Controlling micro-porous size in TiO2 pellets processed by sol-gel and rapid liquid phase sintering

Abstract A fast and lower electric energy consumption process to synthesize TiO 2 pellets with interconnected micropores, is proposed. Pellets were prepared by rapid liquid-phase sintering (RLPS) at different temperatures (900, 1000 and 1100 °C) and times (2, 5, 7 and 10 min). The density of these samples increases when temperature rises and decreases for longer sintering times; the highest density, of 2.78 g/cm 3 was obtained when sintering at 1100 °C/2min. The addition of PEG and the annealing at 450 °C/2 min produced pores of 38.51 ± 27.51 μm and 48.98 ± 32.34 μm when PEG3350 and PEG8000 respectively, were used. An additional RLPS at 1100 °C/2 min gives rise to TiO 2 pellets in a rutile phase, with pores of 76.82 ± 34.23 μm and 173.04 ± 68.03 μm for PEG3350 and PEG8000, respectively. Interconnectivity of pores is obtained in all samples. The elastic module of these pellets was 39.22 ± 0.16 GPa, for the sample prepared with PEG3350; and 121.30 ± 0.04 GPa for the one made with PEG8000. The achieved pore size and interconnectivity at 1100 °C/2 min are a result of the optimized sintering conditions and the better control of PEG vapor pressure released when the intermediate annealing at 450 °C/2 min is introduced.