热处理对SrFe_(12)O_(19)/-αFe_2O_3材料组织及磁性能的影响

Effects of heat-treatment technology on microstructures and magnetic properties of SrFe12O19/α-Fe2O3 nanocomposite

采用溶胶-凝胶方法制备了纳米复合永磁材料SrFe12O19/-αFe2O3。利用差重分析(DTG)、X射线衍射(XRD)、扫描电镜(SEM)与振动样品磁强计(VSM)探讨了热处理条件对磁性材料制备及其组织结构、磁性能的影响。结果表明,不同的热处理工艺导致相变过程不同,直火煅烧有利于纳米复合永磁材料SrFe12O19/-αFe2O3制备。直火煅烧650℃,纳米复合样品的剩磁、内禀矫顽力和最大磁能积分别为1.33T3、58.1kAm-1和134.8kJm-3,其剩磁和最大磁能积比分段煅烧样品有了较大提高,证明SrFe12O19/-αFe2O3粒子间产生了硬磁相和软磁相之间的交换耦合。

SrFe12O19/α-Fe2O3 permanent magnetic nanocomposite was prepared by sol-gel method and the influence of the heat treatment on preparation, microstructure and magnetic properties were studied by X-ray diffraction (XRD), differential weights analysis (DTG), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). Experimental results show that different phase transformation occurs by different heat-treatment processes. Directly heating-up is in favor of preparation of permanent magnetic nanocomposite SrFe12O19/α-Fe2O3. The remanence (Br), intrinsic coercivity (jHc) and maximum energy product (BH)Max of the SrFe12O19/α-Fe2O3 samples prepared by sintering at 650°C for 3 h are 1.33 T, 358.1 kAm-1 and 134.8 kJm-3. The nano-sized α-Fe2O3 dispersively distributed on SrFe12O19 allow effective exchange coupling between the two phases and exhibits on enhancement of permanent magnetic properties comparing with pure SrFe12O19.