The high temperature corrosion of nickel in SO2 at 500–800°C

The reaction of nickel with SO2 has been studied at 500-800 C and different pressures of SO2 (0.4-100 kPa). The reaction products are NiO and nickel sulphides. The reaction rate goes through a maximum at about 600 C at and above 13 kPa SO2, while the maximum is absent at lower SO2 pressures. It is concluded that the reaction takes place through different reaction paths: (i) the direct reaction of Ni with SO2 and (ii) a reaction path via NiSO4 as an intermediate reaction product. The latter path is the more rapid one and gives rise to the very rapid reaction rates and maximum in the reaction rate at 600 C.