Stability of heterogeneous particle at fluid interfaces in composite slurries
- Cleveland State Univ., OH (United States). Chemical Engineering Dept.
Fabrication of particulate reinforced metal matrix composites (MMC) using casting techniques such as stir-casting and gas-injection involves incorporation of reinforcement in the melt and creation of melt-particle suspension, followed by solidification of the suspension. In this note the stability of spherical particles with smooth but chemically heterogeneous surfaces attached to a curved fluid interface is analyzed from the basic capillary considerations in the absence of buoyancy, gravitational and hydrodynamic forces. While the exclusion of body forces and the geometrical idealizations of a stripwise surface heterogeneity are restrictive assumptions from the processing standpoint, they allow an assessment to be made of the role of capillarity in the case of real heterogeneous solids. For small bubbles and fine particles generally used in particulate reinforced metal matrix composites, capillary effects dominate over gravitational and buoyancy forces. Another simplification produced in the analysis is the assumption of negligible hysteresis of contact angles due to heterogeneous nature of the surface. The hysteresis of contact angle would result in the advancing angle being associated with the regions of high [Eta] values and the receding angle being associated with region of low [Eta] values. This results in a discontinuous jump in the wetting perimeter across the boundary between dissimilar regions. Such effects are ignored in the present treatment. The results of the analysis have been discussed with reference to two composite systems of practical interest.
- OSTI ID:
- 6003551
- Journal Information:
- Scripta Metallurgica et Materialia; (United States), Vol. 29:10; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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