Synthesis of Ni-W/SiO2 nanocomposite coatings and investigation of their corrosion behavior in 3.5 % NaCl solution

In this survey, the Ni-W/SiO2 nanocomposite coatings were synthesized via electrodeposion method and in the solution with the different concentrations of SiO2 nanoparticles by the average current density of 20mA/cm2. Then, field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive Spectroscopy (EDS) were used to analyze the morphology and chemical composition of the coatings. In order to evaluate the corrosion behavior of the coatings, the open circuit potential (OCP), electrochemical Impedance (EIS) and potentiodynamic polarization (Tafel) tests were applied in 3.5% NaCl solution. The corrosion results demonstrated that the corrosion resistances of Ni-W/SiO2 nanocomposite coatings were higher compared to pure Ni-W coating so that the highest value of charge transfer resistance was obtained for Ni-W/SiO2 coating electrodeposited from solution with concentration of 6 g/L SiO2 nanoparticles. The co-deposition of maximum amount of reinforced particles in the matrix and the microstructure without any micro tracks and surface defects are the main reasons for the improvement of electrochemical behavior of this coating.