| AVS 61st International Symposium & Exhibition | |
| Advanced Surface Engineering | Tuesday Sessions |
| Session SE+NS+TR-TuM |
| Session: | Nanostructured Thin Films and Coatings |
| Presenter: | Joerg Patscheider, Empa, Switzerland |
| Authors: | P.H.M. Boettger, Empa, ETH Zurich, Switzerland V. Shklover, ETH Zurich, Switzerland M. Sobiech, Oerlikon Balzers Coating AG, Liechtenstein J. Patscheider, Empa, Switzerland |
| Correspondent: | Click to Email |
Hardness, thermal stability and oxidation resistance are often the main properties to optimize for most tool coatings developments for industrial applications. The thermal conductivity, however, has been regarded to a much lesser extent as property to improve tool life. So far, only little attention has been given to this fact and the explicit role of thermal conductivity in machining Ti and Ni-based alloys. These materials typically have low thermal conductivity, as well as modern tool coatings such as CrAlN and TiAlSiN. This unfavorable combination may lead to the formation of thermal hot spots during machining, which adds to the premature degradation of such coatings. For these reasons the thermal conductivity is an important process parameter.
This talk will discuss the relations between hardness, coatings architecture and thermal conductivity and how advanced coatings can be tuned to achieve significant anisotropy of the thermal conductivity. In arc-evaporated TiOxN1-x and CrOxN1-x thermal conductivity can be adjusted in a wide range between 2 and 35 W/m·K, while keeping hardness and oxidation resistance intact. The data for single phase oxynitrides as well as of multilayered coatings agree well with a newly developed model based on constant phonon scattering cross section of the introduced oxygen. It will be shown how temperature-mitigating multilayer coatings can be prepared using these materials by introducing highly anisotropic thermal conductivity.