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Rheology and Microstructure of Concentrated Zirconia-Alumina Suspensions for Gelcasting Composites

Published online by Cambridge University Press:  15 February 2011

A. Bleier  and
O. O. Omatete
A. Bleier
Affiliation:
Oak Ridge National Laboratory, P. O. Box 2008, Oak Ridge TN 37831
O. O. Omatete
Affiliation:
Oak Ridge National Laboratory, P. O. Box 2008, Oak Ridge TN 37831
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Abstract

The relationships among colloidal stability, suspension rheology, and solids loading are elucidated for zirconia-alumina mixtures containing 20 vol% ZrO2, based on solids. The lower colloidal stability of ZrO2 limits the rheological properties of this system. If the zeta potential of ZrO2 is less than 49 mV, high degrees of pseudoplasticity, high yield stress, high viscosity, and long relaxation times characterize the binary suspensions. These effects occur, despite the fact that ZrO2 is the minor ceramic constituent. If the zeta potential of ZrO2 is maintained above 49 mV, suspensions with high solids loading (55 vol%) can be prepared which behave as Newtonian fluids over the 0-to-200 s−1 shear rate range and as an elastic solid at higher rates. As the solids loading of a highly stable binary suspension is increased, the rheological properties change. They evolve from those of a near Newtonian-like fluid with nearly independent particles (40 vol%) to those of a pseudoplastic fluid with a weakly interacting particle network (50 vol%) to those of an elastic-like solid composed of crowded, strongly repulsive particles (55 vol%). Low-shear conditions for suspension-transport and mold-filling operations that ensure a homogeneous arrangement of ZrO2 and A12O3 particles in a gelcast ceramic seem promising.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 289: Symposium M – Flow and Microstructure of Dense Suspensions , 1992 , 109
Copyright
Copyright © Materials Research Society 1993

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References

1. Omatete, O. O., Janney, M. A., and Strehlow, R. A., Am. Ceram. Soc. Bull. 70 (10), 1641–1649 (1991).Google Scholar
2. Omatete, O. O., Bleier, A., Westmoreland, C. G., and Young, A. C., Ceram. Eng. Sci. Proceed. 12 (9–10), 2084–2094 (1991).Google Scholar
3. Bleier, A., Omatete, O. O., and Westmoreland, C. G., in Better Ceramics Through Chemistry V, edited by Hampden-Smith, M. J., Klemperer, W. G., and Brinker, C. J., (MRS, Pittsburgh, 1992) pp. 269–275.Google Scholar
4. (a) Bleier, A. and Westmoreland, C. G., J. Am. Ceram. Soc. 74 (12), 3100–3111 (1991); (b) A. Bleier, Colloids Surfaces 66 (3), 157–179 (1992).Google Scholar
5. (a) Hunter, R. J., Foundations of Colloid Science, Vol I (Clarendon, Oxford, 1987) pp. 76–89; (b) R. J. Hunter, Foundations of Colloid Science, Vol II (Clarendon, Oxford, 1989) pp. 992–1052; (c) Th. G. M. van de Ven, Colloidal Hydrodynamics (Academic, London, 1989) 582 p.Google Scholar
6. (a) Russel, W. B., Saville, D. A., and Schowalter, W. R., Colloidal Dispersions (Cambridge University Press, Cambridge, 1989), pp. 456–506; (b) J. W. Goodwin and R. W. Hughes, Adv. Coll. Interface Sci. 42, 303–351 (1992).Google Scholar
7. (a) Baik, S., Bleier, A., and Becher, P. F., in Better Ceramics through Chemistry II, edited by Brinker, C. J., Clark, D. E., and Ulrich, D. R. (MRS, Pittsburgh, 1986) pp. 791–800; (b) A. Bleier and C. G. Westmoreland, in Better Ceramics through Chemistry III, edited by C. J. Brinker, D. E. Clark, and D. R. Ulrich (MRS, Pittsburgh, 1988) pp. 145–154; (c) A. Bleier and C. G. Westmoreland, in Better Ceramics Through Chemistry IV, edited by B. J. J. Zelinski, C. J. Brinker, D. E. Clark, and D. R. Ulrich (MRS, Pittsburgh, 1990) pp. 185–190.Google Scholar
8. Bleier, A., and Becher, P. F., Alexander, K. B., and Westmoreland, C. G., J. Am. Ceram. Soc 75 (10), 2649–2658 (1992).Google Scholar
9. Bleier, A., Omatete, O. O., and Westmoreland, C. G., Unpublished data.Google Scholar