锶铁氧体微管的模板法制备及其磁性研究

以Sr(NO3)2和Fe(NO3)3•9H2O为原料与不同比例的柠檬酸在水溶液中形成溶胶, 把溶胶滴于脱脂棉模板上, 水分挥发后在脱脂棉表面形成凝胶, 于不同温度下煅烧后制得了SrFe12O19微管. 利用X射线衍射技术(XRD)﹑扫描电子显微镜(SEM)﹑透射显微镜(TEM)对样品的物相﹑形貌和粒径进行表征, 并利用振动样品磁强计(VSM)对样品进行磁性能研究. 结果表明: 借助脱脂棉模板, 采用溶胶凝胶法制备了外径在8～13 μm之间, 壁厚在0.5～2 μm之间的SrFe12O19微管, 柠檬酸的加入使得微管出现破裂, 微管之间出现聚集, 且管壁上出现大量孔洞, 断面变松散, 比表面积增加. 但随着柠檬酸用量的增加, SrFe12O19微管的矫顽力和饱和磁化强度先提高后下降, 当柠檬酸与金属离子的物质的量比为1∶1时850 ℃煅烧后制得了矫顽力、饱和磁化强度和剩余磁化强度分别为7115.1 Oe、70.1 emu/g和42.4 emu/g的纯的六方磁铅石型SrFe12O19微管, 并就柠檬酸对微管的形成以及磁性能的影响原理做了初步的研究.

Preparation of Strontium Ferrite Microtubules with a Template Method and Their Magnetic Property Analysis

Fe(NO3)3•9H2O, Sr(NO3)2 and different amounts of citric acid were used as crude materials to form sol in the solution. The sol grew on the surface of the absorbent cotton template to form gel. The strontium ferrite microtubules were prepared after the calcination process. The phase, morphology, particle diameter, and magnetic properties of samples were detected by XRD, SEM, TEM and VSM. It was found that the microtubule external diameters were between 8 and 13 μm, the wall thickness was between 0.5 and 2 μm. The addition of citric acid led to the fragmentation of microtubules, and there were many holes on the pipe wall. The specific area increased. As the increase of the citric acid content, the coercive force and the saturation magnetization of the samples increased firstly, and then decreased. As the mole ratio of citric acid to the metal ion was 1∶1, and the calcination temperature was 850 ℃, the coercive force, the saturation magnetization and residual magnetization of the samples were 7115.1 Oe, 70.1 emu/g and 42.4 emu/g respectively. The microtubule formation mechanism and the effect on the magnetic properties were studied systemically also.