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

Rare earth compounds RFe12−xMx with tetragonal ThMn12-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 CeFe10.5Mo1.5 samples melt spun at various surface wheel speeds vs 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 CeFe10.5Mo1.5 phase with impurity phases such as Ce2Fe17, Fe–Mo alloy and CeFe2. When the wheel speed vs is below 25 m/s, CeFe10.5Mo1.5 phase accounts for greater than 85 wt% in the as-spun ribbons, while the Fe–Mo alloy is the only detectable impurity phase. Above vs=25 m/s, as the wheel speed increases, CeFe10.5Mo1.5 phase decreases monotonically to about 60 wt% at vs=60 m/s while the amounts of impurity phases increase. Thermogravimetric measurement indicates that the Curie temperature Tc corresponding to CeFe10.5Mo1.5 phase is 341 K. As a result, the best performing sample melt spun at vs=15 m/s only exhibits an energy product BHmax=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. - Highlights: ► We synthesize CeFe10.5Mo1.5 with ThMn12-type structure by melt spinning. ► Melt spinning dramatically reduces the synthesis time from weeks to hours. ► The as-spun CeFe10.5Mo1.5 ribbons are multiphasic. ► A lower wheel speed vs≤25 m/s favors the formation of CeFe10.5Mo1.5 phase