Aluminum alloy electrolytic staining solution composition

Abstract

The invention provides an aluminum alloy electrolytic dyeing liquid composition which comprises sulfuric acid, ferrous oxide dihydrate KHPO, KHPO, aluminum hexafluorophosphate, an SDS surfactant and a NaHCO3 pH regulator, and an obtained oxidation dyeing film is bright and uniform in color, small in color difference and good in corrosion resistance and weather resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical staining solutions, especially electrolytic staining solutions for aluminum alloys. Background Art

[0002] Aluminum, as the most widely distributed and most abundant element among metallic elements, contains a large amount of aluminum in soil, rocks, animals and plants. Its content accounts for about 8.2% of the total mass of the earth's crust, second only to oxygen and silicon, and more than the sum of iron (about 2.1%), magnesium (about 2.1%) and titanium (about 0.6%). The atomic number of aluminum is 13, the relative atomic mass is 21.9815, and the density is 2.7 g / cm3, which is 1 / 3 of that of copper, and it is called a light metal.

[0003] Compared with other metals, aluminum alloy materials have a series of advantages such as low density, high specific strength, easy processing, excellent electrical and thermal conductivity, easy forming and colorable appearance. Therefore, aluminum alloy materials are widely used in various fields such as aerospace, navigation, aviation, automobiles, bridges, buildings, electrical and electronics, energy and power, metallurgical and chemical industries, agricultural irrigation, machinery manufacturing, packaging and corrosion prevention, electrical appliances and furniture, etc., and are materials with great economic value and commercial significance.

[0004] The electrode potential of aluminum is very low, and it has a strong affinity for oxygen atoms, so it is a relatively active metallic element. In the air, a dense natural oxide film that is non-porous and amorphous will be formed on its surface (the thickness is about 0.001μm - 0.015μm), which can protect the aluminum substrate from further corrosion in neutral and weakly acidic environments and play a certain protective role. However, the film layer is loose, porous and uneven, and the protection ability is insufficient. Therefore, the anodic oxidation method of aluminum alloy that can form a uniform, continuous and dense oxide film on the surface of aluminum alloy materials has been widely used and has become the most important treatment method in the current field of aluminum surface treatment. It uses an electrochemical method to form an oxide film on the aluminum surface. This oxide film has certain hardness, wear resistance and corrosion resistance, and also has certain decorative properties, and can meet the technical requirements of many application fields.

[0005] The coloring and staining of metals refer to the process of obtaining a film layer with a different color from the original substrate surface on the metal surface by chemical or electrochemical methods in a specific solution and maintaining the luster of the metal. It is mainly used for the decoration of metal products to improve the appearance and enhance its corrosion resistance. Due to different process conditions, electrolytic coloring can be divided into the following four types: (1) natural coloring; (2) primary electrolytic coloring; (3) secondary electrolytic coloring; (4) tertiary electrolytic coloring; (5) adsorption coloring.

[0006] CN103334140B discloses a room-temperature golden yellow dyeing process for anodizing aluminum alloys, which is the most suitable process for mass production, including the steps of: 1) pretreatment before anodizing: After hanging the aluminum profiles and performing decontamination and degreasing treatment in the bath solution of the cleaning tank, alkali etching treatment is carried out in the alkali tank, and after one water wash, it enters the neutralization tank for neutralization, and after treatment, it enters the next process through water wash; 2) generating an oxide film by anodizing: The pretreated profiles are subjected to anodizing treatment in the anodizing bath solution, and the time is controlled according to the requirements of the anodizing film. After treatment, it enters the next process through water wash; 3) room-temperature organic golden yellow dyeing: The profiles that have been anodized are entered into the organic golden yellow tank for dyeing; 4) high-temperature sealing: The dyed profiles are subjected to sealing treatment in the sealing tank. The golden yellow aluminum alloy of the process of the present invention has bright and uniform color, small color difference, good corrosion resistance and weather resistance, and the best decorative effect. The process is simple and the cost is low during the production process.

[0007] CN112301398B discloses a method for preparing a golden film, in which an aluminum alloy workpiece is successively subjected to mechanical polishing, chemical polishing, anodizing treatment, alternating current electrolytic dyeing treatment and sealing treatment. The alternating current electrolytic dyeing treatment is a multi-time dyeing treatment with a rising voltage gradient. The dye solution contains 0.3 - 0.8 g / L of alizarin yellow R, 0.5 - 1.2 g / L of alizarin red S, 4 - 7 g / L of potassium permanganate, 20 - 25 g / L of sulfuric acid and 3 - 5 g / L of copper chloride. The present invention combines a multi-time dyeing process with a rising voltage gradient and a dye solution containing copper ions to adjust the color of the dyeing layer, obtaining a golden oxide film with pure color, uniform color and high gloss, and having a good antibacterial effect and good comprehensive performance. Summary of the Invention

[0008] The present invention provides an aluminum alloy electrolytic dyeing solution composition. The obtained aluminum alloy color mold has particularly stable color, is a light green golden yellow aluminum oxide film, and has good corrosion resistance and excellent protective performance.

[0009] An aluminum alloy electrolytic dyeing solution composition, characterized in that the electrolytic dyeing solution includes sulfuric acid, iron(II) oxide dihydrate KH 2 PO 4 、K 2 HPO 4 、aluminum hexafluorophosphate, SDS surfactant and NaHCO 3 pH regulator. The electrolytic dyeing parameters include three electrolytic dyeing processes. The first electrolytic dyeing: voltage 12 - 14 V, temperature 60 - 65 °C, time 12 - 14 min; the second electrolytic dyeing: voltage 10 - 12 V, temperature 55 - 60 °C, time 10 - 12 min; the third electrolytic dyeing: voltage 8 - 10 V, temperature 50 - 55 °C, time 8 - 10 min.

[0010] 2. The aluminum alloy electrolytic coloring solution composition according to claim 1, wherein the dosage of sulfuric acid is 1.2 - 1.4 mol / L.

[0011] The dosage of ferrous oxide dihydrate is 0.1 - 0.2 mol / L.

[0012] The KH 2 PO 4 The dosage is 0.1 - 0.5 mol / L.

[0013] The K 2 HPO 4 The dosage is 0.1 - 0.2 mol / L.

[0014] The dosage of aluminum hexafluorophosphate is 0.05 - 0.07 mol / L.

[0015] The dosage of SDS surfactant is 0.01 - 0.03 mol / L.

[0016] The pH = 4.2 - 4.8.

[0017] The electrolytic coloring solution treats the aluminum alloy and uses the coloring solution through the following steps.

[0018] (1) Pretreatment: including ultrasonic degreasing, alkali washing, chemical polishing and water washing.

[0019] (2) Anodic oxidation: The anodic oxidation solution includes 3 - 4 mol / L sulfuric acid, 0.05 - 0.1 mol / L ferric sulfate, 0.1 - 0.5 mol / L aluminum sulfate and deionized water, voltage 20 - 30 V, time 20 - 30 min, temperature 20 - 25 °C.

[0020] (3) Inorganic salt immersion: The immersion solution includes 0.5 - 0.7 mol / L sulfuric acid, 0.1 - 1 mol / L ferrous sulfate, 0.05 - 0.1 mol / L ferric sulfate, deionized water, immersion time 5 - 7 min, temperature 10 - 15 °C.

[0021] (4) Electrolytic coloring: The electrolytic coloring solution includes 1.2 - 1.4 mol / L sulfuric acid, 0.1 - 0.2 mol / L ferrous oxide dihydrate 0.1 - 0.5 mol / L KH 2 PO 4 、0.1 - 0.2 mol / L K 2 HPO 4 、0.05 - 0.07 mol / L aluminum hexafluorophosphate, 0.01 - 0.03 mol / L SDS, using NaHCO 3 to adjust the pH = 4.2 - 4.8, and perform electrolytic coloring.

[0022] (5) Sealing the holes: Sealing with water vapor.

[0023] The base material selected in this invention is aluminum alloy, and the pretreatment means include ultrasonic degreasing, alkali washing, chemical polishing and water washing.

[0024] (1) Ultrasonic degreasing In fact, most of the various quality problems that occur after the surface treatment of aluminum and its alloy products do not come from the treatment solution, materials and process conditions, but are caused by the grease and stains that are not thoroughly cleaned on the metal surface before various surface treatments. The adhesion force between the oil stain on the surface of the sample in this invention and the matrix surface is small, and it can be removed as long as a suitable method is adopted, and the cleaning difficulty is small. This invention uses ultrasonic degreasing, the degreasing solution is anhydrous ethanol, and the time is 10 min. This method has a fast degreasing speed and no corrosive effect on the metal. After ultrasonic degreasing, the sample is directly dried.

[0025] The main function of the alkali washing process is to remove the natural oxide film on the surface of metallic aluminum, exposing the fresh matrix structure of the sample to ensure the smooth progress of anodic oxidation. In addition, alkali washing can also remove the residual grease on the surface of the sample. In this invention, the alkali washing solution is 1 mol / L NaOH solution, and the sample is immersed in the alkali washing solution at room temperature for 3 min.

[0026] Chemical polishing: During processing, cutting, transportation and sample preparation, there will be scratches or grooves of different depths on the surface of the aluminum sheet, resulting in an uneven surface of the sample. Generally speaking, the uniformity of the film layer on a rough surface is inferior to that on a smooth surface, which will have an adverse effect on the corrosion resistance and wear resistance of the film layer. Therefore, polishing treatment should be carried out before anodic oxidation. So polishing treatment is required before anodic oxidation.

[0027] Water washing: The water washing after alkali washing and polishing is to prevent the solution in the former process from being carried into the solution in the latter process between two adjacent processes, thus affecting each other and destroying the treatment effect, so as to affect the microscopic morphology of the sample after anodic oxidation. The designed water washing process is that after taking out the sample, it is first rinsed clean in tap water, and then rinsed three times with distilled water. The distilled water cannot be reused repeatedly between each process and should be replaced in time. The alkali washing and polishing processes are very simple, but since the surface of high-purity aluminum after alkali washing is more likely to be oxidized in the air, it is necessary to strictly control the time for the sample to be transferred from the alkali washing solution to the polishing solution, and from the polishing solution to the anodic oxidation electrolyte. At the same time, the water washing must ensure that there is no residual liquid from the previous process on the surface of the sample.

[0028] Then, anodic oxidation is carried out on the surface-pretreated aluminum alloy. The anodic oxidation solution includes 3 - 4 mol / L sulfuric acid, 0.05 - 0.1 mol / L ferric sulfate, 0.1 - 0.5 mol / L aluminum sulfate, and deionized water. The voltage is 20 - 30 V, the time is 20 - 30 min, and the temperature is 20 - 25 °C. Reasoning of possibilities: Among them, sulfuric acid provides an acidic environment for anodic oxidation, promoting the progress of the anodic oxidation reaction. The presence of sulfuric acid can adjust the pH value of the solution to ensure that the reaction environment is suitable for the oxidation reaction on the aluminum material surface; Ferric sulfate (0.05 - 0.1 mol / L): Releases ferric ions onto the aluminum material surface, improves the activity and efficiency of the oxidation reaction, shortens the oxidation time, can promote the introduction and dispersion of aluminum sulfate, and improves the compactness of the oxide film. Aluminum sulfate is one of the key components of anodic oxidation. It reacts with aluminum to form a dense oxide film and at the same time provides the effect of a sacrificial anode. After anodic oxidation, aluminum will be oxidized to aluminum ions by the way of the sacrificial anode and embedded in the oxide film. The aluminum ions help to enhance the corrosion inhibition effect of the solution on the aluminum material. The color of the oxide film obtained through the above anodic oxidation is a light yellowish-green oxide film, and the pore size of the obtained aluminum oxide film is 30 - 50 nm.

[0029] (3) Inorganic salt immersion: The immersion solution includes 0.5 - 0.7 mol / L sulfuric acid, 0.1 - 1 mol / L ferrous sulfate, 0.05 - 0.1 mol / L ferric sulfate, and deionized water. The immersion time is 5 - 7 min, and the temperature is 10 - 15 °C.

[0030] Inorganic salt immersion provides a relatively ideal condition for subsequent electrolytic coloring by cleaning and adjusting the matrix environment. At the same time, by adjusting the composition and concentration of inorganic salts, the color characteristics of the anodic oxidation film can be controlled to present the desired color effect. For example, brine can increase the conductivity of the material, contribute to the subsequent electrolytic coloring process, or can ensure uniform coverage on the surface of the anodic oxidation layer and reduce the influence of impurities on the color. Specifically, the possible influencing reasoning is: In an acidic environment, sulfuric acid provides a suitable medium condition, which helps aluminum to combine with aluminum oxide to form bound aluminum. Bound aluminum is the basis of the golden-yellow film. The metal ions in ferrous sulfate and ferric sulfate may affect the formation rate or quality of bound aluminum; or by adjusting the pH value and ion concentration on the surface of the anodic oxidation film, the formation rate and quality of bound aluminum can be optimized, thereby affecting the color depth and uniformity of the film.

[0031] Electrolytic coloring: The electrolytic coloring solution includes 1.2 - 1.4 mol / L sulfuric acid, 0.1 - 0.2 mol / L ferrous oxide dihydrate, 0.1 - 0.5 mol / L KH 2 PO 4 、0.1 - 0.2 mol / L K 2 HPO 4, 0.05 - 0.07 mol / L aluminum hexafluorophosphate, 0.01 - 0.03 mol / L SDS, using NaHCO 3 Adjust the pH to 4.2 - 4.8 and perform electrolytic dyeing. Reasoning of possibilities: The main role of sulfuric acid is to provide an acidic environment. The role of iron(II) oxide dihydrate is to introduce Fe 2+ ions into the solution. Fe 2+ will be reduced to metallic iron by aluminum during electrolysis, forming a brown or yellowish-brown deposit layer. At the same time, Fe 2+ will combine with SO in sulfuric acid 4 2- to form ferrous sulfate (FeSO 4 ), further affecting the color. Potassium dihydrogen phosphate and phosphates mainly function to adjust the pH value of the solution. Aluminum hexafluorophosphate introduces PF 6 - anions into the solution to form a hexafluoride delocalized bond. PF 6 - has good dispersion performance and combines with Al 3+ to form an aluminum hexafluorophosphate complex ([Al(PF6) 3 - ), which will affect the final dyeing effect. Aluminum hexafluorophosphate also inhibits the precipitation of other metal ions (such as Fe 2+ ) in the solution, reducing the impact on the color. The main role of SDS is to act as an emulsifier and surfactant to prevent the deposits generated during electrolysis from coking, and it also helps to maintain the viscosity and stability of the electrolyte, reducing the impact on the electrode reaction. Using NaHCO 3 Adjust the pH to 4.2 - 4.8. Sodium bicarbonate helps to maintain the pH value of the solution between 4.2 and 4.8. This pH range is crucial for the electrochemical reaction of aluminum, neither making the system too alkaline to cause passivation nor too acidic to affect the dissolution of aluminum.

[0032] In some embodiments, the electrolytic dyeing includes three times of electrolytic dyeing: The first electrolytic dyeing: voltage 12 - 14 V, temperature 60 - 65 °C, time 12 - 14 min; The second electrolytic dyeing: voltage 10 - 12 V, temperature 55 - 60 °C, time 10 - 12 min; The third electrolytic dyeing: voltage 8 - 10 V, temperature 50 - 55 °C, time 8 - 10 min.

[0033] The voltage used in the electrolytic dyeing is a three-stage voltage. The three-stage stepped-down voltage may avoid the following problems: ​(1)Local overoxidation: High voltage may cause excessive local oxidation, resulting in black or gray areas; (2) Membrane non-uniformity: Higher voltage may cause uneven membrane growth, affecting the final effect; (3) Color stability: Slowly reducing the voltage allows the oxidation reaction to be completed step by step, reducing color differences caused by rapid oxidation. The stepped control of voltage helps the oxidation reaction to proceed within a controllable range, ensuring the density and uniformity of the oxide film.

[0034] After dyeing, sealing is required. The methods of sealing are not limited to hot water sealing treatment, steam sealing treatment or metal salt sealing treatment, which are not the focus of this invention and will not be elaborated here.

[0035] Beneficial technical effects: The present invention provides an electrolytic coloring solution composition for aluminum alloy, which includes sulfuric acid, ferrous oxide dihydrate KH 2 PO 4 、K 2 HPO 4 、aluminum hexafluorophosphate, SDS surfactant and NaHCO 3 pH regulator. By means of the processes of pretreatment - anodic oxidation - inorganic salt immersion and electrolytic coloring - sealing, a light green and golden alumina film with particularly stable color is prepared, which has good corrosion resistance and excellent protective performance. Generally speaking, the color of the oxide film is bright, uniform, with small color difference, good corrosion resistance and weather resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] APPENDIX Figure 1 Coloring diagrams of Examples 1 - 3 and Example 4 of the present invention.

[0037] APPENDIX Figure 2 Physical effect diagram of the aluminum alloy of Example 1 of the present invention (with frosting).

[0038] APPENDIX Figure 3 Physical effect diagram of the aluminum alloy of Example 3 of the present invention (with frosting). DETAILED DESCRIPTION OF THE INVENTION Example 1

[0039] An electrolytic coloring solution composition for aluminum alloy, which is used for electrolytic coloring of aluminum alloy and processes the aluminum alloy through the following steps: (1)Pretreatment: including ultrasonic degreasing, alkali washing, chemical polishing and water washing.

[0040] (2)Anodic oxidation: The anodic oxidation solution includes 3 mol / L sulfuric acid, 0.05 mol / L ferric sulfate, 0.1 mol / L aluminum sulfate and deionized water, with a voltage of 20 V, a time of 20 min, and a temperature of 20 - 25 °C.

[0041] (3) Inorganic salt immersion: The immersion solution includes 0.5 mol / L sulfuric acid, 0.1 mol / L ferrous sulfate, 0.05 mol / L ferric sulfate, and deionized water. The immersion time is 5 min, and the temperature is 10°C.

[0042] (4) Electrolytic coloring: The electrolytic coloring solution includes 1.2 mol / L sulfuric acid, 0.1 mol / L ferrous oxide dihydrate, 0.1 mol / L KH 2 PO 4 , 0.1 mol / L K 2 HPO 4 , 0.05 mol / L aluminum hexafluorophosphate, 0.01 mol / L SDS, using NaHCO 3 to adjust the pH to 4.2, and electrolytic coloring is carried out. The electrolytic coloring includes three times of electrolytic coloring. The first electrolytic coloring: voltage 12 V, temperature 60°C, time 12 min; the second electrolytic coloring: voltage 10 V, temperature 55°C, time 10 min; the third electrolytic coloring: voltage 8 V, temperature 50°C, time 8 min.

[0043] (5) Sealing: Steam sealing. Example 2

[0044] An electrolytic coloring solution composition for aluminum alloy, which is used for electrolytic coloring of aluminum alloy and processes the aluminum alloy through the following steps: (1) Pretreatment: It includes ultrasonic degreasing, alkali washing, chemical polishing, and water washing.

[0045] (2) Anodic oxidation: The anodic oxidation solution includes 3.5 mol / L sulfuric acid, 0.075 mol / L ferric sulfate, 0.075 mol / L aluminum sulfate, and deionized water. The voltage is 25 V, the time is 25 min, and the temperature is 22.5°C.

[0046] (3) Inorganic salt immersion: The immersion solution includes 0.6 mol / L sulfuric acid, 0.4 mol / L ferrous sulfate, 0.07 mol / L ferric sulfate, and deionized water. The immersion time is 6 min, and the temperature is 12.5°C.

[0047] (4) Electrolytic coloring: The electrolytic coloring solution includes 1.3 mol / L sulfuric acid, 0.15 mol / L ferrous oxide dihydrate, 0.3 mol / L KH 2 PO 4 , 0.15 mol / L K 2 HPO 4 , 0.06 mol / L aluminum hexafluorophosphate, 0.02 mol / L SDS, using NaHCO 3Adjust the pH to 4.5 and perform electrolytic coloring. The electrolytic coloring includes three times of electrolytic coloring. The first electrolytic coloring: voltage 13 V, temperature 62.5 °C, time 13 min; the second electrolytic coloring: voltage 11 V, temperature 57.5 °C, time 11 min; the third electrolytic coloring: voltage 9 V, temperature 52.5 °C, time 9 min.

[0048] (5)Sealing: Sealing with steam. Example 3

[0049] An electrolytic coloring solution composition for aluminum alloy, the composition is used for electrolytic coloring of aluminum alloy, and the aluminum alloy is treated by the following steps: (1)Pretreatment: including ultrasonic degreasing, alkali washing, chemical polishing and water washing.

[0050] (2)Anodic oxidation: The anodic oxidation solution includes 4 mol / L sulfuric acid, 0.1 mol / L ferric sulfate, 0.5 mol / L aluminum sulfate and deionized water, voltage 30 V, time 30 min, temperature 25 °C.

[0051] (3)Inorganic salt immersion: The immersion solution includes 0.7 mol / L sulfuric acid, 0.8 mol / L ferrous sulfate, 0.09 mol / L ferric sulfate, deionized water, immersion time 7 min, temperature 15 °C.

[0052] (4)Electrolytic coloring: The electrolytic coloring solution includes 1.4 mol / L sulfuric acid, 0.2 mol / L ferrous oxide dihydrate 0.5 mol / L KH 2 PO 4 、0.2 mol / L K 2 HPO 4 、0.07 mol / L aluminum hexafluorophosphate, 0.03 mol / L SDS, use NaHCO 3 Adjust the pH to 4.8 and perform electrolytic coloring. The electrolytic coloring includes three times of electrolytic coloring. The first electrolytic coloring: voltage 14 V, temperature 65 °C, time 14 min; the second electrolytic coloring: voltage 12 V, temperature 60 °C, time 12 min; the third electrolytic coloring: voltage 10 V, temperature 55 °C, time 10 min.

[0053] (5)Sealing: Sealing with steam. Example 4

[0054] An electrolytic coloring solution composition for aluminum alloy, the composition is used for electrolytic coloring of aluminum alloy, and the aluminum alloy is treated by the following steps: (1)Pretreatment: including ultrasonic degreasing, alkali washing, chemical polishing and water washing.

[0055] (2) Anodization: The anodizing solution includes 3.5 mol / L sulfuric acid, 0.075 mol / L ferric sulfate, 0.075 mol / L aluminum sulfate and deionized water. The voltage is 25 V, the time is 25 min, and the temperature is 22.5 °C.

[0056] (3) Electrolytic dyeing: The electrolytic dyeing solution includes 1.3 mol / L sulfuric acid, 0.15 mol / L ferrous oxide dihydrate, 0.3 mol / L KH 2 PO 4 , 0.15 mol / L K 2 HPO 4 , 0.06 mol / L aluminum hexafluorophosphate, 0.02 mol / L SDS, using NaHCO 3 to adjust the pH = 4.5, and electrolytic dyeing is carried out. The electrolytic dyeing includes three times of electrolytic dyeing. The first electrolytic dyeing: voltage 13 V, temperature 62.5 °C, time 13 min; the second electrolytic dyeing: voltage 11 V, temperature 57.5 °C, time 11 min; the third electrolytic dyeing: voltage 9 V, temperature 52.5 °C, time 9 min.

[0057] (4) Sealing: Steam sealing.

[0058] Characterize the dyeing effects of Examples 1 - 3 and Example 4.

[0059] According to the existing knowledge, or classified in CN114544514B, for color defect points, when 1.0 ≤ ΔE < 2.0, the severity of the color defect is considered medium; when 2.0 ≤ ΔE < 4.0, the severity of the color defect is considered relatively large, and there are obvious differences visible to the naked eye; when ΔE ≥ 4.0, the severity of the color defect is very large, and the color difference is very significant; for comparative analysis points, when ΔE < 0.25, it is considered that there is no color difference from the test standard sample point; when 0.25 ≤ ΔE < 0.5, it is considered that the color difference from the test standard sample point is very small; when 0.5 ≤ ΔE < 1.0, it is considered that the color difference from the test standard sample point is small to medium. And for the Lab value, L represents brightness. When it is necessary to change the color brightness, only adjust L. The L value increases to become brighter, and the L value decreases to become darker; a and b represent color components. Changing the values of a and b can change the color tone and color saturation.

[0060]

[0061] As can be seen from the above content, see Appendix Figure 1 , Appendix Figure 2 and Appendix Figure 3 , the color of the oxide film prepared in the embodiment of the present invention is yellowish green, with more yellow, and the corresponding color difference is small, the color is bright and uniform, and the color difference is small. See Appendix Figure 1The fourth embodiment has an obvious color difference and is overall dark greenish-black.

[0062] As described above, these are only the preferred embodiments of the present invention and do not impose any formal restrictions on the present invention. Therefore, any simple modifications, equivalent changes, and decorations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An aluminum alloy electrolytic dyeing liquid composition, characterized in that The electrolytic staining solution includes sulfuric acid, ferrous oxide dihydrate KH2PO4, K2HPO4, aluminum hexafluorophosphate, SDS surfactant and NaHCO3 pH regulator. The electrolytic staining parameters include three electrolytic stainings. The first electrolytic staining: voltage 12-14 V, temperature 60-65°C, time 12-14 min; the second electrolytic staining: voltage 10-12 V, temperature 55-60°C, time 10-12 min; the third electrolytic staining: voltage 8-10 V, temperature 50-55°C, time 8-10 min.

2. The aluminum alloy electrolytic dyeing liquid composition according to claim 1, characterized in that The amount of sulfuric acid used is 1.2-1.4 mol / L.

3. The aluminum alloy electrolytic dyeing liquid composition according to claim 1, characterized in that The dosage of ferrous oxide dihydrate is 0.1-0.2 mol / L.

4. The aluminum alloy electrolytic dyeing liquid composition according to claim 1, characterized in that The KH2PO4 dosage is 0.1-0.5 mol / L.

5. The aluminum alloy electrolytic dyeing liquid composition according to claim 1, characterized in that The dosage of K2HPO4 is 0.1-0.2 mol / L.

6. The aluminum alloy electrolytic dyeing liquid composition according to claim 1, characterized in that The dosage of aluminum hexafluorophosphate is 0.05-0.07 mol / L.

7. The aluminum alloy electrolytic dyeing liquid composition according to claim 1, characterized in that The dosage of the SDS surfactant is 0.01-0.03 mol / L.

8. The aluminum alloy electrolytic dyeing liquid composition according to claim 1, characterized in that The pH=4.2-4.8.

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