Electrochemical Surface Modification of Nickel-based Alloys

Electrochemical surface modification was carried out on nickel-base alloys 800 and 600 in borate buffer solution (pH=8.4) and 0.1 mol/L H2SO4 solution respectively. Passive films formed on nickel-based alloys 600 and 800 were investigated systematically by potentiodynamic scanning, Mott-Schottky curves and photo-current spectroscopy. The results showed that a positive shift in flat band potential and higher carried density was presented in H2SO4 solution. There was no significant change in flat band potential and significant decrease of carrier concentration for electrochemically modified specimens. Therefore, the rate of dissolution of passive films was reduced, and corrosion resistance was improved greatly.