(S1.10-S0074)Microstructure analysis of Ga doped ultra-fine grained magnets fabricated by HDDR and pressless sintering

摘要

Grain size refinement is one of effective approaches to increase the coercivity in Nd-Fe-Bmagnets, and high coercivity over 1.9 T was reported in a sintered magnet with 1 μm grain size fabricated bypress-less sintering process (PLP) [1]. Since hydrogenation disproportionation desorption recombination(HDDR) prior to He-jet milling leads to further grain size refinement, higher coercivity is anticipated in thesintered bulk subjected to HDDR (HDDR sintered magnet) [2]. However, the coercivity of the HDDR sinteredmagnet remained only 1.3 T. This work presents the microstructure of HDDR and PLP magnets to discuss thepossible origins of the low coercivity in the HDDR sintered magnets.