Electro-deposited nanocomposite coatings and their behaviours against aqueous and high-temperature corrosion: A review

Nanocomposite coatings have recently gained tremendous attention and consideration in corrosion prevention due to their mechanical and physiochemical properties. These properties have influenced the behaviour of the nanocomposite coatings in aqueous and high-temperature environments. Electrodeposition is a cheap electrochemical technique used to modify the surface structure of materials and produce high-quality nanocomposite coatings. In this review, electro-deposited nanocomposites, processing methods and electrodeposition of nanocomposite coating were studied. Also, the corrosion behaviour of some of these nanocomposite coatings in aqueous and high temperatures was extensively reviewed

Modified hydroxyethyl cellulose as a highly efficient eco-friendly inhibitor for suppression of mild steel corrosion in a 15% HCl solution at elevated temperatures

Natural polymer-based corrosion inhibitors have been studied for the prevention of steel corrosion in various corrosive environments over recent years, yet they did not show impressive inhibition performance especially at high temperatures. The present study introduces a facile and practical method to enhance the inhibition activity of natural polymers (hydroxyethyl cellulose (HEC) as a carbohydrate model) on the basis of polyurethane chemistry. The ability of chemically modified hydroxyethylcellulose (CHEC) in suppressing mild steel (MS) corrosion was assessed using weight loss, electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), and potentiodynamic polarization (PDP) techniques, and further confirmed by field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). All electrochemical measurements revealed that the incorporation of only 1% of polyurethane prepolymer to the CHEC structure greatly enhanced its inhibition efficiency in the acidic solution, even at high temperatures. CHEC adsorbed on the MS surface and functioned as a mixed-type inhibitor, with a maximum inhibition efficiency of 93% at 80 °C. In addition, the morphology of MS surface in the presence of CHEC confirmed the protective role of the additive and XPS results clearly revealed CHEC adsorption on the MS surface. Furthermore, density functional theory computations and molecular dynamics simulations provided corroborating molecular-level insights on the electronic structure of CHEC and its interactions with the metal surface. These findings demonstrate that the polyurethane prepolymer method is a new and effective approach for enhancing the anticorrosion performance of natural polymer-based corrosion inhibitors in aggressive acidic media at high temperatures

SEM-EDS characterization of natural products on corrosion inhibition of Al-Mg-Si alloy

The corrosion resistance of aluminum and its alloys is the subject of tremendous technological importance due to their increased industrial applications. The corrosion protections and the mechanism of corrosion inhibitions of natural products for an Al-Mg-Si alloy in seawater were investigated at room temperature. The surface morphology was studied by means of macro scale electrochemical techniques and localized microscopic methods, i.e., Scanning electron microscope (SEM) with associated elemental analysis by energy dispersive spectrometer (EDS). SEM examinations provided morphological characterization of the surface of Al-Mg-Si alloy sample before and after immersion in seawater; meanwhile surface analytical techniques by the EDS allowed us to investigate detail the chemical composition of aluminum oxide layers. The experiments were performed with Al-Mg-Si alloy, immersed in a 5 L beaker containing seawater with and without the natural products for 60 days at room temperature. The SEM results indicate that the natural products (natural honey, vanillin, and tapioca starch) absolutely inhibited the corrosion products on the specimen surfaces. They also protected the passive film from dissolution in seawater. The EDS spectrums were determined that carbonaceous, carbonyl, methoxy and hydroxyl groups as functional groups of natural products in inhibition mechanism