A chromium-free phytic acid passivating coatings for galvanized parts is studied. The corrosion resistance of the passivation coating is tested with dropping,neutral salt spray,salt solution soaking and electrochemical methods,X-ray fluorescent spectrometry(XRF) and stereomicrography are used to explore the structure of phytic acid passivating film.It is found that the film mainly consists of zinc phytate and polysilicic acid.The film is so compact that it can inhibit the infiltration of corrosive medium ef...