Thermomagnetic behaviour and microstructure of a rapidly quenched Nd4.5Fe77B18.5 alloy

Abstract

Changes in the phase composition and crystallite size, as well as changes in the magnetic behaviour of Nd4.5Fe77B18.5 alloy, caused by thermomagnetic measurements, was observed in regard of the optimal magnetic state of this alloy. In the optimized magnetic state, the formed nanocomposite consisted of Fe3B/Nd2Fe14B and partly of alpha-Fe with a mean crystallite size LT 30 nm, as determined by X-ray diffraction and transmission electron microscopy. An increased amount of alpha-Fe, the presence of Nd2O3 and different Fe-B phases, as well as an increase in the mean crystallite size were observed after thermomagnetic measurements had caused a quality loss of the hard magnetic properties.