CrN/Cr multilayer coating on 316L stainless steel as bipolar plates for proton exchange membrane fuel cells

CrN/Cr multilayer coating is prepared on 316L stainless steel as bipolar plates for proton exchange membrane fuel cell (PEMFC) by pulsed bias arc ion plating (PBAIP). Interfacial conductivity of the bipolar plate with CrN/Cr multilayer is improved obviously, presenting an interfacial contact resistance (ICR) of 8.4 mΩ cm−2 under 1.4 MPa. The results tested by potentiodynamic and potentiostatic measures in simulated PEMFC environments show that the bipolar plate with CrN/Cr multilayer has good anticorrosion performance. The corrosion current density of the bipolar plate with CrN/Cr multilayer is approximately 10−8.0 A cm−2 at 0.6 V (vs. SCE) in a 0.5 M H2SO4 + 5 ppm F− solution at 70 °C with pressured air purging. The results of SEM and ICR before and after corrosion tests indicate that the bipolar plate with CrN/Cr multilayer is considerably stable electrochemically. The bipolar plate with CrN/Cr multilayer combined the prominent interfacial conductivity and the excellent corrosion resistance, showing great potential of application in PEMFC.

► The structure of CrN/Cr multilayer was designed to improve the anticorrosion and yields good results as anticipated.
► The bipolar plate with CrN/Cr multilayer exhibits prominent interfacial conductivity and excellent corrosion resistance.
► The results of SEM and ICR before and after corrosion tests indicate that the bipolar plate with CrN/Cr multilayer is considerably stable electrochemically.