Further improving the mechanical and tribological properties of low content Ti-doped DLC film by W incorporating

Abstract

W/Ti-doped diamond-like carbon (DLC) films were fabricated on Si substrates by co-sputtering W and Ti targets in methane and argon mixture atmosphere. The composition and the microstructure, internal stress, mechanical and tribological properties of the films were measured by X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), Raman spectra, BGS 6341 type film stress tester, nano-indentor and reciprocating ball-on-disc tester, respectively. The results indicated all films showed the amorphous structural characteristics and a constant thickness value of ∼600nm (195±15nm Ti interlayer was designed in order to minimize the influence of Ti interlayer), and the Ti content increased from 0 to 34.5% as the W target current increased from 0A to 14A. As the W concentration increased from 0 to 2.6at.%, the hardness increased to 12.7GPa and the internal stress maintained at a low value and almost no change. Meanwhile, the friction coefficient and wear rate showed the lowest value (0.023 and 1.2×10−8mm3/Nm, respectively). With the W content increased to 34.5at.% further, the internal stress, friction coefficient and wear rate of film are dramatically increased.