Further improvement of mechanical and tribological properties of Cr-doped diamond-like carbon nanocomposite coatings by N codoping

Abstract

In this study, the effects of nitrogen codoping on the microstructure and mechanical properties of Cr-doped diamond-like carbon (DLC) nanocomposite coatings were investigated in detail. Compared with undoped DLC coatings, the Cr-DLC and N/Cr-DLC coatings showed higher root-mean-square (RMS) roughness values. However, from the X-ray photoelectron spectroscopy (XPS) and Raman results, the fraction of sp2 carbon bonds of N/Cr-DLC coatings increased with increasing N content, which indicated the graphitization of the coatings. The hardness and elastic modulus of N/Cr-DLC coatings with 1.8 at. % N were about 26.8 and 218 GPa, respectively. The observed hardness increase with N codoping was attributed to the incorporation of N in the C network along with the formation of CrC(N) nanoparticles, as confirmed from the transmission electron microscopy (TEM) results. The internal stress markedly decreased from 0.93 to 0.32 GPa as the N content increased from 0 to 10.3 at. %. Furthermore, N doping significantly improved the high-temperature dry friction behavior of DLC coatings. The friction coefficient of N/Cr-DLC coatings with 8.0 and 10.3 at. % N was kept at about 0.2 during the overall sliding test at 500 °C. These results showed that appropriate N doping could promote the mechanical and tribological properties of Cr-DLC nanocomposite coatings.

Diamond-like carbon film preparation using a high-repetition nanosecond pulsed glow discharge plasma at gas pressure of 1 kPa generated by a SiC-MOSFET inverter power supply

“…iamond-like carbon (DLC) films have attracted considerable attention because of their significant potential applications in a wide range of fields related to mechanical sliding parts, 1) biomaterials, 2) and gas-barrierimproved polyethylene terephthalate bottles. 3) Currently, DLC films have been prepared by physical vapor deposition (PVD) 4) and chemical vapor deposition (CVD) 5) under low gas pressures, typically below 10 Pa.…”

Evolution of the mechanical and tribological properties of DLC thin films doped with low-concentration hafnium on 316L steel

“…At the present time, the most general approach of modifying DLC thin films through the incorporation of metallic elements (Me-DLC), including Ti, Zr, Ni, Ag, Cr, Al, etc, which can reduce the internal stress to improve the adhesion, mechanical, and tribological properties, has gained increasing attention as an expanding area of applied materials [16][17][18][19][20][21][22][23]. Among those doping metals, carbide formers (MeC), like Ti [24,25], Cr [26,27], and Zr [28,29], can exist as either metallic clusters dissolving in DLC thin films or metal carbide phases embedding in the carbon matrix, which significantly influence the mechanical and tribological properties as well as relatively lower internal stress than that of pure DLC thin films.…”

Effects of Substrate Temperature on Film Hardness and Hydrogen Content in Diamond-like Carbon Films Prepared with a Repetitive Nanosecond Pulsed Glow Hydrogen/Methane Discharge Plasma

“…Diamond-like carbon (DLC) films have attracted broad interest in various industrial fields owing to their excellent material properties [1]. Increasing the deposition rate and reducing the cost of deposition is necessary to enable DLC films to be widely used in industry.…”