Coating Characterizations

Abstract

Coatings, as most industrial products, must be tested at the Research and Development stage, in production environment, but it should be kept in mind that coating properties depend strongly on both the spray conditions and powder used and both must be regularly tested. Tests at the research and development level use techniques more or less sophisticated such as metallography and image analysis. In production tests deal with the control of quality (adhesion--cohesion, mechanical properties, thermal properties, wear resistance, corrosion resistance…) and are more targeted towards the service conditions, without neglecting some simple tests from simple visual observation of the coated part to some specific characteristics required by the coating or component specifications. The aim of this chapter is not to describe in detail all the characterization and testing methods that could be used for thermal-spray coatings but to give the reader information about the most used techniques and which information can be drawn from them. It starts with the specificity of coating characterization methods and presents the nondestructive methods. They are successively described: the metallography and image analysis, materials characterization, void content and network architecture, adhesion--cohesion, mechanical properties, and testing of wear resistance and corrosion.