Magnetic Properties and Microstructure of Ce and Zr Synergetic Stabilizing Ti-lean SmFe12-based Strip-Casting Flakes

Recently ThMn 12 -type samarium iron alloys have been promising materials for permanent magnets. Due to the high abundance and low cost, Ce as a possible stabilizer can be introduced into ThMn 12 -type alloys. The effect of Ce doping on the magnetic moment and phase stability in Ti -lean (Ce,Sm,Zr)(Fe,Co,Ti) 12 compounds were predicted by the first -principles calculations. The Ce x Sm 0.8-x Zr 0.2 (Fe 0.8 Co 0.2 ) 11.5 Ti 0.5 (x = 0 - 0.8) alloys with ThMn 12 structure were produced by strip -casting into flakes by a wheel speed of 1.5 m/s and annealed at 1000 degrees C for 24 h. The Ce 0.8 Zr 0.2 (Fe 0.8 Co 0.2 ) 11.5 Ti 0.5 annealed flake shows a high saturation magnetization value of 13.6 kGs at room temperature. With the increase of Ce substitution in the annealed flakes, the content of alpha-(Fe,Co,Ti) phase decreases and the saturation magnetization increases. The 1:12 phase and the 1:9 phase have an orientation relationship that can be expressed as [0 0 - 1] 1:12 //[1 0 0] 1:9 and (02 0) 1:12 //(0 1 0) 1:9 . Besides, annealing process promotes the formation of 1:12 phase transformed from 1:9 phase. Coercivity is expected to be improved by obtaining uniform microstructure and suppressing the formation of soft alpha-(Fe,Co,Ti) phase in the ThMn 12 - based alloys.