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以Co(NO3)2.6H2O和Fe(NO3)3.9H2O为原料,采用直接溶液合成法制备CoFe2O4纳米粉体。分析了纳米粉体的物相结构、微观形貌及合成机理,研究了热处理温度对粉体磁性能的影响。结果表明:所得CoFe2O4粉体为立方尖晶石铁氧体,颗粒细小、分散均匀,平均粒径约为5nm。500℃以下热处理的粉体表现出良好的超顺磁性;500℃以后,随热处理温度上升,颗粒尺寸变大,粉体的比饱和磁化强度Ms、比剩余磁化强度Mr和矫顽力Hc均增大。室温下CoFe2O4粉体的Ms为3.4A.m2/kg。当热处理温度为900℃时,Ms增大到59.5A.m2/kg,Hc增大到97.0kA/m。
Co (NO3) 2.6H2O and Fe (NO3) 3.9H2O were used as raw materials to prepare CoFe2O4 nanopowders by direct solution synthesis. The phase structure, microstructure and synthesis mechanism of nano-sized powders were analyzed. The influence of heat treatment temperature on the magnetic properties of the powders was also studied. The results show that the obtained CoFe2O4 powder is cubic spinel ferrite with fine particles and uniform dispersion with average particle diameter of about 5 nm. 500 ℃ heat treatment after the powder showed good superparamagnetic; 500 ℃ later, with the heat treatment temperature increases, the particle size becomes larger, the specific saturation magnetization Ms, the ratio of remanent magnetization Mr and coercivity Hc are increased Big. The Ms of CoFe2O4 powder is 3.4A.m2 / kg at room temperature. When the heat treatment temperature is 900 ℃, Ms increased to 59.5A.m2 / kg, Hc increased to 97.0kA / m.