Fabrication and magnetic properties of Ce–Fe–B/Alnico SPS magnets produced by two alloy method

In this paper Ce–Fe–B melt-spun ribbons with a nominal composition Ce 29.8 Fe 68.7 Ge 0.5 B, and Alnico 5 melt-spun ribbons with a nominal composition of Co 24.5 Al 8 Ni 14 Cu 2.5 Nb 1 Fe 50 were first fabricated. The two types of ribbons were ground and thoroughly mixed to produce magnetic powder, which was then consolidated into Ce–Fe–B/Alnico composite magnets by spark plasma sintering, SPS. The magnetic properties, phase composition, microstructure, and interaction mechanisms of the SPS magnets are systematically investigated, and their applicability is analyzed. By incorporating Alnico, which possesses high saturation magnetization, M s , into Ce–Fe–B, which has low M s , composite magnets with enhanced properties are obtained. The resulting magnetic properties reached remanence, B r = 0.52 T, intrinsic coercivity, H cj = 113.43 kA/m, and maximum energy product, (BH) max = 17.68 kJ/m 3 in the 10% Alnico containing composite, which are further enhanced to B r = 0.54, H cj = 86.2 kA/m and (BH) max = 22.8 kJ/m 3 . The magnet temperature stability enhanced noticeably for higher Alnico contents. Compared with Ce–Fe–B SPS magnets prepared using the same sintering process, the B r increased by 31.6% and 35%, and the maximum energy product increased by 45.5% and 84.4%, respectively, for 10% and 20% Alnico containing composites. The uniform distribution of the two-phase structure resulted in good coupling between the phases, avoiding nucleation-driven demagnetization.