Mechanical properties of Ti(C,N) and TiN thin films on cutting tools measured by nanoindentation

Increasing demands on production processes in terms of performance, reliability and environmental compatibility shape the specification profile for modem wear resistant coating systems. The behavior of PVD coated cutting tools are determined by a large number of characteristics and mechanical properties like hardness, residual stresses, coefficient of friction, density, surface roughness etc. For application of coated tools the knowledge of film hardness and residual stresses are also of a great interest. For the present work, three different substrate materials, high speed steel, cemented carbides and cermets, were coated with TiN or Ti(C,N). The deposition processes were carried out with the Cathodic Are Ion Plating process (AIP). During the coating processes, the layer thicknesses were varied. The film hardness and the intrinsic stresses are consequences of deposition conditions, e.g. ion bombardment, external heating during deposition and residual layer thickness after coating. This paper reveals first results of film hardness and intrinsic stresses and shows correlations of these effects with the layer thickness. A Nanoindenter(TM) XP was used to evaluate the film hardnesses. The residual stresses were determined using the stripe bending test.