Investigation on physical and electrochemical properties of TiN-coated Monel alloy used for bipolar plates of proton exchange membrane fuel cell

The Bipolar Plate (BP) is a key component of Proton Exchange Membrane Fuel Cells (PEMFCs) that should contain a high electrical conductivity and corrosion resistance. In this research, Monel alloy due to higher corrosion resistance and higher ductility in comparison to other common alloys is selected as an appropriate option for metallic BPs. At first, the bare Monel alloys are exposed to oxidation condition at 120 degrees C and different times. The results show that the Interfacial Contact Resistance (ICR) values increase over time, due to surface oxidation necessitate surface coating of the bare alloy. Therefore, a crystalline Titanium Nitride (TiN) layer is coated on the alloy by Cathodic Arc Evaporation (CAV). The coating was performed with different roughness and thicknesses. The characterizations are performed by XRD, XRF, SEM, contact angle, ICR, and corrosion tests. It is specified that the best sample has the ICR value of 8.47 m Omega cm(2) in 150 N cm(-2) and corrosion rate of 0.53 mu A cm(-2) that is lower United States Department of Energy (DOE) values. Accordingly, TiN-coated Monel alloy can be used for BP.