Orientation dependent tribological behavior of TiN coatings

Abstract

The preferred growth direction of cathodic arc physical vapor deposition-produced TiN coatings changes from (1 1 1) to (2 2 0) with high voltage pulsed bias application in the presence of Ar gas. In this study, tribological properties of these coatings were investigated via reciprocating wear tests against an inert counterbody for observing the role of orientation on tribological properties. Friction coefficients and wear of (2 2 0) oriented coatings were observed to be significantly lower compared to (1 1 1) oriented coatings. Micro-Raman investigations of the wear debris formed during tribotest revealed clear differences between (1 1 1) and (2 2 0) oriented films. Wear debris obtained from (2 2 0) oriented coatings consisted of nc TiO2 phases (anatase and rutile) whereas (1 1 1) oriented coatings produced amorphous Ti oxides. This behavior is attributed to the orientation dependent oxidation kinetics of the coatings as verified with isothermal oxidation tests. A mechanism for improved tribological behavior is proposed based on the obtained results.

Effect of substrate bias voltage on defect generation and their influence on corrosion and tribological properties of HIPIMS deposited CrN/NbN coatings

“…The difference in oxidation behaviour during the tribological tests could be associated with their stoichiometry and/or crystallographic orientation [37][38][39][40]. The change in the stoichiometry due to the preferential re-sputtering of coated flux at different bias voltages caused the variation between the chromium nitride and niobium nitride layers in the structure [41].…”

“…Whereas all other coatings (deposited at -40 V, -100 V, -150 V) with (200) preferred orientation were easily oxidised. The reason for this differences in oxide growth rate was suggested to be associated with surface energy of the different grain structures [37].…”

Effect of high-voltage pulse bias on the stress and morphology of CA-PVD TiN coatings

“…Recently, we have adapted this method to unfiltered cathodic arc systems and observed similar preferred orientation changes as seen in the filtered arc systems [6,7]. We also determined the critical role of Ar presence in the gas mixture in these changes [8].…”

Effect of chamber pressure on defect generation and their influence on corrosion and tribological properties of HIPIMS deposited CrN/NbN coatings

“…To understand the tribological properties of these coatings, the influence of the chamber pressure on crystallographic orientation was studied. It is well known that crystallographic orientation influences tribological behaviour of the coatings [43][44][45][46]. In addition, Raman spectra were obtained from the corresponding wear track and wear debris of the CrN/NbN coatings to evaluate the nature of the oxides produced at the tribological contact.…”