放电等离子烧结新型NdFeB永磁材料研究

研究了采用放电等离子烧结技术制备新型NdFeB永磁材料。重点考察了工艺条件对磁体的磁特性、尺寸精度和密度的影响。利用B-H回线仪、扫描电镜和电子能谱对其磁特性、显微组织结构和成分进行了分析测试，同时考察了材料在电解液中的电化学特性及其氧化腐蚀特性。结果表明：与传统烧结NdFeB相比，这种新型NdFeB磁体的显微组织明显不同，其晶粒尺寸细小均匀，富钕相弥散分希；磁体的最佳磁特性为最大磁能积2401kJ／m^3矫顽力1260kA／m；密度达到7．58g／cm^3；尺寸精度为20μm；磁体同时具有良好的抗腐蚀性。

Study on A New Kind of NdFeB Magnet Prepared by Spark Plasma Sintering

A new kind of NdFeB magnet was produced by spark plasma sintering technique. Magnetic properties, microstructure and constituents were investigated by means of B-H loop-line instrument, scanning electron microscope and energy dispersive X-ray detector. The effects of processing conditions on the magnetic properties, dimensional precision as well as density were studied. The electrochemical property in electrolytes and the corrosion behavior in oxidation environment were examined for the magnets. It is found that the microstructure of SPS NdFeB magnet is different from that of conventional one, the grain size is fine and uniform while the distribution of the Nd-rich phase is heterogeneous. The optimal magnetic properties of the SPS NdFeB magnets obtained so far are of a maximum energy product of 240 kJ / m3 and a coercive force of 1 260 kA/m. The density of the magnet reaches 7. 58 g/cm3 as well as the dimensional precision of the magnets is about 20 p.m. Meanwhile, the electrochemical property and the corrosion resistance of SPS NdFeB magnets are much better if compared with conventional one.