Investigation of Sample Preparation Method for Microstructural Observation of Thermal Spray Coatings

Abstract

Usually, the mechanical polishing methods have been used to prepare a sample for the microstructural observation of thermal spray coatings. In this study, the microstructure of thermal coatings prepared by an argon ion beam polishing was investigated. Especially, it was focused in this study to investigate the influence of the sample preparation method on the area ratio of porosity of thermal coating. The experimental results revealed that the microstructure of thermal coatings in SEM image was changed by the polishing method. The cross section microstructure fabricated by the argon ion beam polisher showed that it creates a mirror surface with minimized artifacts such as smearing of pores which can be made by conventional mechanical polishing method. As the results, the sample polished by the argon ion beam exhibits higher porosity than that by the conventional mechanical polishing method.