Alternative Chromium-Free Passivation Combined with Nano-electrodeposition for Electrogalvanized Steel

摘要

The combination of chromium-free passivation and nano-electrodeposition was reported to replace chromic acid passivation for electrogalvanized steel. The microstructure, corrosion resistance, scratch resistance and wear resistance of nanocrystalline zinc coating after chromium-free passivation were investigated. It was demonstrated that the nanocrystalline zinc coating after chromium-free passivation mainly consists of ZnO, Zn-3(PO4)(2), Ti2O3 and/or (Zn(OH)(2), ZnHPO4 and TiO2), which possesses better comprehensive properties than conventional coarse-grained zinc coating after commercial trivalent chromium passivation. The reason was also discussed in detail.