Polypyrrole electrodeposited on copper from an aqueous phosphate solution: Corrosion protection properties

Abstract

Highly adherent and homogenous polypyrrole films were electrodeposited at copper from a dihydrogen phosphate solution. The polypyrrole films were electrosynthesized in the overoxidized state by cycling the copper electrode from -0.4 to 1.8 V (SCE) in a pyrrole-containing phosphate solution. The growth of the polypyrrole films was facilitated by the initial oxidation of the copper electrode in the phosphate solution to generate a mixed copper-phosphate, copper oxide or hydroxide layer. This layer was sufficiently protective to inhibit further dissolution of the copper electrode and sufficiently conductive to enable the electropolymerization of pyrrole at the interface, and the generation of an adherent polypyrrole film.Potentiodynamic polarization measurements, Tafel analyses and open-circuit potential data revealed that the polypyrrole coating effectively protects the copper substrate from corrosion in a chloride solution. However, the corrosion protection properties were reduced with longer immersion times.

Corrosion protection of copper using polypyrrole electrosynthesised from a salicylate solution

“…In this case, the R2 represents the resistance of the deposited corrosion film. Parameters extrapolated for the bare metal are in agreement with already published literature [25,45]. Both resistance values are significantly higher for the ppy-sal coated copper than for the bare copper, highlighting the corrosion protection offered by the polymer.…”

“…The calculated corrosion currents were used to estimate the corrosion inhibition efficiency, g of the ppy-sal, according to Eq. 2 [25]:…”

“…Other anions suitable for the electrodeposition of polypyrrole on copper include citrate, acetate and benzoate [24], phosphate [25], saccharinate [14] and salicylate [26].…”

Polypyrrole Composites: Electrochemical Synthesis, Characterizations and Applications

“…Electrochemically deposited PPy films on Cu displayed good protection against Cu corrosion in a 3.5% NaCl solution (Herrasti et al, 2007). The effectiveness of the protection is enhanced when the PPy film is electrosynthesized from a solution of dihydrogen phosphate (Redondo & Breslin, 2007) or sodium saccharinate (Bazzaoui et al, 2007). PPy films electrodeposited onto Ni-Ti alloy employing sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol OT or AOT) solutions improved the corrosion performance of the alloy at the open circuit potential and at potentials where the bare substrate suffers pitting attack (Flamini & Saidman 2010).…”

Two‐step electrosynthesis of polypyrrole for corrosion protection of stainless steel

“…Since the corrosion inhibition effects of polyaniline for stainless steel (SS) were discovered by DeBerry in 1985 [1], the mechanism of corrosion protection by conducting polymers has attracted considerable interests [2][3][4][5][6][7][8][9][10]. It is generally accepted that the coating of a metal with conducting polymer will produce some sort of barrier effect [10,11].…”