聚碳硅烷热解SiC陶瓷结构与微波吸收性能

以聚碳硅烷(PCS)为原料,通过800-1200℃热解制备了PCS-SiC陶瓷,采用SEM、XRD与拉曼光谱对样品形貌、晶相及自由碳结构进行了表征。测量了样品直流电导率,并用矩形波导法测试了试样在8.2-12.4 GHz(X波段)频率范围的复介电常数,根据传输线理论计算出不同厚度材料的反射损耗。结果表明,随着热解温度的升高,样品电导率升高,同时复介电常数实部与虚部增加,吸波性能得到改善。PCS-SiC陶瓷中自由碳石墨化是引起极化能力及电导损耗提高的原因。

Structure and Microwave Absorbing Property of Polycarbosilane Derived Silicon Carbide Ceramic

SiC ceramic was fabricated through pyrolyzing polycarbosilane(PCS) at 800-1 200 ℃.The morphology,crystal phase and micro structure of free carbon were characterized by SEM,XRD and Raman spectrum,respectively.The DC conductivity of samples was tested.The complex permittivity of SiC ceramics derived from PCS(PCS-SiC) were measured by the method of rectangular waveguide using vector network analyzer in the frequency range of 8.2-12.4 GHz(X band).Based on transmission-line theory,the microwave absorbing properties of samples were calculated.The results show that DC conductivity,real and imaginary parts of permittivity increase with the evolution of pyrolysis temperature due to graphitization of free carbon in PCS-SiC ceramic.And,the microwave absorbing properties were improved due to enhancement of polarization and loss.