Sintering behavior of TiO2 nanoceramic by Spark Plasma Sintering

Reference	Presenter	Authors (Institution)	Abstract
12-021	Diego Seiti Fukano Viana	Alvarez Roca, R.(Universidade Federal de São Carlos); Viana, D.S.(Universidade Federal de São Carlos); Eiras, J.A.(Universidade Federal de São Carlos); Londoño, F.A.(Universidad de Antioquia);	Nanocrystalline TiO2 has been used in a wide range of applications, such as electro-electronic and sensing devices and photoelectric and photocatalytic processes. Moreover, much interest has been drawn toward to the sintering and full densification of nanoceramic TiO2. However, preparing a fully-dense nanocrystalline TiO2 can be difficult because the grains grow rapidly at the later sintering stages and due to that the phase transformation from anatase to rutile can contributes to the densification process. On the other hand, Spark Plasma Sintering (SPS), which has been used for the fabrication of a variety of materials, is highly appropriate for rapid densification of ceramic nanoparticles and the nanostructure preservation. In the present work, this technique has been used in order to obtain a fully-dense TiO2 nanoceramics. The microstructure of the samples sintered by SPS was investigated using scanning electron microscopy (SEM) while densities were determined by the Archimedes’ method. The final phases, confirmed by R-X, and final relative densities and grain sizes, studied between 800-900 °C of sintering temperature under a pressure of 75-90 MPa, were 90-95 % and ~ 60-90 nm, respectively. The shrinkage under heating was continuously monitored and used to check the mechanisms involved in the green compact densification. We assumed that the first and intermediate sintering stages occurs by GB sliding and particle rotation mechanism probably controlled by the interface diffusional processes. Additionally, the electric conductivity was investigated as a function of temperature. The results of densification, microstructure and conductivity were compared with the results found in the literature and discussed.
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