THE EFFECT OF TIO2 AND MNO2 ON DENSIFICATION AND MICROSTRUCTURAL DEVELOPMENT OF ALUMINA

The effect of MnO2 and TiO2 as additives during the densification and microstructural development of Al2O3 has been investigated between the temperature range of 1250 and 1550 degrees C. Sintered density, avera ge grain size, microhardness measurements and microstructural features were evaluated to correlate densification with grain growth and secon d phase formation. Each additive both singly and in combination, was f ound to increase the final sintered density and microhardness values o f the samples. 3 wt% MnO2 when added with 0.5-3 wt% TiO2 lowers the si ntering temperature to 1250 degrees C. Excessive grain growth and drai ning of second phase were observed in these samples that were sintered above 1350 degrees C. (C) 1997 Elsevier Science Limited and Techna S. r.l.