Mechanically alloyed isotropic and anisotropic Nd-Fe-B magnetic material

Abstract

Starting from elemental powders, hard‐magnetic Nd‐Fe‐B can be produced by mechanical alloying and a solid‐state reaction. Due to the short reaction time at relatively low temperatures (typically 30 min at 700 °C), the magnetically isotropic particles are microcrystalline and show a high coercivity. These powders can be compacted to dense isotropic magnets by hot uniaxial pressing. An additional deformation at elevated temperatures is used to form magnetically anisotropic samples. With regard to microstructure, magnetic properties, compaction, and formation of anisotropy, the magnetically alloyed material is comparable with the rapidly quenched Nd‐Fe‐B. The formation characteristics and the magnetic properties of resin‐bonded powder, hot compacted isotropic material, and hot deformed anisotropic samples are described.