Corrosion behavior of intermetallic compound of TiAl–5Nb in molten LiCl–Li2O

The corrosion behavior of TiAl–5Nb intermetallic compound was investigated in molten LiCl–Li2O with immersion experiment in air at 750 °C. TiAl–5Nb showed much better corrosion resistance in molten LiCl–Li2O than 310SS stainless steel. TiAl–5Nb exhibited a fast weight loss at the initial stage of corrosion, and then the weight loss stabilized as a slow corrosion rate. The corrosion scale show a bilayered structure: the outer layer is composed of large grains of γ-LiAlO2, whereas the inner layer is a compact titanium oxide-rich (Li2TiO3, TiO2) layer. The fast corrosion at the beginning of corrosion is due to the fast growth of γ-LiAlO2, and the slower corrosion rate at the latter stage of corrosion is owing to the formation of protective inner layer of titanium oxides (Li2TiO3, TiO2).