A ZrN nanocrystalline coating for polymer electrolyte membrane fuel cell metallic bipolar plates prepared by reactive sputter deposition†
Song Xu,Paul Munroe
RSC Advances Pub Date : 07/28/2015 00:00:00 , DOI:10.1039/C5RA09733A
Abstract

To improve the surface performance and durability of 316L stainless steel (SS) used in polymer electrolyte membrane fuel cell (PEMFC) environments, a ZrN coating with an average grain size of ∼15 nm, was deposited by reactive sputter-deposition using a double glow discharge plasma technique. The corrosion behavior of the as-deposited coating was examined and compared to uncoated 316L SS in simulated PEMFC environments (i.e., 0.5 M H2SO4 + 2 ppm HF solution) by potentiodynamic and potentiostatic polarizations along with electrochemical impedance spectroscopy (EIS). The results showed that the corrosion resistance of the ZrN-coated 316L SS was significantly higher than that of uncoated material. Additionally, in comparison with uncoated 316L SS, the interfacial contact resistance (ICR) between the ZrN-coated 316L SS and the simulated gas diffusion layer (i.e., conductive carbon paper) was reduced by two orders of magnitude and remained mostly unchanged after potentiostatic polarization for 5 h. Furthermore, the average contact angle with water for the ZrN coated 316L SS (84.9°) was higher than that of uncoated material (64.4°), indicating that the ZrN-coated 316L SS is more hydrophobic.

Graphical abstract: A ZrN nanocrystalline coating for polymer electrolyte membrane fuel cell metallic bipolar plates prepared by reactive sputter deposition