Inhibition of corrosion of pure iron by quaternized poly(4-vinylpyridine)-graft-bromodecane in sulphuric acid

Abstract

A brief review is given to study inhibitive action of Poly (4-vinylpyridine) - Graft - Bromodecane (P4VPBrD) at three degrees of quaternisation (25%, 45% and 60 %) on the corrosion behaviour of pure iron was investigated in desaerated molar sulphuric acid solution using weight loss measurements, potentiodynamic polarisation, and impedance spectroscopy (EIS) methods at free corrosion potential. A polarisation measurement shows also that the compound acts as a mixed-type inhibitor and was adsorbed on the iron surface according to the Langmuir adsorption isotherm model. The parameters, which characterise the corrosion behaviour, can be determined from plots and diagrams of Nyquist. There inhibition efficiency (E %) increases with the all inhibitors concentration. Trends in the increase of charge transfer resistance and decrease of capacitance values also shows the molecular adsorption on the metal surface. The temperature effect on the corrosion, behaviour iron metal in 1M H 2SO 4 without and with inhibitor at 510 -5M was studied at the temperature range from 298 to 338 K, the associated activation energy have been determined and proved that the adsorption is a spontaneous process. © 2012 by ESG.