Abstract
The corrosion behavior of duplex stainless steel (DSS, Fe - 22% Cr - 9% Ni - 3% Mo) alloy after varying exposure periods in 10% H2SO4 solution was investigated. The influences of minor Ru additions, namely, 0.14%, 0.22%, and 0.28%, on the passivation of this DSS were also reported. The study was performed using open-circuit potential, potentiodynamic polarization, potentiostatic current-time, electrochemical impedance spectroscopy, and weight loss measurements. Electrochemical measurements indicated that the presence of Ru passivated the DSS alloy by decreasing its corrosion parameters. This effect remarkably increased with increasing the Ru content as well as the immersion time of DSS in the chloride solution before measurements. Weight-loss time data after varied exposure intervals (24 - 168 h) confirmed the electrochemical ones and showed that the weight-loss and corrosion rate of DSS significantly decreased in the presence of Ru and the increase of its content in the DSS alloy.