Hydrogen storage properties of Mg-doped Ti1.2Fe alloys synthesized by mechanical alloying
(1. Department of Materials Science and Engineering,
Zhejiang University, Hangzhou 310027, China;
2. Department of Chemical Engineering,
Instituto Superior Tecnico, Lisboa 1049-001, Portugal)
Zhejiang University, Hangzhou 310027, China;
2. Department of Chemical Engineering,
Instituto Superior Tecnico, Lisboa 1049-001, Portugal)
Abstract: Hydrogen storage properties and phase components of Mg-doped TiFe alloys, that were prepared by Ti, Fe and Mg metal powders using a mechanical alloying technique, were studied. XRD analyses show that the main phase of all the Mg-doped Ti1.2Fe alloys is the TiFe phase. Some TiFe2 phase and α-Ti phase exist as secondary phases and Mg is dispersed in the alloy matrix. 3% Mg-doped and 5% Mg-doped Ti1.2Fe alloy samples can be fully activated within three hydriding/dehydriding cycles at room temperature and the hydrogen storage capacities of the alloys can reach 222mL/g and 198mL/g, respectively. Both two samples exhibit only one plateau region in their P-C-T curves with a low hydrogen absorption/desorption pressure hysteresis. The effect and mechanism of Mg addition as well as overstoichiometric Ti on the activation properties and hydrogen storage capacities of the alloys was also discussed.
Key words: TiFe alloy; Mg; hydrogen storage properties; mechanical alloying