Electromagnetic wave absorbing ceramics composites made of polymer-derived SiC with BN@CNTs pyrolyzed higher than 1200℃  

作　　者：Bin Ren Yumeng Deng Yujun Jia Xiaopeng Wu Guanghui Feng Qian Wang Hejun Li 

机构地区：[1]State Key Laboratory of Solidification Processing,Shaanxi Key Laboratory of Fiber Reinforced Light Composite Materials,Northwestern Polytechnical University,Xi’an 710072,China [2]Henan Key Laboratory of High Performance Carbon Fiber Reinforced Composites,Institute of Carbon Matrix Composites,Henan Academy of Sciences,Zhengzhou 450046,China

出　　处：《Journal of Materials Science & Technology》2023年第36期213-227,共15页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.52232005,52172104,and 52293370);Fundamental Research Funds for the Central Universities(China,Nos.3102020QD0411 and D5000220152);Fundamental Research Funds for the Central Universities(No.3102019TS0409);Cre-ative Research Foundation of Science and Technology on Thermo-Structural Composite Materials Laboratory.

摘　　要：Polymer-derived ceramics(PDCs)pyrolyzed at high temperatures are promising electromagnetic wave(EMW)absorption materials for aerodynamically heated parts of aircraft under harsh environments.Nev-ertheless,high-temperature pyrolysis results in a significant increase of electrical and dielectric proper-ties of the ceramics,causing extensive reflection of EMW.To address this challenge,boron nitride-coated carbon nanotubes(BN@CNTs)were fabricated and introduced into polymer-derived SiC(PDC-SiC)by py-rolyzing its precursor higher than 1200℃to form SiC-BN@CNT ceramic composites.The fabricated com-posites with 3 wt.%BN@CNTs pyrolyzed at 1200℃have an effective absorption bandwidth(EAB)of 4.2 GHz(8.2-12.4 GHz)at a thickness of 3.4 mm and the minimum reflection loss(RL min)of-57.20 dB.The ultra-broad EAB of 12.62 GHz(5.38-18 GHz)is obtained by simulation through periodic structure design-ing.The RL of the metamaterials was also measured using an arch testing method at a frequency range of 2-18 GHz and an EAB of 11.52 GHz(6.48-18 GHz)is obtained.The excellent absorption is attributed to the BN layer that limits the electrical conduction of the ceramic composites while retaining the high loss of CNTs.The introduction of BN@CNTs causes the refinement of SiC grains,which provides plenty of interfaces and enhances the interface polarization loss.This work successfully solves the problem that PDCs pyrolyzed at elevated temperatures cannot be used as EMW absorption materials by applying BN coating on CNTs served as absorbers for PDC-SiC.The results of this work greatly broaden the application scope of the PDC systems for EMW absorption.

关 键 词：Electromagnetic wave absorption Polymer derived ceramic BN@CNTs Harsh environment High pyrolysis temperature 

分 类 号：O441.4[理学—电磁学] TB332[理学—物理]