Zinc phosphating solution of aluminium and aluminium alloy

Abstract

The invention belongs to the field of metal surface treatment, relating to a zinc phosphating solution of aluminium and aluminium alloy. The invention is mainly used for zinc phosphating treatment of the aluminium and aluminium alloy in the industries of home appliances, automobiles, hardware, building materials and railway locomotives. The zinc phosphating solution is composed of 8-25g / l of PO4<-3>, 6-16g / l of NO3<-1>, 1.6-8.0g / l of Zn<+2>, 0.12-0.38g / l of F<-1>, 0.6-8.0g / l of Fe<+2>, 0.01-1.5g / l of Ni<+2>, 0.0002-0.0006g / l of accelerating agent, 0.001-1.2g / l of organic complexing agent and the balance of water. When the phosphating solution of the invention is used for processing the aluminium and aluminium alloy, the obtained phosphating film has favourable matching capability with the coating, and the griding test of the paint film can reach 0 grade. The phosphating solution of the invention does not use toxic chromium, and the phosphating film does not contain chromium so as to solve the problems of environment pollution and toxic hazard on the human body when the chromium is used for processing the aluminium and aluminium alloy, and lower treatment cost.

Description

technical field

[0001] The invention relates to the field of metal surface treatment, in particular to a zinc-based phosphating solution for aluminum and aluminum alloys, which is mainly used for zinc-based phosphorus before coating of aluminum and aluminum alloys in the industries of household appliances, automobiles, hardware, building materials and railway locomotives treatment. Background technique

[0002] Aluminum and aluminum alloys are widely used because of their unique properties, but their chemical properties are extremely active, unstable, and easy to be corroded. They need good surface treatment to improve and improve their surface properties, improve corrosion resistance, and enhance coating. Layer adhesion, thereby expanding its application field.

[0003] Before the present invention, the surface treatment of aluminum and aluminum alloys mainly included processes such as anodic oxidation, chromate conversion, chromate-phosphate conversion and tannate convers...