TiN and TiCxNy are commercial CVD coatings widely used for cutting tool applications. A promising route for improving hardness and oxidation resistance is the addition of silicon . Therefore investigations were performed using a thermal CVD process with a gas mixture containing TiCl4 and SiCl4. This work is focused to the investigation of structure, composition and properties of the TiSiCN coatings deposited on hardmetal inserts. The ratio of the silicon precursor to TiCl4 is varied. The structure was analyzed by SEM, TEM and XRD. A maximum hardness about 40 GPa was observed at a silicon content around 12 at.% . In this silicon concentration range a TiCxNy grain size below 20 nm was determined. The investigation of the oxidation behavior shows an increase of the oxidation resistance with the silicon content.
 I. Endler, M. Höhn, J. Schmidt, S. Scholz, M. Herrmann, M. Knaut, Surface & Coatings Technology, 215 (2013), 133.