Reproducibility of corrosion parameters for the acidic dissolution of pure iron: potentiostatic polarisation

Polarisation curves were determined potentiostatically for pure polycrystalline iron corroding in oxygen-free 0.5 M H2SO4. Four different working electrode pre-treatments (abrasion/polishing, pre-polarisation and time to establish Ecorr) were employed and the reproducibility of Ecorr and calculated corrosion parameters (icorr, Tafel slopes and i0) for each treatment was determined. Electrode pre-treatment effects changes in working electrode catalytic activity with subsequent variation in the reproducibility of polarisation curves and measured and calculated corrosion parameters. A method incorporating abrasion/polishing followed by anodic/cathodic pre-polarisation resulted in general in improved parameter reproducibility and cathodic and anodic Tafel slopes close to those predicted by the reaction mechanisms.