Synthesis, structural characterization, electrical properties and chemical stability of a (ZrO2)0.97(Y2O3)0.03−x(MgO)2x solid solution

Abstract

This paper is concerned with ternary solid state ZrO₂–Y₂O₃–MgO where the zirconia tetragonal phase is stabilized by incorporation of yttrium and/or magnesium in the ZrO₂ lattice. This subject is especially important due to the broad application of yttria stabilized zirconia (YSZ) in (among others) electroceramic systems in particular as potential component of the composite anode material for SOFC technology. A series of samples with a starting composition corresponding to 3 mol% yttria-stabilized zirconia (3YSZ) and increasing substitution of yttrium by magnesium were synthesized. The resulting samples were examined in terms of structural properties, phase composition, electrical properties and chemical stability. The obtained results show close correlation between the amount of incorporated magnesium and structural parameters of the tetragonal phase as well as electrical properties of all samples. The substitution of yttrium with magnesium in the 3YSZ system leads to a significant decrease of conductivity and the appearance of a monoclinic phase in the system for x > 0.015 (3 mol% of Mg²⁺). Moreover, it was confirmed that exposing the ZrO₂–Y₂O₃–MgO ternary system to a CO₂ and H₂O atmosphere can significantly decrease its chemical stability. From the point of view of both, basic and application research, these studies make an important contribution to the current knowledge of the properties of the ZrO₂–Y₂O₃–MgO ternary solid solution system.