Evaluation of self-healing ability in protective coatings modified with combinations of layered double hydroxides and cerium molibdate nanocontainers filled with corrosion inhibitors

Self-healing coatings in anti-corrosion applications

“…EIS can be used to estimate coating degradation and corrosion kinetics even when the time of coating exposure in a corrosive medium is not long. This technique is usually aided by SVET [45,50,62,96,121] or localized impedance spectroscopy (LEIS) [122]. In some cases, however, the properties of self-repairing coatings are assessed solely on the basis of the results obtained by EIS [55,102].…”

“…The performance of a self-healing coating in corrosive media can be investigated using various techniques, such as electrochemical impedance spectroscopy (EIS), the scanning vibrating electrode technique (SVET) and the scanning ion-selective electrode technique (SIET) [45,50,53,57,58,62,63,96]. EIS can be used to estimate coating degradation and corrosion kinetics even when the time of coating exposure in a corrosive medium is not long.…”

“…Figure 6 schematically shows how a capsule is created using the particular methods [29]. As the building material, the following are used: poly(urea-formaldehyde) (PUF) [32][33][34][35], melamine-urea-formaldehyde (MUF) [35,36], phenol-formaldehyde [37], epoxy resin [38,39], methylene diphenyl diisocyanate (MDI) [40], poly(methyl methacrylate) (PMMA) [41,42], polystyrene [32,41], poly(allylamine) [43], polyvinyl alcohol (PVA) [43,44], polyurethane [40], polyphenol, amphiphilic block copolymers (polypyrrolidones, poly(ethylene oxide) [31], poly(caprolactone)) [31,32], cerium molybdate [45], zinc and aluminium nitrate [46,47], silica [27,32,[48][49][50], silver [42], gold [51], copper(II) sulphide [51], c-AlO(OH) [51], tin(IV) oxide [51] and titania oxides [42,52,53] and CaCO 3 microbeads [54]. The capsule material and the way of preparing capsules affect their shape and size.…”

“…The scanning ion-electrode technique is used to map local changes in pH on the coating surface. The combined use of the electrochemical techniques mentioned above gives a holistic picture of the self-healing ability [45]. X-ray photoelectron spectroscopy (XPS) and electron-probe microanalysis (EPMA) are used to study the self-repairing mechanism [108].…”

“…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.…”