TY  - JOUR
AB  - The behaviour of iron electrodes immersed in pH 8.9‐11.0 Na2HPO4 solutions was studied by potentiodynamic measurements (cyclic voltammetry) and scanning electron microscopy (SEM). The influence of proton and phosphate content, scan rate, anodic switching potential and other devised potential/time perturbation regimes were evaluated in order to obtain an understanding of the reactions involved during the passivation process. The oxidation‐reduction peaks were analysed using a thermodynamic approach. It was possible to reveal the most important reactions coming about on the electrode surface, which comprise, initially, the formation of Fe3(PO4)2 and Fe(OH)2 at ca. −0.8 V/SCE. Subsequently, these ferrous species are further oxidized to γ‐FeOOH at ca. −0.36 V/SCE, the latter being transformed into Fe2O3 in the passive region. Depending on the pH value (11.0) and scan rate (slow), Fe3O4 is clearly present as an intermediate oxide structure between the ferrous and ferric species mentioned earlier. In addition, scan rate was discovered to play a remarkable influence on the surface morphology observed during the SEM examinations.
VL  - 51
IS  - 3
SN  - 0003-5599
DO  - 10.1108/00035590410533138
UR  - https://doi.org/10.1108/00035590410533138
AU  - Giacomelli Cristiano
AU  - Spinelli Almir
PY  - 2004
Y1  - 2004/01/01
TI  - A potentiodynamic and SEM study of the behaviour of iron in pH 8.9‐11.0 phosphate solutions
T2  - Anti-Corrosion Methods and Materials
PB  - Emerald Group Publishing Limited
SP  - 189
EP  - 199
Y2  - 2024/04/23
ER  -