Recycling of scrap sintered Nd–Fe–B magnets as anisotropic bonded magnets via hydrogen decrepitation process

Abstract

The scrap sintered Nd–Fe–B magnets were recycled as the raw materials for bonded magnets using the hydrogen decrepitation (HD) process. The HD powders have the lowest oxygen and hydrogen content by hydrogenation at 150 °C with 1 bar H2 pressure and dehydrogenation at 600 °C. The powders with the largest particle size (>380 μm) bear the best magnetic properties (Br = 110.59 emu/g, Hcj = 9005.80 Oe). The magnetic properties of the resulting bonded magnet prepared from the above powders were Br = 7.02 kGs, Hcj = 4.56 kOe, (BH)max = 7.13 MGOe.