Oxalic acid anodic oxidation process method for hard aluminum alloy shell part

Abstract

Provided is an oxalic acid anodic oxidation process method for the hard aluminum alloy shell part, a step boosting method is introduced to adjust and match the oxidation voltage, the oxidation time, the boosting speed and the frequency of an electrolytic cell; the three technical indexes of the appearance, the film thickness and the insulation resistance of an oxalic acid anodic oxidation film layer formed on the surface of a shell part meet the standard acceptance requirements, the percent of pass is high, the problem that the percent of pass of oxalic acid anodic oxidation of a duralumin material shell is low is thoroughly solved, the part scrapping problem caused by film ablation and black spots is greatly reduced, the insulation resistance consistency of different parts of the shell part is ensured, and the quality of an oxalic acid anodic oxidation film layer of the shell part is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of surface treatment and specifically designs an oxalic acid anodic oxidation process method for hard aluminum alloy shell parts. Background technique [0002] Aluminum and aluminum alloy oxalic acid anodic oxidation process is to place aluminum alloy parts on the anode of oxalic acid electrolyte, apply a certain current and voltage, and form an aluminum oxide film within a certain period of time, called oxalic acid Anodization: The applicable parts materials for oxalic acid anodization are mainly aluminum-magnesium anti-rust aluminum alloys (5A02, 5A05) and pure aluminum (1060, 1035), etc. Generally, it is not suitable to use the second series of aluminum-copper hard aluminum alloys (2A12, 2A11) , due to the high content of copper in the hard aluminum alloy material, there are the following problems in the electrochemical reaction process of oxalic acid anodization: ①The surface of the part is prone to blac...

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Problems solved by technology

[0002] The oxalic acid anodizing process of aluminum and aluminum alloys is to place aluminum alloy parts on the anode of oxalic acid electrolyte, apply a certain current and voltage, and within a certain period of time A kind of aluminum oxide film formed is called oxalic acid anodization; the parts materials suitable for oxalic acid anodization are mainly aluminum-magnesium antirust aluminum alloys (5A02, 5A05) and pure aluminum (1060, 1035), etc., generally It is not suitable to use the second series of aluminum-copper series hard aluminum alloys (2A12, 2A11). Because the hard aluminum alloy materials contain high copper elements, the following problems exist during the electrochemical reaction process of oxalic acid anodization: ①The surface of the parts is prone to black spots, Film layer ablation problem: According to the oxalic acid anodizing process of pure aluminum and anti-rust aluminum alloy, the oxidation terminal voltage needs to reach 110V ~ 120V, and the shell parts are hard aluminum alloys, which contain a large amount of copper elements. Dissolution and precipitation, the precipitation part has no film layer locally, resulting in the appearance of small and dense black spots, and as the oxidation continues, the black spot part has no film layer, and the insulation resistance decreases. Under the action of continuously rising voltage, the oxidation The film cannot withstand the passage of a large current, resulting in ablation of the film layer; ②The thickness and insulation resistance of the oxide film do not meet the technical requirements: the hard aluminum alloy is oxidized with oxalic acid, due to the slow film forming speed and the precipitation of copper ions The film layer is discontinuous, and the thickness of the film layer can only reach 10μm. When testing the insulation resistance of the film layer, it is less than 200MΩ under the condition of 500V. At the same time, there is a problem of poor insulation resistance stability in different parts of the shell parts; the above defects will seriously affect the military industry. The reliability of the product fiber optic gyroscope, therefore, in order to improve the pass rate and reliability of the product, it is necessary to improve

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