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ICACC - 2014
Robert Hollerweger (R. Hollerweger)
Talk
"Oxide phase stabilization and high temperature oxidation resistance of Zr and Ta alloyed Ti-Al-N coatings"
R. Hollerweger1, H. Riedl1, M. Arndt2, R. Rachbauer2, P. Polcik3, J. Paulitsch4, P. H. Mayrhofer4

1 Christian Doppler Laboratory for Application Oriented Coating Development at the Institute of Materials Science and Technology, Vienna University of Technology, 1040 Vienna, Austria
2 OC Oerlikon Balzers AG, 9469 Balzers, Principality of Liechtenstein
3 Plansee Composite Materials GmbH, 86983 Lechbruck am See, Germany
4 Institute of Materials Science and Technology, Vienna University of Technology, 1040 Vienna, Austria
Oxidation resistance of Ti1-xAlxN hard coatings is a key issue for cutting, drilling and machining applications. However, the formation of porous oxide scales at temperatures > 800 C is limiting the coating lifetime. Alloying Zr or Ta to TiAlN has proven to significantly retard the oxidation processes. Nevertheless, detailed investigations on the structure-property-relations of these alloying elements and their influence on the oxidation resistance and phase formation are still missing. Therefore, Zr and Ta alloyed Ti1-xAlxN coatings were deposited by cathodic arc evaporation and isothermally annealed at 850 and 950 C in synthetic air for 5 h. For investigating the oxidation kinetics differential scanning calorimetry and thermo gravimetric analysis were used. X-ray diffraction of the oxidized films indicates that Zr favors the formation of a dense anatase dominated oxide scale, whereas Ta favors the formation rutile dominated oxide scale. Remarkably, both oxide scales result in a significant increase of the oxidation resistance as compared to multi-phased oxide scales like typically obtained for Ti1-xAlxN.
 


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