Influence of synthesis conditions on the structure and phase formation during the SHS hydration of titanium

Abstract

SHS hydrogenation of titanium sponge in various modes of hydrogen deficiency and excess is investigated. According to data of the time-of-flight mass spectroscopy, a nonuniform H+ distribution is found over the sponge bulk during the synthesis in the H2 deficiency mode and a uniform one is found in the H2 excess mode. The surface structure of the Ti sponge before and after SHS hydrogenation is compared by SEM. An increase in structure lamination compared with the initial sponge is found for the hydrogenated sponge irrespective of the H2 content. Layers acquire a regular geometric shape and are arranged in a definite order with a repeated motif. Distances between the layers vary from the micron to nanometer sizes. The phase formation mechanism during the hydrogenation of titanium is investigated by time-resolved X-ray diffraction. The final product is formed through a series of intermediate phases according to the solid-phase mechanism: α-Ti → α-Ti[H] → β-Ti[H] → TiH2.