Electrochemical Investigations on the Corrosion Behavior of 904L Stainless Steel in LiBr Solutions

The pitting corrosion susceptibility of 904L stainless steel in aerated LiBr solutions was investigated. The influence of various experimental variables, including electrolyte concentrations, pH, scan rate, temperatures, and constant potential has been studied using electrochemical measurements, such as cyclic potentiodynamic polarization, potentiostatic techniques, and electrochemical impedance spectroscopy (EIS). The surface morphology of 904L stainless steel was examined by scanning electron microscope (SEM). The rate of uniform corrosion and susceptibility toward pitting corrosion increases with an increase in LiBr concentrations and temperature. Increasing the pH of the solution decreases the rate of both uniform and pitting corrosion. An increase in the scan rate enhances the uniform corrosion, but suppresses the pitting corrosion. EIS diagrams displayed a depressed semicircles with the center under the real axis. Bode plots support the result that the uniform corrosion resistance of the alloy in LiBr solutions decreases with increasing Br- anion concentration. The observations suggest that this one time constant may actually be the overlap of two-time constants.