Preparation of fiber reinforced porous silicon carbide monoliths

Abstract

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 2.71cm3/g and 30m2/g, respectively.