Al2O3 @ TiO2—A simple sol–gel strategy to the synthesis of low temperature sintered alumina–aluminium titanate composites through a core–shell approach

A simple sol–gel based core–shell approach for the synthesis of alumina–aluminium titanate composite is reported. Alumina is the core and titania is the shell. The coating of titania has been performed in aqueous medium on alumina particle by means of heterocoagulation of titanyl chloride. Further heat treatment results in low temperature formation of aluminium titanate as well as low temperature sintering of alumina–aluminium titanate composites. The lowering of the reaction temperature can be attributed to the maximisation of the contact surface between the reactants due to the core–shell approach involving nanoparticles. The mechanism of formation of aluminium titanate and the observations on densification features in the present process are compared with that of mixture of oxides under identical conditions. The sintered alumina–aluminium titanate composite has an average grain size of 2 μm.