Arginine-derived inhibitor-based anticorrosion coating for carbon steel in 3-nitro-1,2,4-triazol-5-one (NTO) medium: Integration of experimental and multiscale simulations

As a representative insensitive high explosive, 3-nitro-1,2,4-triazol-5-one (NTO) has garnered significant attention due to its ability to substantially reduce the risk of accidental detonation in munitions. However, its inherent acidity induces severe interfacial corrosion of metal casings, thereby limiting its engineering applications. Based on the micro-corrosion mechanism of NTO on carbon steel (CS), this study designs an arginine-derived corrosion inhibitor, N2-[(phenylamino)thioxomethyl]-arginine (PTA). Electrochemical tests reveal that PTA exhibits an outstanding corrosion inhibition efficiency of 98.0% in NTO solution. Density functional theory (DFT) and molecular dynamics (MD) simulations elucidate the inhibition mechanism of PTA, demonstrating that it not only co-adsorbs with NTO⁻ onto the CS surface to form a dense and stable protective film but also disrupts the strong interactions between NTO⁻ and Fe, thereby suppressing nitro group-induced reduction, decomposition, and excessive surface oxidation. Furthermore, a PTA-loaded mesoporous silica (mSiO₂) nanoparticles (NPs)-reinforced epoxy resin (EP) composite coating was constructed. Benefiting from the enhanced barrier properties of PTA@mSiO₂ NPs and the synergistic effect between PTA and NTO⁻, the low-frequency impedance of the composite coating remained as high as 1.29 × 10⁹ Ω·cm² after 30 days of immersion in NTO solution, exhibiting a two-order-of-magnitude improvement compared to the pure EP coating. This study proposes an effective corrosion control strategy to mitigate NTO-induced corrosion, providing insights into the development of advanced corrosion protection strategies for broader applications.