Method for compounding nano ceramic silane composite film before spraying aluminum product

Abstract

The invention discloses a method for compounding a nano ceramic silane composite film before spraying an aluminum product. The composite film uses a sol-gel technology, is treated by a nano SiO2 silane treatment fluid and dewatered to form a three-dimensional network structure on the basis of an Si-O-Si bond, and is compounded with the surface of the aluminum product on the basis of an Si-O-Al covalent bond. Since the nano ceramic silane composite film is subjected to chromium-free treatment, the invention solves the problem of chromium pollution in aluminum product industry. No substance affecting the film formation is generated in the surface treatment process and attached to the surface of the aluminum product, so the aluminum product does not need to be washed with water before spraying. The added nano filler is dispersed in the network-structure film layer, and can form a bridge bond on the surface of the aluminum product after being compounded with hydrolyzed silane, so that the film is tightly combined with the aluminum product without any crack; and the film is compounded with the aluminum product in a combination mode of chemical covalent bond, thereby obviously increasing the adhesive force of the coating.

Description

technical field [0001] The invention relates to the technical field of aluminum material surface treatment, in particular to an aluminum material compounded with a composite film before the aluminum material is sprayed. Background technique [0002] At present, aluminum materials are generally treated with chromate to form a chromized layer before spraying, and the chromated waste contains a large amount of harmful components such as hexavalent chromium ions. Because of these hexavalent chromium and its loss and diffusion, it constitutes a pollution hazard to the ecological environment. The second is the strong alkali hazard of chromium slag. When chromium slag is piled up in the open air, a large amount of hexavalent chromium ions will be dissolved, lost, and infiltrated into the ground surface after long-term rainwater washing, thereby polluting groundwater, rivers, and lakes, and endangering farmland, aquatic products, and human health. Hexavalent chromium ions are very...

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Problems solved by technology

[0003] Because the traditional chromizing bath process contains fluoride ions, aluminum fluoride will be produced on the surface of the aluminum workpiece during the processing of the aluminum material. Aluminum fluoride is insoluble in water. If it is not washed with water, it will seriously affect the aluminum fluoride. The adhesion of the material after spraying, the coating even falls off, so the aluminum material must be washed with water before spraying

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