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

Aluminosilicate precursor material for mullite formation was synthesized using wet interaction of the ingredients like aluminum nitrate and silicic acid sol in the aqueous route. The gel was characterized by chemical analysis, measurement of surface area, bulk density and X-ray analysis. Sintering of the gel powder was carried out at different elevated temperatures from 1300°C to 1450°C in presence of Cr2O3 as a doping agent. The different physico-mechanical properties of the sintered compacts, such as, volume shrinkage, bulk density, porosity etc. were measured. X-ray diffraction 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 that Cr2O3 plays a positive role in the formation of mullite at elevated temperature from the aluminosilicate gel precursor.