Characterization of PbO2 coating electrodeposited onto stainless steel 316L substrate for using as PEMFC's bipolar plates

Lead dioxide coatings were electrodeposited onto stainless steel 316L substrates in a fluoride containing plumbite solution with the aim of serving as bipolar plates in PEMFCs. According to XRD results, coatings are composed of non-stoichiometric alpha-Pk(0.828)O(2) with less than 100 nm crystallite size. SEM micrographs revealed that the presence of fluoride ions in electrodeposition solution does not alter the morphology of coatings. Electrical resistivity measurements suggest that fluorine substitutes oxygen in oxide lattice, thereby enhancing electrical conductivity as donor agents. Potentiodynamic polarization results in PEMFC simulated solution prove that the corrosion current density of lead dioxide coated specimens has decreased, at least by three-fold. There is also some evidence that coatings are susceptible to localized corrosion and PbO2/PbSO4 reaction may play an important role in this regard. (C) 2013 Elsevier B.V. All rights reserved.