How to treat powders for the room temperature aerosol deposition method to avoid porous, low strength ceramic films

Abstract

Aerosol deposition features the formation of dense and well adhering ceramic films directly at room temperature, without the need of any heat treatment during or after the deposition. While these claims are true for a suitable ceramic powder, the success of the film deposition is highly dependent on the right choice of the powder. Beside the commonly stated particle size that should be in the sub-micrometer to micrometer range, other influencing powder parameters exist, some of which have not yet been fully identified.In this work, ceria nanopowders were thermally pretreated and the quality of subsequent sprayed films was observed. A minimum crystallite size in the powder was determined in order to enable the underlying deposition mechanism. Furthermore, the conversion of kinetic particle energy to the formation of surface energy during impact was estimated. A first universal behavior is found leading to a recommendation for a suitable AD powder preparation.