Abstract
In many empirical studies on the structure and properties of thermally sprayed coatings, a set of two predefined parameters (e.g. porosity and elastic modulus) is correlated over a narrow range of structural variation assuming a continuous correlation function. Such a data evaluation assumes the existence of physical correlation’s between material behavior and microstructure. The experimental approach, undertaken in this study, comprises a maximum range of morphologies for starting materials with nearly identical chemical compositions to reveal the influence of microstructural changes of diverse defect species on different coating properties. The large matrix of structural and physical data is statistically correlated without any preconceived assumptions concerning the mathematical functions or the physicochemical nature of the property-microstructure-correlation’s. The divergent morphologies are realized by using different coating processes such as vacuum (VPS) and atmospheric (APS) plasma spraying, water stabilized plasma spraying (WSP), wire arc (WAS)- and flame spraying (FS), including variation of process specific parameters. The microstructure is systematically analyzed along length scales starting from defects in the micrometer down to the nanometer range. The microstructure and its anisotropy is quantified by small angle neutron scattering (SANS). The phenomenological coating behavior is successively investigated starting from basic properties such as electrical and thermal conductivity, elastic constants, residual stresses up to application oriented properties such as wear resistance. Property combinations presuming high sensitivity to microstructural changes are preferentially characterized and statistically correlated.
