Double-Ligand Strategy to Construct an Inhibitor-Loaded Zn-MOF and Its Corrosion Protection Ability for Aluminum Alloy 2A12.

A promising double-ligand strategy for the delivery of active corrosion inhibitors by a Zn(II)-based metal-organic framework (Zn-MOF) is developed. Zn-MOF compounds were synthesized by a facile one-pot solvothermal method and characterized. The Zn-MOF is based on the corrosion inhibitor benzotriazole (BTA) and 2,5-furandicarboxylic acid (HFDA) ligand, which is a promising renewable building block alternative to terephthalic or isophthalic acid. The crystal structure and morphology are characterized by single-crystal X-ray diffraction analysis, powder X-ray diffraction analysis (PXRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The synthesized MOF crystallites are in the trigonal space group 3 with the cell parameters in a three-dimensional (3D) anionic framework. Their ability to inhibit the corrosion process of aluminum alloy 2A12 in NaCl solution was also evaluated by immersion tests in solutions with and without a MOF. The postcorrosion analysis was performed by SEM and X-ray photoelectron spectroscopy (XPS). Additional information about the inhibition efficiency was obtained by electrochemical impedance spectroscopy (EIS). The results suggest that the as-synthesized MOF can release the inhibitors and form protective layers effectively on the surface of the aluminum alloy. The use of inhibitor-loaded MOF nanocontainers provides promising opportunities for the smart delivery of inhibitors and effective corrosion protection of 2A12 aluminum alloys.