Enhanced mechanical property and tunable dielectric property of SiC_(f)/SiC-SiBCN composites by CVI combined with PIP  

作　　者：Chaokun SONG Yongsheng LIU Fang YE Laifei CHENG Pengfei ZHANG Nan CHAI 

机构地区：[1]Science and Technology on Thermostructure Composite Materials Laboratory,Northwestern Polytechnical University,Xi’an 710072,China [2]Beijing Spacecrafts,Beijing 100000,China [3]Institut fur Materialwissenschaft,Technische Universitat Darmstadt,Darmstadt D-64287,Germany

出　　处：《Journal of Advanced Ceramics》2021年第4期758-767,共10页先进陶瓷（英文）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.52072304,51632007,and 51872229);the 111 Project of China(B08040);the National Science and Technology Major Project(Grant No.2017-VI-0007-0077).

摘　　要：The SiBCN matrix via chemical vapor infiltration(CVI)or/and polymer infiltration pyrolysis(PIP)technologies was orderly introduced to SiC_(f)/SiC composites to optimize the mechanical property and electromagnetic(EM)shielding effectiveness simultaneously.The BN interface with the thickness of 350 nm was designed to obtain a little stronger interface bonding.The flexural strength of SiC_(f)/SiC-SiBCN composites reached 545.45±29.59 MPa thanks to the crack deflection between the CVI SiC and CVI SiBCN,as well as CVI SiBCN and PIP SiBCN matrix because of the modulus difference between them.The fracture toughness(KiC)with the value of 16.02±0.94 MPa·m^(1/2) was obtained owing to the extension of crack propagation path.The adverse effect of stronger interface bonding was eliminated by the design of matrix microstructure for SiC_(f)/SiC-SiBCN composites.The thermal conductivity in the thickness direction was 7.64 W·(m·K)^(-1) at 1200℃and the electric resistivity decreased to 1.53×10^(3) Ω·m.The tunable dielectric property was obtained with the coordination of wave-absorption CVI SiBCN matrix and impedance matching PIP SiBCN matrix,and the total shielding effectiveness(SE_(T))attained 30.01 dB.It indicates that the SiC_(f)/SiC-SiBCN composites have great potential to be applied as structural and functional materials.

关 键 词：SiC_(f)/SiC-SiBCN composites chemical vapor infiltration(CVI) polymer infiltration pyrolysis(PIP) mechanical property electromagnetic characteristic 

分 类 号：TB332[一般工业技术—材料科学与工程]