Journal of the American Ceramic Society, Vol.85, No.9, 2200-2208, 2002
Advances in the modeling and measurement of drained compressibility
We have re-examined the analysis of centrifugal consolidation experiments for the determination of drained compressibility. Existing models for centrifugation of ceramic powder suspensions are prone to error, because they do not fully account for spatial variations of both the centrifugal acceleration and packing density. We present a new model that accounts for these two effects. We also derive dimensionless parameters that separately describe the error contributions that result from the heterogeneities of both the centrifugal acceleration and packing density. These dimensionless parameters make it no longer necessary to determine drained compressibility by the complicated method of nondestructively measuring the density profiles of centrifuge cakes and then substituting these profiles into a complex mathematical equation that is difficult to solve. Instead, one can evaluate drained compressibility by applying a correction factor to a simple experimental method of measuring the cake height during multispeed centrifugation. In turn, this procedure provides a valuable, new tool to characterize the effects of ceramic processing variables on their tendency to produce density gradients during powder consolidation.