Influence of pyrolytic carbon interface thickness on microstructure and mechanical properties of SiC/SiC composites by NITE process

• Published in: Composites science and technology Vol. 68; no. 1; pp. 98 - 105
• Main Authors: Shimoda, Kazuya, Park, Joon-Soo, Hinoki, Tatsuya, Kohyama, Akira
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2008; Elsevier
• Subjects: A. Ceramic-matrix composites (CMCs); Applied sciences; B. Interface; B. Stress/strain curves; Building materials. Ceramics. Glasses; Ceramic industries; Cermets, ceramic and refractory composites; Chemical industry and chemicals; Cross-disciplinary physics: materials science; rheology; E. Powder processing; Exact sciences and technology; Materials science; Other materials; Physics; Specific materials; Structural ceramics; Technical ceramics; B. Stress/strain curves; A. Ceramic-matrix composites (CMCs); B. Interface; E. Powder processing; Ceramic matrix composite; Scanning electron microscopy; Fiber reinforced material; Mechanical properties; Experimental study; X ray diffraction; Composite material; Non oxide ceramics; Nanometer scale; Pyrocarbon; Transmission electron microscopy; Silicon Carbides; Matrix fiber interface; Infiltration; Manufacturing; Microstructure; Carbides
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2007.05.037

Unidirectional SiC/SiC composites were prepared by Nano-Infiltration and Transient Eutectic-phase (NITE) process using SiC nano-powder infiltration technique, and the effects of pyrolytic carbon (PyC) interface thickness between fibers and matrix on density, microstructural evolution and mechanical properties were characterized. SiC fibers both with and without PyC interface were employed as reinforcement and SiC nano-powder was employed for matrix formation with 12 mass% sintering additives of the total powder. The thickness of PyC layer deposited by chemical vapor deposition (CVD) process was highly-accurately controlled at about 0.25, 0.50 and 1.00 μm. Nearly full-dense SiC/SiC composites with uncoated fibers caused strong interaction between fibers and matrix, resulting in a brittle fracture behavior without fiber pull-out. Higher strength with a pseudo-ductile fracture behavior could be obtained using 0.50 μm of PyC interface thickness, where a lot of deflects and branches of the propagating cracks and fiber pull-out were observed. Induced PyC interface conditions strongly affect the density, microstructural evolution, and therefore dominate mechanical properties and fracture behaviors.