Magnetic properties, microstructure, and phase evolution of PrxFebal.TiyB20−x (x=4–9; y=2.5–5) nanocomposites

Magnetic properties, microstructure, and phase evolution of Pr lean and boron-enriched PrxFebal.TiyB20−x (x=4–9; y=2.5–5) melt-spinning ribbons with nanostructures have been investigated. Based on thermal magnetic analysis (TMA), for y=2.5, two phases, namely Pr2Fe14B and α-Fe, were found for ribbons with x=9, while additional two metastable phases, Pr2Fe23B3 and Fe3B, existed for x=4, 7 and 8. With the decrease of Pr content, the remanence increases but coercivity decreases. The optimal properties of Br=9.5 kG, iHc=10.7 kOe, and (BH)max=17.8 MG Oe are achieved in Pr9Febal.Ti2.5B11 nanocomposites. On the other hand, higher Ti substitution for Fe in Pr7Febal.TiyB13 ribbons could refine the grain size and suppress the metastable Pr2Fe23B3 and Fe3B phases effectively. The excellent permanent magnetic properties are mainly dominated by the nanoscaled microstructures and the coexistence of sufficient magnetically soft phases, Fe3B, Pr2Fe23B3 and α-Fe, with magnetically hard Pr2Fe14B phase.