Electrochemical Corrosion Behavior of SiO2 Superhydrophobic Inhibitor in Al7075

Abstract

The automotive industry has been employing Al alloys to reduce the weight of chassis; however, this can present some corrosion problems. In this research, we study the electrochemical behavior of SiO2 superhydrophobic on Al 7075. The electrochemical techniques employed were cyclic potentiodynamic polarization (CPP), performed at a scan rate of 60 mV/s from −800 to 800 mV vs. OCP, and electrochemical impedance spectroscopy (EIS) at ±10 mV with frequencies ranging from 10 mHz to 100 kHz, as per ASTM G61 and ASTM G106. The electrolytes employed were NaCl and H2SO4 at 3.5 wt.% simulating marine and industrial atmospheres. The results showed that the coating presented an efficiency of 81% when exposed to NaCl, but the corrosion in this medium is localized. In H2SO4, the corrosion type is uniform.