Abstract

The corrosion behavior of carbon steel AISI 1020 in LiBr in comparison with NaCl aqueous solutions were studied from polarization curve measurements in a rotating disk electrode under a combination of salt concentration and rotation speed of the electrode. Assuming the occurrence of hydrogen evolution and oxygen reduction as the cathodic counterparts of the iron oxidation under a predetermined kinetic model, the corresponding kinetic parameters were obtained applying a numerical method to experimental data. It was found that, despite of the close similarities observed between corrosion behavior of carbon steel in LiBr, NaCl and the mixture LiBr+NaCl, there are distinct differences in kinetics for partial reactions. Some relevant aspects are the significant differences for iron oxidation and hydrogen evolution in the kinetics parameters that indicates higher kinetic rate for LiBr in comparison with NaCl solutions. This can be related with morphological attributes of the pits. For oxygen reduction the fluid dynamics regime and transport properties of the electrolyte of each salt solution are the main factors affecting the oxygen kinetic behavior.