The effect of fluorine doped diamond-like carbon coatings on the corrosion behaviour of cobalt chromium molybdenum substrates

Abstract

In this research, the coating of diamond-like carbon (DLC) doped with fluorine (F-DLC) on the cobalt chromium molybdenum (CoCrMo) substrate was carried out using the radio frequency plasma enhanced chemical vapor deposition method. Then, the effect of F-DLC coating on the roughness, wettability and corrosion resistance of the CoCrMo substrate was investigated. Raman spectroscopy results showed that doping DLC coating with fluorine causes the formation of more graphite in the structure. According to the attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) analysis, fluorine was present in the structure of F-DLC coating as C–F and C–F₂ groups. In addition, it was found that F-DLC coating has a rougher surface than DLC coating, and the water contact angle is higher in F-DLC coating due to CF and CF₂ bonds. Electrochemical measurements showed that the CoCrMo substrate’s corrosion resistance could be enhanced greatly through applying F-DLC coating.