Skip to main content Accessibility help
×
Home

Rheological and Related Colloidal Aspects of Aqueous Processing that affect the Development of Microstructure

  • Alan Bleier (a1) and C. Gary Westmoreland (a1)

Abstract

Shear flow in α-A12O3 suspensions having a volume fraction of solids (φ) in the range between 0.17 and 0.50 was investigated between pH 4 and 12. It is Newtonian if the magnitude of the zeta potential exceeds a critical value which depends on φ;its value is 39 mV if φ= 0.40 and 74 mV if φ= 0.50. If this potential is less than the critical value, shear flow is pseudoplastic; its yield value markedly changes (e.g., 0 to >100 Pa) in a slightly φ-dependent, narrow pH range (<0.5 units). If a second oxide, t-ZrO2 , is present, its pH-dependent colloidal behavior governs the overall rheology, though its concentration may be only 11 % that of α-A12O3. Scanning electron microscopy of composite pieces indicates that a detrimental, rheologically detectable interaction between α-Al2O3 and t-ZrO2 can be avoided and the distribution of t-ZrO2 can be optimized during pressure casting by control of pH. Best conditions correspond to either Newtonian flow or pseudoplastic flow with a very low yield value.

Copyright

References

Hide All
1. 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. (Mater. Res. Soc. Proc. 23, Pittsburgh, PA, 1986), pp. 791800.
2. Bleier, A. and Westmoreland, C. C., in Better Ceramics Through Chemistry III, edited by Brinker, C. J., Clark, D. E., and Ulrich, D. R. (Mater. Res. Soc. Symp. Proc. 121, Pittsburgh, PA, 1988), pp. 145154.
3. Bleier, A. and Westmoreland, C. G., in Interfacial Phenomena in Biotechnology and Materials Processing, edited by Moudgil, B. and Attia, Y. A. (Elsevier Science, New York, 1988), pp. 217236.
4. (a) Bleier, A., Becher, P. F., Baik, S., and Westmoreland, C. G., in Abstracts of the 89th Annual Meeting (Am. Ceram. Soc., Westerville, OH, 1987), p.37;
4 (b) Bleier, A., in Abstracts of the 61st Colloid and Surface Science Symposium (Am. Chem. Soc., Ann Arbor, MI, 1987), Paper No. 64; in Abstracts of the Symposium on Particle Deposition at the Solid-Liquid Interface (Soc. Chem. Ind., London, 1988), Paper No. 9; submitted for publication, Colloids Surfaces;
4(c) Bleier, A. and Westmoreland, C. G., to be submitted for publication (Am. Ceram. Soc., Westerville, OH).
5. (a) Lynch, J. F., Ed., Engineering Property Data on Selected Ceramics. Vol, III, Single Oxides, Battelle Columbus Labs, Columbus, OH, 1981, p. 541l;
5 (b) Becher, P. F. (private communication).
6. (a) Henry, D. C., Proc. R. Soc. Lond. A133, 106 (1931);
6 (b) Smith, A. L., in Dispersion of Powders in Liquids, 3rd Ed., edited by Parfitt, G. D. (Applied Science, London, 1981), pp. 99148;
6(c) Hunter, R. J., Zeta Potential in Colloid Science (Academic, London, 1981), p. 71.
7. (a) Hunter, R. J., Foundations of Colloid Science, Vol. I (Clarendon, Oxford, 1987), pp. 7689;
7(b) Hunter, R. J., Foundations of Colloid Science, Vol. II (Clarendon, Oxford, 1989), pp. 9921052;
7(c) van de Ven, Th. G. M., Colloidal Hydrodynamics (Academic, London, 1989), 582 p.
8. Einstein, A., Investigations on the Theory of the Brownian Movement (Dover, New York, 1956), pp. 3662.
9. Bleier, A. and Westmoreland, C. G., unpublished results.

Related content

Powered by UNSILO

Rheological and Related Colloidal Aspects of Aqueous Processing that affect the Development of Microstructure

  • Alan Bleier (a1) and C. Gary Westmoreland (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.