Review of CVD TiN coatings for wear-resistant applications: deposition processes, properties and performance

Titanium nitride (TiN) deposited by chemical vapor deposition (CVD) techniques has been the premier wear-resistant coating in many applications for the last several decades. This review presents a history of developments in the technology of CVD TiN coatings. The CVD processes and equipment are discussed and the current knowledge on the thermodynamics and kinetics of the deposition process is presented. Various properties of CVD TiN coatings, such as hardness, adhesion, morphology and frictional properties, are discussed in the context of applications where wear resistance is required. Particular emphasis is given to applications in metal cutting where TiN has remained the mainstay of the various new and recent developments in coating design for cutting tools. Recent results of correlation between machining performance, deposition parameters, coating morphology and properties are presented. Throughout the paper, gaps in the existing understanding of the technology are pointed out. Finally, the paper presents a glimpse into the future of CVD TiN technology for wear-resistant applications.