Influence of phase transition on the tribological performance of arc-evaporated AlCrVN hard coatings

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• 作者：R. Franz ; J. Neidhardt ; R. Kaindl ; B. Sartory ; R. Tessadri ; M. Lechthaler ; P. Polcik ; C. Mitterer
• 关键词：Hard coatings ; AlCrVN ; Lubricious oxides ; Arc-evaporation
• 刊名：Surface and Coatings Technology
• 出版年：2009
• 出版时间：15 January 2009
• 年：2009
• 卷：203
• 期：8
• 页码：1101-1105
• 全文大小：589 K

文摘

V-alloyed AlCrN hard coatings were synthesised by reactive arc-evaporation in an industrial-sized deposition system at bias voltages ranging from − 40 to − 150 V. X-ray diffraction analysis has shown that higher energetic growth conditions stabilise the desired metastable face-centered cubic (fcc) crystal structure of Al_0.70Cr_0.05V_0.25N even at very high Al/Cr ratios resulting in hardness values comparable to Al_0.70Cr_0.30N. Ball-on-disc tests were used to assess the friction at 700 °C where Al_0.70Cr_0.05V_0.25N coatings revealed a generally lower coefficient of friction due to the formation of a tribolayer containing the lubricious oxide V₂O₅ as evidenced by Raman spectroscopy. The single-phase fcc-Al_0.70Cr_0.05V_0.25N coating appears to be more oxidation resistant leading to a reduced formation of V₂O₅ and, hence, an increase in friction. The cutting performance was evaluated by conducting side milling tests under dry conditions, where Al_0.70Cr_0.05V_0.25N coatings showed a competitive performance regardless of the growth conditions.