Oxidation behavior of vanadium in annealed AlCrVY(O)N thin films characterized by X‐ray absorption spectroscopy

Abstract

Great efforts are being made to optimize tool coatings for use at elevated process temperatures. The reason for this is to enable machining with minimized lubrication quantities. During operation, temperatures between 300 and 1000 °C can occur depending on the material and tool design. Thus to enable the machining of high-strength materials, the tool coatings must be optimized with regard to their temperature resistance, which is also significantly affected by their oxidation properties. AlCrVY(O)N thin films are potential candidates for such coating applications as the addition of V to AlCrN favors the formation of so-called Magnéli phases at high temperatures, that is, V oxides with varying stoichiometry, to reduce friction. X-ray absorption spectroscopy is applied to characterize the oxidation behavior of V in the thin films prepared in a combined dcMS/HiPIMS process for as-deposited AlCrVY(O)N thin films and after thermal treatment in the ambient atmosphere. The V average oxidation state is determined by analyzing the pre-edge feature at the V K-edge. Systematic changes in preoxidation, a high oxidation resistance below 800 °C, and promoted V oxidation for higher preoxidized coatings above 800 °C are found.