Magnetic property enhancement of directly quenched Nd-Fe-B bulk magnets with Ti substitution

Magnetic properties, phase evolution, and microstructure of directly quenched NdyFe85−x−yTixB15 (x = 0-4; y = 8-10) bulk magnetic rods with a diameter of 0.7 mm were studied. The experimental results show that Ti substitution can not only suppress the formation of the Nd2Fe23B3 and one unknown phases, leading to the presence of the large amount of Nd2Fe14B phase, but also refine the grain size, resulting in the remarkable enhancement of magnetic properties. Besides, proper Ti substitution and Nd concentration can well modify phase constitution and uniformly refine grain size. In this study, the optimal magnetic properties of Br = 6.5 kG, iHc = 10.3 kOe and (BH)max = 8.7 MGOe are achieved in Nd9.5Fe72.5Ti3B15 magnet.