Static, dynamic and cycling studies on hydrogen in the intermetallics LaNi 5 and LaNi 4.77Al 0.22

Abstract

The use of intermetallic-H 2 alloys in chemical heat engines requires a precise determination of the thermochemical properties: isotherms, absorption-desorption kinetics, hysteresis effects, mass of hydrogen to be transferred etc. An experimental apparatus was devised to study these properties simultaneously. We report here on studies concerning the LaNi 5 and LaNi 4.77Al 0.22 systems. The variation in the properties of these compounds was followed from the activation procedure up to the operation after 1250 cycles. The “quasi-static” results are comparable with the published data, but those concerning the kinetic and cycling studies present some differences. The experimental conditions under which the studies are carried out seem to play an important role.