Hot Corrosion Behavior of Electrical Discharge-Coated Duplex Stainless Steel Under Sulfur Environment

An approach is suggested to enhance the hot corrosion resistance of SS2205 alloy by using Ni and Cu powders mixed in a dielectric medium during the electrical discharge coating process on the alloy surface. Three distinct coatings were created by altering the concentration of Cu and Ni particles in the dielectric fluid. The cross-sectional morphology, phase composition, and elemental composition of the coatings were assessed using SEM, XRD, and EDS analysis. The hot corrosion test was conducted in a box-type furnace at 700 °C for 80 h in a sulfur environment. The coating contains Ni₃C, as proven by XRD. The metastable Ni₃C decomposes at high temperature and produce Ni in the coating structure. The presence of the nickel and a dense, uniform coating contributed to the coatings’ remarkable resistance to hot corrosion.