The corrosion behavior of Cu-Fe and Cu-Fe-Al was studied in NaCl solutions without and with different concentrations of some inorganic additives, Na2MoO4, K2Cr2O7, and KIO3. The measuring techniques used were, open-circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The potentiodynamic polarization measurements indicated that the corrosion current, Icorr, o;f Cu–Fe is less than that of Cu–Fe–Al. The investigated additives in 3.5% NaCl shift corrosion potential Ecorr to more positive values (except in K2Cr2O7 reverses the action for Cu-Fe alloy) and increase Icorr. Impedance measurements indicated that Nyquist plots for Cu–Fe and Cu–Fe–Al may be regarded as part of semicircle (arc), the values of Rp for Cu–Fe are higher than those for Cu–Fe–Al except in K2Cr2O7. On the other hand, the values of Cdl for Cu–Fe are lower than those obtained for Cu–Fe–Al. The presence of these additives in NaCl solutions increases the values of polarization resistance (Rp) and decreases the values of (Cdl).
Key words: Copper alloys, corrosion, passivators, NaCl.
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