Formation of perovskite-type hydrides and thermal desorption processes in Ca–T–H (T = 3d transition metals)

Formation abilities of perovskite-type hydrides in Ca1+xT–H, where T = 3d transition metals and x = 0–1.0, were examined. CaNiH3 and CaCoH3 were found to form the cubic perovskite structure. In the former hydride, the maximum amount of Ni vacancy is estimated to be approximately 20%, CaNi0.8H3, using powder neutron diffraction measurements. The thermal desorption processes of CaT–H for T = Fe, Co or Ni were investigated by the relationship between perovskite- and complex-type hydrides.