Enhanced corrosion protection of epoxy coating through g-C3N4/g-C3N5 homojunction nanomaterial: Mechanisms and molecular dynamic insights

YD Yao and FJ Tang and W Sun, CONSTRUCTION AND BUILDING MATERIALS, 481, 141682 (2025).

DOI: 10.1016/j.conbuildmat.2025.141682

Corrosion not only leads to the failure or collapse of steel structures but also incurs significant economic costs. The application of protective coatings represents an effective strategy for the prevention or mitigation of corrosion in steel structures. In this study, g-C3N4/g-C3N5 homojunction nanomaterials were synthesized through a high-temperature calcination process and characterized using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The g-C3N4/g-C3N5 homojunction nanomaterial was incorporated into epoxy resin to produce a g-C3N4/g-C3N5 homojunction- modified epoxy coating (N4N5/EP), which was subsequently applied to steel plates. The adhesion strength, elastic modulus, hardness, surface wettability, and water absorptivity were measured. The corrosion resistance of N4N5/EP-coated steel plates was evaluated using electrochemical impedance spectroscopy and salt spray test. Additionally, molecular dynamics (MD) simulations and first-principles calculations were employed to investigate the corrosion mechanism. The results indicate that the g-C3N4/g-C3N5 homojunction enhances the adhesion strength, elastic modulus, hardness, water hydrophobicity, and corrosion resistance of the epoxy coating. The MD simulations reveal a high degree of compatibility with the epoxy coating, while the density functional theory analysis of the g-C3N4/g-C3N5 homojunction demonstrates a significant binding energy with the epoxy matrix. This study provides valuable insights into the applications of carbon nitride-based homojunction materials for the corrosion protection of steel structures.

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