Study on the Properties of Fuel Cell 304 Stainless Steel Bipolar Plates with Flow Channels Milled Using Different Methods

Various materials are currently used as bipolar plate flow channel substrates in proton exchange membrane fuel cells (PEMFCs): stainless steel, carbon steel, copper, aluminium, graphite, etc. Stainless steel has the best corrosion resistance among these materials but is more difficult to machine. Stainless steel exhibits the following characteristics during cutting: severe processing-induced hardening, a large cutting resistance, a high cutting temperature and chips that do not break easily and are prone to adhesion and tool wear. In the experiments reported here, SUS304 stainless steel was used as a substrate to explore the impact of using different methods, rotation rates, feed rates and cooling methods to mill flow channels for the subsequent anti-corrosion treatment of the specimens. After milling, the flow channels and the specimens were plated with chrome-carbon (Cr-C) to improve the corrosion resistance and conductivity of the substrates. After plating, the specimens that were fabricated using the high-speed milling machine performed better in all aspects and exhibited overall better corrosion resistance and electrical properties, as measured by potentiodynamic and potentiostatic polarization tests, than the other specimens. The results of our study can serve as a reference for the processing of PEMFC bipolar plates.