Hydrogenation of TiFe by high-energy ball milling

The hydrogenation properties of TiFe, TiFe2 and pure Ti during high-energy ball milling in hydrogen atmosphere were studied. By ball milling, TiFe cou ld absorb hydrogen without activation treatment. For Ti powder, a single ph ase TiH1.924 was formed. In addition, TiFe2 could also be hydrided by ball milling in hydrogen, which was ascribed to decomposition to form TiFeHx, Ti H1.924 and Fe. Based on the hydrogenation properties of Ti, TiFe, and TiFe2 during dynamic ball milling and the thermal stability of the milled powder s, it is proposed that the reactions in the milling of TiFe in hydrogen inv olve four steps: (1) fresh surfaces created by collision with the balls; (2 ) absorption of hydrogen by the powder; (3) oversaturation of hydrogen in t he powder; (4) decomposition of TiFeHx to TiH1.924 and Fe. (C) 2000 Elsevie r Science S.A. All rights reserved.