Interaction mechanism, magnetic properties and microstructure of Ce-Fe-B/Alnico spark plasma sintered magnets

By combining rare earth-based Ce-Fe-B and rare earth free Alnico powders, composite Ce-Fe-B/Alnico spark plasma sintered (SPS) magnets have been fabricated and reported for the first time. It is observed that the two phases exit in the alloys interacting magnetostatically. The Alnico phase constitutes alpha(1) and alpha(2) phases as a consequence of spinodal decomposition process, while the Ce-Fe-B phase contained Ce2Fe14B and CeFe2 phases. By increasing the content of Alnico phase, the remanence magnetization and the maximum energy density of the composite alloys increased owing to the higher saturation magnetization of Alnico phase. Magnetic properties, such as remanence magnetization J(s) = 0.93 T, intrinsic coercivity H-cj = 202 kA/m and maximum energy density (BH)(max) = 19.8 kJ/m(3) were obtained in spark plasma sintered composite magnets containing 15 wt% Alnico. The recoil loops demonstrated the presence of anisotropy variations in the alloys specifically at high applied magnetic field. Analysis of the Curie temperature and elemental analysis validated that the constituent phases of SPS magnets exist in the alloys. This work may shed light on the development of composite magnets with distinct phases and enhanced magnetic properties.

Automated summary

Composite Ce-Fe-B/Alnico spark plasma sintered (SPS) magnets, combining rare earth-based Ce-Fe-B and rare earth free Alnico powders, were fabricated for the first time. Alnico phase and Ce-Fe-B phase exhibited different magnetic properties, with an increase in Alnico phase leading to enhanced magnetic properties of the composite alloys. These results may contribute to the development of composite magnets with distinct phases and improved magnetic properties.