The effects of SiC precursors on the microstructures and mechanical properties of SiCf/SiC composites prepared via polymer impregnation and pyrolysis process

Abstract

SiCf/SiC ceramic matrix composites (CMC) are considered to be promising candidates for potential structural and functional usages in several strategic engineering applications. In the current work, SiCf/SiC were fabricated by seven repeated polymer impregnation and pyrolysis (PIP) cycles using three types of polycarbosilane (PCS) precursors. SMP-10 had the highest ceramic yield of 81.7% and the lowest melting temperature (room temperature). The CMC prepared using these precursors had high relative density and strength. Due to the fiber pull-out mechanism during fracture, the stress–strain curves displayed a jagged failure behavior. The maximum four-point bending strength of 305MPa was obtained from the CMC made with the NaBond precursor. Several pieces of evidence were provided to reveal the strength deterioration of the NaBond-CMC material at 1500°C in Ar atmosphere.