| Aerogel is a very lightweight solid materials which has excellent properties, including of aspects of acoustics, electrical, optical, nuclear physics.Therefore,at this stage about the application of the aerogel has reached a staggering number.In this paper, sol-gel methodwas used to prepare aerogel.AnhydrousAlcl3and tetraethoxysilane (TEOS) were used as precursor.In the process of preparation Propylene oxide was joined.Finally supercritical drying process was used.Experiment studied the different solutions to the preparation of the aerogel samples (Aluminum source, alcohol water ratio, dosage of epoxy propane, etc).Reinforcing fiber is mullite fiber was used as reinforcing fiber to prepare Al2O3-SiO2aerogel composite.After a series of experiments,the optimal ratio ofAl2O3-SiO2aerogel was confirmed:n (Al):n (Si)=12:1, n (Si):n (H2O):n (EtOH): n (PO)=1:223:61:25.5.With this ratio/Translucent, lightweight and monolithicAl2O3-SiO2aerogel was prepared.Thedensityoftheaerogel was about40g/m3.After supercritical drying,linear Shrinkage was about8%.And after1200℃heating treatment,total weight loss was 7.55%.Theproducthadaparticularthree-dimensionalnetworkmicrostructure, whichwasformedby the long strip of grains stack and crosslinking.And after1200℃heating treatment,aerogel still had surface area of173m2/g.And in this paper,the influence of different fiber matrix to composite properties was studied.Mullite fiber was used to composite with aerogel.The microstructure of the composite material was observed.The thermal conductivity of composite materials was0.062W/m·k.With comparison,Al2O3-SiO2aerogel composite materials had a significantly lower thermal conductivity, and heat insulation performance was obviously improved... |
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