An Inhibitive Effect of Aeration on the Pitting Corrosion of Steels in Ethanolic Environments

Abstract

This work is aimed at improving the understanding of the localized corrosion of carbon steel in ethanolic solutions. The role of ethanol dehydration, chloride, and oxygen level in the pitting behaviour of carbon steel in ethanolic environments in the presence of supporting electrolytes was investigated. Open Circuit Potential measurement, Cyclic Potentiodynamic Polarization and Potentiostatic testing were conducted on specimens exposed to ethanolic environments prepared from pure dehydrated ethanol to study the pitting behaviour of carbon steel. Corrosion and passivation potentials significantly reduce due to the change in the cathodic reaction and the decrease in passivation kinetics under de-aerated conditions. SEM and EDX examination indicated that no pitting corrosion is observed without chlorides, and chloride significantly destabilizes the surface film resulting in decreases of both corrosion potential and passivation potential. A decrease in the dissolved oxygen in the solution reduces but does not eliminate the pitting susceptibility. Iron oxide is identified as the significant corrosion product at different water and oxygen content. Therefore, ethanol aeration can be a proper method to increase pitting corrosion resistance in ethanolic solutions.

A New Understanding of Graphene Influencing the Protective Performance of Zinc-Rich Coatings

“…As reported, the galvanic corrosion between zinc particles and graphene can accelerate the oxygen-consumption corrosion of zinc particles . Hence, the decrease of oxygen concentration at the defect is attributed to the promoted oxygen-consuming corrosion of zinc powder under the effect of graphene on the side wall of the coating, which was demonstrated in Figure S1. , …”

“…27 Hence, the decrease of oxygen concentration at the defect is attributed to the promoted oxygen-consuming corrosion of zinc powder under the effect of graphene on the side wall of the coating, which was demonstrated in Figure S1. 28,29 EIS of different specimens was tested to evaluate the protective performance of the top layer FC/Gr-ZRT under the presence of mechanical damage by assessing the interfacial electrochemistry between the metal and the electrolyte. 30 In Figure 5, both specimens display two time constants, ascribed to the corrosion products film related to zinc and copper and the corrosion of copper, respectively.…”