About ionic conductivity/diffusion relationships in yttria doped zirconia

Abstract

Abstract. The values of the oxygen self-diffusion coefficients (measured using 180 tracer) are compared to the ionic conductivity (measured by impedance spectroscopy) of 9.5 mol% yttria doped zirconia single crystals in the tem~rature range 240 -800 ~ in air.Electrical conductivity measurements in polycrystals, exhibiting a grain boundary contribution to the ionic conductivity, are furthermore discussed in the frame of a "brick/boundary model".

Effect of high-content Yttria on the thermal expansion behaviour and ionic conductivity of a stabilised cubic Hafnia

“…This demonstrates that the samples do not suffer of microstructure or phase instability as proven earlier when applying thermal treatment during process and associating X-Ray patterns analysis. Generally, doped-hafnia samples show a lower ionic conductivity than the most currently employed 8YSZ material (Zr0.852Y0.148O1.926) in fuel cell or thermal barrier fields [31,43,65,68] as presented in Fig. 8.…”

“…When there is movement of other charge carriers or electrons, HR < 1. When other defects like vacancy pairs or impurity-vacancy pairs participate to diffusion which is not seen in conductivity, HR > 1 [31,42,64,65] . Thus, in the case where diffusion of oxygen ion is done by only one type of defect (free mobile vacancy), the diffusion coefficient from conductivity is equal to the migration coefficient and proportional to the concentration of vacancies.…”

“…The enthalpy of association is then linked to the strain energies developed in a structure with strong ionic radii mismatch and high dopant content. This approach has been well studied by several authors with different samples compositions [35,65,66,[74][75][76] .…”

Zirconia Pressure Sensors: From Nanopowders to Device

“…It was also reported that the addition of Al 2 O 3 may reduce the specific grain boundary [14][15][16]. A model explaining the influence of the grain sizes on the bulk and grain boundary conductivity was proposed in [17].…”

Estudio del proceso de sinterización de componentes cerámicos para pilas de combustible de óxidos sólidos

“…Esta correlación se cumple mejor a temperaturas relativamente elevadas (superiores a 800 K) a las que predomina la difusión intrínseca sobre la extrínseca 41 .…”