Phase Evolution and Stability of Aluminum Titanate Prepared by Solid -State Route and Solution Combustion Route

Abstract

Aluminum titanate (Al2TiO5) powder was synthesized using two different route, namely, solid-state route and solution combustion route. In solid-state route, two different types (micron and nano-size powder) of Al2O3 precursor powder was used. Phase evolution and powder morphology were investigated by X-ray diffraction method and Field emission scanning electron microscope (FESEM) respectively. In case of large particle Al2O3 precursor powder, Al2TiO5 (AT) phase was formed at 1500oC with a yield of 97%. Whereas using nano-Al2O3 precursor powder, AT phase was formed at 1350oC with a yield of 91% and almost phase pure powder can be prepared at 1500oC. Average particle size of the AT powder was 11 µm (using large particle Al2O3) and 10.2 µm (using nano-size Al2O3) for calcination at 1500oC. AT powder was also synthesized by citrate-nitrate solution combustion method. The molar ratio of metal (Al:Ti) and citric acid was varied to get a uniform and complete combustion. A significant amount Al2TiO5 phase was formed at 1350°C. The stability of the solid state route prepared AT powder was investigated by keeping the powder at 1150°C/6hr. It was observed from the XRD analysis that only 40% AT-phase was retained in samples prepared with micron size Al2O3, but, in case of sample prepared using nano size Al2O3, 93% AT-phase was retained.