Study of Al7075 Localized Corrosion Inhibition by a SiO2 Superhydrophobic Coating Employing an Electrochemical Noise Technique

Abstract

Aluminum presents localized corrosion when exposed to marine and industrial environments. In this research, we study the pitting susceptibility of Al7075 coated by a SiO2 sol–gel coating as a corrosion inhibitor employing the electrochemical noise technique. The analysis methods were power spectral densities (PSDs) in noise impedance (Zn), complaints by wavelet transform, recurrence plots, and Hilbert–Huang study due to the chaotic behavior of the EN signal. To perform the EN, the parameters employed were 2048 data, 1 datum per second in NaCl, and H2SO4 electrolytes at 3.5 wt.% simulating marine and industrial environments. EN tests were performed following ASTM G199. The results showed an increase in the localized corrosion process when SiO2 coating was applied. This is due to the cracking morphology of the coating.