Investigation of Morphology, Electrical and Electrochemical Properties of Gold Coating on Metallic Bipolar Plates of Fuel Cells

Polymer electrolyte membrane fuel cells have received more attention than other fuel cells because of their advantages such as low operating temperature, high power density and short startup time. One of the most important components of a polymer electrolyte membrane fuel cell is bipolar plate which has various types. Metallic bipolar plates have advantages such as higher strength, lower thickness and lower weight than graphite-based composite bipolar plates. Corrosion resistance and interfacial contact resistance of metallic bipolar plates are some of the challenges of using metallic bipolar plates. For this reason, metallic bipolar plates are coated to increase corrosion resistance and reduce contact resistance. In this study, the properties and morphologies of gold coating on copper and stainless steel substrates were studied by using electroplating and sputtering methods. The surface morphologies of the specimens were investigated by scanning electron microscopy. In addition, interfacial contact resistance tests were used to evaluate contact resistance of coated and uncoated specimens. Finally, corrosion resistances of the specimens were studied using galvanostatic and potentiostatic tests. The results showed that the use of electroplating method produces many holes and pores in the specimen surface. It was also found that using sputtering method significantly resulted in an increase in corrosion resistance and decrease in contact resistance of coated specimens.