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.