The influence of Fe2O3 doping on the pore structure and mechanical strength of TiO2-containing alumina obtained by freeze-casting

This work investigated TiO2/Fe2O3 doped alumina prepared by the freeze-casting technique and using camphene as the solvent. Dendritic pores were formed in the TiO2 doped alumina, a structure conferred by the frozen camphene. Contrary to this trend, further Fe2O3 doping of TiO2-containing alumina resulted in the formation of non-dendritic structures. This behavior was attributed to the higher density of α-Fe2O3 (5.24 g cm−3) when compared to α-Al2O3 (3.95 g cm−3) and anatase TiO2 (3.89 g cm−3), which reduced critical solidification front velocity, thus forming material with different pore shape. Fe2O3 doping also improved the densification of TiO2–alumina and inhibited the formation of cracks, reflected by superior mechanical strength with best results ~150% higher for 10% Fe2O3 loaded samples as compared to TiO2–alumina samples.