Abstract
Aerosol Flame Spraying (A.F.S) combines the atomization of a colloidal suspension with the lateral injection of the aerosol in a flame. The aerosol droplets are partially dried when crossing the flame and deposited as a coating onto a substrate. The coating is then consolidated by a heat treatment. In this paper, a modeling of the trajectories, acceleration and vaporization of the droplets is presented. This model supposes that the droplets dry at a constant rate until they impact onto the substrate. It predicts the size and water content of droplets at impact. From these data and hydrodynamic properties (viscosity, surface tension, contact angle) of the suspensions, the morphology and size of the lamella deposited on the substrate can be determined by using classical impact models. A colloidal monoclinic zirconia suspension with a 60-nm particle diameter is used in this study. In spite of the complexity of the mixing of suspension spray and flame, and the diversity of the thermal histories of the droplets, the observation of the latter after impact shows that the results of the model are quite consistent with measurements.
