Parts | Days | Selection | Search | Downloads | Help
DS: Fachverband Dünne Schichten
DS 34: Hard and Superhard Coatings
DS 34.4: Talk
Thursday, February 28, 2008, 16:30–16:45, H 2032
AlCrVN - Design of high-temperature low-friction hard coatings — •Robert Franz1, Jörg Neidhardt1, Markus Lechthaler2, Peter Polcik3, and Christian Mitterer1 — 1Christian Doppler Laboratory for Advanced Hard Coatings at the Department of Physical Metallurgy and Materials Testing, University of Leoben, Austria — 2Oerlikon Balzers Coating AG, Balzers, Principality of Liechtenstein — 3Plansee Lechbruck GmbH, Lechbruck, Germany
As environmental and economical considerations favour cutting with reduced coolants, controlling the friction becomes a major issue for the development of wear protective tool coatings. Common state-of-the-art coatings like AlCrN exhibit a relatively high friction especially at elevated temperatures, which leads to even higher thermal loads at the cutting edge and consequently to failure by thermal degradation. The incorporation of V into AlCrN results in a distinct reduction of the coefficient of friction at 700∘C as the lubricious oxide V2O5 is formed. The new AlxCryVzN coatings were synthesised by means of physical vapour deposition using an industrial-scale arc-evaporation system. The desired metastable face-centered cubic (fcc) structure was stabilised even at an Al concentration of x=0.7 by using higher energetic growth conditions. Due to this structural evolution hardness and residual stress values comparable to fcc-AlCrN were retained. Annealing experiments in ambient air at temperatures ranging from 550-700∘C revealed the formation of a V-rich oxide scale due to the immiscibility of V2O5 with the other oxides formed (Al2O3 and Cr2O3).