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Title: A computational study of yttria-stabilized zirconia: II. Cation diffusion

Authors:
; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1419995
Grant/Contract Number:
DEFG02-11ER46814
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 126; Journal Issue: C; Related Information: CHORUS Timestamp: 2018-02-09 04:14:17; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English

Citation Formats

Dong, Yanhao, Qi, Liang, Li, Ju, and Chen, I-Wei. A computational study of yttria-stabilized zirconia: II. Cation diffusion. United States: N. p., 2017. Web. doi:10.1016/j.actamat.2017.01.008.
Dong, Yanhao, Qi, Liang, Li, Ju, & Chen, I-Wei. A computational study of yttria-stabilized zirconia: II. Cation diffusion. United States. doi:10.1016/j.actamat.2017.01.008.
Dong, Yanhao, Qi, Liang, Li, Ju, and Chen, I-Wei. Wed . "A computational study of yttria-stabilized zirconia: II. Cation diffusion". United States. doi:10.1016/j.actamat.2017.01.008.
@article{osti_1419995,
title = {A computational study of yttria-stabilized zirconia: II. Cation diffusion},
author = {Dong, Yanhao and Qi, Liang and Li, Ju and Chen, I-Wei},
abstractNote = {},
doi = {10.1016/j.actamat.2017.01.008},
journal = {Acta Materialia},
number = C,
volume = 126,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.actamat.2017.01.008

Citation Metrics:
Cited by: 2works
Citation information provided by
Web of Science

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  • This paper reports on the nature of Pt electrodes studied in the temperature range of 745{degrees}--266{degrees} C under O{sub 2}-N{sub 2} gas mixtures. The sample had a physical barrier mounted on the cathode to limit the gas diffusion of oxygen. At high-temperature {ital T} {gt} 500{degrees} C, this current-limiting process dominated the electrode polarization behavior. For {ital T} {gt} 500{degrees} C, the limiting current was observable only at high overpotential (with {eta} {gt} 1000 mV). The principal experimental feature was that the Butler--Volmer equation was obeyed, with cathodic and anodic transfer coefficients of 1/2 and 3/2, respectively, and with anmore » effective exchange current independent of {ital P}{sub O{sub 2}}. The transition from the Tafel sloped region to the limiting-current region was sharp. The thermal exchange current data gave an activation energy of 2.8 eV for {ital T} {gt} 500{degrees} C and 1.1--1.3 eV for {ital T} {lt} 500{degrees} C.« less
  • Ionic conductivity data of yttria zirconia, Y/sub 4x/Zr/sub 1-4x/O/sub 2-2x/, reported in the literature as functions of oxygen vacancy concentration, x, and temperature, T, have been analyzed according to a theoretical model developed in a previous paper and applied to calcia stabilized zirconia. Because of the different charge compensation mechanism in yttria stabilized zirconia, Y/sub 4x/Zr/sub 1-4x/O/sub 2-2x/, than that in calcia stabilized zirconia, Ca/sub 2x/Zr/sub 1-2x/O/sub 2-2x/, the theory predicts the occurrence of a maximum of ionic conductivity at an oxygen vacancy concentration, x = 0.03125 (= 1/32), which is just half the oxygen vacancy concentration at the maximum,more » x = 0.0625 (= 1/16), in calcia stabilized zirconia. This was clearly confirmed by recent experimental results of Ioffe et al. and appears to substantiate further the basic validity of the theoretical model. Results of the theoretical analysis on yttria stabilized zirconia obtained herein are compared with those on calcia stabilized zirconia are also discussed in relation to the ionic conductivity data of the various rare earth oxide-stabilized zirconia systems. The basic assumptions and limitations of the theoretical model are critically examined, and possible modifications of the theoretical model are suggested.« less
  • The deformation behavior of high purity superplastic 3YTZ is characterized by n = 2, p = 3 at high stresses and n = 3 and p = 1 at low stresses. A recent analysis by Berbon and Langdon, based on a model by Arzt et al., is capable of rationalizing some of the experimental data in terms of diffusion creep from a limited number of discrete sources/sinks. An approach involving rearrangement caused by grain growth can explain the retention of an equiaxed grain size even during diffusion creep. The lack of appropriate diffusion data severely restricts the validity of conclusionsmore » based on a good match between experimental data and theoretical predictions. Based on the model by Arzt et al., a critical grain size is developed beyond which conventional Coble diffusion creep will operate. Experiments at coarser grain sizes are necessary to validate the approach based on diffusion creep. A complete analysis for deformation in 3YTZ must account for the influence of impurity content on the transition from n {approximately} 2 at high stresses to n {approximately} 3 at low stresses.« less
  • The thermal conductivity of yttria-stabilized zirconias has been determined numerically, by applying a nonequilibrium molecular dynamic calculation. Comparing random configurations and Monte Carlo configurations in which chemical correlations are taken into account, we have established that the short range order developing in yttria-stabilized zirconia gives rise to an increase in lattice thermal conductivity for high dopant concentrations and temperatures below 800 K. At higher temperatures or for lower concentrations, the short range order does not influence the thermal conductivity. This conclusion is consistent with experiment. The results are discussed in relation with the various phonon scattering mechanisms.