Additive for chromium-free passivation treatment solution on aluminum and its alloy surface and its application method

Abstract

The invention belongs to the technical field of metal surface treatment, in particular to an additive for a chromium-free passivation treatment solution on the surface of aluminum and its alloys and a method for using the same. The composition of additives includes: coupling agent: methyltriethoxysilane, which can increase the hardness of the network structure film formed by fluorozirconic acid; active agent: alkyl sulfate, which can improve the uniform thickness and smoothness of the converted film; stabilizer : Sodium benzoate, which can prolong the service life of the bath solution; Wetting agent: Polyethylene glycol, which can form hydrophilic groups on the surface of aluminum materials, reduce surface tension, and make the film of network structure more flexible and Dense. The additive can stabilize the passivation solution without being affected by harsh external conditions, facilitate the formation of nano-scale zirconium compound particles in the chromium-free passivation solution, change the density of the grid-like film layer, and increase the automatic repair function of the cutting port. Conducive to the stability of the coating network structure.

Description

technical field [0001] The invention belongs to the technical field of metal surface treatment, and in particular relates to an additive for a chromium-free passivation treatment solution on the surface of aluminum and its alloys and a method for using the same. Background technique [0002] Aluminum and its alloys must undergo surface treatment before painting, and the process steps are: (1) Degreasing; (2) Washing; (3) Lighting; (4) Deionized water washing; (5) Treatment with chrome-free passivation solution; (6) dry. [0003] A colorless corrosion-resistant passivation layer is formed on the aluminum surface by spraying or soaking, but the process requirements are quite strict, such as water temperature, water quality, time, the strength of the airflow stirred with air bubbles, etc., will form on the aluminum surface. The quality of the passivation film is affected, and the passivation film is colorless and cannot be judged by the naked eye, which brings inconvenience to...

AI Technical Summary

Problems solved by technology

But the cut end surface layer of this kind of film has no automatic repair function, the cut end is easy to corrode, so the paint on the end surface is easy to fall off and burst

Therefore, manufacturers with a daily processing capacity of more than 500 square meters generally have high operating costs and difficult control of the conversion film quality, especially the conversion film cutting port does not have an automatic repair function, which ultimately affects the quality of finished products after coating