Peroxide route to synthesize strontium titanate powders of different composition

Abstract

Abstract The calcium titanates CaTiO 3 , Ca 3 Ti 2 O 7 and Ca 4 Ti 3 O 10 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 Ca 3 Ti 2 O 7 4 Ti 3 O 10 3 , considering the green densities, the densities at a given time and the theoretical densities of the titanates for the calculations. The phase CaTi 4 O 9 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 CaTi 2 O 5 below 700°C. A phase Ca 2 TiO 4 can not be synthesized using the peroxide route.