Synthesis of CeFe10.5Mo1.5 with ThMn12-type structure by melt spinning

Abstract Rare earth compounds RFe 12− x M x with tetragonal ThMn 12 -type structure are of great research interest for potential applications as permanent magnets. These materials are known to serve as the precursors for nitriding and hydriding processes which in certain conditions can dramatically increase the Curie temperature, spontaneous magnetization, and affect the magnetic anisotropy. In this paper, we report the phase study of CeFe 10.5 Mo 1.5 samples melt spun at various surface wheel speeds v s between 5 m/s and 60 m/s. The results from quantitative Rietveld analysis indicate that the as-spun ribbons are a mixture of primary CeFe 10.5 Mo 1.5 phase with impurity phases such as Ce 2 Fe 17 , Fe–Mo alloy and CeFe 2 . When the wheel speed v s is below 25 m/s, CeFe 10.5 Mo 1.5 phase accounts for greater than 85 wt% in the as-spun ribbons, while the Fe–Mo alloy is the only detectable impurity phase. Above v s =25 m/s, as the wheel speed increases, CeFe 10.5 Mo 1.5 phase decreases monotonically to about 60 wt% at v s =60 m/s while the amounts of impurity phases increase. Thermogravimetric measurement indicates that the Curie temperature T c corresponding to CeFe 10.5 Mo 1.5 phase is 341 K. As a result, the best performing sample melt spun at v s =15 m/s only exhibits an energy product BH max =0.121 MGOe at room temperature. Although such a number is modest for a permanent magnet, further nitriding is expected to greatly enhance the Curie temperature, and hence the magnetic performance.