Microstructural Characterization, Mechanical Performance, and Anti-Corrosive Response of Zinc Multifaceted Coating on Mild Steel

Zinc has attracted significant attention in research due to its cost-effective use as an electrodeposited material, effectively protecting various types of steel from corrosion and wear. However, despite its advantages, zinc has limitations in fully guarding steel against corrosion. Recent studies propose that blending zinc with other metals during the coating process can proficiently shield mild steel from deterioration. The motivation for this study stems from recognizing the restrictions of zinc electrodeposition and the limited exploration of zinc multi-facet composite coatings for mild steel. In this study, the electrodeposition technique was employed to apply a coating to mild steel using zinc and nanoparticles of calcium oxide (CaO) and manganese oxide (MnO2). The coating bath's chemical composition included mass variations of 0-12 g/L for CaO and MnO2, along with 10 g/L each of boric acid, thiourea, and Na2SO4, and 15 g/L of K2SO4 and ZnSO4. The coating process occurred over a twenty-minute period, with a pH of 4.8, voltage set at 3.2V, current density at 1 A/cm2, temperature at 47°C, and stirring rate at 200 rpm. Results obtained from the coated mild steel demonstrated that Zn-6CaO-6MnO2 exhibited the greatest coating thickness at 0.2308 mm, and it showcased impressive corrosion resistance at 2.0618 mm/year. The Zn-CaO-MnO2 coating displayed a substantial deposit of crystallites in its microstructure, assisted by the presence of manganese, contributing to a smoother surface texture.