrylic emulsion includes: adding 40-50 parts by weight of polyethylene wax to 80-100 parts by weight of deionized water, heating to 50-80°C, and after the polyethylene wax melts and the water separates into layers, adding 0.5-1 parts by weight of sodium dodecyl sulfate and 0.5-0.8 parts by weight of potassium persulfate to maintain the temperature at 50-80°C; starting to add 15-17 parts by weight of acrylic monomer, the solution changes from colorless and transparent to milky white; after the addition is complete, adding 1-2 parts by weight of sodium bicarbonate, 1-2 parts by weight of polyvinyl alcohol, adding 0.5-1 parts by weight of ammonia water, and then adding an appropriate amount of 45-55 wt% NaOH aqueous solution to adjust the pH to 7-8, thus obtaining the polyethylene acrylic emulsion.

[0010] Furthermore, the molecular weight of the polyethylene wax is 800-1000.

[0011] Furthermore, the acrylic monomer was added dropwise over 20 minutes.

[0012] An electrophoretic coating preparation process includes the following steps:

[0013] Dissolve gum arabic in deionized water at 35-45℃; pour it into polyethylene acrylic emulsion at 35-45℃; add ammonium octanoate; stir until the solution is uniform to obtain electrophoretic coating.

[0014] Furthermore, the electrophoretic coating is used for aluminum alloy anodizing electrophoresis. Preferably, before the electrophoretic treatment, the aluminum alloy is subjected to at least one of the following pretreatments: degreasing, water washing, acid pickling, alkaline etching, and anodizing.

[0015] An aluminum alloy processing technology includes the following steps:

[0016] 1. Hanging the material: Hang the aluminum alloy profiles to be processed on the hanger;

[0017] 2. Degreasing: Place the mounted aluminum alloy profiles into the degreasing tank for degreasing. Use sulfuric acid with a concentration of 140-190g / L to treat for 1-5 minutes at room temperature. Then, put them into the water washing tank for washing and adjust the pH to 2-3 to obtain the degreased aluminum alloy profiles.

[0018] 3. Alkali etching: Place the aluminum alloy profile in an alkaline washing tank and treat it with NaOH aqueous solution at a temperature of 45-60℃ for 30s-15min; after alkaline washing, rinse the aluminum profile with water for 10s-1min to obtain the alkaline etched aluminum alloy profile.

[0019] IV. Neutralization: Place the alkaline-etched aluminum alloy profile obtained in step III into a neutralization tank, neutralize it with sulfuric acid at a concentration of 140-190 g / L for 2-5 minutes, and then wash it with water to obtain the neutralized aluminum alloy profile.

[0020] V. Anodizing: Place the neutralized aluminum alloy profile obtained in step four at a temperature of 18-22℃, a voltage of 15-18V, and a current density of 100A / m. 2 ~150A / m 2 After anodizing in a sulfuric acid solution with a concentration of 140–190 g / L for 20–37 min, the sample is washed with water.

[0021] VI. Electrophoresis: The anodized aluminum alloy profile treated in step five is subjected to electrophoretic coating, followed by water washing; the parameters for the electrophoretic treatment are: voltage: 100-200V, electrophoresis time: 1-2min, current density: 25-30A / m 2 ;

[0022] 7. Drying: Dry the washed aluminum alloy profile to obtain corrosion-resistant electrophoretic aluminum alloy. The drying parameters are: drying temperature 80-100℃, drying time 30-45min.

[0023] Furthermore, the corrosion-resistant aluminum alloy withstands a test temperature of 35±2℃ and a neutral salt spray concentration of 5±1wt% for a time greater than or equal to 1500h.

[0024] Furthermore, the thickness of the corrosion-resistant aluminum alloy coating is 10-15 μm, and the hardness is 4H-5H, as determined according to GB / T6739-1996; the adhesion grade of the coating is 0-1, as determined according to GB / T1720-79(89).

[0025] The advantages of this invention are:

[0026] 1. The polyethylene acrylic acid in this invention is a high molecular weight polymer formed by the polymerization of ethylene and acrylic acid. In the polymer, the ethylene portion provides the polyethylene acrylic acid with hydrophobicity, ductility, and weather resistance, while the acrylic acid portion imparts polarity, adhesiveness, and high hardness to the polymer molecules. The increase in the acrylic acid portion increases the polymer's adhesiveness, polarity, and hardness, lowers the polymer's melting point, and increases transparency and adhesion.

[0027] 2. This invention uses gum arabic, ammonium octanoate and polyethylene acrylic emulsion to synthesize electrophoretic coating. No other additives are needed. The synthesis process is simple and easy to operate.

[0028] 3. The addition of gum arabic as a molecular weight regulator in this invention enables the original polyethylene acrylic emulsion to adhere to the aluminum surface, resulting in a tight bond between the formed paint film and the aluminum alloy profile, good surface appearance quality, and high corrosion resistance. Detailed Implementation

[0029] This embodiment provides an electrophoretic coating, comprising the following components by weight: 1-5 parts gum arabic; 5-20 parts deionized water; 100-150 parts polyethylene acrylic emulsion; and 0.5-5 parts ammonium octanoate.

[0030] In this embodiment, the electrophoretic coating consists of the following components by weight: 1-3 parts gum arabic; 5-10 parts deionized water; 100-110 parts polyethylene acrylic emulsion; and 0.5-1 parts ammonium octanoate.

[0031] In this embodiment, the preparation method of the polyethylene acrylic emulsion includes: adding 40-50 parts by weight of polyethylene wax to 80-100 parts by weight of deionized water, heating to 50-80°C, and after the polyethylene wax melts and the water separates into layers, adding 0.5-1 parts by weight of sodium dodecyl sulfate and 0.5-0.8 parts by weight of potassium persulfate to maintain the temperature at 50-80°C; starting to add 15-17 parts by weight of acrylic monomer, the solution changes from colorless and transparent to milky white; after the addition is complete, adding 1-2 parts by weight of sodium bicarbonate, 1-2 parts by weight of polyvinyl alcohol, adding 0.5-1 parts by weight of ammonia water, and then adding an appropriate amount of 45-55 wt% NaOH aqueous solution to adjust the pH to 7-8, thus obtaining the polyethylene acrylic emulsion.

[0032] In this embodiment, the polyethylene wax has a molecular weight of 800-1000. It was purchased from Rushan Beihua New Material Technology Co., Ltd. A low molecular weight is beneficial for the emulsification of polyethylene and acrylic acid.

[0033] In this embodiment, the acrylic monomer is added dropwise over 20 minutes.

[0034] This embodiment provides a preparation process for electrophoretic coating, including the following steps:

[0035] Dissolve 1-3 parts of gum arabic in 5-10 parts of deionized water at 35-45℃; pour this solution into 100-110 parts of polyethylene acrylic emulsion at 35-45℃; then add 0.5-1 parts of ammonium octanoate; stir until the solution is homogeneous to obtain the electrophoretic coating. Adding gum arabic allows the polyethylene acrylic emulsion to adhere to the aluminum surface, and through the rational selection of the component formulation, they can better interact and influence each other, resulting in a synergistic effect that improves the corrosion resistance of the coating film.

[0036] In this embodiment, the electrophoretic coating is used for aluminum alloy anodizing electrophoresis. Before the electrophoretic treatment, the aluminum alloy is subjected to at least one of the following pretreatments: degreasing, water washing, acid pickling, alkaline etching, and anodizing.

[0037] This embodiment provides a corrosion-resistant aluminum alloy treatment process, including the following steps:

[0038] 1. Hanging the material: Hang the aluminum alloy profiles to be processed on the hanger;

[0039] 2. Degreasing: Place the mounted aluminum alloy profiles into a degreasing tank for degreasing. Use sulfuric acid with a concentration of 140-190 g / L to treat for 1-5 minutes at room temperature, then place them in a water washing tank to wash and adjust the pH to 2-3 to obtain degreased aluminum alloy profiles. Degreasing can reduce the adhesion of the oil film on the aluminum alloy profiles or even turn it into oil droplets that leave the surface, making it easy to remove surface oil stains and uniformly etch them in the next step of alkaline etching.

[0040] 3. Alkali etching: Place the aluminum alloy profile in an alkaline washing tank and treat it with NaOH at a temperature of 45-60℃ for 30s-15min; after alkaline etching, wash the aluminum profile with water for 10s-1min to obtain the alkaline-washed alloy profile; alkaline washing can remove oil stains and natural oxide film from the surface of the profile, exposing the base metal surface, which is conducive to the formation of a high-quality oxide film on the surface during anodizing. On the other hand, it can lightly polish the slightly rough surface.

[0041] IV. Neutralization: Place the alkaline-etched aluminum alloy profile obtained in step III into a neutralization tank and neutralize it with sulfuric acid at a concentration of 140–190 g / L for 2–5 minutes, followed by water washing to obtain the neutralized aluminum alloy profile; V. Anodizing: Place the neutralized aluminum alloy profile obtained in step IV into a temperature of 18–22℃, a voltage of 15–18V, and a current density of 100A / m. 2 ~150A / m 2 After anodizing in a sulfuric acid solution with a concentration of 140–190 g / L for 20–37 min, the aluminum alloy is washed with water. The oxide film formed by anodizing can be tightly bonded to the aluminum alloy profile and the surface paint film, thereby improving the corrosion resistance of the aluminum alloy.

[0042] VI. Electrophoresis: The anodized aluminum alloy profile prepared in step five is subjected to electrophoretic coating until the paint film thickness reaches 10μm, followed by water washing. The parameters for the electrophoretic treatment are: voltage: 100-200V, electrophoresis time: 1-2min, current density: 25-30A / m 2 ;

[0043] 7. Drying: Dry the washed aluminum alloy profile to obtain corrosion-resistant electrophoretic aluminum alloy profile. The drying parameters are: drying temperature of 80-100℃ and drying time of 30-45min.

[0044] In this embodiment, the corrosion-resistant aluminum alloy withstands a test temperature of 35±2℃ and a neutral salt spray concentration of 5±1wt% for a time greater than or equal to 1500h.

[0045] In this embodiment, the thickness of the corrosion-resistant aluminum alloy coating is 10-15 μm, the hardness is 4H-5H, and it is determined according to GB / T 6739-1996; the adhesion grade of the coating is 0-1, and it is determined according to GB / T 1720-79(89).

[0046] Preferred embodiments of the present invention will now be described in more detail. While preferred embodiments of the present invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products. In the following embodiments, unless otherwise explicitly stated, "%" refers to weight percentage, and "parts" refers to parts by weight.

[0047] Experimental group 1

[0048] Preparation process of polyethylene acrylic emulsion:

[0049] Add 45 parts of polyethylene wax with a molecular weight of 800-1000 to 90 parts of deionized water and heat to 75°C. After the polyethylene wax melts and the water separates into layers, add 0.75 parts of sodium dodecyl sulfate and 0.75 parts of potassium persulfate and maintain the temperature at 75°C. Slowly add 15 parts of acrylic monomer over 20 minutes. The solution changes from colorless and transparent to slightly milky white. After the addition is complete, add 1.5 parts of sodium bicarbonate, 2 parts of polyvinyl alcohol, and 1 part of ammonia. Then add an appropriate amount of 50% NaOH aqueous solution to adjust the pH to 7, thus obtaining the polyethylene acrylic emulsion.

[0050] Electrophoretic coating preparation process:

[0051] Dissolve 1 part gum arabic in 6 parts deionized water at 40°C; pour it into 100 parts polyethylene acrylic emulsion at 40°C; add 0.5 parts ammonium octanoate; stir until the solution is homogeneous to obtain the electrophoretic coating.

[0052] Anodizing and electrophoretic process for aluminum alloy profiles:

[0053] 1. Hanging the material: Hang the aluminum alloy profiles to be processed on the hanger;

[0054] 2. Degreasing: Place the mounted aluminum alloy profiles into the degreasing tank for degreasing. Use sulfuric acid with a concentration of 160g / L to treat for 3 minutes at room temperature, then put them into the water washing tank for washing. Adjust the pH to 3 to obtain the degreased aluminum alloy profiles.

[0055] 3. Alkali etching: Place the aluminum alloy profile in an alkaline washing tank and treat it with NaOH at 55°C for 10 minutes; after alkaline washing, rinse the aluminum profile with water for 1 minute to obtain the alkaline-washed alloy profile.

[0056] IV. Neutralization: Place the alkaline-etched aluminum alloy profile obtained in step III into a neutralization tank, neutralize it with sulfuric acid at a concentration of 160g / L for 3 minutes, and then wash it with water to obtain the neutralized aluminum alloy profile.

[0057] V. Anodizing: The neutralized aluminum alloy profile obtained in step IV is placed at a temperature of 20℃, a voltage of 16V, and a current density of 130A / m. 2 After anodic oxidation in a sulfuric acid solution with a concentration of 160 g / L for 30 min, the sample was washed with water.

[0058] VI. Electrophoresis: The anodized aluminum alloy profile prepared in step five is subjected to electrophoresis using the prepared electrophoretic coating until the coating thickness reaches 10 μm, followed by water washing. The parameters for the electrophoresis treatment are: voltage: 150V, electrophoresis time: 2 min, current density: 26 A / m 2 ;

[0059] 7. Drying: Dry the washed aluminum alloy profile to obtain corrosion-resistant electrophoretic aluminum alloy profile. The drying parameters are: drying temperature is 100℃ and drying time is 40min.

[0060] Experimental group 2

[0061] Dissolve 2 parts of gum arabic in 7 parts of deionized water at 40°C; pour it into 102 parts of polyethylene acrylic emulsion prepared in test group 1 at 40°C; add 0.6 parts of ammonium octanoate; stir until the solution is uniform to obtain electrophoretic coating. The anodic electrophoretic process for other aluminum alloy profiles is the same as that in test group 1.

[0062] Experimental group 3

[0063] Dissolve 3 parts of gum arabic in 8 parts of deionized water at 40°C; pour it into 104 parts of polyethylene acrylic emulsion prepared in test group 1 at 40°C; add 0.7 parts of ammonium octanoate; stir until the solution is uniform to obtain electrophoretic coating. The anodic electrophoretic process for other aluminum alloy profiles is the same as that in test group 1.

[0064] Experimental group 4

[0065] Dissolve 4 parts of gum arabic in 9 parts of deionized water at 40°C; pour it into 106 parts of polyethylene acrylic emulsion prepared in test group 1 at 40°C; add 0.8 parts of ammonium octanoate; stir until the solution is uniform to obtain electrophoretic coating. The anodic electrophoretic process for other aluminum alloy profiles is the same as that in test group 1.

[0066] Experimental group 5

[0067] Dissolve 5 parts of gum arabic in 10 parts of deionized water at 40°C; pour it into 108 parts of polyethylene acrylic emulsion prepared in test group 1 at 40°C; add 1 part of ammonium octanoate; stir until the solution is uniform to obtain electrophoretic coating. The anodic oxidation electrophoretic process for other aluminum alloy profiles is the same as that in test group 1.

[0068] The performance of the corrosion-resistant electrophoretic aluminum alloys treated in each test group was tested, and the results are shown in Table 1:

[0069] Table 1. Film properties of electrophoretic coatings in each test group

[0070]

[0071] Note: The thickness of the paint film was determined according to GB 1764-79; the hardness of the paint film was determined according to GB / T 6739-1996; the adhesion of the paint film was determined according to GB / T 1720-79(89); and the salt spray resistance of the paint film was determined according to GB / T 10125-2012.

[0072] According to the experimental results in Table 1, the electrophoretic coating prepared by the process of this invention has the advantages of high adhesion and high corrosion resistance. It can be used as an anti-corrosion coating for metals. After use, the neutral salt spray resistance test of the metal can reach 2000h.

[0073] Comparison Group 1

[0074] Dissolve 3 parts carrageenan in 8 parts deionized water at 40℃; pour it into 104 parts of polyethylene acrylic emulsion prepared in test group 1 at 40℃; add 0.7 parts ammonium octanoate; stir until the solution is uniform to obtain electrophoretic coating. The anodic oxidation electrophoretic process for other aluminum alloy profiles is the same as that in test group 1.

[0075] The experimental results of control group 1 are as follows: Unlike gum arabic, carrageenan does not act as a molecular weight regulator. The electrophoretic coating prepared using carrageenan has poor uniformity, and the coating cannot adhere to the surface of the aluminum alloy profile.

[0076] Comparison Group 2

[0077] Preparation process of polyethylene acrylic emulsion:

[0078] Add 45 parts of polyethylene wax with a molecular weight of 800-1000 to 90 parts of deionized water and heat to 75°C. After the polyethylene wax melts and the water separates into layers, add 0.75 parts of sodium dodecyl sulfate and 0.75 parts of potassium persulfate and maintain the temperature at 75°C. Slowly add 15 parts of acrylic monomer over 10 minutes. The solution changes from colorless and transparent to slightly milky white. After the addition is complete, add 1.5 parts of sodium bicarbonate, 2 parts of polyvinyl alcohol, and 1 part of ammonia. Then add an appropriate amount of 50% NaOH aqueous solution to adjust the pH to 7, thus obtaining the polyethylene acrylic emulsion.

[0079] The results of the comparative group 2 experiment are as follows: When the acrylic acid was added too quickly, it agglomerated and formed a white, waxy, hard solid, preventing the reaction from proceeding. Compared with the five experimental groups, it can be seen that the acrylic monomer should not be added too quickly, otherwise it will agglomerate and form a white, waxy, hard solid, preventing the reaction from proceeding, thus failing to form the polyethylene acrylic emulsion, and consequently, failing to prepare the electrophoretic coating.

[0080] Comparison Group 3

[0081] Add 45 parts of polyethylene wax with a molecular weight of 1000-8000 to 90 parts of deionized water and heat to 75°C. After the polyethylene wax melts and the water separates into layers, add 0.75 parts of sodium dodecyl sulfate and 0.75 parts of potassium persulfate and maintain the temperature at 75°C. Slowly add 15 parts of acrylic monomer over 20 minutes. The solution changes from colorless and transparent to slightly milky white. After the addition is complete, add 1.5 parts of sodium bicarbonate, 2 parts of polyvinyl alcohol, and 1 part of ammonia. Then add an appropriate amount of 50% NaOH aqueous solution to adjust the pH to 7, thus obtaining the polyethylene acrylic emulsion.

[0082] The results for control group 3 are as follows: a white granular suspension was formed, which was insoluble in water and could not be tested. Compared with the five experimental groups, it can be seen that only low molecular weight polyethylene wax can react with acrylic monomers to form a polyethylene acrylic emulsion, which is beneficial for emulsification.

[0083] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0084] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0085] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. An electrocoat paint characterized by: The composition comprises the following components by weight: gum arabic 1-5 parts; deionized water 5-20 parts; polyethylene acrylic acid emulsion 100-150 parts; ammonium octanoate 0.5-5 parts; The preparation method of the polyethylene acrylic acid emulsion comprises: adding 40-50 parts by weight of polyethylene wax with a molecular weight of 800-1000 into 80-100 parts by weight of deionized water, heating to 50-80°C, after the polyethylene wax is melted and the water is layered, adding 0.5-1 parts by weight of sodium dodecyl sulfate and 0.5-0.8 parts by weight of potassium persulfate and keeping the temperature at 50-80°C; starting to drop 15-17 parts by weight of acrylic monomer, the solution changes from colorless and transparent to milky white; after the dropping is completed, adding 1-2 parts by weight of sodium bicarbonate, 1-2 parts by weight of polyvinyl alcohol, 0.5-1 parts by weight of ammonia water, and then adding an appropriate amount of 45-55 wt% NaOH aqueous solution to adjust the pH to 7-8, thereby obtaining the polyethylene acrylic acid emulsion.

2. An electrocoating paint as defined in claim 1, characterized in that: The composition comprises the following components by weight: gum arabic 1-3 parts; deionized water 5-10 parts; polyethylene acrylic acid emulsion 100-110 parts; ammonium octanoate 0.5-1 parts.

3. An electrocoating paint as defined in claim 1, wherein: The acrylic monomer is dropped for 20 minutes.

4. A process for the production of an electrophoretic paint as claimed in any one of claims 1 to 3, characterized in that: The method comprises the following steps: The gum arabic is dissolved in deionized water at 35-45°C; it is poured into the polyethylene acrylic acid emulsion at 35-45°C; then ammonium octanoate is added; the solution is stirred until it is uniform, thereby obtaining the electrophoretic paint.

5. A corrosion resistant aluminum alloy treatment process characterized by: The electrophoretic paint of any one of claims 1-3 is used for anodic oxidation electrophoresis of aluminum alloy.

6. The corrosion resistant aluminum alloy treatment process of claim 5, wherein: Before the electrophoretic treatment, the aluminum alloy is pretreated by at least one of the following: oil removal, water washing, acid pickling, alkali etching, and anodic oxidation.

7. The corrosion resistant aluminum alloy treatment process of claim 5, wherein: The method comprises the following steps: I. Hanging: the aluminum alloy profile to be treated is hung on a hanger; II. Oil removal: the hung aluminum alloy profile is placed in an oil removal tank for oil removal, and then is placed in a water washing tank after being treated with sulfuric acid with a concentration of 140-190 g / L at room temperature for 1-5 min, and the pH is adjusted to 2-3, thereby obtaining the oil-removed aluminum alloy profile; III. Alkali etching: the oil-removed aluminum alloy profile is placed in an alkali washing tank and treated with NaOH aqueous solution at a temperature of 45-60°C for 30 s-15 min; the alkali-etched aluminum profile is washed with water for 10 s-1 min, thereby obtaining the alkali-etched aluminum alloy profile; IV. Neutralization: the alkali-etched aluminum alloy profile obtained in step III is placed in a neutralization tank and treated with sulfuric acid with a concentration of 140-190 g / L for 2-5 min, and then is washed with water, thereby obtaining the neutralized aluminum alloy profile; V. Anodizing: The neutralized aluminum alloy profile obtained in step IV is subjected to anodizing in a sulfuric acid solution having a temperature of 18-22°C, a voltage of 15-18 V, a current density of 100 A / m 2 ~ 150 A / m 2 and a concentration of 140-190 g / L for 20-37 min, followed by water washing. Six, electrophoresis: the anodic aluminum alloy profile treated in step five is electrophoresed using the electrophoretic paint, and then washed with water; the parameters of the electrophoresis treatment are voltage: 100-200 V, electrophoresis time: 1-2 min, current density: 25-30 A / m 2 ; VII. Drying: the water-washed aluminum alloy profile is dried, thereby obtaining the corrosion-resistant electrophoretic aluminum alloy, and the drying parameters are as follows: the drying temperature is 80-100°C, and the drying time is 30-45 min.

8. A corrosion resistant aluminum alloy treated by the process of any one of claims 5-7, characterized by: The corrosion-resistant aluminum alloy has a tolerance time of greater than or equal to 1500 h under the conditions of a test temperature of 35±2°C and a neutral salt spray concentration of 5±1 wt%. The corrosion-resistant aluminum alloy has a tolerance time of greater than or equal to 1500 h under the conditions of a test temperature of 35±2°C and a neutral salt spray concentration of 5±1 wt%.

9. The corrosion resistant aluminum alloy of claim 8, wherein: The coating film of the corrosion-resistant aluminum alloy has a thickness of 10-15 microns, a hardness of 4H-5H, and a film adhesion grade of 0-1, as determined according to GB / T 6739-1996 and GB / T 1720-79(89), respectively.

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