Effects of phase and doping on flash sintering of TiO2

Using TiO2 as a model system, the effects of different doping (un-doped, V-doped vs. N-doped) and starting phases (anatase vs. rutile) on the flash sintering of TiO2 are investigated. The doping and starting phase not only alter the onset flash sintering temperatures via changing the temperature-dependent electric conductivities of the green specimens, but also significantly affect the densification and microstructural development during the flash sintering. In all six cases, the coupled thermal and electric runaway temperatures predicted from measured specimen conductivities agree well with the observed onset flash temperatures (with less than 5 degrees C in differences), supporting a recently-developed quantitative model. (C) 2016 The Ceramic Society of Japan. All rights reserved.