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, average grain size, microhardness measurements and microstructural features were evaluated to correlate densification with grain growth and second phase formation. Each additive both singly and in combination, was found to increase the final sintered density and microhardness values of the samples. 3 wt% MnO2 when added with 0.5-3 wt% TiO2 lowers the sintering temperature to 1250 degrees C. Excessive grain growth and draining 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.