Ionic conductivity of zirconia based ceramics from single crystals to nanostructured polycrystals

Blocking Effect in High Purity Nanostructured Cubic Zirconia Ceramics

“…The corresponding activation energies, E a , were determined from the slopes of the Arrhenius diagrams and the corresponding values are reported in Table 2. As it can be seen, all are of the order of 1 eV, as reported in the literature for cubic zirconia [20][21][22], and are typical of an oxide ions conduction mechanism. Moreover, no influence of the grain size was detected in agreement with previous studies of high purity zirconia [23,24].…”

Planar, impedance-metric NOx-sensor with spinel-type SE for high temperature applications

“…To fit the sensing relevant parts of the spectra, which are found in the low frequency part of the spectra, we propose an ohmic resistor in parallel connection with a constant phase element and in serial with a Warburg impedance in parallel connection with an ohmic resistor to fit the curves. Changes due to concentration chances of NO mainly occur at the three-phase boundary electrolyte/spinel-SE/gas [7]. To identify the spinel-SE relevant parts in the impedance plot, some experiments with NO and O 2 were carried out on the systems Pt/FSZ/Pt and Pt+spinel-SE/AL 2 O 3 /Pt, confirming that the changes in the spectra are mainly caused by concentration changes and the SE-electrode and obviously occur in the low frequency part.…”

About ionic conductivity/diffusion relationships in yttria doped zirconia

“…An example of such a behaviour is provided by the results obtained on 4 mol% Y203 doped zirconia nanomatedais [25]. Figure 10 shows a comparison of a set of ionic conductivities measured on the nanomaterials and on a single crystal of similar composition (3 mol% Y203); resuits obtained on 9.5 tool% YzO 3 doped zirconia single crystals have also been plotted in the same graph.…”

“…Polycrystal represented as a pile-up of bricks separated by grain boundaries. R2 = Rl + Rgb (25) Rv is the resistance of a single crystal of the same composition and geometry. Such an interpretation seems to hold when polycrystals have large grain sizes but are no longer valid for nanomaterials.…”