Some Materials Science Aspects of PVD Hard Coatings

Abstract

Hard coatings deposited by Physical Vapor Deposition (PVD) based on the transition element nitrides are nowadays widely applied to reduce wear and corrosion of tools. In the last two decades, tremendous advances have been achieved in the development of deposition and application technology of hard coatings. The methods to be applied to optimize coating properties are known from materials science, however, only in the last few years significant attempts have been made to use them for designing coatings showing the properties required. The aim of this paper is to show the interrelationships between microstructural parameters like grain size or microstress and mechanical coating properties and their thermal stability. This is demonstrated using conventional coating systems like TiN and CrN as well as nanocomposite coating systems like TiN-TiB2 and TiC-TiB2.