The tribological properties of Zr-C:H coatings deposited on AISI M2 substrate

Zr-C:Hx% coatings are deposited on AISI M2 steel disks using an unbalanced magnetron (UBM) sputtering method with a single zirconium metal target, three graphite targets and various CH4 reactive gas flow rates in the range of 0–5 sccm. The results show that the CH4 flow rate has a significant effect on the microstructural, adhesion and tribological properties of the coatings. Specifically, the microstructure changes from a columnar form to a featureless morphology as the CH4 flow rate increases. Furthermore, an increasing CH4 flow rate increases the coating hardness and results in a lower wear depth and friction coefficient under sliding with an AISI 1045 steel cylinder.