Heat Treatment Of Stainless Steel As Bipolar Plates Of PEMFC

Bipolar plates for PEMFC are one of the critical components and can have a major impact not only on the performance of the stack but also on the cost and have been choke points of industrialization.The majority of PEMFC stack producers utilize bipolar plates based on graphite, carbon composites or metals.Each of these materials has characteristics that are beneficial for fuel cell applications, but are limited by others.An idea bipolar plate would incorporate the merits of these materials, such that it would be high in electrical conductiveity and corrosion protection, of low density but with high mechanical strength, impermeable to reactant gases, chemically inert, thermal conductiveity, and allow for ease of manufacture.In this study a method of heat treatment to embed Ag is put forward which can decreace bipolar plates' contact resistance and not lessen it's corrosion resistance.Inexpensive 304 stainless steel is chosen. After acid saturation Using heat-treatment to embed Ag is a method to enhance the property of the stainless steel's surface and then apply the method to the bipolar plates of PEMFC. Saturated silver nitrate ethanol liquor is used to adhere saturated silver on the surface of the stainless steel; Heat-treatment is carried through in tube furnace to embed Ag so a conduct meshwork is formed. At last a inactivation area is formed on the surface in the meshwork. In the experimentation different process conditions by which silver nitrate is spread on the surface of the stainless steel and the influence of the contact resistance , corrosion resistance , and the texture under different heat-treatment conditions are studied; The content of Ag in the surface of the stainless steel is measured also.The results of the experiment proved that the contact resistance between the stainless steel plate embedded Ag and electrode was the same as copper plating silver and was one thirteenth of which of the original 304# stainless steel. After passivate treatment, corrosion resistant plate gets bettercorrosion resistance. We make certain that the best heat treatment process conditions are as follows: heating up temperature-760°C; holding time-60 minutes; inactivation time-40 minutes.