Corrosion behavior studies on heat-treated severely plastically deformed Nimonic 263 alloy

This study investigates the hot corrosion and electro-corrosion behavior of heat-treated Nimonic 263 alloy, which has been severely plastically deformed through constrained groove pressing (CGP). Renowned for its robustness in high-temperature applications, the alloy’s responses to aggressive environments were assessed, with a focus on hot corrosion and electro-corrosion. For the hot corrosion analysis, the alloy was exposed to a salt mixture of Na 2 SO 4 (87.5 wt%), NaCl (5 wt%), and NaVO 3 7.5 wt%). Over a 100 h duration at 800 °C, the corrosion kinetics revealed varying degrees of aggressiveness, with the heat-treated CGPed specimens exhibiting higher reactivity compared to the as-received specimens. The formation of multiple compounds, including oxides, sulfides, and vanadate compounds, was observed. Volatile compounds, such as NaClO 3 and CrMoO 3 , contributed to the mass loss. Electrochemical analyses were conducted on as-received, CGPed, and heat-treated CGPed specimens. The findings revealed that the heat-treated samples exhibited a significant enhancement in polarization resistance, ranging from 42% to 154%, with the maximum resistance observed in specimens treated at 700 °C.