3-9 Substitutes for Chromate (Cr<6+>) for Passivation on Hot-dip Galvanized Steel
The present work focus on the use of cerium salts, cobalt salts and silicon dioxide as chromate (Cr <6->) replacers for continuous galvanized steel sheet. The composite passivating film was applied roller coat and curing originate films subsequently. The structure of passivating films were observed and characterized by scanning electronic microscopy (SEM). The corrosion behavior of the film was evaluated with neutral salt spray test (NSS) and studied with electrochemical technique. The aim of the present work is to compare the corrosion resistance and electrochemical behavior of the composite chemical conversion film with chromate passivating film. The result of SEM shows that a perfect composite film was obtained on the steel sheet with passivating dope. The results of NSS and linear polarization show that the corrosion performance of the composite film is better than that of chromate (Cr<6+>) passivating film, and the corrosion resistance of the composite film is equivalent to that of the chromate (Cr<6+>) passivating film. SiO<,2> blocks microcracks extension and decreases deformation range, Cerium and cobalt salts retard the anodic polarization of corrosion, these turns passivating film more susceptible to corrosion.
continuous galvanized steel passivation composite film cerium, cobalt SiO<,2>
Yu Wugang Yue Yuanguang Zhang Qifu
Central Iron and Steel Research Institute, Beijing, 100081
国际会议
第七届亚太镀锌大会(The 7th Asia Pacific General Galvanizing Conference)(7th APGGC)
北京
英文
181-185
2007-09-14（万方平台首次上网日期，不代表论文的发表时间）