Additive for surface chromate-free passivation treating fluid of aluminum and aluminum alloy, and application method of additive

Abstract

The invention belongs to the technical field of metal surface treatment, and particularly relates to an additive for surface chromate-free passivation treating fluid of aluminum and aluminum alloy, and an application method of the additive. The additive comprises the components as follows: a coupling agent, an active agent, a stabilizer and a wetting agent, wherein methyltriethoxy silane serves as the coupling agent for enhancing the rigidness of a net-structured membrane formed through an zirconic acid; alkyl sulfate serves as the active agent for enabling the converted membrane to be uniform in thickness and smooth; sodium benzoate serves as the stabilizer for prolonging the service life of groove fluid; polyethylene glycol serves as the wetting agent for forming a hydrophilic group on the surface of aluminum material, reducing the surface tension, and enabling the net-structured membrane to be more flexible and compacter. The additive can stabilize a passivation solution, is free from the influence from harsh surrounding conditions, is convenient for the chromate-free passivation fluid to form nano-level zirconium compound particles, can change the density of a latticed membrane layer, achieves the automatic repairing function of a cutting end opening, and facilitates the stabilization of the network structure of a coating.

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 chromium-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 ...

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