On the production of ultra-fine titanium hydride powder at room temperature

A reactive mechanical grinding (RMG) method has been proposed for producing fine titanium hydride powders. The kinetics of the hydrogen/metal interaction are significantly increased by the high metal deformation under balls shocks and by the reduction of the particles size thanks to metal embrittlement by work hardening and hydriding. Also important is the significant local temperature increase related to the high rate of deformation. On the other hand, RMG tends to increase slightly the powder contamination by the metallic elements constituting the milling tools. The efficiency of the method is dependent on the rotation speed of the planetary system of milling and depends also on sufficient hydrogen pressure during RMG. The important density of defects generated in the grains by the technique is expected to facilitate the hydrogen extraction during dehydriding. (C) 2002 Elsevier Science B.V. All rights reserved.