A Morphological Study on the Titanium-Oxide Foams Processed Using Freeze-Casting

The TiO 2 foam synthesized using freeze-casting is a promising photocatalyst and photovoltaic electrode for a variety of energy applications, because the freeze-casting technique is easy to use, cheap, and suitable for mass-production.Despite its several advantages, little scientific information is available on the processing and morphology of the TiO 2 foams processed by freeze-casting.In particular, no systematic study has been performed on the microstructural evolution and morphological change of the rutile-phase TiO 2 foams during sintering.Therefore, in the present study, several TiO 2 foam samples were produced using the freeze-casting technique, which were then sintered at a relatively high temperature of 1200 o C for 1, 2, and 4 h to compare the morphological changes in the microstructure and to understand the effects of processing parameters of the rutile-phase TiO 2 foams.The foam ligament size increased near linearly with increasing sintering time whereas the average pore size decreased only slightly with increasing sintering time, with changes in particle morphology from sphere to rod and complete phase transformation from anatase to rutile.