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18th Plansee Seminar - 2013
Helmut Riedl (H. Riedl)
Poster
"Phase Stability, Mechanical Properties and Thermal Stability of Y Alloyed Ti-Al-N Thin Films "
Riedl H.1, Hollerweger R.1, Holec D.1, Paulitsch J.2, Rachbauer R.3, Polcik P.4, Mayrhofer P.H.2

1Christian Doppler Laboratory for Application Oriented Coating Development at the Institute of Materials Science and Technology, Vienna University of Technology, Austria
2Institute of Materials Science and Technology, Vienna University of Technology, Austria
3OC Oerlikon Balzers AG, Liechtenstein
4PLANSEE Composite Materials GmbH, Germany
The increasing demands for Ti-Al-N protective coatings trigger further studies to enhance their performance during high-temperature applications. To obtain requirements such as high oxidation and corrosion resistance by simultaneously high hardness and elasticity, the formation of quaternary alloys with 4d-transition metals and reactive elements such as Yttrium is a promising approach. In order to study the impact of varying Al- and Y-content on the industrially preferred cubic structure of Ti1-xAlxN, several coatings were developed using a plasma-assisted reactive magnetron sputtering process. Structural investigations clearly show that Y shifts the solubility limit of Al in single phase cubic structured coatings to lower values. However, evaluation of the thermal stability of our single phase cubic structured Ti1-x-yAlxYyN coatings indicate that the formation of w-AlN is retarded and shifted by about 200C to higher temperatures, as compared to optimized Ti1-xAlxN. Consequently, even after annealing at 1200C hardness values of ~32.4GPa are obtained for c-Ti0.51Al0.47Y0.02N. Furthermore, alloying of around 2at% Yttrium to Ti1-xAlxN promotes the formation of a dense Al-rich outer oxide layer and thereby enhances their oxidation resistance.
 


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2011 - 2017 - Christian Doppler Laboratory for Application Oriented Coating Development