Effect of CaF2 on the Microstructure, Magnetic, and Electrical Properties of Nd–Fe–B Magnets

To increase the electrical resistance of Nd-Fe-B magnets, CaF₂ were used to fabricate Nd-Fe-B/CaF₂ composite permanent magnets by hot-pressing and hot-deformation techniques. The influence of CaF₂ on the microstructures, electrical resistances, and magnetic properties of the Nd-Fe-B/CaF₂ composite magnets has been investigated. The results show that the cross-sectional microstructure of the composite magnets appeared as layered-structure and wet blending contributed to the formation of smooth CaF₂ layers. The electrical resistances of the Nd-Fe-B/CaF₂ composite magnets increased with the amounts of CaF₂ and reached 1280 μΩ cm in the direction parallel to the pressing direction when the volume of CaF₂ was 20 vol.%, which increased 456% higher than that of the Nd-Fe-B magnet (230 μΩ cm). But the maximum energy products of the Nd-Fe-B/CaF₂ composite magnets decreased with the increase of the amounts of CaF₂.