Wear Resistance of TiNx/CFy Coatings Deposited by RF Magnetron Co-Sputtering

Abstract

TiNx/CFy composite coatings were prepared by RF magnetron co-sputtering using twin cylindrical tube targets with Ar and N2 mixtures. The composition of the coatings deposited at various positions was analyzed by X-ray photoelectron spectroscopy (XPS) and Rutherford back-scattering spectrometry (RBS). The results revealed that the composition of the deposited coatings has a wide range of TiNx and CFy contents at different deposition positions, which leads to different structures and performances. The hardness of the composite coatings increases from 32 to 1603 HV with increasing the TiNx concentration. The static contact angle of water ranges from 20° to 102° and decreases upon the incorporation of more TiNx into the CFy polymer. The presence of the CFy groups enhances the contact angle between the coating and the solutions dropped onto it, which could effectively protect the coating from corrosion and improve the wear resistance properties in high relative humidity (RH). The brittleness of the coatings decreases due to the softness of the CFy component, which can bear most of the load and result in less probability of crack formation. XPS results demonstrate the existence of a Ti (C N) chemical bond in the composite coatings, which improves the wear resistance of the coatings. It is indicated that the wear resistance of the TiNx/CFy coatings is independent of the hardness. However, these properties depend on the uniform structure and the existence of chemical bonding between the TiNx and CFy phases. Moreover, a specific ratio between the soft CFy phase and the hard TiNx phase can produce coatings with good wear resistance.