Microstructure and Mechanical Properties of Compact SiC/SiC Composite Fabricated with an Infiltrative Liquid Precursor

Abstract

Continuous SiC fiber reinforced SiC matrix composites (SiC/ SiC) have been studied and developed for high temperature and fusion applications. In this study, SiC/SiC composite was fabricated by polymer impregnation and pyrolysis process with LPVCS, a liquid precursor with active Si-H and -CH=CH 2 groups. The cross-link and ceramization processes of LPVCS were studied and SiC/SiC composite was fabricated with LPVCS. The porosity and mechanical properties of the SiC/ SiC composite was investigated, and the results indicated that the SiC/SiC composite exhibited low porosity and superior mechanical properties owing to the compact matrix derived from LPVCS.

Novel processing approach to polymer‐derived ceramic matrix composites

“…With an increase in the peak MW, a drop in concentration at low MW, and a convergence of GPC curves at higher MW, it was concluded that heat treatments were indeed allowing the volatilization of low MW oligomers from SMP‐10 before the onset of curing/cross‐linking. This conclusion is consistent with previous work on LPCS; however, the loss of low MW oligomers for this study occurred at temperatures (86°C) much lower than previously reported (230°C) …”

“…Li et al also discussed that at temperatures below 230°C, the release of H 2 gas and small oligomers are the primary factors contributing to mass loss of a similar liquid polycarbosilane (LPCS). Similarly, Zhao et al attributed mass loss of their LPCS, between 50 and 250°C, to loss of low MW molecules. The wide MW distributions of these LPCSs (including SMP‐10) brings into question whether low MW oligomers, that would be lost during curing, can be driven off thermally, while the polymer is still in a liquid state; the potential payoff is a preceramic polymer that can be used for PIP processing with a higher ceramic yield and a ceramic chemistry that has not been altered by the use of polymer catalysts.…”

Process modeling of the low‐temperature evolution and yield of polycarbosilanes for ceramic matrix composites

“…This leads to a trade‐off between yield and viscosity embedded within the molecular weight distribution that can be optimized. During both infiltration and heating to the cross‐linking (curing) temperature, significant mass losses have been observed; volatilization of low molecular weight oligomers is acknowledged as the source of this mass loss . Although this type of mass loss has been observed by many, it has not been quantitatively explained.…”

“…During both infiltration and heating to the cross-linking (curing) temperature, significant mass losses have been observed; volatilization of low molecular weight oligomers is acknowledged as the source of this mass loss. [8][9][10][16][17][18][19] Although this type of mass loss has been observed by many, it has not been quantitatively explained. We suggest that the evolution of these low molecular weight species as volatiles is important to control and is why slow heating rates and/or long isothermal holds are typically required to prevent component-level void formation.…”

Mechanical Properties of Cf/SiC Composites with Ameliorated Interface Employing a New Precursor

“…The coating is important in order to improve the mechanical properties of composites. The mechanical properties of Cf/SiC composites with coating, such as PyC, EBC, carbon nanotube, showed more than twice the flexural strength and fracture toughness [9][10][11]. The coating was usually prepared by chemical vapor deposition (CVD) method, however CVD process always cost much time.…”