Oxidation induced phase transformation of duplex stainless steel 25Cr–10Mn–2Ni–3Mo–0.8W–0.8Cu–0.5N

Highlights: ► The weight gain per unit area was in parabolic relation to oxidation time. ► The oxide layer composed mainly of Cr2O3 and Mn2O3. ► Preferential oxidation of manganese led to the formation of ferrite diffusion layer. - Abstract: Isothermal oxidation behaviour of duplex stainless steel 25Cr–10Mn–2Ni–3Mo–0.8W–0.8Cu–0.5N was investigated at 1050 °C in air through scanning electronic microscopy and Raman spectroscopy. The weight gain per unit area was in parabolic relation to oxidation time with a parabolic rate constant (kp) 1.39 × 10−12 g2 mm−4 min−1. An oxidation induced transformed ferrite diffusion layer was observed due to the preferential oxidation of manganese.