快淬Fe3B／Nd2Fe14B永磁材料晶化行为及磁性能的研究

利用熔体快淬和晶化处理的方法制备了快淬Fe3B／Nd2Fe14B永磁材料。采用XRD，DTA，VSM等方法对合金的晶化行为和磁性能进行研究。结果表明：对于Fe3B／Nd2Fe14B熔体快淬永磁粉末，升温速率对各相的析出和分解温度有一定的影响。完全过淬的Nd4.5Fe77B18.5和Nd4Fe77Cr0.5B18.5合金熔体快淬粉在进行973K，7min晶化处理过程中，首先形成Nd2Fe23B3相，然后Nd2Fe23B3相发生分解，其产物为Fe3B／Nd2Fe14B，此后再没有发生其它的相转变。当晶化温度大于953K，保温10min后，样品的剩磁、矫顽力和最大磁能积明显提高。微量元素Cr的添加对相转变温度有影响，同时可以细化晶粒，提高矫顽力，从而改善材料的永磁性能。

Study on the Crystallization Behavior and Magnetic Properties of Melt-Spun Fe3B/Nd2Fe14B Composite Magnets

Fe3B/Nd2Fe14B nanocomposite magnetic powders were prepared by melt quenching and heat-treatment.The microstructure and crystallization behavior were studied by X-ray diffraction(XRD),differential thermal analysis(DTA),and vibrating sample magnetometer(VSM).It is found that the heating-up rate will affect the formation and decomposition of the phases at a certain extent for melt-spun Fe3B/Nd2Fe14B powders.It is confirmed that the overquenched Nd4.5Fe77B18.5 and Nd4Fe77Cr0.5B18.5 samples were decomposed to Fe3B/Nd2Fe14B via metastable Nd2Fe23B3 during annealing at 973 K for 7 min.Hci,Jr and(BH)max have been obviously improved for the samples annealed above 953 K for 10 min.The addition of Cr is effective for refining the grain size and increasing the intrinsic coercivity,resulting in an improvement of hard magnetic properties.