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In – situ mechanical characterization of the TiN/NbN, NbN/CrN and TiN/CrN multilayer thin films
|Karolina A. Rzepiejewska-Malyska 1, HANNA WRZESIŃSKA 3, Magdalena Parlinska-Wojtan 2, Ryan Major 4, Johann Michler 1, Asif Syed 4
1. EMPA Materials Research and Technology (EMPA), Feuerwerkerstr. 39, Thun 3602, Switzerland
TiN/NbN, NbN/CrN and CrN/TiN multilayer coatings with 20 periods and a thickness of a single layer of around 25 nm were synthesized by magnetron sputtering. Hardness and Youngs modulus of the multilayers films were measured by nanoindentation and compared to reference samples of TiN, NbN and CrN. Some multilayer systems exhibited an increase of hardness, compared to the reference samples. To understand the underlying deformation mechanisms a new nanoindentation instrument based on the Hysitron Picoindenter has been developed for use inside a high resolution scanning electron microscope. The technique allows for observation of pile-up, sinking-in and crack propagation as well as other phenomena during the indentation loading cycle. The in-situ indentations revealed that the pile-up/sink-in behavior of the multilayer is different to the one observed for pure coatings.To understand the governing sub-surface deformation mechanisms, transmission electron microscopy (TEM) samples from the indented areas were prepared in cross-section via focused ion beam machining. The related TEM micrographs revealed that the thickness of individual layer decreased significantly within the residual imprint. Possible deformation mechanisms related to these observations will be discussed.
Presentation: Oral at E-MRS Fall Meeting 2007, Symposium J, by Karolina A. Rzepiejewska-Malyska
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-05-11 17:44 Revised: 2009-06-07 00:44