Preventing Segregation during Centrifugal Consolidation of Particulate Suspensions: Particle Drafting

Abstract

Dilute, dispersed, multicomponent suspensions containing Ce-ZrO,, AI,O,, and varying Al,O,-platelet contents were centrifugally consolidated. Despite the favorable conditions for segregation, phase and size segregation did not occur in the highest Al,O,-platelet content suspension. The suspension properties did not consist of agglomeration, high solids fractions, or high suspension viscosities typically attributed with segregation prevention. Thus, a new mechanism is suggested, considering the effects of hydrodynamic particle interactions (interference drag or "drafting") on particle arrangement during consolidation. Particle drafting is proposed and supported as a mechanism for preventing segregation, and the importance of hydrodynamic particle interactions in ceramic processing is discussed.

Stabilization and control of rheological properties of Fe2O3/Al(OH)3-rich colloidal slurries under high ionic strength and pH

“…There is a need to prepare stabilized colloidal slurries containing sub-micrometer particles with high solids loadings, while still maintaining relatively low viscosities, to achieve a uniformly consolidated compact [6,7]. The fact that such slurry contains sub-micron particles with high solids loadings implies that many rheological problems are essentially related to the tendency to aggregate particles, which often gives rise to an inhomogeneous packing morphology.…”

Centrifugal Gel Casting: A Combined Process for the Consolidation of Homogenous and Reliable Ceramics

“…As a result, if very high concentrated slurries are used, the time for cast formation will be further delayed. Nevertheless, an increase in solid content is essential in many cases to avoid segregation specially in multicomponent slurries 17,18 . In addition, it is also reported that the more concentrated the initial slurry, the higher the packing density of the cast body 8,19 …”

“…Nevertheless, an increase in solid content is essential in many cases to avoid segregation specially in multicomponent slurries. 17,18 In addition, it is also reported that the more concentrated the initial slurry, the higher the packing density of the cast body. 8,19 Use high centrifugal accelerations for processing highly concentrated slurries is an effective solution for a fast process without significant segregation of particles.…”