Electrochemical Investigations on Semi-conducting Properties of a Passive Film on Conducting Polypyrrole Coated Low Carbon Steel in a Simulated Concrete Pore Solution

• Autor(a) principal: Munot,H.
• Data de Publicação: 2019
• Outros Autores: Deshpandea,P., Deligeorgiev,T.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://scielo.pt/scielo.php?script=sci_arttext&pid=S0872-19042019000100003
• topic: corrosion; passive film; concrete pore solution; rebar; conducting polypyrrole

Conducting polypyrrole was synthesized by the chemical oxidative method, and characterized using FTIR spectroscopy. An epoxy based paint containing conducting polypyrrole was prepared and applied on a low carbon steel sample, using a film applicator. The uncoated and painted steel samples were kept immersed in the simulated concrete pore solution. The Mott-Schottky technique was used to study the passive film formation on an uncoated low carbon steel, and the conducting polypyrrole coated low carbon steel was immersed in a simulated pore solution. The peaks at 1447 cm-1 and 1149 cm-1 are the responsible peaks of protonated nitrogen atoms in polypyrrole. The peak at 1538 cm-1 refers to the C-C stretching vibration in the pyrrole ring, and the peak at 1042 cm-1 denotes the C-H stretching vibration in the pyrrole ring. The M-S slope indicates that the passive film on uncoated low carbon steel exhibited n-type semi-conductive behaviour, and that the polypyrrole coating exhibited p- n type behaviour. However, with the increasing chloride contents and immersion time, the polypyrrole coating exhibited only p type behaviour.