Enhanced mechanical property and tunable dielectric property of SiCf/SiC-SiBCN composites by CVI combined with PIP

• 作者: Chaokun SONG Yongsheng LIU Fang YE Laifei CHENG Pengfei ZHANG Nan CHAI
• 来源期刊: 先进陶瓷（英文版）
• 年，卷（期）: 2021,（4）
• 所属期刊栏目: Research Article
• 页码范围: 758-767
• 页数: 10页
• 语种: 英文

摘要

The SiBCN matrix via chemical vapor infiltration (CVI) or/and polymer infiltration pyrolysis(PIP) technologies was orderly introduced to SiCf/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 SiCt/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·m1/2 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(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 1.53×103 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 (SET)attained 30.01 dB.It indicates that the SiCf/SiC-SiBCN composites have great potential to be applied as structural and functional materials.