The decrepitation process, and related changes in the sample temperature, were analyzed in order to explain the experimentally observed weight-gain curve; due to H uptake. It was shown that the expansion of the specific surface, which resulted from decrepitation of the sample, was the most important parameter which controlled the H-diffusion process. It was suggested that decrepitation accelerated the diffusion rate by 5 orders of magnitude. A 1-dimensional model of decrepitation was presented for the detailed analysis of H diffusion. On the basis of this model, the experimental weight-gain curve and particle size distribution of the decrepitation product were reproduced with reasonable accuracy.

The Influence of Decrepitation on the Diffusion Kinetics of Hydrogen in Nd-Fe-B. P.Liszkowski, K.Turek, H.Figiel: Journal of Alloys and Compounds, 2000, 307[1-2], 297-303