Progress in Research of Passivation for Galvanized Steel

Zinc plating is a main method for improving the corrosion resistance of steel plates. But in various environments, zinc is easy to be corroded. In order to increase the surface quality of galvanized steel, to slow down the corrosion rate of zinc coating and to, extend the service life, the passivation treatment is needed. In this paper, the progress in research of passivation for galvanized steel is summarized firstly. The development and current application of conventional passivation and chromium-free passivation are discussed secondly. Then the chromium-free passivation of organic and inorganic treatment processes are introduce. The advantages and existing problems of different treatment technologies are presented. The development tendency of passivation technology is also evaluated.