Influence of synthesis conditions on formation of core–shell titanate–ferrite particles and processing of composite ceramics

Strontium titanate–nickel ferrite (SrTiO3–NiFe2O4) composite and core–shell particles have been prepared by the combination of sol–gel and co-precipitation route. Modifications of the synthesis procedure (pH value, functionalization of core and shell particles) have been carried out in order to maximize the electrostatic forces between the phases and thus optimize the core–shell morphology of the synthesized powder. It was found that the synthesis pH has considerable influence on the morphology of as-synthesized particles as well as their phase composition. Prepared powders were processed into dense composite ceramics by conventional sintering in air and/or by spark plasma sintering. Particle morphology and thus particle synthesis procedure has proven to have a direct impact on the density, homogeneity and phase composition of the sintered ceramics.