Shear-assisted fluidized bed powder-coating

This study addresses a novel concept of dense-fluidized bed coating of objects where the effectiveness of coating is promoted by the intentional and controlled establishment of shear flow around the object. The fluidized powder is sheared by the controlled oscillatory motion of the object with respect to the fluidized bed. The proof-of-concept is given with experiments carried out using a commercial powder specifically manufactured for dry coating applications in fluidized bed. Systematic analysis of the effect of different levels of shear rate on particle mobility/adhesion and effectiveness of coverage was performed. A simple model has been developed to provide a mechanistic framework for the interpretation of the results.