Engineering a zinc-rich ethyl silicate coating based on nickel oxide nanoparticles for improving anticorrosion performance

Abstract

In this research, nickel oxide (NiO) nanoparticles with different concentrations of 1, 2, 3, and 4 wt% were added to a zinc-rich ethyl silicate (ZRES) coating containing 90 wt% zinc dust particles to promote the cathodic and barrier performance of coating systems. FTIR, XRD, and EDX analysis indicated the chemical composition and created bonds in ZRES coatings. SEM, AFM and TEM images showed the surface roughness and particle size in ZRES structure. Also, TEM confirmed the uniform dispersion of NiO nanoparticles in the coating matrix loaded with 3 wt% NiO particles. The effect of NiO content and the anticorrosion behavior of nanocomposite coatings were investigated by different techniques, including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) and salt spray tests. Results revealed that ZRES coatings containing 3 wt% NiO nanoparticles had boosted sacrificial anode and barrier protection during 120 days of immersion in a 3.5 wt% NaCl solution. The addition of 3 wt% NiO into the coating system significantly reduced corrosion products and blisters while increasing corrosion resistances from 3069 Ω cm2 to 16482 Ω cm2 compared with the control ZRES sample. This high-performance anticorrosion behavior of the nanocomposite coatings is mostly due to the NiO nanoparticles, which have the capability to moderate the zinc dissolution rate in addition to improving the barrier by filling porosity and creating tortuous paths.