ACTIVATION CHARACTERISTICS OF CHEMICALLY TREATED LANI4.7AL0.3

The H-2 activation characteristics of the hydriding AB5 intermetallic compound LaNi4.7Al0.3 were determined before and after chemical surface treatment in an F-containing aqueous solution (F-treatment). The F-treatment results in an Ni-rich surface which is overlaid by a net-like LaF3 layer and results in a pronounced decrease in the time required for activation, as much as two orders of magnitude. The ease of activation is attributed mostly to the Ni-rich sublayer, although the LaF3 overlayer may contribute to long term protection of the sublayers from deleterious gases such as air and H2O vapor. Increasing the ease of activation will allow the use of thinner wall, lower cost containers for practical hydriding applications.