Oxidation resistance and heat transfer simulation of MoSi2-based coatings on carbon fiber reinforced C-Al2O3 aerogel composite

Fiber-reinforced aerogels with excellent properties such as low density and low thermal conductivity are potential thermal insulation materials. The slurry method and the embedding sintering method were used to fabricate MoSi2-aluminoborosilicate glass coatings on the surface of a carbon fiber-reinforced C-Al2O3 aerogel composite under a low-oxygen atmosphere. The microstructure and phase composition of the coatings with different MoSi2 contents before and after static oxidation were investigated. The resulting composite exhibited excellent radiating properties and outstanding oxidation resistance. The total emissivity of the as-prepared coatings was above 0.8185 in the wavelength range of 300–2500 nm. The sample with 40 wt% MoSi2 in the outer coating had superior thermal endurance with a weight loss of only 0.54% after isothermal oxidation at 1200 °C for 180 min. This can be attributed to the optimum viscosity of the binder, which would relieve thermal stress defects and block oxygen diffusion. To further evaluate the thermal protection performance of the coatings, the heat transfer characteristics were simulated using the Fluent software package.