HYDROGENATION OF MECHANICALLY ALLOYED TITANIUM-BASED POWDERS

Abstract

This work focused on studying the hydrogen storage characteristics in some of the Tibased alloys. Amorphous alloys were synthesized by mechanical alloying. Subsequent annealing produced mainly crystalline phases. Hydrogenation of the amorphous Ti-Zr- Ni alloys, at 300 °C, exhibited good hydriding properties. However, hydrogenation of the Ti-V-Ni counterparts' powders exhibited slower rates, though, with higher hydrogen capacity. In general, hydrogenation of the annealed crystalline alloys showed slower hydrogenation kinetic rates due to the formation of a hindering surface oxide layer. In addition, a first investigation of these alloys hydrogenation / dehydrogenation at cryogenic temperature of ≈ -193 °C showed very fast kinetic rates. The mechanically alloyed powders were successfully hydrogenated at room temperature by reactive mechanical milling.