Porous carbon-bonded carbon fiber composites impregnated with SiO₂-Al₂O₃ aerogel with enhanced thermal insulation and mechanical properties

To improve the thermal insulation and mechanical properties of lightweight carbon- bonded carbon fiber composites (CBCF), a porous CBCF decorated with nano SiO₂-Al₂O₃ aerogel was prepared by sol-gel impregnation. Results showed that the nano aerogel were uniformly assembled within the pores in the CBCF framework. The aerogel played a significant role on reducing the thermal conductivity of CBCF, which could be mainly ascribed to reduced radiation and gas thermal conductivity of CBCF. Moreover, the aerogel in the CBCF pores hindered the bending fracture or elastic bending/rotation of the fibers and enhanced the mechanical properties of the composites.