SOME OBSERVATIONS CONCERNING ALPHA-BETA TRANSITIONS IN HYDROGEN-PALLADIUM

In a series of experiments, Pd wire was cooled from 250 deg C to room temperature and held for periods up to 120 hrs. while immersed in 10/sup -4/ molar LiOH solution containing high concentrations of dissolved H/sub 2/ (up to 120 STP cc H/sub 2//kg H/sub 2/O). The absorption of H/sub 2/ by the Pd was followed by resistance measurements. Very little H/sub 2/ was absorbed at temperatures below 150 deg C. At no time did the Pd transform completely to the beta phase. Partial transformation occurred when sufficient H/sub 2/ was absorbed above 150 deg C to allow cooling into the two-phase region at essentially constant H/sub 2/ concentration in the metal. Thus, the failure to transform completely was the result of the low rate of absorption and was not caused by inhibited nucleation of the beta phase or by slowness of the transformation itself. It is suggested that retarded absorption of H/sub 2/ is a characteristic of Pd in basic solution at low temperatures. (auth)