Assessment of Thermal Nitridation to Protect Metal Bipolar Plates in Polymer Electrolyte Membrane Fuel Cells

摘要

Thermally (gas) nitrided Nb-30Ti-20W wt percent exhibited excellent corrosion resistance and maintained good electrical conductivity in 80 deg C H_2SO_4 environments designed to simulate proton exchange membrane (PEM) fuel cell bipolar plate conditions. This result supports proof of principle for thermally nitrided alloys as candidate bipolar plate materials, although such Nb-base alloys are too costly for most PEM fuel cell applications. Investigation of the corrosion resistance of a series of relatively inexpensive, thermally nitrided model Ni-X base alloys designed to form Cr_2N, CrN, NbN, TiN, or VN surface layers have identified nitrided Ni-Cr base alloys as showing corrosion resistance nearly equal to that of the nitrided Nb-30Ti-20W.