Hostname: page-component-8448b6f56d-gtxcr Total loading time: 0 Render date: 2024-04-25T06:34:15.953Z Has data issue: false hasContentIssue false
  • English
  • Français

The CaO-TiO2-ZrO2 System at 1200 °C and the Solubilities of Hf and Gd in Zirconolite

Published online by Cambridge University Press:  15 February 2011

D. Swenson ,
T. G. Nieh  and
J. H. Fournelle
D. Swenson
Affiliation:
Chemistry and Materials Science, Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, CA 94551
T. G. Nieh
Affiliation:
Chemistry and Materials Science, Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, CA 94551
J. H. Fournelle
Affiliation:
Department of Geology and Geophysics, University of Wisconsin, 1215 Dayton St., Madison, WI 53706
Get access

Abstract

Phase equilibria are established in the CaO-TiO2-ZrO2 system at 1200 °C, using X-ray diffraction and electron probe microanalysis. The existence of two previously reported ternary phases, zirconolite (CaZrTi2O7) and calzirtite (Ca2Zr5Ti2O16), is confirmed. Each of these phases exhibits a significant range of homogeneity between TiO2 and ZrO2 while maintaining a nearly constant concentration of CaO. The ternary solubilities of the constituent binary phases are found to be negligible, with the exceptions of the perovskites, which display mutual solubility of at least 22 mol.% and may in fact form a series of continuous solid solutions. The solubilities of Hf and Gd in zirconolite are also investigated. While Hf-bearing samples did not reach thermodynamic equilibrium under the experimental conditions employed, the existence of a Hf analog to zirconolite, CaHfTi2O7, is conclusively demonstrated. The phase is stable at the stoichiometric composition, and its lattice parameters are very close to those reported in the literature for stoichiometric zirconolite. A Gd-bearing sample of the composition Ca0.88Zr0.88Gd0.24Ti2O7 is found to be essentially single phase zirconolite, in agreement with previous investigations at higher temperatures.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 412: Symposium V – Scientific Basis for Nuclear Waste Management XIX , 1995 , 337
Copyright
Copyright © Materials Research Society 1996

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. Ringwood, A. E., Kesson, S. E., Reeve, K. D., Levins, D. M. and Ramm, E. J., in Radioactive Waste Forms for the Future, edited by Lutze, W. and Ewing, R. C. (Elsevier Science Publishers, New York, 1988) pp. 233–334.Google Scholar
2. Coughanour, L. W., Roth, R. S., Marzullo, S. and Sennett, F. E., J. Res. Nat. Bur. Stand. 54, pp. 191–199 (1955).Google Scholar
3. Figueiredo, M. O. and Santos, A. Correia Dos in Zirconia '88: Advances in Zirconia Science and Technology, edited by Meriani, S. and Palmonari, C., Elsevier Science Publishers Ltd., Essex, UK, 1989, pp. 81–87.Google Scholar
4. Figueiredo, M. Ondina, Santos, A. Correia dos, Cortina, C. Parada and Basto, M. João in Scientific Basis for Nuclear Waste Management XV, edited by Sombret, C. G. (Mater. Res. Soc. Proc. 257, Pittsburgh, PA 1992), pp. 251–256.Google Scholar
5. Rossell, H. J., J. Solid State Chem. 99, pp. 52–57 (1992).Google Scholar
6. Jostsons, A., Vance, E. R., Mercer, D. J. and Oversby, V. M., in Scientific Basis for Nuclear Waste Management XVIII, edited by Murakami, T. and Ewing, R. C. (Mater. Res. Soc. Proc. 353, Pittsburgh, PA 1995), pp. 775–781 Google Scholar
7. Lumpkin, G. R., Smith, K. L. and Blackford, M. G., J. Mater. Res. 6, pp. 2218–2233 (1991).Google Scholar
8. Vance, E. R., Smith, K. L., Thorogood, G. J., Begg, B. D., Moricca, S. S., Angel, P. J., Stewart, M. W. A., Blackford, M. G. and Ball, C. J., in Scientific Basis for Nuclear Waste Management XV, edited by Sombret, C. G. (Mater. Res. Soc. Proc. 257, Pittsburgh, PA, 1992), pp. 235–241.Google Scholar
9. Rossell, H. J., J. Solid State Chem. 99, pp. 38–51 (1992).Google Scholar
10. Vance, E. R., Ball, C. J., Day, R. A., Smith, K. L., Blackford, M. G., Begg, B. D. and Angel, P. J., J. Alloys Comp. 213/214, pp. 406–409 (1994).Google Scholar
11. Vance, E. R., Angel, P. J., Begg, B. D. and Day, R. A., in Scientific Basis for Nuclear Waste Management XVII, edited by Ewing, R. C. (Mater. Res. Soc. Proc. 333, Pittsburgh, PA, 1994), pp. 293–298.Google Scholar
12. Vance, E. R., Begg, B. D., Day, R. A. and Ball, C. J., in Scientific Basis for Nuclear Waste Management XVIII, edited by Murakami, T. and Ewing, R. C. (Mater. Res. Soc. Proc. 353, Pittsburgh, PA, 1995), pp. 767–774.Google Scholar
13. Clevinger, M. A. and Hill, K. M., editors, Phase Equilibria Diagrams: Phase Diagrams for Ceramists-Cumulative Indexes. Volumes I-IX. Annuals '91 and '92. High Tc Monograph, The American Ceramic Society, Westerville, OH, 1992.Google Scholar
14. Rossell, H. J., Nature 283, pp. 282–283 (1980).Google Scholar
15. Gatehouse, B. M., Grey, I. E., Hill, R. J. and Rossell, H. J., Acta Cryst. B37, pp. 306–312 (1981).Google Scholar
16. Pyatenko, Yu. A. and Pudovkina, Z. V., Kristallogr. 6, pp. 196–199 (1961).Google Scholar
17. Rossell, H. J., Acta Cryst. B38, pp. 593–595 (1982).Google Scholar
18. Shannon, R. D., Acta Cryst. A32, pp. 751–767 (1976).Google Scholar
19. McCauley, R. A. and Hummel, F. A., J. Solid State Chem. 33, pp. 99–105 (1980).Google Scholar