Synthesis and characterization of light and high-strength C/A1₂O₃ composite aerogels

Resorcinol-formaldehydeJalumina composite (RF/A1₂O₃) aerogels were prepared using sol-gel techniques and supercritical fluid CO₂ drying. RF/A1₂O₃ aerogels were successfully converted to light and high-strength carbonJalumina composite (C/A1₂O₃) aerogels after high temperature thermal treatment process. The effects of different thermal treatment temperature on the aerogels structures were studied. The structures and properties of aerogels were analyzed by means of BET, XRD, SEM, TEM and the compressive strengths were also measured. The experimental results showed that the as-synthesized C/A1₂O₃ aerogels with great monolithic morphology exhibited a three-dimensional network structure. With the increasing of thermal treatment temperature, both specific surface area and compressive strength of aerogels were first increase and then decrease. In particular, the C/A1₂O₃ aerogels treated by the thermal treatment temperature of 1 400 °C had the highest specific surface area and compressive strength (831 m^{2 ·}g^-1 and 9.5 MPa, respectively).