Effects of platinum content on tribological properties of platinum/nitrogen doped diamond-like carbon thin films deposited via magnetron sputtering

摘要

Platinum(Pt)and nitrogen(N)were co-incorporated in diamond-like carbon(DLC)thin films using a magnetron sputtering system to form PtN-DLC thin films for tribological applications.The Pt content in the PtN-DLC films prepared on Si substrates was controlled by varying RF power applied to a Pt target at a fixed N2 flow rate.The tribological properties of the PtN-DLC films were investigated with respect to the Pt content in the films.The uncoated Si substrate surface tested against a steel ball of 6 mm in diameter had significant abrasive and fatigue wear,while no significant wear was found on the N-DLC coated sample surface,indicating that the N-DLC film effectively prevented its underlying Si substrate from wear.However,the incorporation of Pt in the N-DLC films reduced the wear resistance of the films by degrading sp3-bonded cross-linking structures of the films so that significant wear tracks were found on the surfaces of the PtN-DLC films.Therefore,the increased radio frequency(RF)power applied to the Pt target decreased the wear resistance of the PtN-DLC films as a result of the increased Pt content.