Bulk anisotropic composite rare earth magnets

摘要

Bulk anisotropic composite Nd_(13.5)Fe_(80)Ga_(0.5)B_6/alpha-Fe and Nd_(14)Fe_(79.5)Ga_(0.5)B_6/Fe-Co magnets with (BH)_(max)=45-50 MG Oe have been synthesized by blending a Nd-Fe-Ga-B powder with an alpha-Fe or Fe-Co powder followed by hot compaction at 600-700 deg C and hot deformation (die upsetting) at 850-950 deg C with a height reduction of 71 percent. The composite Nd_(13.5)Fe_(80)Ga_(0.5)B_6/alpha-Fe and Nd_(14)Fe_(79.5)Ga_(0.5)B_6/Fe-Co magnets show microstructures consisting of a very large soft phase up to approx 50 mu m, which is more than 1000 times larger than the upper size limit of the soft phase expected from the existing models of interface exchange coupling.