High coercivity in rare-earth lean nanocomposite magnets by grain boundary infiltration

Abstract

A significant enhancement in coercivity was achieved by grain boundary modification through low temperature infiltration of Pr75(Cu0.25Co0.75)25 eutectic alloy in rare-earth lean (Pr/Nd)-Fe-B/α-Fe nanocomposite magnets. The infiltration procedure was carried out on ribbons and hot-deformed magnets at 600-650 °C for different time durations. In Nd2Fe14B/α-Fe ribbons, the coercivity increased from 5.3 to 23.8 kOe on infiltration for 4 h. The Pr2Fe14B/α-Fe hot-deformed magnet shows an increase in coercivity from 5.4 to 22 kOe on infiltration for 6 h. The increase in the coercivity comes at the expense of remnant magnetization. X-ray diffraction studies confirm the presence of both the hard Nd2Fe14B and soft α-Fe phases. A decrease in the soft α-Fe phase content was observed after infiltration.