EIS and ENM as tools to evaluate inhibitive performance of second generation of phosphate-based anticorrosion pigments

The anticorrosion performance of zinc aluminum phosphate pigment was evaluated using electrochemical impedance spectroscopy, the electrochemical noise method and DC polarization. The results of the electrochemical tests revealed the superiority of zinc aluminum phosphate in comparison with zinc phosphate in terms of inhibitive characteristics. The trend and magnitude of resistances and current density plus the appearance of the impedance spectra and the power spectral density of the current noise indicated deposition of a layer on the surface of samples exposed to ZPA extract. SEM/EDX analysis confirmed the precipitation.