EXAFS study of atmospheric corrosion products on zinc at the initial stage

The corrosion resistance and structural information of zinc atmospheric corrosion products at the initial stage were investigated by using ex-situ electrochemical impedance spectroscopy (EIS) in methanol and extended X-ray absorption fine structure spectroscopy (EXAFS). EIS in methanol performs excellent resolution to the corrosion resistance of the surface layer from various atmospheric exposures. The corrosion resistance of zinc exposed to air of 100% RH for 48 h was found three times larger than that of zinc exposed to an air of 95% RH. The EXAFS data reveal that hydrozincite and amorphous zinc hydroxide are the corrosion products of zinc exposed to atmospheres of 100% RH and 95% RH, respectively.