High-performance SiC/SiC composites by improved PIP processing with new precursor polymers

As they are potential candidates for fusion reactor structural materials, R&D are being conducted on SiC-based composite materials (CREST-ACE program). To improve the efficiency of the polymer impregnation and pyrolysis (PIP) process for SiC/SiC composite fabrication, a new precursor polymer, poly-vinylsilane (PVS) with SiC filler addition, was adopted as a matrix precursor and process optimization was performed. Consequently, high-density SiC/SiC composite with high mechanical properties was efficiently fabricated. Importantly, near-stoichiometric SiC matrix was developed by blending of poly-carbosilane (PCS) and poly-methylsilane (PMS). Remarkable improvements in tensile properties and fatigue characteristics (at 1573 K) were attained when inorganic powder fillers, BMAS or ZrSiO4, were added to the polymer mixture as the matrix precursor. These results are encouraging to make economically and environmentally attractive fusion reactors utilizing SiC/SiC composites as major structural materials.