Effect of mechanically induced modification on TiH2 thermal stability

Interrupted thermal desorption and X-ray diffraction techniques were used to study the effect of graphite and boron additives on non-equilibrium decomposition of mechanically activated commercial TiH2. The phase transformation sequence is described as a number of consecutive reactions corresponding to desorption peaks. The process is compared to non-equilibrium decomposition of commercial TiH2. The mechanical pre-treatment with additives significantly eases and accelerates decomposition of TiH2 to αTi(H), but hinders the stage of αTi(H) → αTi transformation. Only a small portion of pure αTi was detected for as-milled TiH2 and TiH2/B powders after the final TPD. No αTi was formed in the case of as-milled TiH2/C.

Research highlights
► Interrupted TPD to study thermal decomposition of milled TiH2, TiH2/B and TiH2/C.
► Ball-milling, especially with B and C, accelerated the first stage TiH2−x → αTi(H).
► Ball-milling significantly suppressed the final stage αTi(H) → αTi.