Electrochemical behavior and the rate of general corrosion of NiAl intermetallic compound in the unbuffered sodium chloride solutions

Highly reproducible Tafel anodic and cathodic plots were obtained on NiAl intermetallic compound in the neutral and nearly neutral unbuffered NaCl solutions. The corrosion potentials and corrosion current densities were determined by the Tafel extrapolation technique at various pH values and concentrations of NaCl. The corrosion current density and Tafel slopes were determined by fitting the equation for the corrosion current density, which involves both anodic and cathodic reactions, to the experimental anodic and cathodic polarization curves in the pre-Tafel region of polarization curves. The results obtained by two methods are in good agreement.

Research highlights► Corrosion currents and corrosion potentials of NiAl in NaCl solutions are determined. ► Effect of solution concentration and pH on corrosion current and potential is found. ► The pH value separating the ranges of reduction of oxygen and hydrogen ions is found.