Fabrication and Phase Evolution of Pr2Fe14C-based Magnetic Nanoparticles Prepared by Mechanochemical Method

Abstract A facile mechanochemical method for fabricating Pr 2 Fe 14 C-based magnetic nanoparticles was reported. H and C were introduced by the decomposition of heptane during the high-energy ball milling process and reacted simultaneously with Pr 3 Fe 14 B x (X=0-0.2) alloy to form Fe 7 C 3 , PrH 2+δ and α-Fe phases. Subsequently, the H 2 released from the PrH 2+δ and Pr 2 Fe 14 C-based magnetic materials were obtained during a fast vacuum annealing process. Compared with the traditional heat-treatment which involved time-consuming annealing and multi-steps cooling process, the zero holding time annealing with a fast heating rate will effectively reduce the energy consumption. Addition of small amounts of boron is demonstrated to promote the formation of Pr 2 Fe 14 C and reduce the quantity of magnetically soft Pr 2 Fe 17 and α-Fe phases. The optimal magnetic properties of M r =5.9 kG, i H c =19.8 kOe and ( BH ) max =8.0 MGOe were obtained in Pr 3 Fe 14 B 0.1 sample after ball-milling for 7 hours and subsequently annealing. Microstructure morphology analysis of the as-annealed Pr 3 Fe 14 B 0.1 powder reveals that the particles are almost rectangular shapes with an average size of about 117 nm. This bottom-up approach for fabrication of Pr 2 Fe 14 C nanoparticles may provide new thoughts for the preparation of high-performance magnetic materials.