Creating corrosion inhibitors with ultrahigh efficiency and elucidating the atomic-scale mechanisms underlying their corrosion resistance are important to each engineering and scientific communities. Herein, we report KZnP3O9 crystal and glass corrosion inhibitors for the corrosion safety of carbon metal Q235 in HCl resolution. The KZnP3O9 crystal demonstrates superior corrosion resistance over its glass counterpart, featured by a extra compact protecting corrosion product movie with greater time dependence of impedance and decrease areal and linear roughness. Molecular dynamics (MD) simulations reveal that the metaphosphate ion has a better adsorption vitality on the Q235 substrate than orthophosphoric acid and pyrophosphoric acid, and the Fe ion is not directly adsorbed by its interplay with the phosphate ion. Particularly, the KZnP3O9 crystal demonstrates the very best electrochemical impedance (525 Ω·cm2) and corrosion inhibition effectivity (95%) amongst all inorganic phosphate corrosion inhibitors. This may be attributed to the double-bridging oxygen of a single PO4 tetrahedron for the crystal, which kinds an infinite P3O9 chain or ring with a better adsorption vitality, versus the zero- or single-bridging oxygen of every PO4 tetrahedron for the glass, which has remoted PO4 or P2O7 buildings with decrease adsorption vitality.
