Abstract
The effects of CuO on the sintering driving force and the grain growth kinetics of TiO2 have been investigated. The sintering temperature, 900oC, is below the eutectic point of CuO-TiO2 system. The Cu-rich grain boundary complexions are formed during sintering. Poorer densification is observed for the 1 mol% CuO-doped TiO2 densified under pressure-less constrained sintering in comparison to free sintering. No significant anisotropy is developed under free and constrained sintering. The applied uniaxial stress required in the thickness direction to densify 1 mol% CuO-doped TiO2 under constrained sintering at 750-950oC varies in the range of 200-1100 kPa, consistent with those calculated theoretically. By measuring dihedral angles, the Cu-rich grain boundary complexions have lower grain boundary energy to enhance driving force of sintering than pure TiO2 grain boundaries. The grain growth results show high grain boundary mobility and lower activation energy in CuO-doped TiO2 system. With grain boundary complexions existing, the polycrystalline CuO-doped TiO2 system can be densified under constrained sintering.