Influence of MnO and TiO2 additives on density, microstructure and mechanical properties of Al2O3

The effects of MnO and TiO2 additives on the sintering of sol-gel processed alumina were investigated. Sintered density, average grain size and microstructural features were examined along with the mechanical properties. The addition of MnO produced a relatively uniform, dense microstructure at high temperature. TiO2 up to 0.2 wt% was found to be the most effective additive in promoting grain growth. TiO2 doping also achieved theoretical density at 1400 C. The secondary phase, Al2TiO5 mostly precipitated at triple junctions and occasionally along the grain boundaries. 20 refs.