High-Pressure X-ray Studies of the Ni-H, Re-H and Al-H Systems

Abstract

The room tempearture equations of state of the metallic hydrides NiH_x and ReH_x have been studied to 123 GPa and of the nonmetallic hydrides AIH₃/AID₃ to 53 GPa by means of x-ray diffraction in a diamond anvil cell. The partial hydrogen volume in ALH₃/AlD₃ is found to reduce to that characteristic of metallic hydrides at∼47 GPa. The evolution of the partial hydrogen volume with pressure in the metallic hydrides is discussed in light of existing empirical models.