Papers by Keyword: SiC-Based Composites

Abstract: SiC-Si₃N₄ powders and modified SiC-based ceramic matrix composites (CMCs) were fabricated using polycarbosilane (PCS), divinylbenzene (DVB) and Si₃N₄ filler. Si₃N₄ was introduced into CMCs fabricated through polymer infiltration and pyrolysis (PIP) to lower down the carbon content by in-situ carbothermal reaction, which derived from pyrolyzed PCS-DVB. The oxidation resistance and three point bending strength of modified C/SiC composites were effectively enhanced. The phase composition, microstructure of SiC-Si₃N₄ powders and modified C/SiC composites were investigated by XRD, SEM and TEM.

Abstract: CF/SiC and Hi-Nicalon/SiC composites were prepared by precursor pyrolysis-hot pressing, and the microstructure and fracture behavior of the composites were investigated. Because of a strongly bonded fiber/matrix interface primarily resulting from the direct reactions between the fibers and matrix, Hi-Nicalon/SiC composite exhibited a typical brittle fracture behavior. However, CF/SiC composite displayed a tough fracture behavior with extensive fiber pullout, which was primarily attributed to a weakly bonded fiber/matrix interface as well as higher strength retention of the fibers. As a result, CF/SiC composite achieved better mechanical properties of 691.6 MPa in strength and 20.7 MPa•m1/2 in toughness, which were much higher than those of Hi-Nicalon/SiC composite.