Electropolymerization and possible corrosion protection effect of polypyrrole coatings on AA1050 (UNS A91050) in NaCl solutions

• Effect of solution chemistry on the electropolymerization and the electrochemical properties of polypyrrole coatings on aluminum is studied by means of electrochemical techniques, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy. It is shown that the protection effect of the coating in long-term exposures and when exposed to more concentrated NaCl solutions depends on the chemistry of electropolymerization electrolyte. The results show that nitrate anions passivate the aluminum substrate during the electropolymerization process. The resulting coating is less prone to blistering in a NaCl solution and probably due to its higher electrochemical activity presents a higher anodic protection effect. The galvanic interaction of polypyrrole coating with aluminum in a NaCl solution is directly observed using focused ion beam-assisted SEM.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

Aluminum

Conductive polymer

Corrosion protection

Galvanic interaction

Passivation

Polypyrrole

Aluminum coatings

Aluminum corrosion

Anodic protection

Electrolytes

Electropolymerization

Galvanic corrosion

Ion beams

Polypyrroles

Scanning electron microscopy

Sodium chloride

X ray photoelectron spectroscopy

Aluminum substrate

Electrochemical activities

Electrochemical techniques

Long term exposure

Polypyrrole coatings

Solution chemistry

Corrosion resistant coatings

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