Aluminaaerogelswerepreparedthroughadditionofpropyleneoxidetoaqueousorethanolicsolutionsof hydratedaluminumsaltsAlCl3·6H2O,followedbydryingwithsupercriticalethanol.Microstructureofaluminaaerogels werecontrastedandanalyzedatdifferenttemperaturbymeansoftransmissionelectronmicroscopy,powderX-raydiffractionandnitrogenadsorption/desorptionanalysis.Theresultsshowthattheaerogelmicrostructurescontainhighly reticulatednetworksofboehmitefibers,nosignificantlossinmonolithicityoccurredduringheattreatmentofalumina aerogelsat500℃and1000℃,thesurfaceareais429m2/gand174m2/g.Thephaseconversionintherangefrom20 to1000℃areasfollows:boehmite→γ-Al2O3→δ-Al2O3.