Electrodeposition of polypyrrole on iron from aqueous solutions of pyr
role and oxalic acid yields strongly adherent, smooth polymer layers.
The electrochemical process proceeds at a constant current density of
2mA cm(-2). The potential-time curve is characterized by a short induc
tion period, where active iron dissolution occurs. The perfect perform
ance of the polymer coating is attributed to the formation of an iron(
II) oxalate interlayer. The influence of current density, pyrrole conc
entration and KNO3 addition on the electrodeposition process and the e
lectrochemical and physical properties of the layers are studied in de
tail.