Hydrogen solubility in uranium intermetallic compounds with Fe₂P type structure

Hydrogen absorption properties of UMAl (M=Ni, Co) intermetallic compounds with a Fe₂P type structure were examined in the temperature range from 298K to 523K and at the hydrogen pressures up to about 2 MPa by using a modified Sieverts apparatus. UNiAl had great capacities for hydrogen absorption per formula unit, but UCoAl didn't have. The crystal structures and lattice parameters of the compounds were examined by X-ray diffraction analysis. In UNiAl-H system, there exists α (dilute solid solution), β (UNiAlH hydride), and γ (UNiAlH₂ hydride) phases. The standard enthalpy changes of formation of the hydrides were estimated from the equilibrium pressure-composition isotherms. (author)