Anticorrosion efficiency of organic coatings depending on the pigment volume concentration of polyaniline phosphate

Polyaniline (PANI) was synthesized by reaction in an aqueous solution of ammonium peroxodisulfate and phosphoric acid. PANI was characterized by means of scanning electron microscopy and its physical-chemical properties were determined. Simultaneously with the synthesized PANI epoxy-ester coatings containing 3, 5, 10, 15, 20 and 24 vol.% of PANI as a corrosion inhibitor were formulated. The coatings were tested for their mechanical properties, film hardness and corrosion resistance. The testing of the anticorrosion efficiency of PANI as corrosion inhibitor was based on accelerated corrosion tests: in condensed water, NaCl mist, and condensing water and SO2. The prepared PANI displayed inhibition effects in corrosion reactions progressing on a steel base under the organic coating. The synthesized PANI provides good anticorrosion efficiency in an epoxy-ester coating. The studied system does not contain any heavy metals harmful to the environment. (C) 2008 Elsevier B.V. All rights reserved.