Dissolution Kinetics of Titanium Pyrochlore Ceramics at 90°C by Single-Pass Flow-Through Experiments

Abstract

Corrosion resistances of titanium-based ceramics are quantified using single-pass flow-through (SPFT) experiments. The materials tested include simple pyrochlore group (B2Ti2O7, where B=Lu3+ or Gd3+) and compositionally complex pure phase pyrochlore (PY12) or zirconolite- and brannerite-bearing pyrochlore-dominated (BSL3) ceramics. Experiments are conducted at 90°C over a range of pH-buffered conditions with typical duration of experiments in excess of 120 days. Apparent steady-state dissolution rates at pH=2 determined on the Gd2Ti2O7 and Lu2Ti2O7 samples indicate congruent dissolution, with rates of the former (1.3×10-3to 4.3×10-3) slightly faster than the latter (4.4×10−4 to 7.0×10−4g m−2d−1). Rates for PY12 materials into pH=2 solutions are 5.9×10−5 to 8.6×10−5 g m−2 d−1. In contrast, experiments with BSL3 material do not reach steady-state conditions, and appear to undergo rapid physical and chemical corrosion into solution. Dissolution rates of PY12 display a shallow amphoteric behavior, with a minimum (2.7×10−5 g m−2 d−1) near pH values of 7. Dissolution rates display a measurable increase (~10X) with increasing flow-through rate indicating the strong influence that chemical affinity exerts on the system. These results step towards an evaluation of the corrosion mechanism and an evaluation of the long-term performance of Pu-bearing titanate engineered materials in the subsurface.

This is a preview of subscription content, access via your institution.

References

  1. 1.

    B.D. Begg, W.J. Weber, R. Devanathan, J.P. Icenhower, S. Thevuthasan, and B.P. McGrail, Am. Ceram. Soc. Trans. (in press).

  2. 2.

    W.L. Boucier, unpublished LLNL report, 1999.

    Google Scholar 

  3. 3.

    P.M. Dove and D.A. Crerar, Geochim. Cosmochim. Acta, 54, 955–969 (1990).

    CAS  Article  Google Scholar 

  4. 4.

    P. Aagaard and H.C. Helgeson, Amer. J. Sci., 282, 237–285 (1982).

    CAS  Article  Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to J. P. Icenhower.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Icenhower, J.P., Mcgrail, B.P., Schaef, H.T. et al. Dissolution Kinetics of Titanium Pyrochlore Ceramics at 90°C by Single-Pass Flow-Through Experiments. MRS Online Proceedings Library 608, 373 (1999). https://doi.org/10.1557/PROC-608-373

Download citation