Influence of Embedded Nanocontainers on the Efficiency of Active Anticorrosive Coatings for Aluminum Alloys Part I: Influence of Nanocontainer Concentration

Abstract

This work presents an effective anticorrosive coating for the industrially important aluminum alloy, AA2024-T3. The protective coating was designed by dispersing mesoporous silica nanocontainers, loaded with the nontoxic corrosion inhibitor, 2-mercaptobenzothiazole, in a hybrid sol-gel (SiOx/ZrOx) layer. The concentration of the embedded nanocontainers was varied (0.04-1.7 wt %) to ascertain the optimum conditions for anticorrosion performance. Attaining high efficiency was found to be a compromise between delivering sufficient corrosion inhibitor and preserving the coating barrier properties. The impact of nanocontainer concentration on the thickness and adhesion of freshly cured coatings was also investigated. The barrier properties of the intact coatings were assessed by electrochemical impedance spectroscopy. The active corrosion inhibition was evaluated during a simulated corrosion process by the scanning vibrating electrode technique. This study has led to a better understanding of the factors influencing the anticorrosion performance and properties of active anticorrosive coatings with embedded nanocontainers.

Polyelectrolyte-modified layered double hydroxide nanocontainers as vehicles for combined inhibitors

“…LDH-NO 3 was added to the inhibitor containing solution and le under stirring for 24 hours. Aer centrifugation and washing steps (2 times), the procedure was repeated with a second portion of MBT solution to guarantee a complete exchange of NO 3 À with MBT À . In the end, the reaction products were isolated by centrifugation and washed 2-4 times with boiled distilled water to ensure that all MBT in excess was removed.…”

Self-healing coatings in anti-corrosion applications

“…Halloysite nanotubes and boehmite nanoparticles are employed as reservoirs for corrosion-inhibiting compounds [57][58][59]. Cerium cations [58,[60][61][62], 8-hydroxyquinoline [48,57], benzotriazole [45,48,49,63,64], mercaptobenzimidazole (MBI) [63], dicyclopentadiene (DCPD), alkoxysilanes [65], silyl ester [24], linseed oil [37,44,66], hexamethylene diisocyanate (HDI) [40], triethanolamine (TEA) [41], monomers and catalysts for ROMP [67], magnesium ions [68], chromium(III) and cerium(IV) oxides [34] and cerium(III) chloride [60,69] are used as corrosion inhibitors. The action mechanisms connected with the particular compounds are presented in Table 1.…”

Micro/nanocapsules for anticorrosion coatings

“…This inhibitor can be incorporated in layered double hydroxides (LDHs), anion-exchange polystyrene containers, cerium molybdate nanospheres (CeMo), halloysite nanotubes, silica nanocontainers (SiNC), and silica nanocapsules with mesoporous shells (SiNC) as well as in polyurea microcapsules (Borisova et al, 2012;Kartsonakis et al, 2011;Maia et al, 2016;Maia et al, 2012;Montemora et al, 2012;Shchukin et al, 2008;Tedim et al, 2010). The polystyrene, CeMo and silica containers are usually loaded with MBT using the saturated solution of this inhibitor (in acetone or ethanol), placed into a sealed container under vacuum conditions; while encapsulation of MBT in polyurea microcapsules happens via micro-emulsion oil-in-water in a single step polymerization process.…”

“…The extensively investigated inhibitors for corrosion protection of aluminum alloys in different encapsulated forms are triazole (Yang and Van Ooij, 2004) and thiazole derivatives, mainly benzotriazole (BTA) (Fix et al, 2009;Shchukin et al, 2006) and mercapto-benzothiazole (MBT) (Borisova et al, 2012;Maia et al, 2016;Maia et al, 2012). Other possibility for protection of aluminum alloy is the 8-hydroxyquinoline Haase et al, 2012;Kartsonakis and Kordas, 2010;Snihirova et al, 2014) and cerium ions Zheludkevich et al, 2005) encapsulated in different nanocontainers.…”