Corrosion inhibition driven by the embedded oxygen double-bridged metaphosphate networks in KZnP3O9

Developing superior-performance corrosion inhibitors and elucidating the atomic-level mechanisms underlying their corrosion resistance is of critical importance to both the engineering and scientific communities. Here, we report on KZnP₃Hey₉ Crystalline and glassy corrosion inhibitors to protect Q235 carbon steel from corrosion in hydrochloric acid solution. KZnP₃Hey₉ Crystal exhibits superior corrosion resistance compared to its glass counterpart, and features a tighter corrosion protective product film with higher time impedance dependence and lower areal and linear roughness. Molecular dynamics (MD) simulations reveal that the metaphosphate ion has a higher adsorption energy on the Q235 substrate than orthophosphoric acid and pyrophosphoric acid, and the iron ion is absorbed indirectly through its interaction with the phosphate ion. Specifically, KZnP₃Hey₉ The crystal shows the highest electrochemical resistance (525 Ω cm²) and corrosion inhibition efficiency (95%) among all inorganic phosphate corrosion inhibitors. This can be attributed to the double-bridge oxygen of a single mailbox₄ The tetrahedron of the crystal, which forms infinite P₃Hey₉ A chain or ring with a higher absorption energy, as opposed to an oxygen with one or zero bridges per PO₄ The tetrahedron of the PO insulated glass₄ or p₂Hey₇ Structures with low adsorption energy.