Densification and anisotropic grain growth in Sr2Nb2O7

Sr : Nb stoichiometry and donor-doping with La were found to affect densifi cation behavior and anisotropic grain growth in Sr2Nb2O7 ceramics. La-dopin g improved the high temperature a.c. resistivity, but inhibits grain growth by grain boundary pinning. The presence of excess Nb was found to promote anisotropic grain growth by forming a liquid at the grain boundaries in bot h undoped and doped Sr2Nb2O7. Anisotropic grain growth in La-doped Sr2Nb2O7 can be controlled by incorporating large template particles in a Nb-rich m atrix. High sintered densities (similar to 98% of theoretical) were achieve d in both undoped and La-doped samples.