Electrochemical Properties of MgZnCa-Based Thin Film Metallic Glasses Fabricated by Magnetron Sputtering Deposition Coated on a Stainless Steel Substrate

Steels are majorly used for diverse structural applications; however, they suffer severe degradation in a corrosive environment which necessitates the need for a protective surface coating. In this paper, the electrochemical study of MgZnCa alloy thin film coating on an AISI 304 stainless steel was reported. The study intends to investigate the influence of coating thickness on the electrochemical performance of the ternary MgZnCa alloy thin film. The polarization results indicated that better corrosion resistance is achieved when the MgZnCa coating is applied on the steel substrate, as the corrosion current density of the 4 µm coating (0.28 mA/cm2) is lower than for the uncoated substrate (0.44 mA/cm2). As the MgZnCa coating thickness increases from 4 to 6 µm, a decrease in the corrosion density with a resultant increase in the corrosion potential was observed. The microstructural characterization revealed fewer corrosion attacks for the coated substrates as compared with the uncoated material with the presence of more degradation products. The corrosion resistance of the steel substrate is enhanced by the application of MgZnCa coating and increasing coating thickness is significantly beneficial.