Single‐Crystal Elastic Constants of Yttria‐Stabilized Zirconia in the Range 20° to 700°C

Kandil, H. M.; Greiner, J. D.; Smith, J. F.

doi:10.1111/j.1151-2916.1984.tb19534.x

Cited by 192 publications

(80 citation statements)

References 31 publications

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“…Lattice parameters were calculated Table I and show a slight increase for increasing dopant concentration, in accordance with literature. 6,56,57 For conductivity measurements on single crystals, Pt paste was painted onto the two sides and annealed at 1000…”

Section: Methodsmentioning

confidence: 99%

Revisiting the Temperature Dependent Ionic Conductivity of Yttria Stabilized Zirconia (YSZ)

Ahamer

Opitz

Rupp

et al. 2017

J. Electrochem. Soc.

141

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The temperature dependent conductivity of yttria stabilized zirconia (YSZ) exhibits a bending in Arrhenius' plots which is frequently discussed in terms of free and associated oxygen vacancies. However, the very high doping concentration in YSZ leads to such a strong defect interaction that the concept of free vacancies becomes highly questionable. Therefore, the temperature dependent conductivity of YSZ is reconsidered. The conductivity of YSZ with different doping concentration was measured in a broad temperature range. The data are analyzed in terms of two different barrier heights that have to be passed along an average path of an oxygen vacancy in YSZ (two barrier model). For 8-10 mol% yttria, the two barriers are in the range of 0.6 eV and 1.1-1.2 eV, respectively. The conductivity and thus the barrier heights also depend on the cooling rate after a high temperature pre-treatment. This indicates that different frozen-in distributions of dopants affect the vacancy motion by different energy landscapes. Temporarily existing defect configurations, possibly with a strong effect of repulsive oxygen vacancy interaction, are suggested as the reason of high barriers. Future dynamic ab-initio calculations may reveal whether this modified model of the YSZ conductivity is mechanistically meaningful. Yttria stabilized zirconia (YSZ) is among the most important ion conducting solids and acts as a kind of model material representing fast oxide ion conductors. Owing to this model character of YSZ, but also due to its application in solid oxide fuel cells (SOFCs), solid oxide electrolysis cells (SOECs) and oxygen sensors, a vast amount of papers can be found dealing with its oxide ion conduction. The ionic conductivity is based on the motion of oxygen vacancies, introduced by Y 3+ ions replacing Zr 4+ . For concentrations above ca. 8 mol%, yttria doping also stabilizes the cubic structure down to room temperature. A detailed review of the science of YSZ and related materials is far beyond the scope of this paper but a few important facts regarding the ionic conductivity of zirconia-based solid electrolytes can be briefly summarized as follows:1-9 i) Doping concentrations above ca. 8 mol% Y 2 O 3 lead to a decrease of the conductivity, despite increasing oxygen vacancy concentration. ii) The conductivity not only depends on the vacancy concentration but also on the kind of dopant. For example, Sc-doped zirconia shows significantly higher conductivity than YSZ. iii) The temperature dependence of the conductivity cannot be described by a single activation energy (E act ) but shows higher E act values at lower temperatures.Numerous theoretical studies were performed in order to understand these experimental observations and to get a deeper insight into defect thermodynamics and kinetics of doped zirconia and of the closely related ceria-based ion conductors, see e.g. Refs. 10-29. Those model studies employed different simulation approaches such as molecular dynamics (MD), density functional theory (DFT) and kinetic Monte Carl...

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Section: Methodsmentioning

confidence: 99%

Revisiting the Temperature Dependent Ionic Conductivity of Yttria Stabilized Zirconia (YSZ)

Ahamer

Opitz

Rupp

et al. 2017

J. Electrochem. Soc.

141

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“…15. Recently, potycrystalline elastic moduli data for yttria-stabilized zirconia has been obtained [2,3,9,18,20] using single crystal elasticity data. The compositional dependence of these elastic moduli data showed an increase with increasing Y203 tool% content.…”

Section: Room Temperature Elastic Constantsmentioning

confidence: 99%

Elastic constants of the iron oxide doped yttria-stabilized zirconia

et al. 1989

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Ultrasonic compressional and shear wave velocity measurements have been made on the (ZrO2)I_A (Y2Q)A-x (Fe203)x system at 5 M Hz. The amounts of Fe203 dopant ranging from 0 up to 1 0 mol % were mixed with the ceramic matrix. In this paper the ultrasonic compressional and shear wave velocity measurements made on this system at room temperature are discussed. The elastic moduli, Poisson's ratio and density are found to be sensitive to the.additions of the Fe203 dopant and they show an anomalous behaviour. A qualitative explanation of the compositional dependence of the elastic moduli and Poisson's ratio is given in terms of changes in packing density, bond strength, co-ordination number and cross-link density.

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“…• C elastic constants of LSF64 24 and YSZ, 49 it is possible show that the • C equilibrium curvature difference in Figure 6 corresponds to a chemical strain of 3 × 10 −6 that is within the Figure 2 noise). However, this may also be due to the larger grain size of the dilatometry-tested bulk samples which would be expected to produce less grain-boundary-induced strain (the dilatometry-tested samples had an average grain size of 1.7 ± 0.2 μm while the porous thick films which had a grain size that was too large for analysis via the Williamson-Hall Method, 50 i.e.…”

Section: Porous Thick Films-mentioning

confidence: 78%

Porous Thick Film Lanthanum Strontium Ferrite Stress and Oxygen Surface Exchange Bilayer Curvature Relaxation Measurements

Yang

Nicholas

2014

J. Electrochem. Soc.

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Here, the chemical oxygen surface exchange coefficient and film stress of porous La 0.6 Sr 0.4 FeO 3-δ (LSF64) thick films were simultaneously measured in situ between 275-375 • C and 275-700 • C, respectively, using a bilayer curvature measurement technique. The magnitude and activation energy of the porous LSF64 thick film oxygen surface exchange coefficients were consistent with those from large grained, bulk samples. However, unlike large-grained, dilatometry-tested bulk LSF64 samples that only exhibited measurable chemical stress above 525 • C, the fine-grained, curvature-tested porous LSF64 thick films studied here exhibited measurable chemical stress over the complete temperature range from 275 to 700 • C. Further, the porous LSF64 thick films exhibited a kink in their Arrhenius chemical stress behavior ( Oxygen-exchange-capable mixed ionic electronic conducting (MIEC) materials are widely used in electrochemical devices such as solid oxide fuel cells (SOFCs), 1-5 catalysts, 6,7 and gas separation membranes. 8,9 However, debate exists on the oxygen surface exchange rates of even the most-common MIEC materials. For instance, chemical oxygen surface exchange coefficient (k) discrepancies greater than 4 orders of magnitude are reported at identical temperature and oxygen partial pressure conditions for the MIEC material La 0.6 Sr 0.4 FeO 3-δ (LSF64). [10][11][12][13] Similarly, large k discrepancies have been observed for other MIEC materials such as lanthanum strontium cobalt iron oxide [14][15][16][17] and reduced cerium oxide. [18][19][20][21] Since recent studies have shown that strain can alter k, 20,21 it is likely that some of these observed k discrepancies are due to differences in MIEC stress state. Unfortunately, simultaneous k and stress state measurements on MIEC materials are largely absent from the literature. Here, the stress and oxygen surface exchange coefficients of porous LSF64 thick films atop single crystal (Y 2 O 3 ) 0.13 (ZrO 2 ) 0.87 (YSZ) substrates were simultaneously measured in situ using a new bilayer curvature measurement technique. Theoretical BackgroundPorous thick film stress measurement.-Stresses in dense thin films (i.e. those with film to substrate thickness ratios less than 1:1000) can be rigorously extracted from bilayer curvature measurements using Stoney's Equation:whereλ St is the thickness averaged film stress predicted from Stoney's Equation, κ is the bilayer curvature, h s is the substrate thickness, h f is the film thickness, and M S is the substrate biaxial modulus defined as E S / (1 − υ S ) where E S is substrate Young's modulus and υ S is the substrate Poisson's Ratio. 22,23 Stoney's equation is convenient because the thickness averaged film stress (λ) (which is the same as the stress at each point in the film due to the film's thinness) can be extracted * Electrochemical Society Student Member.* * Electrochemical Society Active Member. z E-mail: jdn@msu.edu from bilayer curvature measurements without knowledge of the film elastic properties. In contrast, stre...

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Single‐Crystal Elastic Constants of Yttria‐Stabilized Zirconia in the Range 20° to 700°C

Cited by 192 publications

References 31 publications

Revisiting the Temperature Dependent Ionic Conductivity of Yttria Stabilized Zirconia (YSZ)

Revisiting the Temperature Dependent Ionic Conductivity of Yttria Stabilized Zirconia (YSZ)

Elastic constants of the iron oxide doped yttria-stabilized zirconia

Porous Thick Film Lanthanum Strontium Ferrite Stress and Oxygen Surface Exchange Bilayer Curvature Relaxation Measurements

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