1996 Volume 29 Issue 2 Pages 223-228
The hydriging reaction kinetics of LaNi4.7Al0.3 under isothermal conditions were studied in detail using a double-walled reactor which possessed high heat conductivity. The reaction characteristics in the α+β phase region were discussed from the viewpoint of rate-controlling steps.
It was found that several rate-controlling steps were involved during hydriding reactions from the α to the β phase regions and the rate-controlling step changed with the change of phase regions. For the hydriding reaction in the α+β phase region, the rate-controlling step was found to be the phase transformation process at the interface between the α and the β phases.
The hydriding reaction kinetics of other rare earth-nickel based alloys, LaNi5–xAlx (x = 0, 0.1, 0.2) and MmNi4.5Al0.5 (Mm: mischmetal), were determined in the same way, and similar results were obtained.
