Preparation and ablation resistance of carbon fiber with yttrium silicate coating

Abstract

AbstractIn order to solve the shortcoming of fiber oxidation in a high‐temperature environment and improve the antiablative performance, yttrium silicate is coated on the carbon fibers’ surface by the sol‐gel process. In the present work, investigations of the ablation resistance of carbon fiber composites with yttrium silicate coatings (YS‐CFs) prepared by different sol contents and sintering temperatures are reported. The results show that YS‐CFs exhibit excellent ablation resistance in the oxyacetylene test with a heat flow of 1.5 MW/m2. The surface coating of carbon fiber is composed of a mixture of cristobalite, yttrium monosilicate, and yttrium disilicate. The best ceramic coating could be obtained by dipping 20% silica sol and 14% yttrium sol in turn and sintering at 1300°C. In this case, the linear and mass ablation rates reach the minimum values of .667 μm/s and 2.975 mg/s, respectively. YS‐CFs could be used as reinforcements for thermal protection materials in high‐temperature environments.