Microstructure and Tribological Behavior of Cr-DLC Nanocomposite Films

Abstract

AbstractCr-diamondlike carbon (Cr-DLC) nanocomposite films with the Cr content varying up to 27 at. % were synthesized by reactive magnetron sputtering. Their microstructure and tribological properties were studied using transmission electron microscopy (TEM) and pin-on-disc experiments, respectively. Electron diffraction and high- resolution TEM studies show that the films, with ∼ 9 at. % Cr, deposited using low (−200 V) and high (−1000 V) specimen bias during processing are composed of nanocrystalline metallic Cr and face-centered cubic chromium carbide, respectively surrounded by an amorphous matrix. The Cr-DLC film deposited at high bias exhibited enhanced adhesion to Si substrate and wear resistance compared to those deposited at low bias with the same Cr content. Wear rate of the films deposited at high bias is relatively independent of Cr content up to about 10 at. % (of the order of 10−7 mm3/N-m) and then increases with increasing Cr content. The coefficient of friction for the films with a Cr content less than 19 at. % is low and remains between 0.1-0.16.