Mechanical and electromagnetic wave absorption properties of Cf-Si3N4 ceramics with PyC/SiC interphases  

作　　者：Wei Zhou Lan Long Yang Li 

机构地区：[1]College of Metallurgy and Materials Engineering,Hunan University of Technology,Zhuzhou 412008,China [2]State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China

出　　处：《Journal of Materials Science & Technology》2019年第12期2809-2813,共5页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 51604107);the Natural Science Foundation of Hunan Province (Grant No. 2019JJ50115 and 2019JJ50768)

摘　　要：Aiming to obtain microwave absorbing materials with excellent mechanical and microwave absorption properties, carbon fiber reinforced Si3N4 ceramics(Cf-Si3N4) with pyrolytic carbon(PyC)/SiC interphases were fabricated by gel casting. The influences of carbon fibers content on mechanical and microwave absorption properties of as-prepared Si3N4 based ceramics were investigated. Results show that chemical compatibility between carbon fibers and Si3N4 matrix in high temperature environment can be significantly improved after introduction of Py C/SiC interphases. As carbon fibers content increases from 0 to 4 wt%, flexural strength of Si3N4 based ceramics decreases slightly while fracture toughness obviously increases. Moreover, both the real and imaginary parts of complex permittivity increase with the rising of carbon fibers content within the frequency range of 8.2–12.4 GHz. Investigation of microwave absorption shows that the microwave attenuation ability of Cf-Si3N4 ceramics with Py C/SiC interphases is remarkably enhanced compared with pure Si3N4 ceramics. Effective absorption bandwidth(<-10 d B) of10.17–12.4 GHz and the minimum reflection less of-19.6 d B are obtained for Si3N4 ceramics with 4 wt%carbon fibers in 2.0 mm thickness. Cf-Si3N4 ceramics with Py C/SiC interphases are promising candidates for microwave absorbing materials with favorable mechanical property.Aiming to obtain microwave absorbing materials with excellent mechanical and microwave absorption properties, carbon fiber reinforced Si3N4 ceramics（Cf-Si3N4） with pyrolytic carbon（PyC）/SiC interphases were fabricated by gel casting. The influences of carbon fibers content on mechanical and microwave absorption properties of as-prepared Si3N4 based ceramics were investigated. Results show that chemical compatibility between carbon fibers and Si3N4 matrix in high temperature environment can be significantly improved after introduction of Py C/SiC interphases. As carbon fibers content increases from 0 to 4 wt%, flexural strength of Si3N4 based ceramics decreases slightly while fracture toughness obviously increases. Moreover, both the real and imaginary parts of complex permittivity increase with the rising of carbon fibers content within the frequency range of 8.2–12.4 GHz. Investigation of microwave absorption shows that the microwave attenuation ability of Cf-Si3N4 ceramics with Py C/SiC interphases is remarkably enhanced compared with pure Si3N4 ceramics. Effective absorption bandwidth（<-10 d B） of10.17–12.4 GHz and the minimum reflection less of-19.6 d B are obtained for Si3N4 ceramics with 4 wt%carbon fibers in 2.0 mm thickness. Cf-Si3N4 ceramics with Py C/SiC interphases are promising candidates for microwave absorbing materials with favorable mechanical property.

关 键 词：Silicon nitride Carbon fibers PyC/SiC interphases Mechanical properties Microwave absorption 

分 类 号：TB34[一般工业技术—材料科学与工程]