Effect of carbon-based filler dimensions on the anti-corrosion performance for epoxy composite coating

Inorganic nanoparticle modified epoxy resins (EP) has been widely studied to enhance anti-corrosion performance. However, the effect of nanofillers dimensions plays an important role, which has not been systematically explored. Herein, the dimensional effect of nanofillers was systematically investigated by selecting homologous carbon-based materials, i.e., carbon black (CB), carbon nanotubes (CNT) and graphene (G) as zero-dimensional (0D), one-dimensional (1D) and two-dimensional (2D) material. The dimension of nanofillers was confirmed by transmission electron microscopy. Electrochemical impedance spectroscopy and salt spray testing revealed the differences in corrosion protection of composite coating. The morphology and types of corrosion products were investigated in depth. After soaking for 28 days, the charge transfer resistance ( R ct ) of EP decreased from 2.17 × 10 10  Ω⋅cm 2 to 3.45 × 10 7  Ω⋅cm 2 . However, the R ct of EP doped G coating only decreased by one order of magnitude and remained at 1.94 × 10 11  Ω⋅cm 2 , exhibited superior anti-corrosion performance. This research provided unique insights into the development of new anti-corrosion nanofillers.