Effect of uniaxial stress on ionic conductivity of 14 mol%-yttria-stabilized zirconia single crystal

In the present study, the ionic conductivity of the 14 mol%-yttria stabilized zirconia single crystal subjected to the tensile or compressive stress was examined at various temperatures. The conductivity was increased by the tensile stress and the improvement in the conductivity was higher at the lower temperature and also for the specimen with the <100> orientation. On the other hand, the conductivity was decreased by the compressive stress. The change by the compressive stress was higher at the lower temperature, but it was generally smaller than that in the tensile test. The maximum improvement achieved by applying the tensile stress was about 18% at 850 K in the present study. The present experimental results qualitatively agreed with the molecular dynamics simulations on the oxygen diffusion. The oxygen displacement in the fluorite lattice caused by the applied stress could be attributed to the change in the conductivity.

Research highlights
► The experiment shows that the stress can improve the conductivity of YSZ.
► The stress is effective when applied in the <100> direction at low temperature.
► The experimental result qualitatively agrees with the MD simulation.
► The improvement could be attributed to the oxygen displacement in the lattice.