Significance of formed adherent complex by use of phosphorylated polyphenol coating

Abstract

Purpose The purpose of this paper is to report on the use of phosphorylated polyphenol (PP)-coated galvanised iron (GI) surface to study the degradation of coating with different time intervals and long-term exposure in different salty media. Design/methodology/approach The as-obtained PP complex on GI was evident by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The coated coupons were exposed to different salty media such as 3.5 per cent NaCl, 1.5 per cent Na2SO4 and tap water at set time intervals. Electrochemical polarisation was performed to study the anodic and cathodic polarisation behaviour at each time interval. Findings The adherent foliolate nanopattern of iron zinc phosphate and zinc dihydrogen phosphate on GI surface was evident by SEM, FT-IR, EDS and XRD. The coated coupons exhibited good corrosion resistance. This coating performs as an alternative to time-consuming multistep operations of phosphating treatment. Originality/value The mode of the experiment treatment using modified PP coating especially on GI in different corrosive exposures at set time intervals is a novel approach in this research.