A Sedaghat - Ph.D. student
E aheri-Nassaj - Professor, Department of Materials Science and Engineering, Tarbiat Modares University
G.D Soraru - ,۳Professor, Departmentof Materials Engineering and Industrial Technology, University of Trento
R Ceccato - Professor, Materials & Energy Research Centre, PO Box ۱۴۱۵۵-۴۷۷۷, Tehran, Iran

Via sol-gel method, it can be obtained, the homogeneous distribution of mullite in alumina matrix. In this work, alumina-mullite nanopowder was synthesized by aluminium chloride hexahydrate and colloidal silica via sol-gel method and in the other works it had been prepared by alumina and TEOS. According to the XRD patterns of alumina-mullite 15%vol. precursors calcined at different temperatures, transitional alumina (γ, κ) & silica phases (quartz, tridymite) crystallize at around 900°C. Then it transforms to α alumina & mullite in the range of 1000-1300°C completely. Specific surface area and density of the nanopowder calcined at 900oC are 105.4 ± 0.4 m2/g & 3.646 ± 0.007 g/cm3 respectively. Then the nanopowder was observed by TEM.

Nanopowder; Alumina; Mullite; Sol-gel processes; Phase transformation