Niobium Sputter Coated Stainless Steel as a Bipolar Plate Material for Polymer Electrolyte Membrane Fuel Cell Stacks

Niobium (Nb) sputter coated 316L stainless steel (SS) is investigated as an alternative to a previously developed Nb clad 304L SS material for use in a bipolar plate component of a polymer electrolyte membrane fuel cell (PEMFC) stack. The electrochemical properties of the Nb sputter coated 316L SS are evaluated via static corrosion and interfacial contact resistance testing and through potentiodynamic and potentiostatic measurements conducted under half-cell environments of a standard PEMFC stack. The experimental results show that the electrochemical properties of the sputtered Nb coatings are quite viable for the PEMFC bipolar plate application, while the thickness of the sputtered Nb coating is substantially thinner than that of the roll clad Nb coating.