Towards Reliable Thermal Spray Coatings: An Integrated Approach

Thermal sprayed coatings are used extensively in engineering components for a variety of protective coating applications. Thermal spraying is a highly dynamic process resulting from rapid heating /accelerating of powder particles in a flame, followed by impact and rapid solidification of the droplets (splats). A splat resulting from the flattening of an individual droplet is the basic building block (unit cell) of the thermal sprayed microstructure. Phase and microstructure of the splats (intrinsic) and the integration of the splats (extrinsic) are both affected by processing condition and the properties of a plasma sprayed deposit are directly related to this complex anisotropic microstructure. These affect both performance and reliability of sprayed surfaces.