Reaction sintering of colloidal processed mixtures of sub-micrometric alumina and nano-titania

Even though homogeneous final materials were obtained in all cases, full reaction was obtained only in materials treated at 1400 °C. The microstructure of the composites obtained by quenching was formed by an alumina matrix with bimodal grain size distribution and submicrometric aluminium titanate grains located inside the largest alumina grains and at triple points. However a cooling rate of 5 °C/min led to significant decomposition of aluminium titanate. This fact is attributed to the small size of the particles and the effect of the alumina surrounding matrix.