[en] Highlights: • Passivity degradation of UNS N08800 in thiosulphate solution is investigated. • Thiosulphate can be reduced on a passive surface. • Elemental sulphur particles are found on the passive film. • Pitting potentials evolve substantially due to competitive adsorption of thiosulphate and chloride ions. • Sulphur ions can incorporate into the outer layer of the passive film. - Abstract: Reduced sulphur induced corrosion of steam generator (SG) tubing in pressurized water reactor (PWR) is assumed to occur at low temperature. Corrosion of UNS N08800 in chloride and thiosulphate solutions at 20, 40 and 90 $\mathrm{℃}$ is systemically investigated by using polarization technique, electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). It is concluded that thiosulphate can be reduced to S°, S₂²⁻ and S²⁻, and incorporate into the passive film, which significantly depends on temperature. The evolution on pitting potentials in chloride + thiosulphate solution can be ascribed to the competitive adsorption of these two ions on the passive surface.