Surface growth defects in PVD coatings

The surface of PVD coatings contains sporadic growth defects such as peaks and craters. These sites are potentially detrimental for corrosion resistance of the coating. The distribution of growth defects can be analyzed using stylus profilometry. By scanning a standardized area on a series of samples we investigated the influence of deposition parameters on the defect density. The microstructure of a single defect can be studied by SEM in combination with focused ion beam (FIB). High-resolution imaging and EDX provide a detailed insight on the defect cross-section, both in microstructure as in chemical analysis. A special case is the application of this method on samples subjected to corrosion tests.