High Temperature Corrosion Behavior of High Velocity Oxy Fuel Sprayed Nicrmofecoal-30%Sio2 and Nicrmofecoal-30%Cr2o3 Composite Coatings on Astm Sa213-T22 Steel in A Coal-Fired Boiler Environment

High-velocity oxy fuel (hvof) sprayed coatings can improve the corrosion resistance of bare astm sa213-t22 boiler steel. in this report, we have investigated the nicrmofecoal-30%sio2 and nicrmofecoal-30%cr2o3 composite coatings were deposited on bare astm sa213-t22 boiler steel for corrosion protection. high-temperature corrosion studies were conducted in a molten salt (na2so4-60%v2o5) environment at 700ºc under thermo-cyclic conditions. the as-sprayed composite coatings are characterized for microstructure and mechanical properties. the thermo-gravimetric method was utilized to understand the kinetics of corrosion. characterization of the corrosion products was examined by using scanning electron microscope (sem)/ energy dispersive spectroscopy (eds) and x-ray diffraction (xrd) techniques. the obtained results suggest both the composite coatings are favorable to corrosion resistance over the bare astm sa213-t22 boiler steel. the nicrmofecoal-30%cr2o3 composite coating was concluded to present a superior corrosion resistance in the high-temperature corrosion environment because of the uniform distribution of the composite coating matrix and the development of protective protection cr2o3 in the scale. the molten salt heat-treated chromium oxide containing coating shows good corrosion stability than the silica composite. this could be attributed to the high temperature assisted formation metal chromates, chromites and oxide layers.