Al2O3-SiO2 aerogel reinforced with aluminum silicate nanofibers: a strategy to preserve the properties of Al2O3-SiO2 aerogel

Aluminum silicate nanofibers (ASNFs) have attracted significant attention due to their excellent stability and high-temperature properties. Al2O3-SiO2 aerogel (ASAs) has high porosity and low thermal conductivity, but its mechanical properties need to be improved. Reinforcing aerogels with fibers can lead to remarkable enhancements in their properties. Reducing the fiber diameter has proven to be an effective means of improving the structural integrity and mechanical stability of aerogel composites. In the context of this study, we prepared aluminum silicate nanofibers (ASNFs) with a diameter of 170 nm through the utilization of electrostatic spinning. These ASNFs were then successfully integrated with aluminum silicate aerogels (ASAs) to create a novel composite material known as aluminum silicate nanofiber-reinforced Al2O3-SiO2 aerogel (AS/ASNFAs). Its microstructure, mechanical properties and heat insulation properties have been researched. The results show that the compressive strength of AS/ASNFAs (0.44 MPa) is significantly higher than that of Al2O3-SiO2 aerogel (0.16 MPa). Meanwhile, the AS/ASNFAs has high specific surface area (600 m2/g), low density (0.15 g/cm3), and low thermal conductivity (0.026 W/(m·K)). This work provides a useful solution to improve the comprehensive properties of Al2O3–SiO2 aerogel composites.