Determination of the Effective Properties of Thermal Spray Coatings Using 2D and 3D Models

Abstract

Models, which are developed to determine the effective properties of thermal spray coatings, require the material properties of each constituent of the coating as well as the information about the spatial positions and the geometries of these constituents as input parameters. The complex microstructure of thermally sprayed Yttria-stabilized zirconia (YSZ) coatings consists of irregular voids which are distributed non-uniformly in the coating. It is a common practice in the literature to employ two-dimensional (2D) cross-sectional images of the coatings to derive the geometrical model of the microstructure and conduct the simulations in 2D. In the context of this study, contrary to the 2D approach, a new three-dimensional (3D) reconstruction approach has been developed to model the microstructure of thermally sprayed coatings in 3D. The effective properties of an YSZ coating have been calculated by means of asymptotic homogenization and virtual testing methods. The results of the models, which have been conducted in 2D and 3D, are compared with each other. Finally, the capabilities of these methods with respect to the modeling approach (in 3D and in 2D) are analyzed on the basis of reference measurements.