Study of magnetic properties of Pr2Fe14B/α-Fe nanocomposite magnets

Abstract

Pr2Fe14B/α-Fe nanocomposite magnets were prepared by the melt-spinning technique. The magnetic properties of the magnets were measured by means of a vibrating sample magnetometer(VSM). Alloy compositions were (PrxFe94.3-xB5.7)0.99Zr1 with x=8.2, 8.6, 9.0, 9.4, 9.8, 10.2, 10.6, 11.0 and 11.4(atomic fraction,%). The effects of the wheel speed and alloy composition on the magnetic properties of melt-spun ribbons were investigated systematically. A decrease of remanence Jr with the increase of atomic fraction of Pr is observed causing an increase in coercivity Hci when changing Pr fraction from 8.2% to 11.4 % which is believed to be the cause of the decrease in maximum energy product (BH)max. Despite the low value of Hci obtained for the 8.2 % Pr alloy, (BH)max is substantially raised by the high Jr which reflects the high volume fraction of α-Fe phase. The Jr, Hci and (BH)max of the best sample quenched at a wheel speed of 25 m/s are 1.37T, 501.19kA/m and 227.93kJ/m3, respectively. The magnetic properties in the direction perpendicular to the ribbon surface are much higher than that in the direction parallel with the ribbon surface.