Dissolution characteristics and occupancy sites of hydrogen in amorphous PdSi alloys. Part I

Abstract

Hydrogen solubility has been studied in three amorphous PdSi alloys with silicon contents of 14,18 and 20 at.%. Hydrogen charging was achieved by heating in the temperature range 20–200 °C in an atmosphere of hydrogen gas at pressures up to 12 MPa. The dissolved hydrogen concentrations were analysed by in situ electrical resistivity and thermogravimetry measurements. The heat of solution was determined for hydrogen concentrations ranging from about 0.1 to 6 at.%. The heat of solution was found to depend markedly on the dissolved hydrogen content. Deviations from Sieverts' law were observed concurrently. These features were compared with the dissolution characteristics of hydrogen in the crystalline host metal and were analysed in terms of the distribution spectrum of occupied sites, with particular reference to the influence of the amorphous condition and the incidence of silicon on the available sites.