Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-20T04:10:02.975Z Has data issue: false hasContentIssue false

A Formalism to Describe Demixing of Mixed Oxides of Large and Small Grain Size in an Electric Field

Published online by Cambridge University Press:  15 March 2011

Irina V. Belova
Affiliation:
Diffusion in Solids Group, School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, AUSTRALIA
Mandy J. Brown
Affiliation:
Diffusion in Solids Group, School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, AUSTRALIA
Graeme E. Murch
Affiliation:
Diffusion in Solids Group, School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, AUSTRALIA
Get access

Abstract

In this paper, we address the theory of electric field demixing of the cations in semi-conducting and initially homogeneous mixed ceramic oxides. We include the off-diagonal phenomenological transport coefficients by assuming a random distribution of cations and making use of an exact sum-rule expression. The steady state atomic composition profiles are shown to be quite different when different assumptions are made about vacancy equilibration. We show that in the case of large grained material (where vacancies in the interior do not equilibrate easily to the external oxygen partial pressure), a maximum develops in the steady state vacancy composition profiles. This behaviour is verified by independent Monte Carlo simulations.

Type
Research Article
Copyright
Copyright © Materials Research Society 2004

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Armanet, F., Klimczyk, H., Monceau, D., Petot, C. and Petot-Ervas, G., High Temp. Sc., 31, 147 (1991).Google Scholar
2. Petot-Ervas, G. and Petot, C., Ionics, 4, 336 (1998).Google Scholar
3. Monceau, D., Filal, M., Tebtoab, M., Petot, C. and Petot-Ervas, G., Solid State Ionics, 73, 221 (1994).Google Scholar
4. Martin, M., Solid State Ionics, 136–137, 331 (2000).Google Scholar
5. Teller, O. and Martin, M., Ber. Bunsenges. Phys. Chem., 101, 1377 (1997).Google Scholar
6. Schmalzried, H., Laqua, W. and Lin, P.L., Z. Naturforsch., 34a, 192 (1979).Google Scholar
7. Petot-Ervas, G., Petot, C. and Monceau, D., Solid State Ionics, 53–56, 270 (1992).Google Scholar
8. Martin, M. and Schmackpfeffer, R., Solid State Ionics, 72, 67 (1994).Google Scholar
9. Vedula, K., Oxid. Met., 28, 99 (1987).Google Scholar
10. Hong, J-O., Teller, O., Martin, M. and Yoo, H-I., Solid State Ionics, 123, 75 (1999).Google Scholar
11. Ishikawa, T., Sato, H., Kikuchi, R. and Akbar, S.A., J. Am. Ceram. Soc., 68, 1 (1985).Google Scholar
12. Ishikawa, T., Akbar, S.A., Zhu, W. and Sato, H., J. Am. Ceram. Soc., 71, 513 (1988).Google Scholar
13. Akbar, S.A. and Sato, H., Oxidation of Metals and Associated Mass Transport, edited by Dayananda, M.A., Rothman, S.J. and King, W.E., (TMS, Warrendale PA, 1987) p49.Google Scholar
14. Wang, C.C. and Akbar, S.A., J. Phys. D: Appl. Phys., 28, 120 (1995).Google Scholar
15. Martin, M., Ceram. Trans., 24, 91 (1991).Google Scholar
16. Martin, M. and Schmachpfeffer, R., Ber. Bunsenges. Phys. Chem., 93, 1271 (1989).Google Scholar
17. Belova, I.V. and Murch, G. E., Phil. Mag, in press.Google Scholar
18. Belova, I.V., Brown, M.J. and Murch, G.E., Acta Mater., 51, 1821 (2003).Google Scholar
19. Moleko, L.K. and Allnatt, A.R., Phil. Mag. A, 58, 677 (1988).Google Scholar
20. Brown, M.J., Belova, I.V. and Murch, G.E., Phil. Mag., 83, 1855 (2003).Google Scholar
21. Allnatt, A.R. and Lidiard, A.B., Atomic Transport in Solids, (Cambridge University Press, 1993).Google Scholar
22. Zhang, L. and Murch, G.E., Phil. Mag. A, 62, 267 (1990).Google Scholar
23. Murch, G.E. and Thorn, R.J., Phil. Mag., 36, 529 (1977).Google Scholar
24. Murch, G.E., Am. J. Phys., 47, 958 (1979).Google Scholar