Synthesis and Characterization of Nanoscale Mullite Powder

Nanoscale mullite powder were synthesized via Sol-gel-SCFD and middle temperature treatment by using AIP( aluminum-isopropoxde) and TEOS ( tetraethyl orthosili-cate) as starting materials. Both of the binary aerogel of alumina-silica and calcined nanoscale materials were investigated by using TG-DSC ( thermogravimetry-differentialscanning calorimeter) , TEM( transmission electron microscope) , XRD(X-Ray diffractometer ) and specific surfacearea and porosimetry. TG-DSC indicated the removal of most of the volatiles, i.e. 15.98% up to about 700℃ ,and in the DSC curve , existence of two exothermic peak atabout 445℃ and 1015℃ may be due to the crystallizationof Si-O-Al-O in diphasic gels and mullitization and a small endothermic peak at about 805℃ indicated the decomposition of structural water molecules . On the colligation of the results of TG-DSC, XRD and TEM, the beginning temperature of mullitization in Al2O3-SiO2 aerogel system can be confirmed at about 1015℃. XRD results also showed the formatio