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Tailoring Suspension Flow for the Gelcasting of Oxide andNonoxide Ceramics

Published online by Cambridge University Press:  21 February 2011

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

The rheology of gelcasting slurries of concentrated (30 - 60 vol%) alumina,zirconia, silicon nitride, and sialon powders with isoelectric pointsvarying between pH 5 and 9, was studied by measuring the viscosity and yieldstress as functions of pH. Typically, the rheology is non-Newtonian. Thelowest values of viscosity and yield stress that permit the highest solidsloading were obtained at high and low pH values, where the powders arecolloidally stable, far from the isoelectric points. This relationshipapplies whether or not a polymer dispersant is present. The acrylamidemonomer which is used in gelcasting slurries, lowers these non-Newtonianproperties permitting the preparation of more concentrated slurries. Fluidand pourable gelcasting slurries of each powder had apparent viscosities andyield stresses less than 2.0 Pa·s and 50 Pa, respectively.

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Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 346: Symposium N – Better Ceramics Through Chemistry VI , 1994 , 357
Copyright
Copyright © Materials Research Society 1998

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References

REFERENCES

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