Corrosion-electrochemical behavior of manganese silicides in sulfuric acid electrolytes

Metal silicides are investigated for their potential as electrode materials due to their high chemical resistance and low hydrogen overpotential in acidic environments. This study aims to explore the corrosion-electrochemical behavior of manganese silicides, specifically MnSi and Mn5Si3, in a sulfuric acid electrolyte. The methodology includes preparing the specimens and conducting electrochemical measurements similar to previous studies on iron, cobalt, and nickel silicides. The results indicate that in a 0.5 M H2SO4 solution, manganese does not undergo passivation, exhibiting a free-corrosion potential of approximately -0.7 V. The anodic dissolution rate of manganese is significantly higher than that of silicon and manganese silicides, with the latter having dissolution rates about five orders of magnitude lower than manganese. The study further notes that the dissolution rate decreases with increasing silicon content in the silicide. Additionally, the behavior of silicon in the electrolyte is complicated by its semi-conductive properties and the formation of a SiO2 film on the electrode surface, affecting the mechanism of hydrogen evolution. Overall, this research contributes to understanding the electrochemical performance of manganese silicides for potential applications in electrode materials.