Preparation of Thin-Plate Fe3B/Nd2Fe14B Nanocomposite Permanent Magnets

The quenching conditions for the formation of a nanocomposite microstructure in rapidly-solidified Nd4Fe77.5B18.5 alloys were investigated in order to obtain a hard magnetic material consisting of Fe3B and Nd2Fe14B in the as-quenched state by means of the Cu single-roll melt-spinning technique. It was found for the first time that as-spun Fe3B/Nd2Fe14B hard magnets can be obtained directly from a molten alloy when the melt-spinning process is carried out under a reduced chamber pressure of 1.3 kPa Ar on a Cu-roll surface moving at a velocity of 5 m/s. The as-spun Nd4Fe77.5B18.5 hard magnet has a thickness of 190 μm and magnetic properties of Jr = 1.25 T, (BH)max = 118.1 kJ/m3, and HcJ = 276 kA/m at room temperature. The Fe3B/Nd2Fe14B nanocomposite hard magnets obtained by this technique may be used to produce thin-plate permanent magnets.