Elastic moduli of Ce0.9Gd0.1O2 − δ at high temperatures under controlled atmospheres

The Young's modulus and the shear modulus of Ce0.9Gd0.1O2 − δ (GDC) were evaluated by using a resonance method in the temperature range from room temperature to 1273 K and in the p(O2) range from 10− 24 to 10− 1 bar. It was found that the elastic moduli of GDC under oxidizing conditions gradually decreased with increasing temperature in a constant atmosphere and was almost independent of p(O2) at a constant temperature. However, under reducing conditions, the elastic moduli apparently decreased as p(O2) decreased even at a constant temperature, and such a decrease became more considerable under lower p(O2) conditions. The variation in the elastic moduli of GDC with p(O2) seemed to reflect the variation in the oxygen nonstoichiometry δ. It was demonstrated that the elastic moduli are affected not only by the change in the interatomic distance due to the chemical and/or the thermal expansion but also by the variation in the oxygen nonsotichiometry and the average valence of cerium ions.

► In situ evaluation of elastic moduli of Gd-doped CeO2 for an SOFC electrolyte.
► The elastic moduli varied in response to the oxygen vacancy formation.
► The elastic moduli's change was discussed by assuming classical atomic potentials.
► Origin of the elastic moduli's change due to the vacancy formation was clarified.