Development of starch-modified titanium oxide paired with zinc powder using the electrodeposition technique as a composite superhydrophobic coating for mild steel

Equipment failure brought on by corrosion is one of the biggest issues the chemical and petrochemical industry are challenged with. Coating is a useful strategy to address this problem on mild steel, and the superhydrophobic coating produced by the electroplating process is particularly noteworthy. Zinc bars serve as the anode, mild steel substrates as the cathode, and a sulphate bath solution as the electrolyte in the electrodeposition coating procedure. With the aid of a DC rectifier, the coating is applied to each sample for 15 min at a voltage range of 1.4–1.5 V and an average current density of 0.2816–0.353 A/cm2. Using a magnetic stirrer and a temperature of 40 °C, the procedure is carried out. Investigating the electrochemical and microstructural characteristics of Zn-TiO2-starch coatings electrodeposited on mild steel substrates was the study’s main goal. Each coated sample served as the working electrode during the electrochemical corrosion investigation, while graphite served as the counter electrode and KCl solution as the reference electrode. 3.65% NaCl solution was the electrolytic solution that was employed. The unaltered Zn-TiO2 (control sample) was found to corrode at a rate of 0.00067197 mm/year. The corrosion rates of Zn-TiO2-starch coatings, on the other hand, ranged from 0.00041902 to 0.0002418 mm/year depending on the degree of starch modification. These findings suggest that the highly modified starch coatings provide increased corrosion resistance. The XRD pattern displayed sharp peaks corresponding to Al(ZnSO4) and Fe(Mn,Ti) crystallites on the TiO2 samples, with high diffracting intensity exceeding 2000 c.p.a., suggesting the presence of the most stable phase in those coatings. Microstructural imaging through SEM/EDS revealed a higher dispersion of starch granules in the sample with 4.5 g starch concentration than in the sample with 1.5 g starch concentration.