PHASE-STABILITY AND OXYGEN-ION CONDUCTION IN BI2O3-PR6O11

Oxygen ion conductivity was measured on a number of (Bi2O3)1-x(Pr6O11)x systems from room temperature to 550-degrees-C. At x=0.05, the rhombohedral Bi1.35Pr0.65O3 structure was found to be stable up to 550-degrees-C. At higher concentrations, a mixture of rhombohedral and possibly monoclinic type structures were determined, which at x=0.2 became fully ''monoclinic''. High temperature X-ray powder diffraction confirmed the stability of the observed phases over the temperature range. The optimum ionic conductivity was found for the mixed phase and a value of 1.23 x 10(-2) s/cm was ascertained for x=0.15 at 450-degrees-C.