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ICMCTF - 2014
Christian Koller (C.M. Koller)
Talk
"Ab Initio Guided Design of Corundum Type (Al1-x-yCrxMy)2O3 Thin Films"
C.M. Koller; Christian Doppler Laboratory for Application Oriented Coating
Development at Vienna University of Technology, Austria
X X
J. Ramm; Oerlikon Balzers Coating AG, Liechtenstein
S. Kolozsvári; Plansee Composite Materials GmbH, Germany
D. Holec; Montanuniversität Leoben, Austria
J. Paulitsch; Vienna University of Technology, Austria
P.H. Mayrhofer; Vienna University of Technology, Austria
Sophisticated alloying concepts are of utmost importance for application oriented coating development in order to
obtain specifically tailored and optimised material properties allowing for extended application ranges. Recent
studies on borides, nitrides, or oxides have proven the effectiveness of combining first principle calculations with
experimental developments in obtaining an atomistic-to-macroscopic understanding of high performance
materials. In this work we describe the impact of several selected alloying elements (M) on the quasi-binary
system of (Al1-xCrx)2O3 with focus on their capability to promote the desired corundum type ? phase.
Based on ab initio calculated energies of formation for three different crystallographic structures (?, cubic B1-
like, and cubic ?) it was investigated if elements such as B, Si, Hf, Ta, or Y promote the formation of metastable
cubic phases instead of the desired ? phase. The findings are compared with coatings synthesised by reactive
cathodic arc evaporation. In the case of Fe alloying, for example, our predictions reveal no explicit impact on the
phase stability sequence ?, B1-like, and ?, whereas experiments suggest an increased amount of ? phase fractions.
Detailed analysis of the binding characteristics and structural defect sensibility provides an atomistic
understanding of the sometimes observed discrepancy between calculations and experiments. This advanced
approach allows for a knowledge-based development of high performance Al-Cr-based oxide coatings.
 


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