Sol-gel preparation of Zn-Fe nanocomposite coatings on copper and optimization of process factors on their corrosion protection properties

چکیده مقاله

Abstract: Corrosion protection of metals is one of the main contest in the world; additionally, the need for replacement of hazardous compounds as inhibitor is very important [1]. Thus, we report the development of Zn-Fe nanocomposite coatings by the sol-gel method on copper substrates to improve their corrosion resistance [2,3]. Different calcination temperatures (200, 300, 400 C) and heating times (1, 2, 3 hours) were used in the synthesis stages of the nanocomposite coatings. The corrosion behaviour of the coatings was investigated through potentiostatic polarization and electrochemical impedance spectroscopy (EIS) experiments. Electrochemical results indicated that the nanocomposite coating synthesized at 300 C with the heating time of 2 hours is very efficient in the corrosion protection of copper. The corrosion current density of the coated copper electrode significantly decreases and the corrosion potential shifted to positive values when compared to uncoated copper electrode. The physical characterization and chemical morphology of the sol– gel coatings carried out by scanning electron microscopy (SEM) and X-ray diffraction (XRD) and energy dispersive X-ray detector (EDS) pointed out that the use of optimum calcination temperatures yielded homogeneous and non-cracked surfaces of Zn-Fe nanocomposite coating with improved anticorrosive efficiency. By contrast, the use of another heating temperature results incracked surfaces of Zn- Fe nanocomposite coating with poor anticorrosion efficiency and also probably provokes the diffusion of components from the alloy to the coating–substrate interface [4]