Investigation of (Ti:N)-DLC coatings prepared by ion source assisted cathodic arc ion-plating with varying Ti target currents

Ti and N co-doped diamond-like carbon ((Ti:N)-DLC) nanomultilayered composite coatings were synthesized by ion source assisted cathodic arc ion-plating at C2H2 and N-2 ambient with varying Ti target currents. The compositions, morphologies and microstructures of the coatings were characterized by energy dispersive spectrometer (EDS), scanning electronic microscopy (SEM), atomic force microscope (AFM), X-Ray photoelectron spectrometer (XPS), Raman spectroscopy, X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Hardness and friction coefficient were tested by a hardness tester and a ball-on-disc tribometer, respectively. The (Ti:N)-DLC coating consists of uniform TiN, TiC, Ti(C,N) nanocrystallines embedded into N doped DLC (N-DLC) matrix. With the increase of Ti target current from 20 to 60 A, the sp(2)/sp(3) ratio and the contents of TiN, TiC increase obviously, but the Ti(C,N) content sharply decreases. It was revealed that the coating deposited at Ti target current of 50 A exhibits the highest hardness (27.8 GPa), elastic modulus (491 GPa) and low friction coefficient (0.107). Prime novelty statement: In this study, we provide the (Ti:N)-DLC coating consisting of uniform TiN, TiC, Ti(C,N) nanocrystallines embedded into N-DLC matrix using a direct current ion source assisted cathodic arc ion-plating system, and have a detailed study about the influences of Ti target currents on the composition, phase content, microstructure and mechanical properties of (Ti:N)-DLC nanomultilayered composite coatings. (C) 2016 Elsevier B.V. All rights reserved.