Effect of Cr2O3 on the sintering of aluminosilicate precursor leading to mullite formation

Aluminosilicate precursor material for mullite formation was synthesized us ing wet interaction of the ingredients like aluminum nitrate and silicic ac id sol in the aqueous route. The gel was characterized by chemical analysis , measurement of surface area, bulk density and X-ray analysis. Sintering o f the gel powder was carried out at different elevated temperatures from 13 00 degreesC to 1450 degreesC in presence of Cr2O3 as a doping agent. The di fferent physico-mechanical properties of the sintered compacts, such as, vo lume shrinkage, bulk density, porosity etc. were measured. X-ray diffractio n and SEM analysis of the compacts were further carried out to evaluate the degree of sintering of the powder in presence of Cr2O3 It was observed tha t Cr2O3 plays a positive role in the formation of mullite at elevated tempe rature from the aluminosilicate gel precursor. (C) 2001 Elsevier Science Lt d and Techna S.r.l. All rights reserved.