Preparation of the novel B4C–SiC composite aerogel with high compressive strength and low thermal conductivity

A novel B4C–SiC composite aerogel is synthesized using nano boron carbide suspension, 3-aminopropyltriethoxysilane (APTES), and resorcinol–formaldehyde (RF) as precursors through the sol–gel route and carbothermal reduction process. The effects of different B/Si molar ratios and calcination temperatures on the physical chemistry properties of B4C–SiC composite aerogels are investigated. The addition of the B4C phase is beneficial for improving the comprehensive properties of composite aerogel. The results show that the compressive strength of B4C–SiC composite aerogel is as high as 3.05 MPa. The specific surface area can reach 692.81 m2/g, which ensures that it has a thermal insulation capacity under elevated temperatures. After heat-treated at 1650 °C for 3 h, the thermal conductivity of carbon fiber mat reinforced composite aerogel is 0.058 W/m K (25 °C). This composite aerogel material has great application prospects in the field of high temperature insulation.