Why do thermal spray coatings need metallographic microstructure analysis

       Coating microstructure analysis is to observe, identify and analyze the microstructure state, structure and distribution of coating materials by means of observation techniques such as optical microscope and electron microscope. Its purpose is, on the one hand, it is a routine inspection, based on the existing knowledge, to judge or determine whether the performance of the coating material and the coating preparation process are perfect, and if there is a defect, to find the cause of the defect; on the other hand, it is It is to have a deeper understanding of the internal relationship between the microstructure of coating materials and coating properties, as well as the law and relationship between the formation of coating microstructure and coating preparation technology, in order to develop new coating materials and new coatings. The preparation process provides the basis.



With the development of optical technology and electronic technology, the method for analyzing the structure of coating materials has developed rapidly in recent years, and there are many detection and analysis methods, usually with the help of optical microscope and electron microscope to observe and analyze the coating structure.



When metallographic samples are sampled from sprayed parts or sprayed samples, it should be ensured that the cross-sectional structure of the tested sample does not change due to the cutting operation. Otherwise, erroneous results will be drawn, leading to erroneous conclusions. In order to achieve this purpose, sampling methods such as water-cooled grinding wheel slicer or wire cutting should be used as much as possible. Then according to the requirements of metallographic observation samples, the samples are inlaid, ground, polished and corroded to prepare metallographic samples. The coating structure was observed and analyzed by optical microscopy and electron microscopy.