[Zurück]

E. Aschauer, M. Bartosik, P. Polcik, M. Arndt, H. Riedl, P.H. Mayrhofer:
"Nano beam X-ray diffraction analysis of stress and strain in high-temperature oxidation resistant Ti_1-xAl_xN/Mo-Si-B multilayer coatings";
Vortrag: EUROMAT 2017, THESSALONIKI; 17.09.2017 - 22.09.2017.

High temperatures combined with mechanical loading and oxidative environments are an extremely severe attack for many materials used in industry. Therefore, many components and tools are protected by physical vapour deposited (PVD) coatings as especially the surface is often exposed to highest mechanical and corrosive attack.
The exposure to high temperatures and oxidative environments can lead to phase transformations and chemical reactions, resulting in increased stress levels and thus to crack initiation and delamination. Consequently, knowing the stress evolution within thin films is essential to overcome stress-induced failure.
Recently, we showed that Mo-Si-B/Ti_1-xAl_xN multilayer coatings exhibit excellent mechanical as well as oxidation resistance due to the combination of Ti-Al-N and Mo-Si-B layers. Here, we study the influence of temperature, atmosphere, and bilayer period on the stress evolution within these multilayers by using nano-beam X-ray diffraction. Their bilayer period was varied between 20 to 800 nm and these multilayers were thermally treated in oxidative and inert atmospheres at 1000 °C.
The highly focused synchrotron radiation allows for detailed stress analysis combined with a high-resolution phase analysis along the coating thickness. By correlating these results with additional in-depth scanning electron microscopy and transmission electron microscopy studies, we could clearly identify oxidation and phase transformation related stresses e.g. due to phase transformation of c-AlN to w-AlN.

Projektleitung Paul Heinz Mayrhofer:
Christian Doppler Labors für anwendungsorientierte Schichtentwicklung