Improving corrosion and conductivity of Ti-doped amorphous carbon film coated on 316L stainless steel bipolar plates by nitrogen atoms doping

Amorphous carbon films have recently attracted extensive attention as surface functional films for bipolar plates with excellent conductivity and anti-corrosion properties. In this research, to determine the influence of the amorphous carbon film doped with titanium and nitrogen on the efficiency of proton exchange membrane fuel cells (PEMFCs) and clarify the effect of N atoms on Ti doped amorphous carbon, a series of Ti, N co-doped amorphous carbon films are built on 316L stainless steel at different N2 flow rates. This study provides detailed research about the influence of N atoms content on the microstructure, morphology evolution, corrosion resistance and interfacial contact resistance (ICR) of Ti, N co-doped amorphous carbon films. The results reveal that the N doping of the Ti-doped amorphous carbon film has the potential to enhance the C-sp2 content and refine the grain. The characterization results indicate that introducing N atoms into Ti doped amorphous carbon can reduce the ICR of the film to 2.38 mΩ cm2. The introduction of N atoms can also enhance the anti-corrosive characteristics of the titanium singly doped amorphous carbon film. The Ti, N co-doped film can be used as candidate materials applied to metal bipolar plates. •Ti, N co-doped amorphous carbon with different N contents is prepared.•The appropriate doping of N atoms regulates the surface morphology and structure.•The formation of Ti–N and C–N structure improves sample's corrosion resistance.•Interfacial contact resistance value is reduced with moderately N atoms doped.