A method for preparing zirconium/selenium composite conversion film on the surface of aluminum alloy

Abstract

The invention provides a method for preparing a zirconium-selenium composite conversion film on the surface of aluminum alloy. The method is mainly characterized by comprising the steps of preparing film formation liquid, wherein each liter of film formation liquid is composed of 0.1-5 g of zirconate, 0.1-10 g of selenium type oxide or selenate, 0.1-15 g of organic acid, 0.1-10 g of auxiliary oxidizing agents, 0.1-15 g of film formation accelerants and the balance deionized water; carrying out degreasing treatment and activating treatment on the pre-ground aluminum alloy, placing the aluminum alloy into the film formation liquid with the temperature ranging from 10 DEG C to 60 DEG C for conversion treatment for 5-30 minutes, then taking out the aluminum alloy, washing the aluminum alloy through distilled water, air-drying the aluminum alloy and finally obtaining the zirconium-selenium colorful composite conversion film on the surface of aluminum alloy. The method has the advantages that the operation is simple, the cost is low, the composite conversion film high in uniformity and excellent in compactness can be formed, the corrosion resistance of the aluminum alloy is improved, the environmental friendliness is high, and production is easy.

Description

technical field [0001] The invention relates to a metal surface treatment method, in particular to a method for preparing a conversion film on the surface of an aluminum alloy. Background technique [0002] Aluminum and aluminum alloys are more and more widely used in various fields of the national economy, especially higher requirements for surface decoration and corrosion resistance. The oxide film of aluminum has a protective effect on the aluminum substrate, but the protective effect of the natural oxide of aluminum is very limited, the humidity and salt in the atmosphere will obviously accelerate the corrosion, and because the linear expansion coefficient of aluminum and its alloys is large, the metal activity Generally, the surface is treated by oxidation method. Chemical oxidation treatment is one of the surface oxidation treatment technologies for aluminum alloys. Currently, the chromate chemical oxidation process, which is widely used, has serious problems such as ...

AI Technical Summary

Problems solved by technology

The main problems at present are: the stability of sol; the compounding of sol components; the coating method, coating equipment and process of sol-gel need to be improved

However, its corrosion resistance is still lower than that of chromate film, and it is almost colorless and difficult to distinguish, which brings certain difficulties to industrial operations.

[0006] These existing aluminum and aluminum alloy chromium-free passivation methods always have some deficiencies, for example: the corrosion resistance cannot meet the needs of actual production and life, the passivation effect is not good, and the cost of passivation solution is high, which is not conducive to large-scale production production etc.

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