Powder morphology in thermal spraying

Abstract Thermal spraying (TS) is a suitable method to protect a substrate or to improve its surface properties and achieve the specific surface requirements for a prescribed service environment. In this method the feedstock material is heated up to a melted or semi‐melted state, accelerated to high speed by an energetic flow and sprayed onto a prepared substrate. Powders are the most commonly used feedstock materials in the TS process. Their composition, size distribution, morphology, physical and mechanical properties determine the coating microstructure and related thermo‐mechanical performance. Among other variables, powder morphology plays a fundamental role to ensure the consistency and reproducibility of the feeding mechanism, to control the interaction between feedstock particles and TS heat source, and to influence the microstructure of the coating. This review highlights the crucial function of powder morphology in TS and proposes introductory information on the importance of powder morphology in cold spraying.