Thermal stability and oxidation resistance of Ti-Al-N/Ta-Al-N multilayer coatings

Christian Koller

Research output: ThesisDiploma Thesis


Ambitious material development for surface protection has yielded in a wide variety of coatings, whose purpose is the enhanced resistance against mechanical and thermal failure. In respect of metal processing tools, Ti(1-x)Al(x)N hard coatings are well acknowledged and have until today successfully been investigated in terms of chemical and architectural modifications. The present study adopts the approach of alloying Tantalum (its beneficial attributes regarding high temperature performance have recently been proofed) and proceeds with structural adaptations and different deposition methods, which are of certain interest for industrial application. Ti(1-x)Al(x)N/Ta(1-y)Al(y)N (where x=Al/(Al+Ti) and y=Al/(Al+Ta) stand for the Al content of the individual layers) multilayer coatings were synthesised in an industrial scale deposition plant using two different deposition methods, reactive arc evaporation and reactive sputter deposition. For this purpose, powder-metallurgical Ti-Al and Ta-Al alloyed targets with chemical composition Ti(0.5)Al(0.5) and Ta(0.75)Al(0.25) respectively, were used for the deposition of protective films having a different build-up. The coatings' performance after vacuum annealing treatments at temperatures up to 1400°C was investigated by X-Ray diffraction and nanoindentation. The present results exhibit a strong influence of the bilayer period and Ta content on mechanical as well as thermal properties and consequently, on the age hardening, thermal stability and oxidation resistance of the Ti(1-x)Al(x)N/Ta(1-y)Al(y)N coatings investigated.
Translated title of the contributionThermische Stabilität und Oxidationsbeständigkeit von Ti-Al-N/Ta-Al-N Multilagenschichten
Original languageEnglish
  • Mayrhofer, Paul Heinz, Supervisor (internal)
Award date29 Jun 2012
Publication statusPublished - 2012

Bibliographical note

embargoed until 01-06-2017


  • oxidation resistance
  • thermal stability
  • protective coating
  • TiAlN
  • TaAlN
  • age hardening

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