Influence of hollow cathode plasma on AlCrN-thin film deposition with vacuum arc evaporation sources

In order to provide sufficient wear protection on tools, which supports to increase productivity in the manufacturing processes, the substrates can be coated with different hard material layers. High hardness is one important thin film property to get an optimal wear protection of tools, but if the working temperature exceeds an upper limit the hardness of the thin film is strongly reduced. The concrete valuation of the decrease in the hardness depends on the coating materials. For the standard TiAlN-coating, the maximum operating temperature conditions is therefore limited to 850 °C. Nowadays for high speed cutting and dry or low lubricant cutting applications, a maximum temperature of about 1100 °C [J.L. Endrino, G.S. Fox-Rabinovich, A. Reiter, S.V. Veldhuis, R. Escobar Galindo, J.M. Albella, J.F. Marco; Surface & Coatings Technology 201 (2007) 4505–4511.] is allowed without a decrease in the hardness of the coated layer. Aluminium–Chromium–Nitride (AlCrN)-hard material coatings are one system with this extended operation conditions because of its high resistance to oxidation.A further improvement of AlCrN-thin film coatings will be shown through parallel operations of the hollow cathode (HC) plasma sources with the arc evaporation sources. By means of optical emission spectroscopy (OES) measurements, it can be demonstrated that the additional hollow cathode plasma provides an increase in the amount of excitation and ionisation degree of the evaporated aluminium and chromium in the advanced AlCrN deposition process.How effectively this additional HC-plasma influences the AlCrN-thin film properties, will be demonstrated.