Microstructure and properties of (Cr:N)-DLC films deposited by a hybrid beam technique

• (Cr:N)-DLC film with CrN and CrC crystalline phases was deposited on 316L stainless steel.
• (Cr:N)-DLC film showed low sp3/sp2 ratio, high micro-hardness and improved binding strength.
• (Cr:N)-DLC film showed an excellent tribological property compared with Cr-DLC film.

In this paper, diamond-like carbon (DLC) films doped with CrN nano-crystalline were prepared on 316L stainless steel using a hybrid beam deposition system (including a linear ion source (LIS) and a DC magnetron sputtering of Cr target). The microstructure and composition of the films were studied using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Mechanical and tribological properties were investigated using nano-indentation and tribological tester. The results showed that an N doping could significantly influence the microstructure and properties of the as-deposited films. On one hand, the N atoms doped in the film tended to form Cr–N, –CN–H and C–N bonding, which would enhance the binding strength. On the other hand, the formation of CrN/CrC nano-crystalline due to N doping dispersed in the amorphous DLC matrix could play an important role and increase its hardness. In addition, the (Cr:N)-DLC showed low friction coefficient and wear rate compared with the Cr-DLC film.