Preparation Of Al₂O₃-SiO₂-ZrO₂Composite By Sol-Gel Method

Aerogels that have high porosity and large surface aera in there structure. This point make it become a kind of ideal thermal insulation material. Alumina aerogels with higher stability and good distribution of nano holes so that it can be used in high temperature insulation field. However, the high temperature phase reaction will affect the high temperature properties of alumina aerogels. It is necessary to prepare aerogel composites by doping with reinforcements and opacifiers. As the SiO2and ZrO2joined Al2O3aerogel, the high temperature stability of Al2O3-SiO2-ZrO2aerogel composite was increaser comparing pure Al2O3aerogel.In this paper, the main research contents include:preparation of the Al2O3-SiO2-ZrO2aerogel composite, the influence of different solvents, precursor and crosslinker concentrations on the properties and microstructures. What’s more, we also discuss the heat treatment of the flexile aerogels.In this paper, with AlCl3·6H2O, ZrOCl2·8H2O and tetraethoxysilane (TEOS) as the main raw material and the mixed solution of water and ethanol were chosen as reaction medium and Propylene oxide was added as gelation Promoter. Al2O3-SiO2-ZrO2aerogel composite were synthesized by Sol-gel technology and supercritical drying method.The effects of Parameters of aerogels were discussed. The optimum amount of PO, H2O, EtOH and TEOS are8ml,18ml,16ml and1ml, respectively. ZrOCl2·8H2O adding amount of0.33g, AICl3dosage is1.808g the resulting aerogels performance are best.The density of as-prepared aerogel monoliths without alcohol replacement was0.041g·cm-3, the surface area was507m2·g-1.The Al2O3-SiO2-ZrO2aerogels monoliths with the surface area of367m2·g-1was achieved by heat-treatment at1000℃and weight loss is18%. The density of as-prepared aerogel monoliths with alcohol replacement was0.101g·cm-3, the surface area was357m2·g-1.The Al2O3-SiO2-ZrO2aerogels monoliths with the surface area of135m2·g-1was achieved by heat-treatment at1000℃and weight loss is8%.After the study, we found that two kinds of aerogel suppress the transformation of transformation of tetrahedral Al to octahedral Al. As the result, aerogel at1000℃are not complete densification.The research of aerogel composite with Ceramic Fiber and Mullite Fiber suggests that aerogel particles can be well together with the composite fiber. The Composites high temperature insulation will be increase.