Influence of oxidizing ability of the medium on the growth of lanthanide layers on galvanized steel

Protection mechanisms offered to galvanized steel by lanthanide salts in a 0.1 M NaCl solution were investigated by using electrochemical techniques such as polarization curves, electrochemical impedance spectroscopy (EIS), scanning vibrating electrode technique (SVET) and surface analysis such as scanning electron microscope (SEM) and glow discharge optical emission spectrometry (GDOES). The role of the oxidizing ability of the medium was studied by changing the aeration conditions: aerated, saturated, deaerated and acid deaerated solutions. In aerated solution, the cerium deposition quickly offers an inhibition of the oxygen reduction. Current density cartographies (SVET) are consistent with surface analysis and other electrochemical techniques.