Improved dielectric properties of PDCs-SiCN by in-situ fabricated nano-structured carbons
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- 作者：Quan Li ; Xiaowei Yin ; yinxw@nwpu.edu.cn ; Wenyan Duan ; Laifei Cheng ; Litong Zhang
- 关键词：Polymer derived ceramics ; Nano-structured carbons ; SiC nano-crystals ; Dielectric property ; Microwave absorption property
- 刊名：Journal of the European Ceramic Society
- 出版年：2017
- 出版时间：April 2017
- 年：2017
- 卷：37
- 期：4
- 页码：1243-1251
- 全文大小：3895 K
- 卷排序：37
文摘
In order to enhance dielectric properties of polymer derived SiCN ceramics (PDCs-SiCN), nano-structured carbons were in-situ fabricated in PDCs-SiCN by pyrolysis of ferrocene-modified polysilazane. Microstructure evolutions, dielectric and microwave absorption properties of PDCs-SiCN decorated with nano-structured carbons were investigated. Nano-structured PDCs-SiCN ceramics are composed of carbon nanowires as well as interpenetrating graphene-like free carbons, SiC nano-crystals, Si3N4 nano-crystals and amorphous SiCN. Relative complex permittivities of nano-structured PDCs-SiCN increase with increasing ferrocene contents and annealing temperatures. Free carbons in PDCs-SiCN play a dominating role on the improved dielectric properties. Polarization loss is the primary dielectric loss. Loss tangent of PDCs-SiCN exceeding 0.7 is obtained when free carbons are only 2.57% in weight. Nano-structured PDCs-SiCN exhibit good microwave absorption property. The reflectivity is smaller than −14 dB in the whole X band when material is composed of both impedance and microwave absorption materials.