Reaction Mechanism of Fe-Cr Alloy with O₂-SO₂-SO₃ Reaction

Sulfidation-oxidation behaviors of Ni16Cr, Nil6Cr3Ti, Ni16Cr 2Nb alloys have been studied at 700℃ in O₂-10% (SO₂+SO₃). Corrosion products are observed and examined with X-ray diffraction and SEM. Under experimental condition, containing SO₃ corrosion rate of Ni16Cr alloy is rapider. Nb has little effect on degradation of alloy. When alloy containes Al or Ti, the oxidation rate of these alloys is slower. Products of corrosion consist of two layers; external layer (NiO + Ni₃S₂) mixture and internal layer sulfids and oxides containing all test alloying elements.