Grain growth control in Nb-doped BaTiO3

Further modifications on materials selection and ceramic processing varied the Nb incorporation extent significantly. Mechanochemically activated BaCO3 reactant and ultrafine TiO2 led to an early reaction. It provided a wide temperature range for Nb5+ incorporation as the BaCO3-TiO2 reaction progressed. Complete, homogeneous Nb incorporation in these materials allowed a strong grain growth inhibition on sintering and avoided accumulation of needle-shaped phases. Simultaneously to the grain growth inhibition phenomenon a considerable increase in titanium vacancy concentration was detected. Resulting materials stabilized in a pseudocubic phase and showed high dielectric features at room temperature.