Novel whisker-reinforced Al₂O₃–SiO₂ aerogel composites with ultra-low thermal conductivity

Novel aluminium borate whisker (ABOw)/Al₂O₃–SiO₂ aerogel composites were prepared by adding ABOw into an Al₂O₃–SiO₂ solution using a quick gel and supercritical fluid drying method. The microstructures and thermal and mechanical properties of the prepared ABOw/Al₂O₃–SiO₂ aerogel composites were investigated. The ABOw is randomly and homogeneously dispersed in the Al₂O₃–SiO₂ aerogel and the well-integrated nature of the material leads to enhanced mechanical properties and smaller linear shrinkage compared to those determined for pure Al₂O₃–SiO₂ aerogels. The compressive strength of the aerogel composites exhibit lightweight, ultra-low thermal conductivity (i.e. 0.040 W/(m·K)) and high compressive strength (i.e. 1.40 MPa at 10% strain), which is five times higher than the strength of pure Al₂O₃–SiO₂ aerogels. This aerogel composite prepared in this study makes a potential application in thermal insulation materials.