Electrodeposition and Corrosion Behavior of Zinc-Nickel Films Obtained From Acid Solutions: Effects of TEOS as Additive

Zinc-nickel composite film has been electrodeposited on carbon steel surface via adding tetraethylorthosilicate (TEOS) in electrolating solution. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results showed that the phase and surface morphology of zinc-nickel films could be changed with varying the concentration of TEOS in electroplating bath. Polarization curves and electrochemical impedance spectroscopy (EIS) results indicated that the films obtained with the TEOS addition possessed better corrosion resistance. Open circuit potential (OCP) results indicated that the film obtained at 0.005 M of TEOS still showed cathodic protection ability to the substrate after immersion in 3.5 wt% sodium chloride solution for hundreds of hours. This can be attributed to the optimizational effect with suitable concentration of TEOS to be added in electrolating bath. The results indicated that TEOS may act as an additive to be used in surface coating technology.