Study on phosphating on the magnesium alloys

In this paper, the solution mainly containing Zn(H2PO4)2 was used to prepare phosphating coatings on AZ31,AZ61 and AZ91 magnesium alloys. The effects of the phosphating parameters and the composition of phosphating solution on the formation of the coatings were investigated by orthogonal tests. The corrosion behaviors of the phosphating coatings were also studied and it is found that there was no hydrogen evolution in at least 1h. In the last, 60~80μm organic coatings were painted on the phosphated magnesium alloys,the organic coatings adhered to the phosphating coating, and the anti-corrosion abilities were improved .