Epoxy nanocomposite coating based on calcium zinc phosphate with dual active/barrier corrosion mitigation properties

In this paper, a high-performance epoxy nanocomposite with dual active/barrier protection ability based on calcium zinc phosphate (CZP) nanopigment was fabricated. Then chemistry, morphology, and anti-corrosion ability of the commercial zinc phosphate (ZP) and CZP pigments were studied. By electrochemical techniques, the inhibition potency of the CZP nanopigment was examined in a NaCl solution on mild steel (MS) substance and compared with that of ZP. Results revealed a higher corrosion inhibition degree of the CZP compared to the ZP. The growth of a protective layer on the metal coupons exposed to the CZP extract was illustrated by X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared (FT-IR) spectroscopy. The reinforcement effects of CZP and ZP pigments on the epoxy composites' corrosion resistance were proved by electrochemical impedance spectroscopy (EIS) and salt spray test results. The better protection properties of the CZP loaded coating (23,600 M Omega cm(2)) compared with the unfilled coating (0.014 M Omega cm(2)) and the one loaded with ZP (0.26 M Omega cm(2)) were understood from the EIS test results.