Properties of sputter-deposited MoS2/metal composite coatings deposited by closed field unbalanced magnetron sputter ion plating

Abstract

It has been proved that the co-deposition of a proper amount of titanium can significantly improve the properties of sputter-deposited MoS2 coatings, leading to the deposition of coatings, which are harder, much more wear resistant and also less sensitive to atmospheric water vapour during tribological testing. The MoS2/Ti coatings, studied here by the authors, also give excellent industrial results in a wide range of applications. In this paper the mechanical and micro-structural properties of MoS2 coatings containing titanium with molar fractions up to 0.44 are studied. The mechanical properties are tested with pin-on-disk and reciprocating wear tests (multipass) in different experimental conditions. Frictional force and friction coefficient against a number of cycles are recorded. Coatings composition is determined by Rutherford and non-Rutherford backscattering (RBS) and coating thickness is measured by cross-section scanning electron microscopy (SEM). Structural analysis is carried out using X-ray diffraction (XRD). The mechanical properties are presented as a function of the Ti content and the optimal titanium concentration is determined. Other metals like Cr, W, Zr and Mo are also investigated. The composition of MoS2/metal composite coatings of the same quality of the MoS2/Ti films (‘optimized’ coatings) is studied by RBS.