Thermal modeling of plasma spray deposition of nanostructured ceramics

摘要

A thermal model for plasma spray deposition of ceramic materials onto metallic substrates has been developed. The enthalpy-based control volume formulation of the heat transfer processes has been used to study the temperature evolution in atwo-dimensional substrate and in the coating as it is grown. In this paper; additional melting of ceramic splats after deposition is examined, with a view to predicting the retention of nanostructures in a spray consisting of agglomerated, nanometer-sized particles. Initial results for thin coatings indicate that when the mean temperature of the incoming particles is close to the fusion point of the ceramic material, the nanostructure distribution in the coating is largely determined by the composition ofthe spray. However, with thicker coatings, additional melting due to prolonged plasma gas heating combined with increased thermal resistance in the underlying coating leads to a loss of nanostructure.