原位聚合法制备聚吡咯-钴铜锌铁氧体复合材料及其电磁性能

Electromagnetic Properties of Polypyrrol-Co_(0. 7)Cu_(0. 1)Zn_(0. 2)Fe_2O_4 Nanocomposites Prepared by in situ Polymerization

采用自蔓延燃烧法和原位聚合法分别制备纳米Co0.7Cu0.1Zn0.2Fe2O4铁氧体和聚吡咯（PPy）-Co0.7Cu0.1Zn0.2Fe2O4纳米复合材料.采用X射线衍射仪（XRD）、透射电子显微镜（TEM）和傅里叶红外光谱（FTIR）对材料的结构和形貌进行表征,使用波导法和振动样品磁强计（VSM）研究了材料的介电性能、微波吸收性能和磁性能.结果表明,制得了纯相的尖晶石结构Co0.7Cu0.1Zn0.2Fe2O4铁氧体,少量Cu2＋离子替代了铁氧体八面体位置上的Co2＋离子,使得材料的晶格常数减小;2种粉体粒子分散性较好,它们的平均粒径分别约为15 nm和50 nm;在5.0~20.0 GHz频率范围内,PPy-Co0.7Cu0.1Zn0.2Fe2O4复合材料的反射损耗在-16.25dB到-20.27 dB之间,且在18 GHz处出现极大值-20.27 dB,带宽为2.0 GHz（最强峰的半高宽）,PPyCo0.7Cu0.1-Zn0.2Fe2O4复合材料的反射损耗明显大于铁氧体;PPy-Co0.7Cu0.1Zn0.2Fe2O4的饱和磁化强度（Ms）和剩余磁化强度（Mr）分别为12.9 A/g和4.29 A/g,小于Co0.7Cu0.1Zn0.2Fe2O4铁氧体的相应值,但复合材料的矫顽力大于Co0.7Cu0.1Zn0.2Fe2O4铁氧体的,为38.96 kA/m.

The nanocrystalline Co0. 7Cu0. 1Zn0. 2Fe2O4 ferrites and the polypyrrol（ PPy）-Co0. 7Cu0. 1Zn0. 2Fe2O4 nanocomposites were prepared by self-propagating combustion method and an in situ polymerization method,respectively. The structure and morphology of the synthesized materials were characterized by X-ray diffraction（XRD）,transmission electron microscopy（TEM） and Fourier transform infrared spectrometry（FTIR）,and the dielectric,microwave absorbing and magnetic capability of the two materials were studied by wave-guide method and vibrating sample magnetometer（ VSM）,respectively. The results show that the pure spinel Co0. 7Cu0. 1Zn0. 2Fe2O4 ferrites are obtained and a small amount Co2 ＋ions of the octahedron ferrites are replaced by Cu2 ＋ions,which results in the reduce of lattice constant of the Co0. 7Cu0. 1Zn0. 2Fe2O4 ferrites. The two powders both have good dispersity and the average size of the two kinds of particles is about 15 nm and 50 nm,respectively. In the measuring frequency range of 5. 0 ~ 20. 0 GHz,the reflection loss of PPy-Co0. 7Cu0. 1Zn0. 2Fe2O4 composites is between- 16. 25 and- 20. 27 dB,and the reflection loss maximum value is about- 20. 27 dB at 18. 0 GHz with a bandwidth of 2. 0 GHz（ full frequency width at about a half of the peak response）,which is obviously higher than that of the Co0. 7Cu0. 1Zn0. 2Fe2O4 ferrites. The saturation magnetization（Ms） and remanent magnetization（Mr） of the PPy-Co0. 7Cu0. 1Zn0. 2Fe2O4 composites are 1. 29 emu /g and 0. 429 emu /g,respectively,which are smaller than those of the Co0. 7Cu0. 1Zn0. 2Fe2O4 ferrite. But the coercive force（ Hc） of the PPy-Co0. 7Cu0. 1Zn0. 2Fe2O4 composites,which is 38. 96 KA /m,is greater than that of the Co0. 7Cu0. 1Zn0. 2Fe2O4 ferrite.