Synthesis And Densification Studies Of Nanocrystalline Titanium Dioxide Ceramics

In this research, we have synthesized nanocrystalline titanium dioxide (TiO 2) ceramic powder through a simple process of hydrolyzing titanium tetraisopropoxide (TTIP) in a mixture of isopropanol and deionized water, and studied its densification behavior. Nitric acid (HNO 3) was added to restrain the hydrolysis process, and consequently to control the grain growth. The synthesized powder was analyzed for its phases, using the X-ray diffraction technique. Transmission electron microscopy (TEM) was used to determine its powder particle-size and morphology. Dense structures, made from the synthesized nanocrystalline powder and commercial TiO 2 powder (Alfa Aesar Company, 99.9% pure), were sintered in the temperature range of 1200-1400°C, to study and compare their densification behavior. Vickers hardness test was carried out to evaluate their mechanical property. Results showed that the synthesized TiO 2 powder was in anatase phase and its particle-size was around 5-10 nm. For both kinds of TiO 2 ceramics, the densification process continued with an increase in sintering temperature and the nanoscale TiO 2 exhibited improved sintered density, compared to the commercial powder at all sintering temperatures. We also observed that at a sintering temperature of 1200°C, the volume shrinkage of nanocrystalline TiO 2 samples was 49%, while only 27% was observed in commercial TiO 2 samples. The trend of variation in hardness of the sintered structures with the increase in sintering temperature (1200 - 140°C), was similar with that of the densification studies. Maximum hardness value of 328.3±16 HV was obtained in specimens sintered at 140°C