Effect of chemical composition of zinc phosphating solution on phosphate coating properties

ABSTRACT

Phosphate coatings have a wide field of applications in industry. The applications of coatings are classified according to the film thickness and the type of solution employed. In this study the phosphating process in the zinc-phosphating-nitrate accelerator on steel gave a phosphating layer of suitable morphology which was investigated by different instruments like SEM/EDS and XRD. The crystal size and the thickness of phosphating layer were found to be iron content dependent. Therefore, adjusting of phosphate, zinc and iron concentrations is very important to get a suitable phosphating effective process. The aim of the present work is to control the iron concentration in the phosphating bath in order to improve the quality and adhesive properties of zinc phosphating coating on steel sheets that always used for military purposes in Helwan Engineering Company in Egypt