Enhancement of Corrosion Resistance with Ti35 Alloy LayerInserted between Cr_0.23C_0.77 Coatings and Stainless Steel Plate of Fuel Cell

We addressed the pinhole corrosion problem at the interface of the surface modified, amorphous Cr_0.23 C_0.77 coating and 316 L stainless-steel plate of fuel cell. The solution was an inserted Ti-alloy layer, deposited by pulse bias arc ion plating. The influence of the Ti-alloy insertion layer on the interfacial corrosion was investigated in operation environment of proton exchange membrane fuel cell (PEMFC). The preliminary results show that the Ti35 alloy transition layer has a major impact. For example, the Ti35-alloy layer significantly increased the corrosion resistance (and bipolar plate service time) under the conditions:at an interface contact resistance of~3. 0 mΩ·cm² and a water-contact angle above 100°. Simulated in PEMFC environment, a well-defined passive region platform showed up in the potentiodynamic polarization curve; the current density was always below 10^-6 A·cm^-2 (0. 6 MPa) in-0. 3 to 0. 9 V range; and the breakdown potential was up to 1. 0 V.