Use of innovative gel electrolytes for electrochemical corrosion measurements on carbon and galvanized steel surfaces

Abstract

This work analyzes the feasibility of using gel electrolytes in portable cells to easily perform electrochemical corrosion measurements on carbon steel and galvanized steel components. A gel manufactured from glycerol and agar, with chlorides and optimized conductivity, has been selected for this study. This gel is easily adaptable to nonflat surfaces and has no risk of crevice corrosion interferences during the measurements. Polarization and electrochemical impedance spectroscopy measurements have been performed with a portable cell with a gel electrolyte. The results have been compared to those obtained in a liquid electrolyte with the same saline composition. The effect of using gel electrolytes on the development of the anodic and cathodic processes when the metal surfaces corrode actively has been analyzed in depth. The changes on the composition of outer oxides due to the gel exposure have also been studied by x-ray photospectroscopy to achieve a better understanding of the results. The gel electrolyte has proved to be an adequate medium for obtaining relevant information about the corrosion performance of active carbon and galvanized steel, although it has a somewhat lower aggressiveness than the liquid electrolyte with the same saline composition.