AU-197 MOSSBAUER STUDY OF THE HYDRIDES OF NI-AU ALLOYS

Hydrides of Ni1-yAuy alloys with y = 0.01, 0.10 and 0.20 were prepared electrolytically or under high pressures of molecular hydrogen and studied by Mossbauer spectroscopy with 77.3 keV gamma-rays of Au-197. At a pressure of 7 GPa, hydrogen-to-metal ratios close to unity could be obtained, while using electrochemical loading or at hydrogen pressures around 1 GPa, only interstitial sites without gold neighbours appeared to be occupied, although the ferromagnetism was already completely suppressed. The isomer shifts of the Mossbauer patterns were found to depend on both long range influences of hydrogen and on direct effects of nearest hydrogen neighbours.