Preparation of fiber reinforced porous silicon carbide monoliths

Fiber reinforced resorcinol-formaldehyde/silica (FR-RF/SiO₂) composites were prepared using sol-gel method followed by ambient pressure drying. Fiber reinforced porous silicon carbide (FRSiC) monoliths with large size were formed from FR-RF/SiO₂ composites after carbothermal reduction at 1300 C. The FRSiC monoliths were stable up to temperatures near 850 C in air, which is almost 200 C higher than mesoporous SiC monoliths can tolerate. X-ray diffraction (XRD) and transmission electron microscopy (TEM) demonstrated that the resulting FRSiC products were composed of β-SiC nanocrystals and mullite fibers. The porosity of FRSiC products is 90.3%. The total pore volume and surface area is 2.71 cm³/g and 30 m ²/g, respectively.