EFFECT OF Sc ADDITION ON THE EXFOLIATION AND ELECTROCHEMICAL CORROSION BEHAVIOR OF Al-Zn-Mg-Cu-Zr ALLOY

摘要

The EXCO test revealed that 0.25 wt. % Sc addition to base 7010 Al-alloy in peak aged condition has no beneficial effect towards exfoliation corrosion behavior. electrochemical impedance spectroscopy (EIS) studies were in confirmatory with the EXCO test showing exfoliation susceptibility of base and Sc containing 7010 Al-alloys. However, a higher Rp was observed in Sc containing alloy compared to the base alloy which could be due to the better passivity of the former than the latter. electrochemical studies showed that Sc addition shifted the Ecorr by 45 mV towards active potential as compared to the base alloy. However, the base and Sc containing alloys revealed two distinct break-down potentials which correspond to their pitting and intergranular corrosion (IGC) susceptibility. Thus, 0.25 wt. % Sc addition to 7010 Al-alloy shows no beneficial effect on the pitting and IGC behavior.