Chromizing-free anodic oxidation treatment method of surface of aviation 2 department and 7 department aluminium alloy

A technology of aluminum alloy surface and anodic oxidation, applied in the direction of anodic oxidation, can solve problems such as reduction, and achieve the effects of reducing corrosion, improving film formation rate, and improving corrosion resistance.

Active Publication Date: 2010-01-13
BEIHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Aiming at the huge threat of chromic acid anodizing process to the environment and the adverse effect of sulfuric acid anodizing on fatigue performance, the purpose of the present invention is to propose a chromium-free solution with environmental protection, low cost and stable process for aviation 2 series, An anodic oxidation treatment method for 7-series aluminum alloys, the invention reduces the concentration of sulfuric acid in the traditional sulfuric acid anodization process, and improves the compactness and uniformity of the oxide film by adding adipic acid or adipic acid salt, and the film thickness is small (10mg / dm 2 ~75mg / dm 2 ) to obtain good corrosion resistance and coating bonding performance

Method used

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  • Chromizing-free anodic oxidation treatment method of surface of aviation 2 department and 7 department aluminium alloy
  • Chromizing-free anodic oxidation treatment method of surface of aviation 2 department and 7 department aluminium alloy
  • Chromizing-free anodic oxidation treatment method of surface of aviation 2 department and 7 department aluminium alloy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] 1. The test material is 2024-clad aluminum plate, the heat treatment system is T3 (2024-T3), and the size is 100mm×50mm×2.5mm;

[0042] 2. Add 2.5ml of 98% H to 100ml of deionized water in the anodizing bath 2 SO 4 And the adipic acid (fatty acid) modifier of 10g;

[0043] Three, the specific steps are

[0044]Alkaline washing step: immerse in NaOH aqueous solution at 50°C for 2 minutes to take it out, and rinse the surface of the sample with water; NaOH aqueous solution is 100ml of tap water with 5g of NaOH added;

[0045] Light-emitting step: put the sample treated by the alkali washing step into the three-acid light-emitting solution at 20°C for 2 minutes, take it out, and rinse the surface of the sample with deionized water; add 5g of CrO to 100ml of the three-acid light-emitting solution 3 , 8ml of HNO 3 , 1 ml of HF. HNO 3 The mass percent concentration is 65%. The mass percent concentration of HF is 40%.

[0046] Anodizing step: Put the sample treated in ...

Embodiment 2

[0058] 1. The test material is brand 2024 bare aluminum plate, the heat treatment system is T3 (2024-T3), and the size is 100mm×50mm×2mm;

[0059] 2. The anodizing bath solution is 100ml of deionized water, adding 5ml of H with a mass percentage concentration of 98%. 2 SO 4 And the ammonium adipate modifier of 10g;

[0060] Three, the specific steps are

[0061] Alkali washing step: immerse in NaOH aqueous solution at a temperature of 60°C for 1min to take it out, and rinse the surface of the sample with water; NaOH aqueous solution is 100ml of tap water with 6g of NaOH added;

[0062] Light-emitting step: put the sample treated by the alkali washing step into the tri-acid light-emitting solution at 25°C for 1 min, take it out, and rinse the surface of the sample with deionized water; add 6g of CrO to 100ml of the three-acid light-emitting solution 3 , 6ml of HNO 3 , 0.8ml of HF. HNO 3 The mass percent concentration is 65%. The mass percent concentration of HF is 40%. ...

Embodiment 3

[0093] 1. The test material is 7050 bare aluminum plate, the heat treatment system is T7451 (7050-T7451), and the size is 100mm×50mm×3mm;

[0094] 2. The anodizing bath solution is 100ml of deionized water, adding 3.5ml of H with a mass percentage concentration of 98%. 2 SO 4 And modifying agent, modifying agent is the mixture of adipic acid and adipate, the adipic acid of 5g and the ammonium adipate of 5g are added in the mixture of 10g.

[0095] Three, the specific steps are

[0096] Alkali washing step: immerse in NaOH aqueous solution at a temperature of 55°C for 1.5min to take it out, and rinse the surface of the sample with water; the NaOH aqueous solution is 100ml of tap water with 5.5g of NaOH added;

[0097] Light-emitting step: put the sample treated by the alkali washing step into the three-acid light-emitting solution at a temperature of 15°C for 3 minutes, take it out, and rinse the surface of the sample with deionized water; add 4g of CrO 3 , 7ml of HNO 3 , ...

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Abstract

The invention discloses a chromizing-free anodic oxidation treatment method of the surfaces of an aviation 2 series and 7 series aluminium alloys, which is an improvement of a surface anodic oxidation treatment method of a sample in a standard aluminium and an aluminium alloy sulfuric acid anodic oxidation technology (HB/Z 233-93) of the PRC aviation industry, a processing solution contains no chromium in an anodic oxidation step, and an anodic oxidation solution comprises sulfuric acid and a modifier. The film weight of a prepared anodic oxidation film is within a range from 10 mg/dm <2> to 75 mg/dm <2> through the matching of anodic oxidation technology conditions, and in addition, the invention meets the corrosion resistance of a film layer and the combination property of the anodic oxidation film and an organic coating and also prolongs the fatigue life of workpieces manufactured by the aviation 2 series and 7 series aluminium alloys.

Description

technical field [0001] The invention relates to an anodic oxidation preparation process, in particular to a chromium-free anodic oxidation treatment method for the surface of aviation 2-series and 7-series aluminum alloys. The aviation 2-series and 7-series aluminum alloys can be grades 2024, 2124, 7050, 7075 and 7475, etc. Background technique [0002] Aluminum and aluminum alloys are one of the most commonly used metals in today's industry. They are stable in dry atmospheres, but are easily corroded in humid atmospheres, especially salty air. In addition, decorative or protective organic When the coating is directly coated on the surface of aluminum and aluminum alloy, the bonding performance of the film layer is poor. Therefore, aluminum and aluminum alloy components are usually anodized in an acidic solution to prepare a porous oxide film on the surface to increase the bonding performance of the external coating. After the oxide film is sealed, it can also greatly impr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D11/06
Inventor 刘建华李明盛华李松梅陈高红于美
Owner BEIHANG UNIV
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