Nitride Metallic Bipolar Plates for Proton Exchange Membrane Fuel Cells

Abstract

Thermal nitridation of Ni- and Fe-base Cr-bearing alloys is under investigation as a means to enable use of metallic bipolar plates in proton exchange membrane fuel cells. Proof of principle for this approach was recently established by a successful single-cell fuel cell test using 50 cm2 active area anode and cathode plates made from a model nitrided Ni-50Cr alloy. Protection of the metal was accomplished by the formation of an electrically-conductive and corrosion-resistant CrN/Cr2N surface layer. This paper presents an overview of efforts to form similar Cr-nitride surfaces on Ni-Cr and Fe-Cr base alloys in commercially available composition ranges.