Smart Coatings For Corrosion Protection Research Articles

Nonconductive layered hexagonal boron nitride preparation via a co-exfoliation strategy and nanohybrid coating construction for corrosion protection

Hexagonal boron nitride (h-BN), an analogue of graphene with similar layered structure, is considered as the promising material in place of graphene for application as nanofiller into polymeric matrices to develop the smart coatings for corrosion protection of metallic substrates, owing to its mechanical robustness and thermal stability together with unique electrically insulating nature. In this work, on the basis of a co-exfoliation strategy, h-BN were exfoliated by riboflavin sodium phosphate (FMN) intercalator, assisted with ball-milling to obtain few-layered nanosheets with improved water-dispersibility as well as improve their compatibility with waterborne epoxy matrix. The results from electrochemical measurement and corrosion product analysis indicate that the incorporation of only 1.0 wt% FMN-exfoliated h-BN (h-BN@FMN nanohybrids) content into waterborne epoxy matrix can realize the optimized long-term corrosion resistance of composite coatings in 3.5 wt% NaCl solution. The two-dimensional morphology and impenetrability of h-BN, together with the compatibility of waterborne epoxy system from the bridge role of FMN molecules to act as a physical barrier against corrosive species (i.e., H2O, Cl− and O2), are the main reasons behind the prominent anticorrosion performance of our composite coating.

Wet-jet milling exfoliated hexagonal boron nitride as industrial anticorrosive pigment for polymeric coatings

The incorporation of inorganic nanofillers into polymeric matrices represents an effective strategy for the development of smart coatings for corrosion protection of metallic substrates. In this work, wet-jet milling exfoliation was used to massively produce few-layer hexagonal boron nitride (h-BN) flakes as a corrosion-protection pigment in polyisobutylene (PIB)-based composite coatings for marine applications. This approach represents an innovative advance in the application of two-dimensional (2D) material-based composites as corrosion protection systems at the industrial scale. Although rarely used as an organic coating, PIB was selected as a ground-breaking polymeric matrix for our h-BN-based composite coating thanks to its excellent barrier properties. The optimization of the coating indicates that 5 wt.% is the most effective h-BN content, yielding a corrosion rate of the protected structural steel as low as 7.4 × 10−6 mm yr−1. The 2D morphology and hydrophobicity of the h-BN flakes, together with the capability of PIB to act as a physical barrier against corrosive species, are the main reasons behind the excellent anticorrosion performance of our composite coating.

Active anticorrosion and self-healing coatings: A review with focus on multi-action smart coating strategies

• Recent trends in active anticorrosion protective coatings are summarized. • Self-healing coatings as defect closing routes for metal protection are reviewed. • Functionalities and multi-action mechanisms in multifunctional coatings are discussed. The development of smart coatings with potential for active anticorrosion and self-healing protection of metals is essential for long-term performance of metallic structures in aggressive chemical environments. Presently, emphasis has been placed on the development of advanced smart coatings for corrosion protection in different applications. Innovative multifunctional coatings with fascinating stimuli-responsive functionalities are considered “smart”. The stimuli-responsive functionalities of these smart coatings when properly harnessed result in a class of coatings with inherent autonomous control of corrosion. Fundamentally, when metals are exposed to aggressive environments, occurrences at the metal-solution interface cause environmental changes. These changes can be controlled when triggers from external environment set off active components of smart coating, thereby enhancing coating's life and functionality. Common triggers include the availability of moisture, concentration of chloride ion, pH gradient, mechanical damage, impact, fatigue, light, redox activity and temperature. In this review, recent technological trends in active anticorrosion and self-healing coatings as functional routes for metal protection are summarized, stimuli responsiveness and mechanisms of inhibition are discussed, and recent multi-action protective systems are particularly focused on.

Smart Coatings for Corrosion Protection: On the Need for New Coating Concepts

Ideally smart coatings for corrosion protection have to be able to protect the underlying metal from corrosion by providing excellent barrier properties, at the same time showing a fast and efficient self-healing in case a defect down to the metal is inflicted into them, while being as delamination resistant as possible.These seem to be basically incompatible properties, as either mobility of species is high or the coating is highly impermeable, i.e. it is difficult to envisage a coating that can be both at the same time. In fact, in recent works we have shown that for excellent self-healing performance especially the resistance against cathodic delamination of a coating should be significantly weakened [1, 2]. Using conductive polymer additions to non-conductive coatings, both high self-healing activity [1-3] as well as high resistance against cathodic delamination [4, 5] can be controlled in a wide range.Based on an in-depth understanding of the underlying mechanisms we are currently working on strategies for developing coatings that show excellent active as well as passive protection properties. Latest progress of the research on this topic well be presented and the implication will be discussed.[1] M. Uebel, L. Exbrayat, M. rabe, T.H. Tran, D. Crespy, M. Rohwerder, On the Role of Trigger Signal Spreading Velocity for Efficient Self-Healing Coatings for Corrosion Protection, Electrochem. Soc. 165 (2018) C1017-C1027[2] H. Tran , A. Vimalanandan , G.Genchev , J. Fickert , K. Landfester, D. Crespy , M.Rohwerder, Regenerative Nano-Hybrid Coating Tailored for Autonomous Corrosion Protection, Advanced Materials 27(25) (2015) 3825-3830[3] A. Vimalanandan, L.P. Lv, T.H. Tran, K. Landfester, D. Crespy, M. Rohwerder, Redox-Responsive Self-Healing for Corrosion Protection, Advanced Materials 25(48) (2013) 6980-6984[4] Anna Merz, Matthias Uebel, Michael Rohwerder, The Protection Zone: A Long-Range Corrosion Protection Mechanism around Conducting Polymer Particles in Composite Coatings: Part I. Polyaniline and Polypyrrole, Electrochem. Soc. 166 (2019) C304-C313[5] Anna Merz, Michael Rohwerder, The Protection Zone: A Long-Range Corrosion Protection Mechanism around Conducting Polymer Particles in Composite Coatings: Part II. PEDOT:PSS, Electrochem. Soc. 166 (2019) C314-C320

Corrosion inhibition of mild steel using chitosan / TiO2 nanocomposite coatings

Coatings tailored to corrosion protection of metallic substrates are of utmost relevance to ensure reliability and long-term performance of coated parts as well as the product value of the coated materials. Presently, there is a strong emphasis on the development of advanced functional and smart coatings for corrosion protection in different technological applications. This work aimed to develop a novel coating based on Chitosan Titanium dioxide (CS/TiO2) nanocomposite to evaluate its corrosion inhibition effect on mild steel. Chitosan Titanium dioxide (CS/TiO2) nanocomposite films were coated on mild steel by sol–gel process, dip coating technique. Sol–gel protective coatings have shown excellent chemical stability, oxidation control and enhanced corrosion resistance for metal substrates. Further, the sol–gel method is an environment friendly technique of surface protection which has traditionally been used for increasing corrosion resistance of metals. For this project, Chitosan Titanium dioxide (CS/TiO2) nanocomposite membranes were prepared using Tetrabutyl Titanate (TBT) as precursor and acetyl acetone as chelating agent by solution casting process. The prepared nanocomposite membranes were coated on a polished metal surface, dried and annealed at 120 °C for two hours. Corrosion protection behavior of these coated mild steel substrates in 0.1 N HCl solutions was evaluated by potentiodynamic polarization studies (Tafel), linear polarization studies (LPR), electrochemical impedance spectroscopy studies (EIS).

Inhibition of Mild Steel Corrosion using Chitosan–Polyvinyl Alcohol Nanocomposite Films by Sol–Gel Method: An Environmentally Friendly Approach

Coatings tailored to corrosion protection of metallic substrates are of the utmost relevance to ensure reliability and long-term performance of coated parts as well as the product value of the coated materials. Presently, there is a strong emphasis on the development of advanced functional and smart coatings for corrosion protection in different technological applications. This work aimed to develop a novel coating based on chitosan and PVA to evaluate its corrosion inhibition effect on mild steel. Chitosan/PVA films were coated on mild steel by dip coating technique. Sol–gel protective coatings have shown excellent chemical stability, oxidation control and enhanced corrosion resistance for metal substrates. Further, the sol–gel method is an environmentally friendly technique of surface protection which has traditionally been used for increasing corrosion resistance of metals. Films so formed were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), the thermal property of the chitosan–PVA film was examined by differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Corrosion protection behavior of these coated mild steel substrates in 0.1 N HCl solutions was evaluated by potentiodynamic polarization studies (Tafel), linear polarization studies (LPR), and electrochemical impedance spectroscopy studies (EIS). The experimental results showed that the chitosan/PVA composite coatings were superior to pure chitosan in corrosion protection. EIS measurements and Tafel polarization method have proven that corrosion resistance of mild steel in 0.1 N HCl solutions, increases with increasing the number of layers of chitosan/PVA films. The results indicated that the polymer film adhered to the mild steel surface and inhibited the mild steel corrosion in 0.1 N HCl.

Smart coatings for corrosion protection by adopting microcapsules

Smart coatings for corrosion protection by adopting microcapsules