超声化学-放电等离子烧结制备Nd_2Fe_(14)B/α-Fe双相复合磁体

Nd_2Fe_(14)B/α-Fe Nanocomposite Magnets Prepared by Sonochemistry-SPS Process

采用超声化学法在介质中分解五羰基铁得到纳米Fe颗粒包覆Nd-Fe-B的复合磁粉,并采用放电等离子烧结(Spark Plasma Sintering,SPS)制备出Nd2Fe14B/α-Fe双相复合磁体。研究了Fe(CO)5的加入量对颗粒的包覆量、复合磁粉显微形貌、磁体微观结构及磁性能的影响。结果表明,五羰基铁溶液的加入量为15ml(Fe与Nd-Fe-B的名义质量比为1∶4)时所制备的磁体具有较高的磁性能:Br=0.959T,Hci=693.3kA/m(8.71kOe),(BH)max=141.93kJ/m3(17.83 MGOe)。适当的Fe(CO)5加入量对烧结磁体的剩磁和最大磁能积有增强作用,而软磁性相的分散程度则对磁体的矫顽力有较大影响,当软磁性相含量不断增加,由于其表面吸附的氧的增加,导致磁体性能下降。

Fe nanoparticles prepared by sonochemical treatment of earbonyl iron were applied to coat micrometer sized Nd-Fe-B permanent magnetic powder. The composite powders were then prepared into bulk nanocomposite Nd2Fe14B/a-Fe magnets by spark plasma sintering （SPS）. The mierostructure of both composite powders and composite magnets and the magnets performance of samples with different amount of Fe（CO）5 addition were invested. The magnet with better magnetic properties of Br =0.959T（9.59kGs）, Hci=696.8kA/m（8.71kOe）, and （BH）max=142.6kJ/m^3（17.83MGOe） were prepared with 15ml Fe（CO）5 coating. The increase of the Fe（CO）5 content promotes the remanence and magnetization, but the coercivity depends mostly on the dispersion of the soft phase. The performance of the magnet decrease when added vast Fe（CO）5 because of pick-up of more oxygen.