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

Abstract Hydrogen absorption in the intermetallic compounds Zr 2 TM (TM = Cu, Ag, Au) with MoSi 2 -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 Zr 2 Cu > Zr 2 Ag ≫ Zr 2 Au. XRD revealed that Zr 2 Cu and Zr 2 Ag could decompose into Cu or Ag and ZrH x ( x  ∼ 2), while Zr 2 Au 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 Zr 2 TM.