SOME PHYSICAL-PROPERTIES OF ZR2CUH4.2 IN RELATION TO THOSE OBSERVED FOR OTHER MOSI2-TYPE HYDRIDES

The intermetallic compound Zr2Cu with the tetragonal MoSi2-type structure produces a metastable ternary hydride Zr2CuHx. Powder X-ray diffraction indicated a monoclinic unit cell for this phase when x almost-equal-to 4.2. Nuclear magnetic resonance of the proton rotating frame relaxation times gave an activation energy of 0.28 eV for hydrogen diffusion in Zr2CuH4.2. Irreversible changes in the proton relaxation times were noted after the Zr2CuH4.2 sample had been heated above 500 K. X-ray diffraction confirmed the decomposition of the original ternary phase into a mixture of ZrH(x) and other components, including metallic copper.