Pull-off force of coated fine powders under small consolidation

Document Type

Article

Publication Date

4-1-2009

Abstract

In this paper, a three-dimensional model taking into account the contact deformation and surface area coverage (SAC) of nanoadditives is proposed to predict the force required to separate two contacting particles (the pull-off force) under consolidation stress up to 10 KPa, for cornstarch, a Geldart group C powder, sparsely and densely dry-coated with nanosilica. The experimental pull-off force measurement is conducted in a Seville powder tester. Comparison of the predicted results with the experimental results indicates (1) that the pull-off force of sparsely coated cornstarch is larger than that of densely coated cornstarch due to the greater hardness and small particle radius of fumed silica; (2) there is not a continuous variation in the pull-off force with the coverage of silica; on the contrary, values of the pull-off force of sparsely coated samples are grouped in similar range, while the values of the pull-off force of densely coated samples are grouped in another range of lower values. (3) Within a range, the SAC does not have a big effect on the pull-off force for sparsely coated samples and only a slight effect for densely coated samples (4) the pull-off force increases with increasing consolidation force due to larger deformation in the contact area; (5) under consolidation stresses up to 10 KPa, the deformation of the cornstarch particles is not large enough to fully embed the nanosized silica. © 2009 The American Physical Society.

Identifier

65549170680 (Scopus)

Publication Title

Physical Review E Statistical Nonlinear and Soft Matter Physics

External Full Text Location

https://doi.org/10.1103/PhysRevE.79.041305

e-ISSN

15502376

ISSN

15393755

Issue

4

Volume

79

Grant

0540855

Fund Ref

National Science Foundation

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