Enhancing the Densification of Nanocrystalline TiO_2 by Reduction in Spark Plasma Sintering

摘要

Fully densified TiO_2 was obtained from spark plasma sintering (SPS) nanocrystalline rutile powder at a temperature of 720℃. The TiO_2 was densified under an applied pressure of 40 Mpa at 720℃. However, the applied pressure was not great enough to cause plastic deformation within the TiO_2 nanoparticle compact. Therefore, simple plastic deformation by applied pressure could not lead to the abrupt densification of TiO_2 during the SPS. In this work, the abrupt densification of nanocrystalline TiO_2 was examined at a low temperature in terms of the Joule heat caused by the flow of current through the compact due to the reduction of Ti~(4+) to Ti~(3+).