Performance Degradation of TiN-and TiC-deposited AISI316 bipolar plates for proton exchange membrane fuel cells

TiN and TiC were deposited on AISI316 bipolar plates for proton exchange membrane fuel cells (PEMFCs) and their effects on the corrosion resistance and overall cell performance were investigated. TiN with a Ti interlayer and TiC with a Ti interlayer were deposited on AISI316 bipolar plates by hollow cathode discharge (HCD) ion plating. The electrochemical behavior of the metallic bipolar plates was examined using a potentiodynamic method, an electrochemical impedance spectroscopy (EIS), and a single cell test. These results revealed that the TiN and TiC coatings considerably improved the corrosion resistance of AISI316. However, the TiN-deposited AISI316 bipolar plates showed a better cell performance than the TiC-deposited AISI316 bipolar plates. The differences in the cell performance stemmed from the differences in the ohmic resistance and charge transfer resistance.