On the mechanism of high-temperature sulphide corrosion of niobium and transport properties of niobium sulphide

Niobium sulphidation kinetics, as well as chemical diffusion and nonstoichiometry in niobium sulphide, Nb1+xS2, have been studied as a function of temperature (973–1273 K) and sulphur vapour pressure (10−4–5 Pa) using microthermogravimetric techniques. It has been shown that the excellent resistance of niobium to highly sulphidizing atmospheres results from very low mobility of point defects in Nb1+xS2 sulphide, which constitutes the main part of the scale on this metal.