The sintering behavior of co-deposited aluminum oxidetitanium dioxide powder prepared by a flame chemical vapor deposition (CVD) technique was studied in the compositional range of 56-73·5 wt% aluminum oxide. Significant densification was observed between 1100 and 1300°C with the co-deposited powder of stoichiometric composition, or of a slight excess aluminum oxide content. The titanium dioxide crystallites appeared to accelerate the densification when they were sufficient in amount and homogeneously mixed with the aluminum oxide. The excellent sinterability of these powders of relatively lower aluminum oxide content resulted in dense (maximum 95·5% of theoretical) and large-grained (20-50 μm) aluminum titanate ceramics at higher temperatures, while the microstructures of specimens from the mechanically mixed powder or from the co-deposited powder having an excess of aluminum oxide were porous and fine-grained. In the case of the co-deposited powder containing slight excess aluminum oxide, small (1-3 μm) aluminum oxide particles were dispersed on the boundary of ß-Al2TiO5 grains.
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