Effect of Pr concentration on the magnetic properties and phase evolution of Ti-substituted PryFe88−yTi2B10 (y = 9.5-7) nanocomposite ribbons

Magnetic properties, phase evolution, and microstructure of melt spun PryFe88−yTi2B10 nanocomposite ribbons with different Pr concentration (y = 9.5-7) have been investigated. For Pr9.5Fe78.5Ti2B10, only the 2:14:1 phase and the α-Fe phase existed, while an additional Fe3B phase appears for the ribbons with y = 9-7.5. On further decrease of the Pr content (y = 7), one extra phase, 2:23:3, is found. The exchange coupling effect, as evidenced by a Henkel plot is found, to decrease with the decrease of the rare earth content, which is attributed to the increasing of grain size with decreasing of Pr content. The magnetic properties of the ribbons first improve with the decrease of y, reaching a maximum at y = 8.5 (Br = 9.6 kG, iHc = 8.5 kOe, and (BH)max = 17.8 MGOe), then decrease with further decrease of the Pr content (Br = 9.8 kG, iHc = 5.6 kOe, and (BH)max = 14.5 MGOe for y = 7). In comparison with the Ti-free PrxFe90−xB10 (x = 9.5-7) ribbons, improved magnetic properties with higher intrinsic coercivity can be obtained in PryFe88−yTi2B10 nanocomposites. The maximum magnetic properties of PryFe88−yTi2B10 nanocomposites can be found in the ribbons with lower rare earth content, i.e. x = 9.5 for the former and y = 8.5 for the latter.