Preparation and Characterization of Alumina-coated Hollow Quartz Fiber Reinforced Al2O3-SiO2 Aerogel Composite

Al2O3-SiO2 sols were synthesized by using aluminum chloride hex hydrate and tetraethoxysilane (TEOS) as precursors, deionized water and ethanol mixture as the solvent, and propylene oxide as the coagulant aids. Alumina coatings were prepared on the surfaces of hollow quartz filament fiber, then a new lightweight and thermal insulating material were successfully prepared by impregnating Al2O3-SiO2 sol into a needle fabric made by coated hollow quartz filament fiber. The coated quartz fiber, aerogels and composites were characterized by Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), energy dispersive spectroscopy(EDS), nitrogen adsorption-desorption(BET), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and tensile tests. The effects of different fiber and calcination temperatures on the microstructures and properties of Al2O3-SiO2 composite aerogels were investigated. The test results indicate that the mechanical properties of the aerogels are improved by introducing quartz filament fabrics and the introduction of alumina coating improves the thermal stability of the material. Compared to other fibers, Al2O3-coated hollow quartz fiber has significant advantages as reinforcement for composite, and their tensile strength is well retained after high temperature heat treatment.