Hydrogen absorption in the intermetallic compounds Zr2TM (TM = Cu, Ag and Au) with MoSi2-type structure (C11b)

Hydrogen absorption in the intermetallic compounds Zr2TM (TM = Cu, Ag, Au) with MoSi2-type structure was characterized by differential scanning calorimetry (DSC) under hydrogen, hydrogen-storage capacity measurement and X-ray diffraction (XRD). The amount of heat for the exothermic peak in DSC due to hydrogen absorption and the maximum hydrogen-storage capacity increased in the order of Zr2Cu > Zr2Ag ≫ Zr2Au. XRD revealed that Zr2Cu and Zr2Ag could decompose into Cu or Ag and ZrHx (x ∼ 2), while Zr2Au can form a solid solution with hydrogen without decomposition. These findings were well explained based on the magnitude and/or sign of the estimated enthalpy change for the decomposition of Zr2TM.