Lani4.9al0.1 And Lani4.7al0.3 Tritium Aging Effects Experimental Research

The influence of tritium aging on hydrogen storage feature of LaNi4.9A10.1 and L aNi4 7A10.3 alloys were investigated by dedeuterating thermodynamics, dedeuterating dynamics and helium-3 release from aged materials. The tritium aging effect changed significantly the features of the equilibrium desorption isotherms for the aged LaNi4.9Ala.iD and LaNi4.7A1o3D. The effects include a decrease of 50 percent of the equilibrium desorption pressure at 373K, an increase of plateau slopes from 0.033 and 0.068 to 0.130 and 0.196, a reduction of the reversible hydrogen storage capacity I .3mmol.g? and an increase of formation heats (ill) from 34.5kimor?and 38.lkJmoF?to 42.5kJ?mof?and 49.9kjmor? Isotopic effects exist in the thermal-desorption of the aged LaNi4.gAlo.i(DT and LaNi47A10,3 (DT), and the separation factor(cL) decrease with hydrogen concentration in solid phase decreasing. The dedeuterating dynamics for the aged LaNi4.9Alo.tD and LaNi4.7AIo3D were investigated based on a dedeuterating dynamics model. The results show that dedeuterating reaction rates decrease with aging time and reduce up to a factor of 100 after 1120 days, Dedeuterating activate energy(E) increase from 34.5 kJ.moF1 and 38. 1kJ.mor to 42.5 k..J moF and 49.9kjmot? respectively. However, tritium aging effect doesn t change dedeuterating reaction orders, dedeuterating reaction order n(with respect to deuterium pressure in gas phase) and b(with respect to deuterium concentration in solid phase) are 0.5 and I, respectively. The results of helium-3 releasing experiments on aged materials show that both LaN i4.gAlo.1(DT) and LaNi4 ,A10.3 (DT) have strongly ability to detain helium-3 in lattice. Even after 1120 days, very little helium-3 have released from the lattice when the samples were heated to 673K, and 98 percent of helium-3 are detained in lattice en the samples were heated to 1000K. X-ray diffraction patterns of the 2140 days tritiumaged LaNi5 samples after show the presence of lattice strains and orientational effects of heliurn-3 in the LaNi5 lattice, the effect of helium varies with crystallographic direction. It is can be concluded that the tritium aging effects were caused by the decay helium-3 in the lattice according the above results.