Fabrication of a pH-Sensitive Epoxy Nanocomposite Coating Based on a Zn-BTC Metal–Organic Framework Containing Benzotriazole as a Smart Corrosion Inhibitor

Abstract

In this study, a pH-sensitive Epoxy/BTA@Zn-BTC smart anticorrosion nanocomposite coating was fabricated by the encapsulation of a benzotriazole (BTA) corrosion inhibitor in a Zn-BTC metal−organic framework (MOF). The corrosion process of the coating was investigated for different durations of storing the coating in a corrosive solution of 3.5 wt % NaCl using potentiodynamic polarization (Tafel) plots and electrochemical impedance spectroscopy. The synthesized BTA@Zn-BTC nanocapsules have a loading capacity of 16.5% for BTA. The BTA encapsulated in Zn-BTC MOF is released as the corrosion zone becomes acidic, and it serves as a corrosion inhibitor. The released BTA inhibitor proved to have an inhibition efficiency of 98.8% to protect aluminum against corrosion in the corrosive solution after 3 days. A possible mechanism has been presented for the formation of a protective film in this process. It is argued that in the active areas of corrosion on the metal surface the local pH decreases and the H + ions produced in the corrosion reaction rapidly penetrate into the BTA@Zn-BTC nanocapsules, releasing the BTA inhibitor. Then, the released inhibitor forms a dense barrier in the corrosion area to decrease the corrosion rate. As found in this study, the durability of this smart coating is significantly prolonged in a 3.5 wt % NaCl solution.

Improved Interfacial Interactions of Dip Coatings by In Situ Introducing Silica to Enhance Corrosion Resistance and Metal Bonding Strength

“…A notable feature of epoxy resins is their excellent adhesion properties. Nanoparticles can be firmly adhered to the interior of the epoxy resins by introducing nanotechnology into epoxy-based coatings, resulting in various types of resin matrix nanocoatings. − Ordinarily, nonuniform nanoparticles doped within resin matrix coatings have a high potential to cause poor corrosion resistance in the resultant coatings. On the other hand, the interfacial air retention after nanoparticle doping may allow the resultant coating to experience osmotic pressure when in corrosive medium, thereby resulting in a reduction in corrosion resistance.…”

“…However, the impedance modulus of pure epoxy coatings is 6 orders of magnitude higher. − In this case, researchers have concentrated their efforts on the development of epoxy-based coatings with nanoparticle doping to further improve the anticorrosion properties. To date, graphene, carbon nanotubes or nanofibers, polyaniline, MOF, and MXene have been doped into epoxy resins to enhance the corrosion resistance of the resultant coatings. The impedance modulus of coatings made using resin matrix nanocomposites barely exceeds 10 9 Ω·cm 2 , particularly when using a one-step dip coating method.…”

Improvement of Anti‐Corrosion Performance of a Cu‐Ni Bimetallic Organic Framework Smart Coating Using Amino‐Substitution Triazole

“…Metal organic frameworks (MOFs) are formed by coordination bonds of metal ions and some organic compounds [20] . These compounds have been used as nano‐carriers for bonding with some particles and their controlled release [7,19,21] . The unique characteristics of MOF carriers are due to their surface chemistry with the presence of additional vacant coordination sites and functional groups [22] .…”

“…Various factors such as cost, amount of inhibitor consumption and the nature of the corrosive media affect the choice of a corrosion inhibitor. Among the organic inhibitors, N‐heterocyclic compounds such as pyridine, tetrazole, triazole, pyrazole, pyridazine, pyrimidine, indole and quinolone have acceptable inhibitory performance to prevent the corrosion of steel species in corrosive media [6,7] . Azoles such as 3‐amino‐1H‐1,2,4‐triazole (3‐AT), 5‐(p‐tolyl)‐1,3,4‐triazole (5‐TTA), 2‐amino‐1,3,4‐ thiadiazole (2‐ATDA), and 2‐aminobenzimidazole(ABI) and 3‐amino‐5‐mercapto‐1,2,4‐triazole (3‐AMTA) are heterocyclic organic compounds with a five‐membered nitrogen‐containing ring.…”

Ultrastable Porous Covalent Organic Framework Assembled Carbon Nanotube as a Novel Nanocontainer for Anti-Corrosion Coatings: Experimental and Computational Studies

“…Recently, the employment of fillers and micro/nanocapsules has been one of the most favorable attitudes to provide active protection and good water/ions shielding properties. So far, double-layer hydroxides, halloysite nanotubes, silica, , graphene oxide (GO), carbon nanotubes (CNTs), and metal–organic frameworks (MOFs) have been employed as containers for hosting organic/inorganic inhibitors. However, their dispersion and chemical stability in organic coatings have always been a remaining moot point that should be addressed.…”