Preparation of Highly Textured Hydrogenation–Disproportionation–Desorption–Recombination Powders for Nd–Fe–B Sintered Magnets

As-cast Nd-Fe-B strips without an annealing treatment were treated by an appropriate hydrogenation-disproportionation- desorption-recombination (HDDR) process, and highly textured HDDR strip powders with uniform Nd-rich grain boundary layers can be obtained. The HDDR powders with a particle size of 50 μm show a Br of 1.13 T and a i H_c of 10.5 kOe. The crystal texture in the HDDR powders may come from the memory for the own crystallographic orientation and the casting texture of Nd₂Fe₁₄B columnar grains in the as-cast strips. The highly textured HDDR powders with uniform Nd-rich grain boundary layers can be used to prepare the fine-grained sintered magnets by a conventional jet-milling technique and sintering process.