Electrochemical Study of Corrosion Behavior of Stellite 6 Alloy and 17-4PH Stainless Steel in Amine Solutions

To provide the power generation industry with scientific evidence, the corrosion behavior of Stellite 6 alloy and 17-4PH stainless steel is studied in morpholine, cyclohexylamine and sodium hydroxide solutions at the same pH around 9.5 using electrochemical test methods such as potentiodynamic polarization, cyclic polarization, and EIS in this research. The microstructures of the tested materials and corroded surfaces are analyzed using SEM/EDX. Stellite 6 alloy and 17-4PH stainless steel are resistant to corrosion in amine solutions by forming oxide films on their surfaces. The oxide film of 17-4PH stainless steel is more resistant to electron transferring than that of Stellite 6 alloy, thus has better resistance to corrosion. However, the oxide film of 17 4PH stainless steel has less durability and it works well only within a certain potential range. Otherwise, Stellite 6 alloy has better overall corrosion and pitting corrosion resistance than 17-4PH stainless steel in amine environments.