On the tribology and micro-drilling performance of TiN/AlN nanolayer coatings

In this study, the TiN/AlN nanolayer coatings were prepared using a new sputtering setup, which was designed and manufactured on the basis of a newly developed technology – the high-rate reactive sputtering process. This setup featured an unbalanced magnetron sputtering system and a balanced magnetron sputtering system. The former was employed to deposit the AlN film, and the latter the TiN film. Through controlling the deposition conditions, a group of TiN/AlN nanolayer coatings with various periods was obtained. The aim of this study was to investigate the influence of periods of the nanolayer coatings on their fundamental mechanical properties and wear behavior first. And then, a field test was conducted to approve the feasibility of applying the nanolayer coatings on micro-drills for circuit board hole-drilling. The results revealed that through controlling of the deposition parameters, the TiN/AlN nanolayer coatings with periods ranging from 2.4 to 67.6 nm were obtained. At periods ≤3.6 nm, the films had extremely high hardness, excellent adhesion and wear performance, as compared with a TiN standard coating. The field test confirmed that the nanolayer coatings could provide a lot enhancement in micro-drilling performance.