Magnetic Properties of Liquid Quenched Nd-Fe-B Alloys

Nd2 Fe14B and Fe15Fe77B8 alloys were prepared both by rapid quenching and by slow cooling from the melt. The resulting crystal structure and magnetic properties were investigated. An X-ray diffraction spectrum of the slowly cooled sample indicated the presence of ¿-Fe and the tetragonal Nd2Fe14B phase, but the peaks in the spectrum of the quenched sample were considerably flattened. As had already been reported, the Hc and magnetization characteristics depended strongly on the quenching rate, but the highest Hc obtained, 2.3 kOe, is only 1/8 that of commercial Nd-system magnets. The relatively low Hc was attributed to too fast a quenching rate.