Influence of sample preparation on metallographic examination of thermal spray coatings

Metallographic examination of thermal spray coatings can be affected by improper sample preparation. Presence of features induced by sample preparation and smeared surface can obscure the actual coating microstructure, leading to mis-assessment by the metallurgist. The presentation describes how parameters of sample preparation processes can change the actual view of the coating microstructure, followed by examples of coatings commonly used in aircraft engines.