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-hydrogen solid solution followed by the formation of titanium hydride. Dehydrogenation 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 initial and final dehydrogenation temperatures and a slightly narrower dehydrogenation temperature range compared to hydride prepared by traditional methods. The extremely fine particle size, large surface area and lattice defects introduced by milling are believed to be responsible for modification of the hydrogen storage behaviour.