Melting of transition metal-hydrogen systems under high pressure

Katayama, Yoshinori; Saito, Hiroyuki; Aoki, Katsutoshi

Hydrogen reacts with many kinds of metals and forms metal hydrides. Early transition metals such as Ti and V form hydrides while solubility of hydrogen in other transition metals such as Fe and Ni is low at ambient pressure. However, Fe and Ni absorb hydrogen under high pressure conditions. To study liquid state of transition metal-hydrogen systems, we have performed X-ray diffraction measurements under high-pressure high-temperature conditions for Ti, V, Mn, Fe, Co and Ni. The sample was heated together with hydrogen source at about 4 GPa. We did not observed clear melting for TiH and VH while we measured X-ray diffraction of liquid transition-hydrogen alloy for Mn, Fe, Co and Ni.