Ceramics-Silikáty 57 (2) 133-137 (2013)

EFFECT OF ALUMINUM POWDER ON THE SYNTHESIS OF CORUNDUM-MULLITE COMPOSITES

Corundum-mullite composites were prepared by reaction sintering from tabular corundum, activated mullite powder, metal aluminum powder and SiO₂ micro powder. The effect of aluminum powder content on the synthesis and densification of the corundum-mullite was studied. All raw materials were mixed and pressed into billets with diameters of 20 mm and height of 15 mm. The green-body billets were sintered at temperature from 1100°C to 1500°C in an air atmosphere. Bulk density, apparent porosity, phase composition and microstructure of final sintered products were analyzed. The results indicated that aluminum powder can promote the densification and mullitization of corundum-mullite composites. At the same time, aluminum powder promoted the formation of columnar mullite. Among materials sintered at 1500°C for 3 h, samples with 8 % aluminum powder had the highest bulk density.

Keywords: Aluminum, Corundum-mullite composites, Sintering, Densification