Investigation of PVD coating on corrosion resistance of metallic bipolar plates in PEM fuel cell

Metallic bipolar plates for the proton exchange membrane fuel cell (PEMFC) offer many advantages over conventional graphitic materials. These include relative low cost, high strength, and ease of manufacture. As a metallic bipolar plate can be easily shaped from thin sheet with complex shape, significant improvement in the fuel cell power/volume ratio can be achieved. However, corrosion of the metallic bipolar plates is a severe problem. Corrosion affects the performance and lifetime of a fuel cell. The 5052 aluminum alloy and SS 316L stainless steel were studied for their performance with that of the graphite. The physical vapor deposition (PVD) coating of YZU001 like-diamond film was applied on the 5052 aluminum alloy. The corrosion rates were determined by Tafel-extrapolation method from the polarization curves. The coated aluminum, 316L stainless steel and graphite were fabricated into single cell to measure contact resistance and to test cell performance. The results indicated that metallic bipolar plates, PVD coated 5052 aluminum and SS 316L, performed better than that of the graphite material at the low voltage and shorter cell life.