Sintering Behavior of Doped Lanthanum and Yttrium Manganite

The sintering behavior of doped manganite powders was found to be highly dependent on changes in calcination conditions and A/B cation ratio. Coarsening of combustion synthesized powders by calcination allowed for higher green densities in dry-pressed compacts, which resulted in higher sintered densities for powders calcined in the temperature range 800°-1200°C. Sintered densities decreased for calcination temperatures greater than 1200°C. Preparation of manganites with a deficiency of A-site cations improved the densification behavior substantially. This effect was attributed to an increased concentration of A-site vacancies which enhanced the diffusion of A-site cations during sintering. Modification of doped manganites by alteration of composition and calcination conditions allowed their sintering shrinkage to be "tailored" to more closely match the shrinkage of yttria-stabilized zirconia.