Effect of BN/SiC interfacial coatings on the tensile properties of SiC/SiC minicomposites fabricated by PIP. Issue 16 (November 2020)

• Record Type: Journal Article
• Authors: Dai, Jianwei; Wang, Yiguang; Xu, Zhenhua; Mu, Rende; Liu, Wei; He, Limin
• Is Part Of: Ceramics international. Volume 46:Issue 16(2020)Part A
• Page Start: 25058
• Page End: 25065
• Publication Date: 2020-11
• Subjects: Ceramic matrix composites -- Interfacial coating -- Precursor infiltration and pyrolysis -- Chemical vapor infiltration -- Tensile properties -- Fracture mechanism; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.06.292
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Boron nitride and silicon carbide interfacial coatings were deposited by chemical vapor infiltration to prepare SiC/SiC minicomposites by the precursor infiltration and pyrolysis process. The tensile properties of the SiC/SiC minicomposites were assessed by the acoustic emission method. A single-layered BN coating increased the strength of the uncoated minicomposite from 416.4 MPa to 478.6 MPa, while the strengths of the BN/SiC-1 and BN/SiC-2 samples with a double-layered coating were 582.3 and 638.1 MPa, respectively. The total thickness of the BN/SiC-2 coating was the same as that of BN/SiC-1, while the BN/SiC-2 sample had a thicker BN layer. Besides the release of residual stress and elastic deformation stages, the stress-strain curve of minicomposite with interfacial coating contains a non-linear stage corresponding to the matrix crack generation, propagation, and deflection. Moreover, minimal fiber debonding was observed in the uncoated minicomposite, whereas fiber debonding of BN and BN/SiC-1 minicomposites occurred at the interface between the BN coating and fibers. In the double-layered BN/SiC-2 minicomposites, following matrix crack generation and propagation into the BN coating, cracks deflected both between the sublayers and at the interface between BN and fibers, where the debonding occurred.