Anticorrosive Performance of Mangifera indica L. Leaf Extract-Based Hybrid Coating on Steel

Pumpkin Leaf Extract Crop Waste as a New Degradable and Environmentally Friendly Corrosion Inhibitor

The pumpkin leaf was extracted by the decoction method, and it was used as an eco-friendly, nontoxic inhibitor of copper in 0.5 M H2SO4 corrosion media. To evaluate the composition and protective capacity of the pumpkin leaf extract, Fourier infrared spectroscopy, electrochemical testing, XPS, AFM, and SEM were employed. The results showed that the pumpkin leaf extract (PLE) is an effective cathode corrosion inhibitor, exhibiting exceptional protection for copper within a specific temperature range. The corrosion inhibition efficiency of the PLE against copper reached 89.98% when the concentration of the PLE reached 800 mg/L. Furthermore, when the temperature and soaking time increased, the corrosion protection efficiency of 800 mg/L PLE on copper consistently remained above 85%. Analysis of the morphology also indicated that the PLE possesses equally effective protection for copper at different temperatures. Furthermore, XPS analysis reveals that the PLE molecules are indeed adsorbed to form an adsorption film, which is consistent with Langmuir monolayer adsorption. Molecular dynamics simulations and quantum chemical calculations were conducted on the main components of the PLE.

Sustainable Secondary-Raw Materials, Natural Substances and Eco-Friendly Nanomaterial-Based Approaches for Improved Surface Performances: An Overview of What They Are and How They Work

To meet modern society’s requirements for sustainability and environmental protection, innovative and smart surface coatings are continually being developed to improve or impart surface functional qualities and protective features. These needs regard numerous different sectors, such as cultural heritage, building, naval, automotive, environmental remediation and textiles. In this regard, researchers and nanotechnology are therefore mostly devoted to the development of new and smart nanostructured finishings and coatings featuring different implemented properties, such as anti-vegetative or antibacterial, hydrophobic, anti-stain, fire retardant, controlled release of drugs, detection of molecules and mechanical resistance. A variety of chemical synthesis techniques are usually employed to obtain novel nanostructured materials based on the use of an appropriate polymeric matrix in combination with either functional doping molecules or blended polymers, as well as multicomponent functional precursors and nanofillers. Further efforts are being made, as described in this review, to carry out green and eco-friendly synthetic protocols, such as sol–gel synthesis, starting from bio-based, natural or waste substances, in order to produce more sustainable (multi)functional hybrid or nanocomposite coatings, with a focus on their life cycle in accordance with the circular economy principles.

Cold-Sprayed Composite Metal-Fluoropolymer Coatings for Alloy Protection against Corrosion and Wear

Results of studying the properties of composite fluoropolymer-containing coatings formed by the cold spray (CS) method on the surface of constructional steel are presented. Different ways of protective coating formation are proposed. The composition of coatings was studied using SEM/EDX analysis. The incorporation of super-dispersed polytetrafluoroethylene (SPTFE) into the coating increases the corrosion resistance of the copper-zinc-based cold-sprayed coating. Analysis of the electrochemical properties obtained using EIS (electrochemical impedance spectroscopy) and PDP (potentiodynamic polarization) indicates that samples treated with SPTFE on a base copper-zinc coating showed lower corrosion current density and higher impedance modulus (j_c = 8.5 × 10^-7 A cm^-2, |Z|_{f=0.1 Hz} = 5.3 × 10⁴ Ω∙cm²) than the specimen with cold-sprayed SPTFE (j_c = 6.1 × 10^-6 A cm^-2, |Z|_{f=0.1 Hz} = 8.1 × 10³ Ω∙cm²). The best anticorrosion properties were revealed for the sample with a cold-sprayed base Cu-Zn layer annealed at 500 °C for 1 h, followed by SPTFE friction treatment and re-annealed at 350 °C for 1 h. The corrosion current density j_c of such a coating is 25 times lower than that for the base Cu-Zn coating. The antifriction properties and hydrophobicity of the formed layers are described. Obtained results indicate that cold-sprayed polymer-containing coatings effectively improve the corrosion and wear resistivity of the treated material.

Environmentally Friendly Anticorrosive Polymeric Coatings

This paper provides a synthetic and comprehensive overview on environmentally friendly anticorrosive polymeric coatings. Firstly, the economic and environmental impact of corrosion is presented to highlight the need of anticorrosive polymeric coatings as a flexible and effective solution to protect a metal. Secondly, the implementation of regulations together with the consumer awareness for environmental considerations and protection of health are the driving force for a progressive but significant change in the sector. Therefore, within the protective organic coatings market, this article provides a review of the most recent developments in environmentally friendly solutions, including bio-based and water-borne epoxy, hyperbranched polyester for low- volatile organic compounds (VOC) coatings, waterborne polyurethane and non-isocyanate polyurethanes (NIPUs), and graphene or bio-based fillers for acrylics. Moreover, this paper outlines new trends such as smart additives, bio-based corrosion inhibitors, and functional antibiocorrosive coatings as superhydrophobics. Finally, industrially relevant applications of environmentally friendly anticorrosive polymeric coatings including solutions for marine and off-shore industries are summarized.