Peroxide route to synthesize calcium titanate powders of different composition

Abstract

The calcium titanates CaTiO3, Ca3Ti2O7 and Ca4Ti3O10 can be synthesized by the wet chemical peroxide route. The first step of the preparation is the precipitation of peroxo-precursors of definite stoichiometry which are transformable into the corresponding titanates by thermal decomposition. The resulting ultra-fine, phase-pure calcium titanate powders have only a small impurity content. They are very sinter active above 1200°C. The rate of densification during sintering of compacts is improved in the sequence Ca3Ti2O7<Ca4Ti3O10<CaTiO3, considering the green densities, the densities at a given time and the theoretical densities of the titanates for the calculations. The phase CaTi4O9 can be obtained after thermal degradation of a corresponding peroxo-precursor at temperatures below 700°C. There are also indications of the formation of the phase CaTi2O5 below 700°C. A phase Ca2TiO4 can not be synthesized using the peroxide route.