Microstructure and tribological behavior of magnetron sputtered WSx/W/DLC/W multilayer films

Abstract:

WSx/W/DLC/W multilayer films were prepared by using magnetron sputtering technique and alternate deposition of WSx, W and diamond-like carbon (DLC) layers on silicon substrates. The microstructure, mechanical properties and tribological behaviors in the atmosphere of the films were characterized by X-ray diffractometry, scanning electron microscopy, nano-indenter and ball-on-disk wear tester. The results show that the surface of all the multilayer films is smooth and dense. As the thickness of single W interlayer increases in the modulation period, α-W, W2C, and β-WC1-x crystalline phases are formed in the multilayer films. The hardness of the multilayer films is greatly improved (up to 17.3 GPa at single W interlayer thickness of 6 nm), the friction coefficient shows a downward trend, the adhesion to the substrate is gradually reduced and the wear rate decreases first and then increases. The multilayer film with single W interlayer thickness of 6 nm exhibits the best wear resistance, its wear rate is about 1.4×10-14 m3N-1m-1.

Key words:WSx, diamond like carbon, W, multilayer films, friction and wear