Influence of additives on phase stabilization of scandia-doped zirconia

Abstract

The effects of small additions of tin, zinc, calcium and boron oxides on phase composition and electrical
conductivity of zirconia-10 mol% scandia were investigated. Compounds containing 1 mol% zinc, tin and
calcium oxides and 1, 3 and 5 wt.% boron oxide were prepared by solid state reaction and characterized by
X-ray diffraction, density measurements, scanning electron microscopy and impedance spectroscopy. Full
stabilization of the cubic structure at room temperature was obtained with additions of 1 mol% calcium oxide
and 2 wt.% boron oxide. Partially stabilized compounds exhibit herringbone structure, characteristic of the β-
rhombohedric phase. Specimens with calcium as additive show total conductivity of 23.8 mS.cm-1 at 750ºC
with activation energy of 1.13 eV. Liquid phase sintering by boron oxide addition is effective to enhance the
densification of the solid electrolyte.