Effect Of Tcp Phase Formation On The Electrochemical Corrosion Behavior Of The Nickel-Based Superalloy Uns N26455

The effect of topologically close-packed (TCP) phase formation on the electrochemical corrosion behavior of the UNS N26455 (Ni-16Cr-16Mo) superalloy was evaluated using different electrochemical techniques. We verified that this superalloy is resistant to highly corrosive environments but its corrosion potential decreases and the anodic current density increases as the TCP phase concentration increases in the microstructure. Its anodic behavior indicates that there is a selective dissolution process associated with this secondary phase, which is completely dissolved before repassivation occurs. Although the repassivation potential remains nearly unchanged, the degraded points configure defects that may negatively affect the material's performance during service.