Aluminum alloy two-step anodizing process

A secondary anodic oxidation, anodic oxidation technology, applied in the direction of electrolytic coating, surface reaction electrolytic coating, coating, etc., can solve the problems of reducing the anti-corrosion performance of anodized film, reducing the anti-corrosion performance of aluminum alloy, local current concentration, etc. , to achieve the effect of low production cost, simple and easy operation, and protection of aluminum alloy

Inactive Publication Date: 2017-10-13
NANJING UNIV OF POSTS & TELECOMM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For the 2xxx series and 7xxx series aviation aluminum alloys with high copper content in the aluminum alloy, the high content of copper will reduce the corrosion resistance of the aluminum alloy, because the electrochemical behavior of more copper alloy phase particles in the alloy and the aluminum alloy matrix The difference is relatively large, which is likely to cause local current concentration during the anodic oxidation process, forming local hole defects in the film layer, thereby reducing the corrosion resistance of the anodized film

Method used

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  • Aluminum alloy two-step anodizing process
  • Aluminum alloy two-step anodizing process
  • Aluminum alloy two-step anodizing process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] (1) Surface pretreatment of aluminum alloy styles

[0024] Grinding and cleaning: Use water sandpaper to grind from 400# to 1200# in sequence, then use ultrasonic cleaning in ethanol solution for 5 minutes, take it out, rinse it with distilled water, and dry it with cold air;

[0025] Chemical degreasing: degreasing solution: sodium hydroxide: 10g / L, coconut oil diethanolamine: 2g / L, nonylphenol polyoxyethylene ether: 0.5g / L. Use a magnetic stirrer in the degreasing solution, the speed is 60r / min, the reaction time is 2min, take it out, wash it with distilled water, and dry it with cold air;

[0026] Pickling light: pickling solution: nitric acid: 5g / L, sodium nitrate: 10g / L, sodium phytic acid: 3g / L. Use a magnetic stirrer in the pickling solution with a rotating speed of 60r / min and a reaction time of 2min, take it out, rinse it with distilled water, and dry it with cold air.

[0027] (2) The first anodizing

[0028] Use a mixed solution of 30g / L oxalic acid and 20...

Embodiment 2

[0036] (1) Surface pretreatment of aluminum alloy styles

[0037] Grinding and cleaning: Use water sandpaper to grind from 400# to 1200# in sequence, then use ultrasonic cleaning in ethanol solution for 8 minutes, take it out, rinse it with distilled water, and dry it with cold air;

[0038] Chemical degreasing: degreasing solution: sodium hydroxide: 15g / L, coconut oil diethanolamine: 4g / L, nonylphenol polyoxyethylene ether: 2g / L. Use a magnetic stirrer in the degreasing solution, the speed is 60r / min, the reaction time is 2min, take it out, wash it with distilled water, and dry it with cold air;

[0039] Pickling light: pickling solution: nitric acid: 10g / L, sodium nitrate: 7g / L, sodium phytic acid: 1g / L. Use a magnetic stirrer in the pickling solution with a rotating speed of 60r / min and a reaction time of 2min, take it out, rinse it with distilled water, and dry it with cold air.

[0040] (2) The first anodizing

[0041] Use a mixed solution of 40g / L oxalic acid and 15g / ...

Embodiment 3

[0049] (1) Surface pretreatment of aluminum alloy styles

[0050] Grinding and cleaning: Use water sandpaper to grind from 400# to 1200# in sequence, then use ultrasonic cleaning in ethanol solution for 10 minutes, take it out, rinse it with distilled water, and dry it with cold air;

[0051]Chemical degreasing: degreasing solution: sodium hydroxide: 20g / L, coconut oil diethanolamine: 8g / L, nonylphenol polyoxyethylene ether: 5g / L. Use a magnetic stirrer in the degreasing solution, the speed is 60r / min, the reaction time is 2min, take it out, wash it with distilled water, and dry it with cold air;

[0052] Pickling: pickling solution: nitric acid: 20g / L, sodium nitrate: 5g / L, sodium phytic acid: 0.1g / L. Use a magnetic stirrer in the pickling solution with a rotating speed of 60r / min and a reaction time of 2min, take it out, rinse it with distilled water, and dry it with cold air.

[0053] (2) The first anodizing

[0054] Use a mixed solution of 50g / L oxalic acid and 10g / L ci...

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PUM

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Abstract

The invention discloses a secondary anodic oxidation process for aluminum alloys. Surface pretreatment is carried out first: the polished aluminum alloy samples are ultrasonically cleaned in an ethanol solution for 5-10 minutes; Sodium oxide 10-20g / L, coconut oil diethanolamine 2-8g / L, nonylphenol polyoxyethylene ether 0.5-5g / L in 2min for degreasing treatment; after rinsing and drying, put the sample into the solution: nitric acid 5-20g / L, sodium nitrate 5-10g / L, phytic acid sodium salt 0.1-3g / L for 1min for light treatment. Carry out the secondary anodizing process, the process parameters of the first anodizing are: the anodizing temperature is 10-25°C, the anodizing voltage is 30-60V, and the anodizing time is 60-150min; the process parameters of the second anodizing The process parameters are the same as the first anodizing. Finally, the sealing treatment is carried out. The composition of the sealing solution is: nickel acetate 0.5-1g / L and boric acid 0.5-1g / L, and the time is 20-40min to obtain a dense anodic oxide film. The invention has the advantages of environmental friendliness, simplicity, and high corrosion resistance of the formed oxide film.

Description

technical field [0001] The invention belongs to the technical field of aluminum alloy processing technology, and in particular relates to a secondary anodic oxidation process of aluminum alloy. Background technique [0002] Aluminum alloy has the advantages of light weight, high structural strength, good plasticity, and excellent electrical conductivity. It is currently widely used in high-tech fields such as building materials, automobiles, mobile phones, and aviation and aerospace. However, due to the poor corrosion resistance of the naturally formed oxide film on the surface of the aluminum alloy in the harsh environment where the corrosive medium exists, it is prone to corrosion and other shortcomings. In order to overcome the shortcomings of the aluminum alloy surface performance, expand its scope of application, and prolong its service life, so In the field of actual production, aluminum alloys always undergo a series of treatments to improve corrosion resistance. In ...

Claims

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Application Information

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IPC IPC(8): C25D11/12C25D11/10C25D11/16C25D11/24
CPCC25D11/12C25D11/10C25D11/16C25D11/24
Inventor 冒佳卫谢欢悦岳森何健程杰刘胜利
Owner NANJING UNIV OF POSTS & TELECOMM
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