LAUSR

Electrochemical measurements were performed on Ni-30Co-16Cr-xMo and Ni-30Co-16Cr-xMo-2Cu (x=7-15, wt.%) alloys to clarify their electrochemical responses and corrosion behaviors influenced by Mo and Cu in 0.5 M aqueous HF acid solution at room temperature. Results indicate that both Mo and Cu play positive roles in improving the corrosion resistance. The enhanced corrosion performance of alloy by Cu addition is observed in all alloys while this is more obvious in alloy with low Mo concentration. Moreover, 2 wt.% Cu addition is found to not only reduce the critical Mo concentration for spontaneous passivation of alloy, but also alter the nature of exposed surface with distinct declines of effective capacitance. Ni-30Co-16Cr-15Mo-2Cu alloy shows the best corrosion resistance among all alloys studied.