Corrosion Behavior and Mechanism of Automotive Galvanized Steel Sheet by Mod Adhesion

The corrosion behavior and mechanism of galvanized auto steel sheet by adhesion of mud were investigated and compared with those of substrate by means of scanning electron microscopy (SEM) , X-ray diffraction (XRD) , and electrochemical impedance spectroscopy (EIS).Results showed that the thickness of rust increased gradually with the acceleration of corrosion rate in the initial period of corrosion, and the corrosion rate was highly dependent on the composition and thickness of the rust layer.Moreover , both the rust resistance and electric charge transfer resistance of the galvanized steel sheet and substrate sheet increased first and then decreased.The contents of dissolved oxygen and relatively high Cl- in mud had great influence on the corrosion rate of specimens.