Corrosion behavior of intermetallic compound of TiAl–5Nb in molten LiCl–Li 2O

Abstract

The corrosion behavior of TiAl–5Nb intermetallic compound was investigated in molten LiCl–Li 2O with immersion experiment in air at 750 °C. TiAl–5Nb showed much better corrosion resistance in molten LiCl–Li 2O 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-LiAlO 2, whereas the inner layer is a compact titanium oxide-rich (Li 2TiO 3, TiO 2) layer. The fast corrosion at the beginning of corrosion is due to the fast growth of γ-LiAlO 2, and the slower corrosion rate at the latter stage of corrosion is owing to the formation of protective inner layer of titanium oxides (Li 2TiO 3, TiO 2).