Microtribological performance of Au–MoS2 nanocomposite and Au/MoS2 bilayer coatings

Abstract Scratch tests, reciprocating microwear, and scanning wear tests were performed on pure Au, bilayer Au/MoS 2 , and co-sputtered Au–MoS 2 using a nanoindentation instrument in dry air. These different lubrication strategies (i.e. nanocomposite and bilayer coatings) were compared in terms of mechanical properties, friction coefficient, and wear behavior. The results were correlated to the tribofilm formation, which was analyzed using ex situ characterization of the wear track with a Scanning Electron Microscope (SEM), micro-Raman spectrometer, and an atomic force microscope (AFM). It was observed that the nanocomposite Au–MoS 2 coatings increased the wear resistance compared to pure Au films, which was explained by the increase in hardness values and the decrease in surface adhesion forces. Similarly for bilayer Au/MoS 2 samples, the wear resistance of the Au film was enhanced by the MoS 2 top layer, which behaved as a sacrificial layer protecting the Au.