Carbon coating for corrosion protection of SS-316L and AA-6061 as bipolar plates of PEM fuel cells

Polymer electrolyte membrane (PEM) fuel cells are considered as the best choice for transportation applications due to their superb advantages such as low pollution, high efficiency and low cost. Metallic bipolar plates make up a prime component in the PEM fuel cells. As metallic bipolar plates, the corrosion resistance of stainless steel (SS-316L) and aluminum alloy (AA-6061) materials coated with graphite in different nanometer thicknesses were investigated. Corrosion tests were carried under simulated fuel cell operation conditions (1 M H2SO4, 70 °C). The results showed that the best thickness for SS-316L is 200 nm. For the AA-6061 material, however, the maximum graphite coating thickness of 600 nm examined in this study still seems inadequate protection for PEM bipolar plates.