Effect of methane flow rate on microstructure and tribological properties of (Cu, Ce)/Ti co-doped DLC films fabricated via reactive magnetron sputtering technology

Abstract

The superior diamond-like carbon (DLC) films are of extremely significance, and three typical elements including hard metal, soft metal and rare earth co-doping could be a feasible way to achieve their promising properties. In this paper, the (Cu, Ce)/Ti co-doping strategy was employed to prepare (Cu, Ce)/Ti-DLC films via vacuum direct current reactive magnetron sputtering technology at different methane flow rate. The evolutions of microstructure, mechanical properties, tribological and anti-corrosion performances of as-prepared films were systematically investigated. Results revealed that as-prepared (Cu, Ce)/Ti-DLC films could exhibit typically nanocrystalline/amorphous characteristics, including TiC, Cu and Ce dispersed in the carbon matrix. As the flow rate of CH4 increased, the carbon content of the films raised gradually while the content of Ti exhibited a reversely discipline, and the hardness and elastic modulus of the films presented an increased trend. Particularly, it possessed superior adhesive strength of 32.9 N, and exhibited the best tribological performances with low friction coefficient of 0.095 and wear rate of 2.53 × 10−7 mm3/Nm for the (Cu, Ce)/Ti-DLC film deposited at CH4 flow rate of 7 sccm. Also, the film deposited at CH4 flow rate of 7 sccm presented optimal corrosion resistant property with the lowest value of 1.474 × 10−8 A · cm−2.