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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.

Vapour deposition technologies have over the last forty years revolutionised the use of industrial cutting tools when used in high performance machining of metals. The foundation of this success was built on the vapour deposition of thin ceramic films, with the first market leader being titanium nitride. The innovation that was to form a platform for future development of PVD coatings was their densification by ion bombardment during the vapour deposition process. This aspect of PVD technology and the emergence of new PVD coatings for cutting tools is discussed in the light of current definitions of innovation. The argument is made that, notwithstanding the fact that PVD is a mature technology it is fertile ground for innovation given its ability to build new structures atom-by-atom. Examples of current research are presented to support this contention. In conclusion, the paper returns to the key issue of innovation and its key role in promoting growth and improved living standards. The point is made that given the knowledge, the technology, the infrastructure and culture then innovation is about people. This is discussed in the light of people using 21st century tools to collaborate as recently witnessed in crowdsourcing. © Institute of Materials Engineering Australasia Ltd.