CoFe2O4纳米粉体的聚丙烯酰胺凝胶法合成、表征及磁特性

摘要

采用改进的聚丙烯酰胺凝胶法制备了CoFe2O4纳米粉体.利用TG-DSC、mR及XRD等多种手段研究了干凝胶的热分解及CoFe2O4的成相过程.实验表明,以EDTA为配位剂,在500℃的烧结温度下可制备出高纯的CoFe2O4纳米粉体.同时发现.通过改变双丙烯酰胺与丙烯酰胺的比例,可以调控粉体的晶粒尺寸;随着双丙烯酰胺比例的增加,晶粒的平均尺寸逐渐减小.通过改变双丙烯酰胺与丙烯酰胺的比例,制备出了平均晶粒尺寸从45到23nm的系列CoFe2O4纳米粉体.SEM和TEM观察显示.制得的粉体粒度分布均匀,颗粒近似呈球形.采用振动样品磁强计对样品的磁性进行了测试分析.%A modified polyacrylamide gel method was used to fabricate CoFe2O4 nanopowders.Thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) analysis, fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) were used in combination to investigate the thermal decomposition process of xerogel and the formation of CoFe2O4 phase.It is demonstrated that high-phase-purity CoFe2O4 nanopowders can be prepared by using the chelating agent ethylenediamine-tetraacetic acid (EDTA) at a calcining temperature of 500 ℃.At the same time, it is found that the grain size of resulted CoFe2O4 powders can be tailored by varying the ratio of bisacrylamide to acrylamide.With increase in the bisacrylamide content, the grain size decreases gradually.By using this method, a series of CoFe2O4 powders with average grain size ranging from 45 to 23 nm have been prepared.Scanning electron microscope (SEM) and transmission electron (TEM) observations reveal that the prepared CoFe2O4 powders are nearly spherical in shape with a narrow particle size distribution.Magnetic properties of the products have been investigated using a vibrating sample magnetometer.