Description of consolidation forces on nanometric powders

Abstract

-The experiments and analyses performed included measurements of the physical properties of TiO 2 powder such as the particle size, density, and consolidation. Experiments with nanometric TiO 2 powder of 204 nm average diameter show that, during consolidation, the adhesion of particles under normal stress is principally due to the van der Waals force for particle radii less than 300nm and the application of external force has no effect on the cohesion of the primary particles within this range; for particle radii around 300nm to 1.0μm the cohesion of the powder system is due to plastic deformation and the application of external force change the cohesion force to a plastic deformation between the agglomerates formed under these forces. This can be observed in the arrangement of the primary particles into dispersed agglomerates with sizes greater than the individual particles. The results obtained with the nanometric TiO 2 powders show a more complex behavior than the micronic powders. This behavior is related to the structure of the nanometric particles in the packed bed; the evolution of this structure is made up of individualized and spherical agglomerate shapes. It has been experimentally observed that the powder structure is not perturbed by stresses of low intensities. A development of the different forces involved in interparticle contacts is outlined. The description of these forces involved in particle cohesion will help to understand the powder cohesion under consolidation.

Developing Noniridescent Structural Color on Flexible Substrates with High Bending Resistance

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Solvent-free synthesis of alumina supported cobalt catalysts for Fischer–Tropsch synthesis

“…When C u < 2: the particle size distribution is known as uniform; C u > 2: the particle size distribution is known as broad. d i 60% and d i 10% are defined as dimensions of the particles corresponding to 60% and 10% of the cumulative percentage undersize distribution (in volume) [12] .…”

Investigation of the effect of consolidation on cement flow behaviour

“…Understanding the behaviour of adhesion interactions between particles and surfaces can 5 contribute to the understanding of the cement powder flow. The different forces involved 6 have to be considered under consolidation namely the Van der Waals, the adhesive and 7 external forces, as was showed by Turki and Fatah (2010). In this context, Flatt (2004)…”