Microstructure and mechanical properties of hard Ti-Si-C-N films deposited by dc magnetron sputtering of multicomponent Ti/C/Si target

Quaternary Ti-Si-C-N films with different silicon contents were deposited on Si (100) substrates by dc magnetron sputtering of multicomponent Ti/C/Si target in an Ar/N(2) gas mixture. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nanoindentation, and scratch tests have been employed to characterize the films. The films were found to have a nanocomposite structure composed of nanocrystallites solely or of those surrounded by mixed amorphous phase, namely: nc-Ti/nc-TiN(x)/nc-Ti(C,N), nc-Ti(C,N)/a-TiSi/a-SIN(x)/a-C/ a-CN. or nc-Ti(C,N)/nc-TiSi(2)/a-SiN(x)/a-C/a-CN depending on the silicon content in the film. The nanohardness and elastic modulus of films first increased with adding silicon and reached their maximum values at 3.4 at.% Si, and then decreased. The highest nanoindentation hardness was 29 GPa which is higher than that of pure TiN coatings. The friction coefficient of Ti-Si-C-N films generally decreased with adding silicon, and with 3.4 at.% Si exhibited the lowest value. (C) 2011 Elsevier B.V. All rights reserved.