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Preparation and Microwave Absorption Performance of SiC/SiO2/Co/SiO2Nanowires

Author: JiaoJinFu
Tutor: XuYongJun
School: Harbin Institute of Technology
Course: Chemical Engineering
Keywords: microwave absorption chemical plating β-SiC nanowires thermostability β-SiC/SiO2 SiO2coating
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Type: Master's thesis
Year: 2013
Downloads: 92
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Abstract


SiC materials have a good performance of microwave absorption.Because of theirphysical and chemical stability, excellent performance of microwave absorption andthermostability, they are paid extensively attention by researchers. β-SiC nanowireswere prepared in this paper. In order to improve absorption properties of β-SiCnanowires and achieve the idea of the “multilayer” absorber, the layer of Co was loadedon the surface of β-SiC nanowires. And the amorphous SiO2was loaded in theoutermost coating layer of the material so that it can improve the high temperaturestability of the material. The microwave absorption of the whole system of β-SiCnanowires was discussed in ths paper.The β-SiC nanowires was prepared at1400℃by using Si, SiO2and MWCNT asthe raw material, and the morphology and structure of the product were characterized inthis paper. The effects of different carbon sources and different sintering temperatureson the synthesis of β-SiC nanowires were discussed, and we concluded the optimalsynthesis conditions.Using β-SiC/SiO2as the raw material by chemical plating, we achieved theuniform the coating layer of Co, and characterized the structure and morphology of thetarget product. The effects of different pH and the different time of chemical plating onthe Co coating layer, and the optimal preparation conditions were discussed.In order to improve the high temperature stability of the material, the SiO2coatinglayer was loaded on the surface of the β-SiC/SiO2/Co nanomaterial. The TG-DTAcurves of β-SiC/Co and β-SiC/SiO2/Co/SiO2were characterized from room temperatureto1000℃, and the curves suggest that β-SiC/SiO2/Co/SiO2nanomaterial is more stableunder high temperature.A series of materials were prepared to obtain the excellent microwave absorbingproperty and high temperature stability, so β-SiC/SiO2/Co/SiO2nanomaterial wassynthesized in this paper. The microwave absorbing properties of β-SiC/SiO2、β-SiC/SiO2/Co and β-SiC/SiO2/Co/SiO2nanocomposite were discussed. The absorbingperformance of the final product （β-SiC/SiO2/Co/SiO2） is the best. The minimumreflection loss is-60dB and the absorption bandwidth of the reflection loss less than-10dB is6.6GHz. therefore the desired results were achieved.

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