23-09-2015 дата публикации
Номер: CN104928663A
Принадлежит:
The invention relates to a chromium-free chemical conversion treatment method for a magnesium alloy surface. The chromium-free chemical conversion treatment method for the magnesium alloy surface comprises the steps of surface pretreatment, alkaline washing for oil removing, water washing, acid pickling, water washing, phosphorization and water washing. Treating fluid used for phosphorization is composed of 20-80 g.L<-1> of sodium dihydrogen phosphate, 1-167 g.L<-1> of calcium hypophosphite and 0.1-10 g.L<-1> of hexamethylenetetramine. The phosphorization treatment temperature is 10-60 DEG C, the pH value is 2.8-7.0, and the phosphorization time is 1-50 minutes. A phosphating film surface prepared through the method is uniform, compact and high in corrosion resistance and can be used independently or serve as the bottom layer of a coating film, and the adhesive force of the coating film to a base body is improved. The reaction temperature is low, the condition is mild, the elements of a ...
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