Influence of a novel doping of Zn-CeO2 + MnO2 on the physical properties of a deposited coating

Abstract

Mild steel can be electroplated with Zinc to enhance the properties of its surface without changing the properties of the substrate. However, the properties of the coating can be improved by alloying the zinc with other metals. In this study, the influence of novel doping of ceria to a zinc-based bath that contains manganese oxide, on the physical properties of deposited coating was investigated. The mild steel was plated at a current density of 2A and pH of 4,3 using a DC rectifier. Ceria was added as a dopant to a zinc bath and the mild steel samples were plated with MnO2 variations of 5 and 10g/L under constant parameters. OPM was used for the characterization of the morphologies of the coatings. The microhardness characteristics of the obtained deposits were analyzed with the use of the Vickers indenter. The corrosion behavior was studied using linear potentiodynamic polarization method in 3.65% NaCl and 0.5M H2SO4 solution. According to the OPM obtained, the compactness and homogeneity of the coatings improved with the addition of ceria up to an optimum 5g/L concentration of MnO2. The results also show that ceria significantly improves the hardness of the coating. The addition of MnO2 has little effect on the hardness of the coating, and a concentration of MnO2 beyond the optimum level reduces the hardness properties. There was improved corrosion resistance of the coatings compared to mild steel and pure zinc coating with the increase in the admix concentration.