Corrosion Studies on Electro Polished Stainless Steels for the Use as Metallic Bipolar Plates in PEMFC Applications

The corrosion resistance of stainless steels in their delivered state and after an electrochemical surface treatment was studied by potentiodynamic voltammetry and microscopic analysis. The used electrolyte contained fluoride and sulphate ions. The polishing procedure varied with respect to current densities, polishing time and proportion of the constituent parts of the electrolyte. Only 316L and 316Ti met the DOE target for corrosion in their untreated state. After the electrochemical treatment the corrosion current for Al6XN and Al265 decreased by more than 50% in comparison to the untreated specimen, thus meeting the DOE target.