Electrochemical corrosion of FV520B stainless steel in solutions bearing hydrogen bromide and acetic acid at high temperature from 130 to 200 °C.

FV520B stainless steel is an important material for compression turbine impellers. Its corrosion resistance at high temperatures is critical for the manufacturing and service reliability management of impellers. Therefore, this study investigated the electrochemical corrosion of FV520B stainless steel in an acetic acid solution bearing hydrogen bromine from 130 to 200 °C by potentiodynamic polarisation, electrochemical impedance and corrosion morphology observation. Active corrosion peaks were evident, and the corrosion current densities increased with the increase of the concentration of hydrogen bromine and temperature. However, the breakdown potential first shifted into noble value and then decreased with the further rise in temperature, where the maximum value was at 175 °C. EIS analysis and corrosion morphology revealed that the presence of pitting potential peak is possibly attributed to the competition between the attack of bromine ion and the growth of a surface oxide film under high-temperature water. [ABSTRACT FROM AUTHOR]