High Temperature Oxidation Resistance of Low Density Carbon Bonded Carbon Fiber Composite

Low density carbon bonded carbon fiber (CBCF) composites are thought to be attractive candidates for thermal insulation applications in aerospace due to their unique properties such as low density, high temperature stability and low thermal conductivity. In the present work, an anti-oxidation low density carbon bonded carbon fiber composite was designed and fabricated for high temperature application. Firstly, PyC coating was deposited uniformly on the surface of carbon fibers to improve the mechanical properties of CBCF through CVI process. After deposited for 210 h, the tensile strength and pressure strength in thickness are increased by 275% and 341%, respectively. Then, a dual-layer coating was designed and prepared to improve the oxidation resistance of CBCF. High temperature oxidation properties at different temperatures were tested by a high temperature muffle furnace in air. The results show that the as-prepared oxidation coating can protect composites effectively under high temperature oxidation conditions. After oxidation at 1700 similar to 1750 degrees C for 300 similar to 360 s, the mass ablation rates are about 1.1x10(-5)similar to 1.5x10(-5)g/(cm(2).s). The formation of a dense glass layer of SiO2 or SiO2 embedded with HfO2 is responsible for the good ablation resistant.