This research involves study effect of MnO-4 anion addition as inhibitor on the polarization behavior of (70%Cu-30%Zn) alloy in salt and basic medium ( 0.6 M NaCl & 0.6 M NaOH) by potentiostatic method where Tafel slopes and corrosion rate (Rmpy) and inhibition efficiency (El%) for each salt and basic environments were measured .
Result of the tests shows that the values of Tafel slopes and corrosion rate decreases with adding the MnO-4 anion in two solutions, the Inhibition efficiency of 70%Cu-Zn30% alloy in NaOH solution more than that observed in NaCl solution. which means that the basic media is more corrosive Cu-Zn alloy even after the addition of inhibitor.