Hard coatings for cutting applications: Physical vs. chemical vapor deposition and future challenges for the coatings community

Since decades, protective hard coatings with thicknesses of a few micrometers are grown by physical or chemical vapor deposition (PVD, CVD) on cutting tools to improve their application performance. For the huge variety of cutting applications, different coating materials are used, which typically belong to the material classes of nitrides, carbides, carbonitrides, borides, boronitrides or oxides, frequently in bi-or multilayer stacks. The present work surveys typical hard coatings belonging to the respective material classes, deposited by PVD as well as CVD. Pioneering studies in this field as well as recent findings contributing to the establishment of comprehensive synthesis - structure - property - application performance relationships of the respective coatings are discussed and the current state-of-research is reviewed. Condensed summaries and comparisons between PVD and CVD coatings are given at the end of each subsection. In addition, current and future challenges for the hard coatings community are surveyed.

Automated summary

The study reviews the current research on protective hard coatings grown on cutting tools by PVD and CVD over decades, including coatings of different material classes, synthesis, structure-property relationships, and application performance. It discusses pioneering studies and recent findings contributing to the establishment of comprehensive relationships for the coatings, as well as provides condensed summaries and comparisons between PVD and CVD coatings. Current and future challenges for the hard coatings community are also surveyed.