Manufacture of Anisotropic NdFeB Powders Process from Sintered Magnets by HD

A manufacture method of anisotropic NdFeB magnet powders was investigated from sintered bulk magnets by hydrogen decrepitation (HD process): it is found that HD temperature plays a very important role affecting the coercivity of the obtained magnetic powders evidently. This temperature determines the fracture way of bulk magnets during HD process as well. In intergranular fracture way through properly controlled HD temperature, at 220 ℃ for instance, anisotropic magnet powders with a coercivity up to 490 kA/m are obtained after a following annealing treatment at 950 ℃.