Low-cost Ce1-xSmx(Fe, Co, Ti)12 alloys for permanent magnets

Ce1-xSmxFe9Co2Ti alloys based on the ThMn12-type crystal structure have been synthesized via melt-spinning of prefabricated alloys and via mechanochemical processing of CeO2- Sm2O3- Fe2O3-TiO2- Co - Ca - CaO powder mixtures. Coercive fields up to 0.8 kOe and 2.1 kOe were obtained in annealed melt-spun alloys with x = 0 and x = 0.5, respectively. Submicron, partially anisotropic particles collected after the mechanochemical synthesis for x = 0.5 and x = 1 exhibited coercivity (energy product) of 1.8 kOe (5.4 MGOe) and 5.8 kOe (9.9 MGOe), respectively. The low magnetic anisotropy field of CeFe9Co2Ti alloy requires at least a partial Sm-substitution for Ce in order to develop a reasonably high coercivity.