NEW BI-LN-V-O ANIONIC CONDUCTORS WITH DELTA-BI2O3 FLUORITE-TYPE STRUCTURE (LN = Y, SM, EU, GD, TB, DY, ER, YB)

An extensive investigation of Bi2O3-Ln(2)O(3)-V2O5 systems (Ln = Y, Sm , Eu, Gd, Tb, Dy, Er, Yb) yields preservation of the metastable fee de lta-Bi2O3 structure in large composition ranges by air-cooling from th e high temperature delta equilibrium domain. Partial substitution of V for Ln in Bi(0.85)Ln(0.15(1-y))V0.15yO0.15y samples (0 less than or e qual to y less than or equal to 0.45) results in a lowering of the equ ilibrium temperatures, as well as an increase of the stability of the related quenched phases. The best stability is observed for samples co rresponding to y = 0.3. The anionic conductivity reaches 10(-3) S/cm a t 300 degrees C and 0.5 S/cm at 700 degrees C for Bi0.85Tb0.105V0.045O 1.545. (C) 1997 Academic Press.