Cyclic stability of the C36-type TiCr2 Laves phase synthesized in the abnormal glow discharge plasma under hydrogenation

Abstract

In this work, the cyclic stability of the C36-type TiCr2 Laves phase synthesized in the abnormal glow discharge plasma was investigated. Melting of titanium-chromium metallic powders by the glow discharge plasma leads to the formation of the TiCr2 hexagonal C36 Laves phase with lattice parameters a = 4.928 Å and c = 15.983 Å. The hydrogenation-dehydrogenation method was used for crushing to increase the effective sorption capacity of the C36-type TiCr2 Laves phase. The stable hydride TiCr2Hx (x ≤ 0.5) phase of structural polytype C36 is formed during the first absorption/desorption cycle at the temperature of 30 °C. After 15 cycles hydride with the stoichiometric composition close to the TiCr2H0.5 phase of C36 polytype with lattice parameters: a = 4.961 Å and c = 16.224 Å was observed by XRD analysis. The hydrogen is localized in the crystal lattice in three main states: in a solid solution trapped by defects, open volume defects, and in the form of hydrides.