The Effect of Electrodeposited PANI on Corrosion Behavior of 316 Stainless Steel Coated by CVD Grown MWCNTs under PEMFC Bipolar Plate Working Condition

Polyaniline (PANI) electrodeposition on bare and carbon nanotube (CNT) coated 316 SS was carried out using a cyclic voltammetry electropolymerization method in diluted H2SO4 media containing aniline monomer. CNTs were grown in a thermal CVD on 316 SS either by direct growth using ethylene precursor or by continuous feeding of an external catalyst, ferrocene, dissolved in toluene as the carbon precursor. Corrosion behavior of the coated materials was assessed by potentiodynamic and potentiostatic methods in an attempt to simulate the working condition of proton exchange membrane fuel cell (PEMFCs) bipolar plates. While a thick PANI coating could not provide a protective barrier to either bare or CNT coated 316 SS samples, a thin PANI layer showed interesting potential to improve the corrosion resistance. However, the deterioration caused by the initial carbon treatment of CNT coated 316 SS, was beyond the protective capacity of PANI to fulfill the anti-corrosive requirements of bipolar plates of PEMFCs.