Powder flow behavior governed by the surface properties of glass beads.

Powder rheology and its sensitivity to surrounding environmental condition by controlling the surface properties of the particles is one of the major challenges of the powder industries. Indeed, handling large quantities needs powders with good flowability, adequate compressibility and few electrostatic charges. We have performed a chemical treatment in order to obtain hydrophobic glass beads and its bulk behavior has been compared with raw glass beads depending on the humidity. We characterized flow properties under different processing equipments. We observed that by performing hydrophobic surface treatment sensitivity of glass beads reduced to the humidity. Furthermore, the influence of the electrostatic charges was an undeniable factor in increasing the viscosity of hydrophobic glass beads and consequently lowering its flowability in front of raw glass beads; at low shear rate. At high shear rate, the powders presented similar behaviors. [Display omitted] • At high shear rate, raw and hydrophobic glass beads had similar flowability. • At low shear rate, hydrophobic glass beads were less flowable than raw glass beads. • Hydrophobic formulation decreased sensitivity of glass beads to the humidity. • Hydrophobic formulation increased the electrostatic charge of glass beads. [ABSTRACT FROM AUTHOR]