Electrochemical analysis and microstructure of value-added functional Zn-ZnO-rice husk ash composite coating of mild steel

Electro-deposition method was used to incorporate rice husk ash (RHA) into the Zn-ZnO- XRHA composite coatingfor mild steel pipeline exterior coating from a chloride-based bath. Zn-ZnO- XRHA composite coatings were obtained for x = 0 g, 10 g and 20 g at a constant bath temperature of 75 °C, constant stirring rate of 400 rpm, 1.4 A current and 15 min deposition span. Scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS), X-ray diffractometry (XRD) and atomic force microscopy (AFM) were used to study the coated surface. Coatings suitability on exposure to adverse environment was assessed in 3.5% NaCl in situ solution using CHI604E electrochemical analyzer. The result showed corrosion protection of the substrate owing to the decline in corrosion rate from 3.2571 mm/yr to 0.1254 mm/yr. The higher positive value of the E_corr of the coatings relative to the substrate inclines the developed coatings to the class of anodic inhibitors.