Study on the magnetic properties, phase evolution and microstructure of Pr xFe 82.2−yTi yB 17.8−x ( x=5–11.8; y=2.5–5.5) nanocomposites

Abstract

Pr lean and boron-enriched ingots, i.e., Pr x Fe 82.2− y Ti y B 17.8− x ( x=5 to 11.8; y=2.5 to 5.5), were adopted for preparing melt-spun ribbons with nanostructures. Based on thermal magnetic analysis (TMA), for y=2.5, two phases, namely Pr 2Fe 14B and α-Fe, were found for ribbons with x=8.9, 10.7 and 11.8, while additional two metastable phases, Pr 2Fe 23B 3 and Fe 3B, prevailed for x=6 and 7.1. With the decrease of Pr content, remanence increases but coercivity decreases. The optimal properties of B r=9.5 kG, i H c=9.6 kOe, and (BH) max=17.7 MGOe are achieved in Pr 8.9Fe 79.7Ti 2.5B 8.9 nanocomposites. Meanwhile, better magnetic properties for easy magnetization at lower field, i.e. i H c=6.8 kOe, B r=9.9 kG and (BH) max=16.1 MGOe, are obtained in Pr 7.1Fe 79.7Ti 2.5B 10.7. The excellent permanent magnetic properties are mainly dominated by the nanoscaled microstructures and the coexistence of sufficient magnetically soft phases, Fe 3B, Pr 2Fe 23B 3 and α-Fe, with magnetically hard Pr 2Fe 14B phase.