Enhanced dispersion stability and fluidity of rutile TiO2 particles using surface fluorination

To investigate the effect of surface fluorination on dispersion stability and powder fluidity of rutile TiO2 particles, they were fluorinated using F-2 gas under various conditions. Reaction temperature, fluorine pressure and reaction time were set at 25 similar to 200 degrees C, 1 similar to 50 kPa, and 1h, respectively. Even at 200 degrees C of fluorination temperature, the crystal structure did not change in XRD results. Some fluorenes were found on the surface of TiO2 particles in XPS results, and their contents increased with increasing the F-2 pressure. From a result of sedimentation test with water, the dispersion stability of TiO2 particles was improved using the surface fluorination. The average size and zeta potentials of fluorinated TiO2 particles were almost 2 times smaller and 2 times larger, respectively, than those (1x10(3) mm and -20 mV) of untreated TiO2 particles. And in the results of FT4 powder rheometer and repose angle, the powder fluidity of rutile TiO2 particles was improved using surface fluorination. Consequently, the fluorine existed on the surface of TiO2 particles made to improve a dispersion stability and fluidity of TiO2 particles. (C) 2018 Elsevier Ltd. All rights reserved.