Damage Phenomena Observed on PVD Coatings Submitted to Repeated Impact Tests

Thin hard coatings obtained by PVD process are widely used to improve the mechanical and friction behaviour of industrial parts. Depending on the friction conditions, the failure mechanisms and resulting selection criteria may be very different. This study aims to investigate the endurance life of some PVD coatings under repeated impact conditions. Impact tests at controlled impact energy have been performed using a hemispherical tip. Long-term tests have been done to determine the coating endurance life while short tests enable us to identify the damage phenomena. Depending on the nature of the PVD coating, cracks, blisters or spalling may be observed under impact. These phenomena may worsen until the complete film rupture occurs.