Deuterium Absorption in Pd 0.9Y 0.1 Alloy

Abstract

Microgravimetric measurements are reported of the pressure–concentration dependence of deuterium in the palladium solid–solution alloy, Pd 0.9Y 0.1. An Intelligent Gravimetric Analyzer (IGA) was used and the measurements were made in the temperature range (60 °C≤ T≤100 °C). The results obtained revealed a hitherto unseen hysteresis effect in the absorption–desorption isotherm. This hysteresis is believed to be due to a reordering of the palladium–yttrium lattice driven by the hydrogen (deuterium) absorption. The second absorption/desorption cycle shows a wider hysteresis loop than the first but further cycles repeat the shape of the second loop. In-situ neutron diffraction measurements were also made on deuterated Pd 0.9Y 0.1 at 303 K. These data support the hypothesis that the hysteresis is due to an order–disorder transition involving the yttrium atoms in the metal lattice.