Technology perspective on CVD and PVD coated metal-cutting tools

This review gives an account of the technological developments in hard coatings that have been commercially implemented in modern metal-cutting tools. Both CVD and PVD coatings have been successfully applied to cemented carbide metal-cutting inserts, in spite of the apparent competition between the two technologies. CVD coatings have evolved over the past 20 years with multilayer configurations that are still predominant today. PVD single-layer coatings have found niche applications, where conventional CVD coatings have not been particularly successful, and are expected to challenge standard CVD coatings with further advancements. Recently, a CVD/PVD layer combination has been commercially introduced. Scenarios for the development of newer coatings such as diamond and CBN are discussed. A failure mode diagram is proposed as a conceptual framework for metal-cutting tool design which takes into account the total system: the wear environment imposed by workpiece and machining parameters, corresponding tool failure modes and the synergy between hard coating and substrate.