In order to investigate the mechanism about the effects of tritium aging on metal hydride
experiments were performed on some aged LaNi 5 materials which had been loaded with DT and stored at room temperature for 2140 days. Tritium aged LaNi 5 retains nearly all the decayed 3He within the bulk. The tritium aging effects were observed by determining the deuterium desorption isotherms in various states. These effects included (1) a right shift of the isotherms
(2) an increase in the plateau slope
(3) a reduction in the reversible storage capacity
and (4) the formation of tightly bound tritium
which was often referred to as the tritium heel. It was found that these effects were completely removed after the 3He had been removed by 1230K heating of the samples. This provides a direct evidence for the mechanism that tritium aging is caused by 3He.