FORMATION OF TITANIUM HYDRIDE AT ROOM-TEMPERATURE BY BALL-MILLING

Titanium hydride with a body centred tetragonal structure was rapidly synthesized at room temperature by ball milling titanium powders under a hydrogen atmosphere. The structure evolution was monitored by x-ray diffraction and Rietveld analysis. Unit cell volume dilation suggests the hydrogenation process begins with the formation of a titanium-hyd rogen solid solution followed by the formation of titanium hydride. De hydrogenation of the hydride produced by milling and titanium hydride prepared by standard techniques was investigated by thermogravimetric analysis (TGA). The hydride formed by the milling process has lower in itial and final dehydrogenation temperatures and a slightly narrower d ehydrogenation temperature range compared to hydride prepared by tradi tional methods. The extremely fine particle size, large surface area a nd lattice defects introduced by milling are believed to be responsibl e for modification of the hydrogen storage behaviour.