Fabrication of Al2O3 aerogel-SiO2 fiber composite with enhanced thermal insulation and high heat resistance

The thermal-resistance Al2O3 aerogels and Al2O3 aerogel-SiO2 fiber composite by using inorganic aluminum salt as the precursor were synthesized by the sol–gel process. The method was straightforward, inexpensive, and safe. Furthermore, it was found that the as-prepared Al2O3 aerogel had high crystal phase transition temperature. As the heat treatment temperature increased to 900 °C, the crystal phase transition from γ-AlOOH to γ-Al2O3 occurred within the Al2O3 aerogel. Meanwhile, the Al2O3 aerogel-SiO2 fiber composite exhibited high Young’s modulus of tensile strength up to 6.59 MPa and low thermal conductivity at 35 °C (0.028 W/(m K)) and high temperature of 600 °C (0.033 W/(m K)). In addition, the results indicated that the Al2O3 aerogel-SiO2 fiber composite had the moderate hydrophobic property as well as mechanical property.