Mechanical properties of monolayer coatings deposited by PVD techniques

Purpose: This research was done to investigate the mechanical properties of monolayer coatings (Ti/CrN, Ti/TiAlN, Ti/ZrN, CrN, TiAl/TiAlN, Zr/ZrN, TiN) deposited by PVD technique (reactive magnetron sputtering method) onto the substrate from the CuZn-40Pb2 brass. A thin metallic layer was deposited prior to deposition of ceramic monolithic coatings to improve adhesion. Design/methodology/approach: The microstructure of the coatings was cross section examined using scanning electron microscope. The residual stress was obtained from the parabolic deflection of the samples, after the coating deposition applying Stoney's equation. The microhardness and Young's modulus tests were made on the dynamic ultra-microhardness tester. Tests of the coatings' adhesion to the substrate material were using the scratch test. Findings: Obtained results show that all the coatings are in a state of compressive residual stress. The stiffness of the examined coatings is between 224 - 330 mN/micrometres, while Young's modulus is between 258 - 348 GPa. Concerning the adhesion of the coatings measured by scratch test, it has been stated that the critical load LC2 for coatings, deposited onto the brass ranges from 41 to 57 N. Research limitations/implications: In order to evaluate with more detail the possibility of applying these coatings in products used in the building and power industries, further investigations should be concentrated on the determination of the tribological properties of the coatings. Originality/value: The paper contributes to better understanding and recognition the structure of thin coatings deposited by PVD techniques. It should be stressed that the mechanical properties of the PVD coatings obtained in this work are very encouraging and therefore their application for products manufactured at mass scale is possible in all cases where reliable, very hard and abrasion resistant coatings, deposited onto brass substrate are needed.