An investigation into the effect of interruptions on cathodic arc plasma deposited TiN films for machining applications, and the development of a cutting test method under controlled atmosphere

There has been increased interest in hard coatings from the metal cutting industry in recent times and research has covered many new avenues for improvement. Methods for hard coating design cover improvements to hardness with microstructure and defect density control, elemental selection for oxidation resistance, layered structures, and nanostructures. In the literature, interruptions during growth of physical vapour deposited films have been used to modify and control stresses to better understand the mechanisms that generate stress during growth. Experiments have covered lower energy systems such as thermal evaporation and some higher energy systems like magnetron sputtering, and have included monitoring stress in-­‐situ. Investigations are made in ultra-‐high vacuum, with high purity targets to eliminate the influence of impurities on growth mechanisms and stress generation, allowing for less ambiguity in conclusions. The influence of interruptions during cathodic arc plasma deposition (CAPD) on residual film properties, in high vacuum reactive environments, using commercial purity targets are not explored in the literature. It is beneficial to investigate this as an avenue for coating improvement for commercial use in metal cutting applications. In this work the effect of interruptions during CAPD of TiN, on film microstructure and mechanical properties are investigated.