The development of PVD coatings for PEM fuel cell bipolar plates

[摘要] This work investigated the suitability of thin film, single and multi-layered coatings, by a Physical Vapour Deposition (PVD) process for polymer electrolyte membrane fuel cell bipolar plates. Due to the multifunctional nature of this particular component a comprehensive approach was used where several key properties were examined for coatings including: ZrN, TiN, CrN, Graphit-iC™, CrN+C, TiN+C and Au. Chemical etching and surface roughness were found to influence the Interfacial Contact Resistance (ICR) of the substrate; however, any observed effect was negated with the addition of a conductive coating. CrN+C and TiN+C multi-layer coatings showed a striking reduction in the ICR compared with the nitride only equivalents. The suitability of pre-coated PVD coatings for serial production via stamping was assessed in collaboration with an industrial partner. The coating durability was found to be influenced by several factors including coating type, thicknesses and position on stamped plate. The multi-layered TiN+C coating was found to noticeably improve the stampability compared to the TiN only coating. The corrosion resistance of the coatings was evaluated under simplified corrosion conditions. Under these conditions TiN+C was found to have two beneficial effects, improving the free corrosion potential and the stability of the carbon topcoat under startup/shutdown potentials.

[发布机构] University:University of Birmingham;Department:School of Chemical Engineering

[关键词] T Technology;TP Chemical technology