The Formation of Protective Nitride Surfaces for PEM Fuel Cell Metallic Bipolar Plates

摘要

The selective gas nitridation of model nickel-based alloys was used to form dense, electrically conductive and corrosion-resistant nitride surface layers, including TiN, VN, CrN, Cr_2N, as well as a complex NiNbVN phase. Evaluation/or use as a protective surface for metallic bipolar plates in proton exchange membrane fuel cells (PEMFC) indicated that CrN/Cr_2N based surfaces hold promise to meet U.S. Department of Energy (DOE) performance goals for automotive applications. The thermally grown CrN/Cr_2N surface formed on model Ni-Cr based alloys exhibited good stability and low electrical resistance in single-cell fuel cell testing under simulated, drive-cycle conditions. Recent results indicate that similar protective chromium nitride surfaces can be formed on less expensive Fe-Cr based alloys potentially capable of meeting DOE cost goals.