Functional PVD Hard Coatings for High Temperature Cutting Processes

Abstract

To improve the wear resistance of cutting tools, PVD (physical vapor deposition) coatings are well established in manufacturing. Therefore, different PVD hard coating systems have been developed until now. Nevertheless, the demands on the functionality of PVD hard coatings have become more specific. Reasons for this include increased cutting speeds, the machining of high strength materials with low heat conductivity as well as the development towards minimum quantity lubrication and dry machining. In summary, all these leads to increasing temperatures at the cutting edge. As a result, the wear resistance to thermally induced failure mechanisms and self-lubricating PVD hard coatings getting more important. In this work, important requirements for PVD coatings for high temperature cutting processes are presented. Furthermore, an overview of self- lubricating oxidic coating systems based on aluminum oxide (Al2O3) and Magnéli-phases as well as their wear behavior in cutting application is given.