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采用溶胶凝胶法及在氢气中还原的工艺制备了纳米FeCo/Al2O3复合材料。利用X射线衍射、透射电镜、振动样品磁强计和M ssbauer谱学对样品微观结构和磁性进行了研究。结果表明:纳米FeCo/Al2O3复合材料中的FeCo合金为体心立方结构;随着还原温度的提高,α-FeCo合金晶粒尺寸变大,Al2O3的存在有效地抑制了α-FeCo合金晶粒的团聚和生长;随着-αFeCo合金晶粒尺寸的变大,样品的比饱和磁化强度增加,而矫顽力先增大后减小,两者分别在1100℃和1000℃时达到最大值62.41 emu.g-1和208.99 Oe,FeCo/Al2O3由超顺磁和磁有序的混合状态转变为完全的磁有序状态;矫顽力的变化是由于FeCo合金的磁学结构由单磁畴结构转变为多磁畴结构造成的。
The nano-FeCo / Al2O3 composite was prepared by sol-gel method and reduction in hydrogen. The microstructure and magnetic properties of the samples were investigated by X-ray diffraction, transmission electron microscopy, vibrating sample magnetometer and M ssbauer spectroscopy. The results show that the FeCo alloy in the nano-FeCo / Al2O3 composites is a body-centered cubic structure. With the increase of the reduction temperature, the grain size of the α-FeCo alloy becomes larger and the presence of Al2O3 effectively inhibits the grain growth of the α-FeCo alloy Reunion and growth. As the grain size of -αFeCo alloy increases, the specific saturation magnetization increases and the coercive force first increases and then decreases, reaching the maximum value of 62.41 emu at 1100 ℃ and 1000 ℃ respectively .g-1 and 208.99 Oe, the FeCo / Al2O3 transition from superparamagnetic and magnetic ordered mixed states to complete magnetic ordered states. The change of coercive force is due to the change of the magnetic structure of the FeCo alloy from a single magnetic domain structure For the multi-magnetic domain structure caused.