The Corrosion Behavior and Mechanism of CoCrFeNi High-Entropy Alloy Subjected to AC Interference in a Simulated Littoral Environment

The corrosion behavior and mechanism of CoCrFeNi high-entropy alloy (HEA) with AC interference in coast marine environment was studied. The results reveal that with the rise in applied i_AC, the i_p value increases, and the R_f value decreases, which suggests that the imposed AC weakens the protective ability of the passivation film and inhibits its re-passivation. H ions and atoms generated due to AC interference damage the compact structure of passive film. Under high i_AC, the corrosion rate of the HEA increases rapidly, and the corrosion morphology evolves from slight pitting to non-uniform general corrosion and severe localized corrosion. The pits produced on the HEA is resulted by the selective dissolution of Ni element.