Aluminum Titanate Formation by Solid‐State Reaction of Fine Al2O3 and TiO2 Powders

Abstract
The formation of Al2TiO5 has been studied in equimolar Al2O3‐TiO2 powder mixtures of ∼1μm particle sizes and moderate purity (∼99.8 wt%) at temperatures around 1300°C, where the free energy of formation is very small. Micro‐structural development and reaction kinetics indicate that different mechanisms operate depending on the advancement of the reaction. The rapid initial reaction stage is interpreted as the nucleation‐growth of Al2TiO5 cells in a virtually non‐reacting matrix. The final reaction stage corresponds to the slow diffusion‐controlled elimination of Al2O3 and TiO2 dispersoids trapped during the growth of the initial Al2TiO5 cells.