The Role of Surface Defects Density on Corrosion Resistance of PVD Hard Coatings

The hard coatings of CrN and TiAlN on different substrates (ASP30, CK45, OCR12) are prepared by thermoionic arc ion plating deposition system BAI 730 (Balzers) and by sputter deposition in CemeCon CC 800 apparatus with four unbalanced magnetron sources in closed field configuration. Special attention is devoted to the surface defects which are as a result of insufficient cleaning procedure as well as those which appear due to deposition processes (droplets, particles incorporated during deposition). Attempts are made to find out the correlation between deposition parameters, surface pre‐treatment, cleaning and the type of substrate with the number and size of defects. Measurements related to the surface characterisation are performed by SEM with the combination of electrochemical corrosion measurements. The electrochemical data are obtained in chloride medium. The results are discussed and compared to the surface defects density.