Coercivity mechanism of hydrogenation disproportionation desorption recombination processed Nd–Fe–B based magnets

Abstract

We have investigated the microstructure change of hydrogenation disproportionation desorption recombination processed Nd12.5Fe73Co8B6.5 powders during the desorption recombination (DR) stage to understand the mechanism of the coercivity development in the DR process. A uniform Nd-enriched layer was found to form along the grain boundaries when coercivity starts to increase in the DR process, which should be the main reason for the coercivity development. However, the composition of this grain boundary layer was found to contain a high concentration of ferromagnetic elements.