Effect of substitution of refractory elements for Fe on the magnetic properties of melt-spun Pr9.5Fe80.5B10 nanocomposites

Magnetic properties and phase evolution of Pr-deficient and B-excess Pr9.5Fe80.5B10 ribbons obtained by refractory elements substitution have been investigated. From thermal magnetic analysis (TMA), it was proved that both Pr2Fe23B3 and Fe3B phases have been completely suppressed for the ribbons with all the selected refractory elements substitution. A slight substitution of the adopted refractory elements (Cr, Nb, V, Ti and Zr) for Fe not only suppresses the formation of metastable Pr2Fe23B3 and Fe3B phases but also leads to the presence of a large amount of the Pr2Fe14B phase. Accordingly, the coercivity of the ribbons was improved remarkably from 8.3 kOe for ternary Pr9.5Fe80.5B10 ribbons to 10.1-13.2 kOe for all chosen refractory element-substituted nanocomposites. The optimal magnetic properties of Br = 9.0 kG, iHc = 13.2 kOe and (BH)max = 16.9 MGOe can be obtained in Pr9.5Fe78.5Nb2B10. Finally, from minor loop analysis, the coercivity of all studied ribbons is mainly dominated by domain wall pinning.