Fabrication of bulk anatase TiO2 by the spark plasma sintering method

Nanocrystalline (7 nm, anatase) and microcrystalline (5 μm, anatase and rutile) TiO2 powders was successfully consolidated by spark plasma sintering (SPS) in the temperature range of 400–550 °C at a pressure of 555 MPa. The consolidated samples of the nanocrystalline powders exhibit an anatase form, when the sintering temperature is low despite the application of high-pressure during SPS. The density of the consolidated samples of the nanocrystalline powders was higher than that of the microcrystalline powders; this is attributed to the difference in the size of TiO2 powders. The consolidated sample of the nanocrystalline powders fabricated at 400 °C shows the lowest contact angle under ultraviolet light illumination. The water contact angle of the consolidated sample of the microcrystalline powders is relatively high as compared to that of the nanocrystalline powders for identical consolidation temperatures. In conclusion, in comparison to the SPS conditions previously reported, we successfully fabricated an anatase-structured bulk TiO2 at lower temperatures by applying a high pressure.