Study on effect of chloride and temperature on corrosion behavior of CoCrFeMnNi high entropy alloy

The effect of chloride ion concentration and solution temperature on the corrosion behavior of CoCrFeMnNi high entropy alloy (HEA) was studied by electrochemical measurements, atomic force microscope (AFM) and immersion test. The result shows that increasing [Cl-]/[OH-] ratio or solution temperature enhances the electrochemical reaction ability, weakens the protection of passive film, and generates more severe pitting corrosion. The negative impact of temperature on the corrosion behavior of the HEA is more obvious than that of chloride concentration. A synergistic effect is produced between solution temperature and chloride ion concentration, which significantly destructs the denseness of passive film, and greatly decreases the anti-corrosion properties of the HEA. The pits occurred on the HEA could be ascribed to the selective dissolution of Fe, Co and Ni elements.