Electrochemical response of zirconia-coated 316L stainless-steel in a simulated proton exchange membrane fuel cell environment

The corrosion resistance of zirconia-coated austenitic stainless-steel 316L was investigated in a simulated proton exchange membrane fuel cell (PEMFC) environment. The zirconia coating was performed using a sol-gel dip coating method and electrochemical tests were carried out at 80 °C in 1 M H₂SO₄ solution to accelerate corrosion. The results showed that the precursor containing zirconium alkoxide and zirconium acetate hydroxide changed into tetragonal zirconia, producing a surface film without cracks. Potentiodynamic tests showed that the corrosion resistance of the zirconia-coated 316L stainless-steel was improved by one order of magnitude compared to the bare specimen in terms of the current density. Potentiostatic experiments also showed enhanced corrosion prevention due to zirconia coating under the simulated PEMFC conditions. However, the high interfacial contact resistance (ICR) of the zirconia film suggested that the modification of the zirconia film should be performed to impart higher electrical conductivity for the successful application of zirconia-coated metallic bipolar plates.