纳米磁性空心微球及其与碳纳米管复合材料的制备及性能研究

发布时间：2018-04-25 00:41

本文选题：CoFe2O4空心微球 + 溶剂热法　；参考：《中北大学》2015年硕士论文

【摘要】：本论文先采用不同制备方法制备CoFe2O4空心微球，旨在探索开发一条简单的制备磁性空心微球的绿色工艺；再采用最佳制备工艺，制备出一系列镍、锌掺杂以及不同稀土元素掺杂的磁性空心微球；为了进一步提高材料的吸波性能，制备了磁性微球与碳纳米管的复合材料。重点考察了这些材料的磁性及0-6GHz(1GHz=1000MHz)频率范围内的微波吸收性能。 (1)分别采用溶剂热法和两种模板法制备尖晶石型钴铁氧体，并研究制备工艺对产物结构、形貌以及性能的影响。结果显示，产物均为空心微球结构，且溶剂热法得到的样品分散均匀且粒径最小(50nm)。该样品的磁性能和吸波性能也较好，饱和磁化强度和矫顽力分别达到88.45emu g-1和227.84Oe，小于-5dB吸收频宽为976MHz。 (2)采用溶剂热法制备了ZnxCo1-xFe2O4和NixCo1-xFe2O4空心微球，以及不同La3+、Ce3+和Nd3+掺杂的Zn0.3Co0.7MxFe2-xO4微球，并采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、振动样品磁强计(VSM)和矢量网络分析仪对样品各性能进行表征。结果表明，，样品均为空心微球结构，Zn0.5Co0.5Fe2O4和Ni0.5Co0.5Fe2O4微球粒径分别为150nm和200nm。其中Zn0.3Co0.7Fe2O4微球的饱和磁化强度和矫顽力分别为55.94emu g-1和26.76Oe。Ni0.1Co0.9Fe2O4微球的饱和磁化强度和矫顽力分别为81.56emu g-1和200.42Oe。此时，两种样品的吸波效果也最佳，最优回损值分别可达-17.4dB和-18.4dB。 (3)分别考察了La3+、Ce3+和Nd3+的掺杂量对Zn0.3Co0.7MxFe2-xO4微球磁性和吸波性能的影响。测试结果显示，La3+和Ce3+的掺杂明显提高材料的矫顽力。三种稀土元素的掺杂都可提高钴锌铁氧体的吸波性能。其中Zn0.3Co0.7La0.2Fe1.8O4、Zn0.3Co0.7Ce0.02Fe1.98O4和Zn0.3Co0.7Nd0.2Fe1.8O4吸波效果最好，最大吸收值分别为-16.85dB、-16.62dB和-16.12dB，且Zn0.3Co0.7La0.2Fe1.8O4小于-5dB的吸收频宽可达3124.8MHz，明显优于Ce3+和Nd3+的掺杂样品。 (4)采用溶剂热法制备了Co0.3Zn0.7La0.2Fe1.8O4/CNTs复合材料，并考察碳纳米管含量对复合材料磁性和吸波性能的影响。当碳纳米管含量为10%时，Co0.3Zn0.7La0.2Fe1.8O4/CNTs复合材料的矫顽力最大(107.14Oe)，此时复合材料的吸波性能也最佳，最大吸收值和小于-5dB的频宽分别为-28.7dB和3496.8MHz。
[Abstract]:In this paper, CoFe2O4 hollow microspheres were prepared by different preparation methods in order to explore a simple green process for the preparation of magnetic hollow microspheres, and then a series of nickel were prepared by the optimum preparation process. The magnetic hollow microspheres doped with zinc and different rare earth elements were prepared. In order to further improve the microwave absorption properties of the composites, the composites of magnetic microspheres and carbon nanotubes were prepared. The magnetic properties and microwave absorption properties of these materials in the frequency range of 0 ~ 6 GHz ~ 1 GHz ~ (1 000 MHz) have been investigated. (1) Spinel cobalt ferrite was prepared by solvothermal method and two template methods, and the effects of preparation process on the structure, morphology and properties of the product were studied. The results show that all the products are hollow microspheres, and the samples obtained by solvothermal method are uniformly dispersed and have the smallest particle size of 50 nm ~ (-1). The saturation magnetization and coercivity reached 88.45emu g-1 and 227.84 Oe, respectively, and the absorption band width less than -5 dB was 976 MHz. ZnxCo1-xFe2O4 and NixCo1-xFe2O4 hollow microspheres were prepared by solvothermal method, and Zn0.3Co0.7MxFe2-xO4 microspheres doped with different La3 ce _ 3 and Nd3 were prepared. The properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and vector network analyzer. The results show that the particle sizes of Zn0.5Co0.5Fe2O4 and Ni0.5Co0.5Fe2O4 microspheres are 150nm and 200nmrespectively. The saturation magnetization and coercivity of Zn0.3Co0.7Fe2O4 microspheres are 81.56emu g-1 and 200.42Oe. the saturation magnetization and coercivity of 26.76Oe.Ni0.1Co0.9Fe2O4 microspheres are 81.56emu g-1 and 200.42Oerespectively. At the same time, the two kinds of samples have the best absorbing effect, and the optimum return loss values can reach -17.4 dB and -18.4 dB, respectively. The effects of doping amount of La3 ce 3 and Nd3 on the magnetic properties and microwave absorption properties of Zn0.3Co0.7MxFe2-xO4 microspheres were investigated. The results show that the doping of La _ 3 and Ce3 can obviously improve the coercivity of the materials. Doping of three rare earth elements can improve the absorbing property of cobalt zinc ferrite. Among them, Zn0.3Co0.7La0.2Fe1.8O4 (Zn0.3Co0.7Ce0.02Fe1.98O4) and Zn0.3Co0.7Nd0.2Fe1.8O4 have the best absorbing effect, the maximum absorption values are -16.85dBU -16.62dB and -16.12dB respectively, and the absorption band width of Zn0.3Co0.7La0.2Fe1.8O4 less than -5dB can reach 3124.8 MHz, which is obviously better than that of Ce3 and Nd3 doped samples. (4) Co0.3Zn0.7La0.2Fe1.8O4/CNTs composites were prepared by solvothermal method, and the effects of carbon nanotube content on magnetic properties and absorbing properties of the composites were investigated. When the content of carbon nanotubes is 10, the coercivity of the CNTs composites is 107.14 Oe, and the maximum absorption value and the frequency width less than -5 dB are -28.7dB and 3496.8MHz. respectively.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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