Characteristics of (TiAlCrNbY)C films deposited by reactive magnetron sputtering

(TiAlCrNbY)C multi-component carbide coatings were prepared by reactive co-sputtering of Ti, Al, Cr, Nb and Y targets in an Ar + CH4 atmosphere. The films were investigated for elemental and phase composition, chemical binding state, texture, morphology, residual stress, roughness, hardness, friction and wear using Xray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM), surface profilometry, hardness measurements, and tribological tests. The metals in the carbide films were found in an almost equiatomic ratio, whereas the carbon content varied from about 46 to 82 at.%. For film composition close to stoichiometry, a single fcc solid solution phase with an (111) preferred orientation was detected. The coatings with higher carbon concentrations (69-82 at.%) exhibited an amorphous structure. Fine grained and smooth surface morphologies were observed by AFM. While the metallic film exhibited a low tensile stress (similar to 0.240 GPa), the carbides coatings were subjected to compressive stress, with values (from 0.200 to 1.950 GPa) strongly depending on CH4 flow rate. The hardness values (13-23 GPa) were found to be lower than those usually reported for binary carbides (30-35 GPa), while the dry friction coefficients were in the range 0.05-0.25. (C) 2009 Elsevier B.V. All rights reserved.