Characterization of detonation gun thermal spray coatings on SA213T91 in simulated boiler environment

Abstract The Ni-Cr and Stellite-21 coated SA213T91 boiler steel deposited by D-gun thermal spray process on the boiler steel were oxidized in the presence of air and Na2SO4-60% V2O5 salt mixture at 900˚C for 100 cycles. One cycle consists 1 hour heating in silicon carbide tube furnace and 20 minute cooling in ambient air. The kinetics of oxidation shows that the D-gun spray coating s technique is better than other coating techniques. The measurements of mass change kinetics corrosion by SEM/EDS, XRD and X-Ray techniques. The Oxidation and hot corrosion mechanisms were sustained by analyzing the results from various techniques. The results of the study have been discussed w.r.t. thermo gravimetric structure.