Effect of Na2SO4 and Fe2(SO4)3 on the oxidation behaviour of AISI-303 Alloy at 900°

Abstract

The effects of NajS04 and Fe2(S04)3 coatings on the oxidation behaviour of AISI-303 alloy at 900° has been studied in flowing air. The coated samples were oxidised for a period up to 24 hr. The oxidation rate increased with increasing amounts of Naj,S04 coatings, but for Fe2(S04)3 coatings it decreased with increasing salt deposition. The influence of Na^O,, + Fe2(S04)3 mixture on the oxidation rates was studied and it was found that the rate increased with increasing the amount of mixture deposition at 900° due to the formation of eutectic i.e. Na3Fe(S04)3. The results indicate the important role played by prior oxide and/or sulphide films, and the need for well-defined surface conditions. The scale morphologies were determined on the basis of X-ray diffraction analysis and scanning electron microscopic studies.