PREPARATION METHOD OF NDFEB MAGNET HAVING LOW MELTING POINT LIGHT RARE-EARTH-COPPER ALLOY AT GRAIN B

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A preparation method of an NdFeB magnet having a low melting point light rare-earth-copper alloy at a grain boundary. The preparation steps comprises : crushing near-stoichiometric 2 : 14 : 1 NdFeB main alloy ingots into particles of 3-5 μm, adding and uniformly mixing with a powder of a light rare-earth-copper alloy having a weight percentage of 3-8% and a mean particle size of 0.1-3 μm, performing shaping under a magnetic field, isostatic pressing, sintering and compacting, and then treating with heat to obtain a product. The light rare-earth-copper alloy is both a liquid sintering aid and a grain boundary phase, and has good wettability with the 2 : 14 : 1 main phase. The light rare-earth-copper alloy is uniformly distributed at the grain boundary of the 2 : 14 : 1 main phase and effectively blocks the exchange coupling between grains of the 2 : 14 : 1 main phase, such that a high coercivity can be obtained. In addition, low-temperature sintering can be realized to eliminate the high-temperature annealing heat treatment, thus simplifying the process and saving energy.