SINTERING BEHAVIOR OF DOPED LANTHANUM AND YTTRIUM MANGANITE

The sintering behavior of doped manganite powders was found to be high ly 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 rang e 800 degrees-1200 degrees C. Sintered densities decreased for calcina tion temperatures greater than 1200 degrees C. Preparation of manganit es with a deficiency of A-site cations improved the densification beha vior substantially, This effect was attributed to an increased concent ration of A-site vacancies which enhanced the diffusion of A-site cati ons during sintering. Modification of doped manganites by alteration o f composition and calcination conditions allowed their sintering shrin kage to be ''tailored'' to more closely match the shrinkage of yttria- stabilized zirconia.