Search Results (115)

Mica is a naturally layered material recognized for its superior insulation and exceptional barrier properties; however, it is prone to agglomeration, and its compatibility with resin remains to be resolved. In this work, phosphate butynediol ethoxylate (PBEO), synthesized by the reaction of a commercial corrosion inhibitor, butynediol ethoxylate, with phosphorus pentoxide, was employed to modify mica nanosheets (MNs), as evidenced by FTIR, Raman, and XPS. The obtained MN@PBEO demonstrated improved water dispersibility and enhanced compatibility with acrylic latex. EIS measurements revealed that the impedance (|Z|_0.01Hz) for the waterborne acrylic coating with 0.5 wt% MN@PBEO was approximately an order of magnitude greater than that of the pure waterborne acrylic coating after 28 days of immersion in a 3.5 wt% NaCl solution. Additionally, compared to the pure waterborne acrylic coating, the 0.5 wt% MN@PBEO/acrylic nanocomposite coating on Q235 carbon steel exhibited a water diffusion coefficient that was roughly ten times lower, demonstrating substantially enhanced corrosion protection, attributable to its superior barrier properties. Full article

Microbial extracellular polymeric substances (EPSs) are emerging as sustainable alternatives to conventional corrosion inhibitors due to their eco-friendly nature, biodegradability, and functional versatility. Secreted by diverse microorganisms including bacteria, fungi, archaea, and algae, EPSs are composed mainly of polysaccharides, proteins, lipids, and nucleic acids. These biopolymers, chiefly polysaccharides and proteins, are accountable for surface corrosion prevention through biofilm formation, allowing microbial survival and promoting their environmental adaptation. Usually, EPS-mediated corrosion inhibitions can take place via different mechanisms: protective film formation, metal ions chelation, electrochemical property alteration, and synergy with inorganic inhibitors. Even though efficacious EPS corrosion prevention has been demonstrated in several former studies, the application of such microbial inhibitors remains, so far, a controversial topic due to the variability in their composition and compatibility toward diverse metal surfaces. Thus, this review outlines the microbial origins, biochemical properties, and inhibition mechanisms of EPSs, emphasizing their advantages and challenges in industrial applications. Advances in synthetic biology, nanotechnology, and machine learning are also highlighted and could provide new opportunities to enhance EPS production and functionality. Therefore, the adoption of EPS-based corrosion inhibitors represents a promising strategy for environmentally sustainable corrosion control. Full article

In recent years, the concept of reusing expired pharmaceuticals as corrosion inhibitors has attracted considerable attention due to the increasing demand for sustainable and eco-friendly solutions. This paper investigates the potential of an expired drug, called Fluimucil, containing N-acetylcysteine (NAC, 300 mg/3 mL), as a green corrosion inhibitor of bronze exposed to 3.5 wt.% NaCl solution and simulated acid rain (pH = 3.4). Potentiodynamic polarization measurements revealed that the drug acted mainly as a cathodic-type inhibitor in both electrolytes. Inhibition efficiency increased with drug concentration, reaching the maximum values of 86.7% in the presence of 36 mM NAC in the saline solution and 90.2% in the presence of 6 mM NAC in simulated acid rain. The anticorrosive effect of the drug was likely due to the adsorption of NAC on the bronze surface, which hindered to some extent the charge transfer reaction and corrosion product formation, thereby offering enhanced protection. Disregarding the nature of the corrosive electrolyte, NAC adsorption on the bronze followed the Langmuir isotherm model, involving a combination of physisorption and chemisorption processes. Surface examination by SEM-EDX confirmed that expired Fluimucil significantly mitigated the surface degradation and the corrosion products on the bronze. Full article

Background/Objectives: Biocorrosion, driven by microbial colonization and biofilm formation, poses a significant threat to the integrity of metal artifacts, particularly those composed of copper and its alloys. Pseudomonas aeruginosa, a bacterial species that reduces nitrates, plays a key role in this process. This study explores the potential of two metabolite-rich plant extracts, Aloe vera and Opuntia ficus-indica, as sustainable biobased inhibitors of microbial-induced corrosion (MICOR). Methods: The antibacterial and antibiofilm activities of the extracts were evaluated using minimal inhibitory concentration (MIC) assays, time-kill kinetics, and biofilm prevention and removal tests on copper, bronze, and brass samples. Spectrophotometric and microbiological methods were used to quantify bacterial growth and biofilm density. Results: Both extracts exhibited significant antibacterial activity, with MIC values of 8.3% (v/v). A. vera demonstrated superior bactericidal effects, achieving reductions of ≥3 log₁₀ in bacterial counts at lower concentrations. In antibiofilm assays, both extracts effectively prevented biofilm formation and reduced established biofilms, with A. vera exhibiting greater efficacy against them. The active metabolites—anthraquinones, phenolics, flavonoids, and tannins—likely contribute to these effects. Conclusions: These findings highlight the dual role of A. vera and O. ficus-indica extracts as both corrosion and biocorrosion inhibitors. The secondary metabolite profiles of these plants support their application as eco-friendly alternatives in the conservation of metal cultural heritage objects. Full article

This paper investigates the corrosion behavior of mild steel in simulated oilfield wastewater under CO₂, H₂S, and their mixture. Using the electrical resistance method, the corrosion rates were monitored, and the influence of corrosion product films on overall performance was analyzed. The results show that the CO₂/H₂S mixture causes the highest corrosion rate. Metallographic examination and X-ray diffraction (XRD) provided insights into the nature of the corrosion products formed on the steel surface. While hydrogen sulfide (H₂S) does not prevent general corrosion, it plays a role in mitigating localized damage. Corrosion leads to deep, narrow pits that weaken the structural integrity without significant surface damage, making it more dangerous than uniform corrosion. In CO₂-only environments, electrochemical reactions form protective oxide layers. However, H₂S alters this process by forming iron sulfides (FeS), which are less protective but still act as a barrier against further corrosion. In mixed CO₂/H₂S environments, interactions between the gases complicate the corrosion dynamics, increasing medium aggressiveness and accelerating material degradation. Understanding these mechanisms is critical for the petroleum industry, where equipment is exposed to harsh conditions with varying CO₂ and H₂S concentrations. Recognizing the dual role of H₂S—its inability to inhibit general corrosion but its effectiveness in reducing pitting—can guide material selection and inhibitor development. This knowledge enhances the durability and safety of oil and gas infrastructure by addressing the most damaging forms of corrosion. Full article

Corrosion protection in reinforced concrete structures exposed to aggressive environments remains a critical challenge in civil and architectural engineering. One promising approach involves the application of corrosion-inhibiting monolayers on the reinforcement, such as those formed using 4-aminobenzoic acid. Two methods have previously been employed to generate these monolayers: one relying on the adhesion of an organic compound and the other utilising an externally modified approach via electrolysis. This study assesses the influence of this treatment on the steel–concrete bond strength and durability, both critical properties for the structural performance of reinforced concrete under service conditions. For this purpose, pull-out tests were performed on specimens subjected to load–unload cycles to analyse bond behaviour and monolayer integrity. The results indicate that these treatments do not adversely affect the bond strength between reinforcement and concrete. Furthermore, the rebars treated with the inhibitor exhibit less corrosion damage than the untreated rebars. This fact is particularly significant in the rebars treated using the natural adhesion method, with the steel section loss being 32–37% lower than in the untreated rebars. These findings support the feasibility of applying this treatment without compromising structural functionality. Full article

This review examines recent advances in corrosion inhibitor technologies, with a focus on sustainable and environmentally friendly solutions that address both industrial efficiency and environmental safety. Corrosion is a ubiquitous problem, contributing to massive economic losses globally, with costs estimated between 1 and 5% of GDP in different countries. Traditional inorganic corrosion inhibitors, while effective, are often based on toxic compounds, necessitating the development of more environmentally friendly and non-toxic alternatives. The present work highlights innovative eco-friendly corrosion inhibitors derived from natural sources, including plant extracts and oils, biopolymers, etc., being biodegradable substances that provide effective corrosion resistance with minimal environmental impact. In addition, this review explores organic–inorganic hybrid inhibitors and nanotechnology-enhanced coatings that demonstrate improved efficiency, durability, and adaptability across industries. Key considerations, such as application techniques, mechanisms of action, and the impact of environmental factors on inhibitor performance, are discussed. This comprehensive presentation aims to contribute to updating the data on the development of advanced corrosion inhibitors capable of meeting the requirements of modern industries while promoting sustainable and safe practices in corrosion management. Full article

The corrosive nature of ionic liquids (ILs) limits their potential as high-performance conductive lubricants in practical engineering applications. This study systematically investigates the effects of benzotriazole (BTA) as a corrosion inhibitor on the lubricating performance of ILs at different concentrations and applied currents, along with the underlying mechanisms. In the 0.5–5 A current range, BTA effectively reduces friction, wear, and arc erosion damage to the friction surface. As the applied current increases, the BTA-Fe reaction film suppresses oxide formation, thereby reducing electrical contact resistance (ECR). Moreover, the effectiveness of BTA is concentration-dependent: at 0.5 A and a BTA concentration of 0.5 wt%, the coefficient of friction (COF) decreases by 16.5%, and wear volume is reduced by 53.4%. Friction testing and surface analysis show that the BTA-IL combination exhibits synergistic lubrication and anti-corrosion effects under current-carrying conditions, with varying wear and lubrication mechanisms depending on the applied current. Full article

The equipment of refineries and oil production facilities is subject to corrosion due to the supply of crude oils with a high content of mineralized water. The use of inhibitors is one of the most common corrosion protection methods. However, increasing requirements of environmental standards give impetus to developing new types of corrosion inhibitors from natural raw materials. The article deals with the synthesis conditions of new corrosion inhibitors (CIs) produced from distilled higher acids of beef fat (DHFAs) or vegetable oils (VO), as well as research on the protective effect of the synthesized corrosion inhibitors compared with industrial inhibitors (5 samples). The gravimetric method studied the protective effect in a solution of salts and jet fuel using a St20 steel plate. At 50 °C and a CIs content of 100 ppm, the protective effect of corrosion inhibitors based on VO and triethanolamine was 9.7–75.6%. Under similar conditions, CIs obtained from DHFAs and diaminoethyl exhibited a protective effect of 81.6–94.1%. When DHFAs and diethanolamine were used to synthesize CIs, the protective effect was 93.0–95.6%. CI synthesized at 130 °C and a DHFAs: diethanolamine ratio of 72:28 showed a 99.2% protective effect at 50 °C and a CI content of 200 ppm, which was higher or equal to the impact of using industrial inhibitors (91.6–99.5%). The results prove the possibility of alternative use of animal fats and waste from their production as new resources for obtaining highly effective equipment corrosion inhibitors. Using alternative inexpensive raw materials (fats, vegetable oils, waste from their output) to obtain CIs will improve the economic performance of inhibitor production. In addition, at least the fatty (oil) part of organic CIs is biodegradable and will not harm the environment. Full article

In recent years, the anti-corrosive properties of natural extracts as environmentally friendly inhibitors have gained considerable interest. This study evaluates the potential of Marjoram (Origanum majorana L.) essential oil (OML), collected from Salé, Morocco, as a corrosion inhibitor for mild steel in 1 M HCl medium. The protection performance of OML was assessed using various electrochemical techniques, including potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), as well as the weight loss method. The influence of OML concentration and temperature on the inhibition performance were investigated. OML demonstrated pronounced inhibitory benefits via increasing the corrosion resistance of mild steel in the corrosive HCl solution, thus reducing the corrosion rate to 0.11 mg cm⁻² h⁻¹ and increasing the inhibition efficiency to 87.1% at an inhibitor concentration of 500 ppm. PDP confirmed that the inhibitor works as a mixed-type inhibitor with cathodic supremacy. EIS revealed that the charge transfer mechanism is the main controlling factor for the corrosion process. The thermodynamic parameters suggested a key role of OML physisorption in inhibition, following the Langmuir isotherm. Importantly, SEM and EDX analyses suggested the formation of a protective layer of the extract onto the steel surface, which shields the surface from corrosive species. This is owed to the functional group-rich phytochemicals of OML. Therefore, the development of bio-based corrosion inhibitors is not only a step towards more eco-friendly industrial practices, but also meets the growing demand for sustainable materials in a world with constrained resources. Full article

Nowadays, the development of plant extracts as corrosion inhibitors to protect metals from corrosion is a popular research direction. However, given the vast diversity of plant species in nature, it is imperative to explore effective methods to improve screening efficiency in order to quickly identify the corrosion inhibition potential of plants. In this work, a new strategy for developing plant-extracted eco-friendly corrosion inhibitors based on the family and genus of plants is proposed. Three plants of different genera in the Asteraceae family, including Artemisia argyi extract (AAE), Chrysanthemum indicum extract (CIE), and Centipeda minima extract (CME), were selected and successfully prepared as novel corrosion inhibitors for Q235 steel in a sulfuric acid solution. The corrosion inhibition behavior and corresponding mechanism were systematically investigated by using some electrochemical tests (open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy) and surface characterizations (Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy). The experimental results illustrated that the main components of the three extracts were similar and that when combined with KI as mixed-type corrosion inhibitors, they could dramatically slow down the metal corrosion rate. The maximum value of the corrosion inhibition efficiency reached 96.29%, 96.50%, and 97.52%, respectively, at 200 mg/L and could increase to 98.64%, 97.65%, and 99.06%, respectively, with a prolonged immersion time. A synergistic effect exists between the three plant extracts and KI, leading to the firm adsorption of the three plant extract molecules onto a Q235 steel surface, thereby forming a robust protective film. This work demonstrated that plants of different genera in the Asteraceae family possessed similar corrosion inhibition capabilities, providing a novel way to select potential corrosion inhibitors from numerous plants based on family and genus classification. Full article

In this research, the high efficacy of Mentha spicata L. extract, commonly known as spearmint, as a corrosion inhibitor with an efficacy rate of 86.98% is highlighted. Analytical techniques, such as scanning electron microscopy (SEM) to obtain a detailed morphological view, Fourier transform infrared spectroscopy (FTIR) to identify the functional groups of flavonoids, and electrochemical impedance spectroscopy (EIS) and Tafel plots for a corrosion assessment, were employed. This study pioneers a greener alternative to traditional corrosion inhibition methods. The distinctive aspect of this research is the innovative spray coating application method used to deliver the spearmint extract onto structural steel. This method involves the strategic use of an airbrush for spray coating, ensuring the uniform and efficient deposition of the organic inhibitor, thus forming a protective barrier against corrosion. This spray coating technique is emerging as an innovative approach for the industrial application of natural corrosion inhibitors, demonstrating significant advances in the corrosion resistance of coated steel. The results not only corroborate the efficacy of natural inhibitors, but also highlight the critical role that sophisticated application techniques play in improving their industrial viability. This methodological innovation presents a pathway to sustainable practices in corrosion management, prioritizing environmental protection and ecological footprint reduction in the quest for corrosion mitigation. Full article

The current demand for heat production via geothermal energy is increasingly rising amid concerns surrounding non-renewable forms of energy. The Dogger aquifer in the Paris Basin (DAPB) in France produces saline geothermal waters (GWs), which are as hot as 70–85 °C, anaerobic, slightly acidic (pH 6.1–6.4), and characterized mainly by the presence of Cl⁻, SO₄²⁻, CO₂/HCO₃⁻, and H₂S/HS⁻. These GWs are corrosive, and the casings of all geothermal wells are carbon steel. Since 1989, these GWs have been progressively treated using petrosourced organic corrosion inhibitors (PS–OCI) at the bottom of the production wells. Currently, there is a great need to test not only new PS–OCIs but also, and above all, biosourced organic corrosion inhibitors (BS–OCIs) to improve the efficiency and environmental friendliness of this carbon-free geothermal energy source. The main objective of this study is to evaluate the potential performance of biosourced corrosion inhibitor candidates (BS–CICs) in terms of their inhibition efficiency (IE) for carbon steel corrosion. This was achieved using a previously established geochemical and electrochemical method to study the mechanisms and kinetics of the corrosion/scaling of carbon steel and optimize short-term corrosion inhibition in standardized reconstituted geothermal water (SRGW) representative of the DAPB’s waters. Four new molecules from the 2-oxazoline family were evaluated individually and compared based on their behavior and inhibition efficiency. These molecules exhibited a mixed nature (i.e., anodic and cathodic inhibitors), with a slight anodic predominance, and showed a significant IE at a concentration of at 10 mg/L during the first hours of immersion of CS-XC38 in SRGW. The average IEs, obtained via the three electrochemical techniques used for the determination of corrosion current densities, i.e., J_corr(Rp), J_corr(Tafel), and J_corr(Rw), are 51%, 79%, 96%, and 93% for Decenox (C10:1), Decanox (C10:0), Undecanox (C11:0), and Tridecanox (C13:0), respectively. Full article

Herein, we take an underground natural gas storage in the Ordos Basin as an example to explore the influence of temperature, CO₂ flow rate, CO₂ partial pressure, and chloride ion concentration on the corrosion rate of N80 and P110 steels in CaCl₂ brine type. Meanwhile, in order to reduce the amount of chemical corrosion inhibitors and improve performance, a novel corrosion inhibitor with a quinoline quaternary ammonium structure named YS-QB was synthesized from 1-methyl-1,2,3,4-tetrahydroisoquinoline, epichlorohydrin, and oleic acid amide propyl dimethylamine. Under normal and high-pressure environments, YS-QB exhibits a superior corrosion inhibition effect to the market product of CX-1. In order to further reduce the amount of corrosion inhibitor and improve the corrosion inhibition effect, orthogonal experiments were conducted to optimize the formula system, and the optimal composite system was finally obtained by forming YS-QB, propargyl alcohol, hexamethylenetetramine, and isopropanol in a mass ratio of 12:1:1:2. At 80 °C, a dosage of 30 mg/L can suppress the CO₂ corrosion rate below 0.076 mm/a, while a dosage of 60 mg/L can suppress the CO₂ corrosion rate below 0.076 mm/a at a high-pressure environment of 120 °C. Combining weightlessness and electrochemical experiments, it is found that the composite corrosion inhibitor performs best when the dosage reached 100 mg/L, and a further increase in the dosage weakens the corrosion inhibition capacity. Based on the polarization curve changes with the dosage of the composite corrosion inhibitor, it can be determined that the final obtained composite corrosion inhibitor system was a cathodic corrosion inhibitor. Full article

The indole nucleus stands out as a pharmacophore, among other aromatic heterocyclic compounds with remarkable therapeutic properties, such as benzimidazole, pyridine, quinoline, benzothiazole, and others. Moreover, a series of recent studies refer to strategies for the synthesis of bisindole derivatives, with various medicinal properties, such as antimicrobial, antiviral, anticancer, anti-Alzheimer, anti-inflammatory, antioxidant, antidiabetic, etc. Also, a series of natural bisindole compounds are mentioned in the literature for their various biological properties and as a starting point in the synthesis of other related bisindoles. Drawing from these data, we have proposed in this review to provide an overview of the synthesis techniques and medicinal qualities of the bisindolic compounds that have been mentioned in recent literature from 2010 to 2024 as well as their numerous uses in the chemistry of materials, nanomaterials, dyes, polymers, and corrosion inhibitors. Full article