Effect of pre-oxidation on hot corrosion resistance of HR3C stainless steel in sulfate salt with or without Fe2O3

HR3C steel exhibits high oxidation resistance in air at 700 degrees C owing to the formation of a dense chmmia scale. In the presence of sulfate salt deposition (Na2SO4:K2SO4 = 1:1), hot corrosion occurs. It leads to the dissolution and re-precipitation of Cr2O3 platelets and severe internal corrosion. Pre-oxidation can notably enhance corrosion resistance with almost no internal corrosion zone. When the deposited sulfate salt contains Fe2O3 (Na2SO4 : K2SO4:Fe2O3 = 1:1:1), HR3C steel suffers even severer hot corrosion. Its scale spalls off easily and internal corrosion develops deep into the steel. Meanwhile, pre-oxidation played almost no positive effect on corrosion in sulfate salt containing Fe2O3.