Abstract: In order to investigate the phenomenon of hydrogen absorption and decrepitation of NdFeB alloy, the diffusion time of hydrogen in HD process of NdFeB alloy was theoretically calculated with the Fick diffusion equation. When NdFeB alloy whose granularity was 5 millimeters was treated with hydrogen decrepitation at 25℃, the total diffusion time of hydrogen which successively entered the center of the alloy granule, Nd-rich phase and Nd2Fe14B phase was 31.5 minutes calculated with the Fick diffusion equation, while the actual time of hydrogen decrepitation was 30 minutes. The results showed that the theoretically calculated hydrogen diffusion time coincides well with the practically needed time in HD process of NdFeB alloy, and indicated that the mathematical model of hydrogen diffusion in HD process of NdFeB alloy based on the Fick diffusion equation tallys well with the practical HD process.
