Investigation polypyrrole coating conditions on mild steels and determination of corrosion of behaviour

11 INVESTIGATION OF POLYPYRROLE COATING CONDITIONS ON MILD STEELS AND DETERMINATION OF CORROSION BEHAVIOUR (Ph.D. Thesis) Abdurrahman ASAN GAZI UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY JANUARY 2002 ABSTRACT Polypyrrole coatings have been successfully electrodeposited on AISI 1117 and AISI 3315 steels in 0,1 M oxalate solutions by electrochemical methods. The effects of electrochemical process such as applied current density, initial monomer and electrolyte concentrations on the formation process of polypyrrole coatings were systematically investigated. The composition and morphology of the coatings were studied potentiodynamic polarization curves, FTIR, XPS and SEM. The corrosion performance of polypyrrole coated steels was evaluated by Tafel extrapolation method in 0.1 M H2SO4, 0, 1 M NaOH and 3 % NaCI solutions. Our results show that passivation of steels, electro polymerisation of pyrrole, the morphology and properties of the coatings were all dependent on the electrochemical process parameters. Electrochemically polymerised polypyrrole promises to be a good candidate for corrosion protection of reactive metals in basic, neutral and chloride containing medium. Polypyrrole coated steels exhibited better corrosion performance in 0.1 M NaOH than 0.1 M H2S04 and 3 % NaCI. Science Code Key Words Page Number Adviser 405.04.00 Electropolymerisation, Polypyrrole, Corrosion, Mild steel 130 Prof. Dr. Melike KABASAKALO?LU