Tritium absorption–desorption characteristics of LaNi4.25Al0.75

As a part of the program to develop metal hydride technology for storing and processing tritium, the tritium absorption–desorption of LaNi4.25Al0.75 was investigated. The pressure–composition–temperature (P–C–T) curves, activation characteristics and the absorption–desorption rate of tritium from LaNi4.25Al0.75Tx at different temperature were measured. And standard enthalpy ΔHθ and entropy ΔSθ changes for T2 absorption and desorption were calculated from van’t Hoff plots based on the measured P–C–T relations. The calculated value of ΔHθ and ΔSθ during the formation of the LaNi4.25Al0.75T2.5 phase is (−31.8 ± 0.8) kJ mol−1 and (−76.5 ± 2.4) J mol−1 K−1, and the value of desorption is (−36.5 ± 0.5) kJ mol−1 and (−84.2 ± 1.5) J mol−1 K−1, respectively. Composition difference between the origin tritium gas and tritium released from 7-day-aged LaNi4.25Al0.75 tritide was analyzed by quadrupole mass spectrometer.