Corrosion Resistance of CrMoCN Coated Stainless Steel Bipolar Plate of Proton Exchange Membrane Fuel Cell

For improving the corrosion resistance of 316L stainless steel (SS316L) bipolar plate in the proton exchange membrane fuel cell(PEMFC)， the CrMoCN coating was prepared on its surface using magnetron sputtering technology at different acetylene gas flow rates (6，10，14 sccm).The elemental composition and surface morphology of the coating samples were characterized using XPS， SEM， etc.， and the corrosion resistance of the samples under normal operation， start/stop， and long-term immersion conditions of proton exchange membrane fuel cells(PEMFC) was tested using electrochemical testing methods.Results showed that the CrMoCN coating was composed of CrN， Mo2 N， MoC，Cr7C3 phases and amorphous carbon.In both constant potential polarization and cyclic high potential polarization tests， the CrMoCN-14 coating prepared with acetylene gas flow rate of 14 sccm showed the best corrosion resistance.Under the long-term immersion conditions， the charge transfer resistance of the CrMoCN-14 coating sample was 3.37×105 Ω·cm2， which was about one order of magnitude higher than that of SS316L，which suggested that the CrMoCN-14 coating had excellent chemical stability and could provide stable protection for SS316L substrate.