A study on cobalt electrodeposition onto a carbon steel electrode

The electrodeposition of cobalt on to a carbon steel working electrode was studied through the comparison between theoretical and experimental polarisation curves. The former was obtained using the Butler–Volmer equation with electrochemical parameters, such as Tafel slope values, exchange current densities, cathodic limit current densities and equilibrium potential values. The following results were obtained: the anodic region refers to the iron oxidation with a Tafel slope of about 0·055 V decade−1, which is near the theoretical value (0·059 V decade−1); the experimental cathodic region represents the cobalt and hydrogen ion reduction; the limiting current density (−1 × 10−3 to −1 × 10−2 A cm−2) obtained was near the calculated value, −3·7 × 10−3 A cm−2.