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Abstract A Novel 5,10,15,20-tetra (thiophen-2-yl) porphyrin (P1) and 5,10,15,20-tetrakis (5-Bromothiophen-2-yl) porphyrin (P2) were successfully synthesized, and their chemical structures were proved based on its correct elemental analysis and spectral data (IR and 1H-NMR). These compounds were examined as corrosion inhibitors for stainless steel 304 (SS304) in 2 M HCl utilizing mass reduction (MR) and electrochemical tests at inhibitor concentration (1 × 10–6–21 × 10–6 M). The protection efficiency (IE %) was effectively enhanced with improving the concentration of investigated compounds and reached 92.5%, 88.5% at 21 × 10–6 M for P1 & P2, respectively and decreases with raising the temperature. Langmuir's isotherm was constrained as the best fitted isotherm depicts the physical–chemical adsorption capabilities of P1 & P2 on SS304 surface with change in ΔGo ads = 22.5 kJ mol−1. According to the PDP data reported, P1 and P2 work as mixed find inhibitors to suppress both cathodic and anodic processes. Porphyrin derivatives (P1 & P2) are included on the surface of SS304, according to surface morphology techniques SEM/EDX and AFM. Quantum calculations (DFT) and Monte Carlo simulation (MC) showed the impact of the chemical structure of porphyrin derivatives on their IE %.

The anti-corrosion properties of Moringa oleifera extract (MOE) have been extensively studied for Al in two molar HCl solution using a variety of techniques, including atomic force microscopy, potentiodynamic polarization, electrochemical impedance spectroscopy, Fourier-transform infrared spectroscopy, and weight loss analysis. According to the study, the inhibitory efficiency (% IE) increases with extract dose but decreases with temperature rise from 25 to 40 °C. The highest 90.1 percent inhibitory efficiency was achieved at 25 °C extract dosage of 300 ppm. MOE functions as a mixed-type inhibitor, affecting both anodic and cathodic processes, according to PDP research. The double layer capacitance (Ceff) declines from 214 to 56 µFcm−2 and the charge transfer resistance (Rct) increases from 3.1 to 27.2 sΩ cm2 with increasing MOE dose, as demonstrated by the Nyquist plot. The Langmuir adsorption isotherm is followed by MOE's adsorption on Al surfaces. The AFM and FTIR measurements corroborate MOE's adsorption on the Al surface. Based on the findings, it can be said that MOE can be utilized as a green inhibitor to reduce metal corrosion in harsh environments. [ABSTRACT FROM AUTHOR]

Abstract Inhibition of copper corrosion by some pyrimidinone derivatives, namely; (E)-N-(3-((1,3-dimethyl-2,4,6-trioxohexahydropyrimidin-5-yl)diazenyl)-2,5-diethoxyphenyl)benzamide (MA-975) and(E)-6-(4-((4-chlorophenyl)diazenyl)-3-methyl-5-oxo-4,5-dihydro-1H-pyrazol-1-yl)-1,3 dimethylpyrimidine-2,4(1H,3H)-dione (MA-978C) in 1.0 M nitric acid (HNO3) was studied using weight loss (WL), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PP) measurements. The efficiency of inhibition increases as the concentration of inhibitor increases, and it also increases as the temperature increases. With the addition of the examined inhibitors, significant corrosion protection was obtained, and (MA-975) showed a very promising % IE (89.59%) at 21 × 10−6 M using the (WL) method. The polarization data revealed that these compounds act as mixed-type compounds and are adsorbed on the copper surface following Langmuir adsorption isotherm forming a protective thin film protecting the metal in the corrosive media. Scanning electron microscopy (SEM) and Energy Dispersive X-ray were used to examine the surface morphology of copper samples. Quantum calculations and Monte Carlo simulation techniques were applied with informative yields and the results matched the experimental findings.

Plant extracts represent abundant sources of biomolecules distributed throughout various plant parts. These biomolecules are extracted using diverse solvents and methods. Within these plant extracts lie bioactive compounds, known for their antioxidant properties and anticorrosive capabilities. Detecting and isolating these active biomolecules from plant extracts necessitates analytical techniques such as gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. The active biomolecules within plant extracts contain heteroatoms within their structures, facilitating their adsorption on steel surfaces and conferring corrosion inhibition properties. The advantages of plant extracts as green corrosion inhibitors include ready availability, ease of application, eco-friendly characteristics, and cost-effectiveness. These extracts adhere to steel surfaces, blocking their active sites and effectively reducing the corrosion rate. This review consolidates the findings on the corrosion inhibition potential of plant extracts from various plant parts, elucidating their performance in different concentrations of sulfuric acid. [ABSTRACT FROM AUTHOR]

Molecular inhibitors added to the corrosive medium attacking metallic materials are a well-established way of combating corrosion. The inhibitive action proceeds via adsorption of the inhibitor on the surface to be protected. Aromatic building blocks in the inhibitor play a major role in its protective action, and further details like substituents, heteroatoms, and molecular geometry contribute. An overview focused on aromatic inhibitors is provided, aiming at the identification of particularly promising inhibitors and their mode of action. Directions for further research and development are pointed out in the conclusion. [ABSTRACT FROM AUTHOR]

This research investigated the corrosion resistance of surface layers on low-carbon steel exposed to a chloride environment at room temperature. This study systematically evaluated the effects of varying pack compositions, coating temperatures, and application durations on the characteristics of the deposited coatings. The potentiodynamic polarization corrosion test was employed to assess the wet corrosion behavior of the specimens. Elemental compositions and microstructural features were analyzed using energy-dispersive X-ray spectroscopy (EDX) in conjunction with scanning electron microscopy (SEM), providing insights into phase distribution. The chromizing, titanizing, and chromotitanizing treatments were conducted at temperatures of 900 °C, 1000 °C, and 1100 °C, respectively, with varying coating times. X-ray diffraction analysis revealed a complex arrangement of elements and compounds within the coatings, including Cr, Ti, Cr1.9Ti, FeTi, Al2O3, Cr2O3, TiO2, Cr1.36Fe0.52, and (Ti0.86)3.58. The study found that as the deposition duration increased, the coating thickness increased, comprising a thin inner layer and a substantially thicker outer layer. This layered structure resulted from the outward diffusion of Fe atoms and the inward diffusion of Cr and Ti atoms. Electrochemical analysis in a 3.5% NaCl aqueous solution indicated a marked enhancement in the corrosion resistance of the coated specimens compared to their uncoated counterparts. The potentiodynamic polarization tests confirmed that the protective coatings significantly reduced the corrosion rate, with performance influenced by both the temperature and duration of the deposition process. These findings highlighted the potential of tailored coating techniques to improve the durability and performance of low-carbon steel in corrosive environments. [ABSTRACT FROM AUTHOR]

The effects of [Co2 (SCN) 4(hmt)2(H2O)6. H2O] (SC1) and [Co (CN)6 (Me3Sn)3(H2O). (qox)] (SCP2) MOF as corrosion inhibitors on C-steel in 0.5 M sulfuric acid solutions are illustrated utilizing mass reduction (MR), electrochemical [potentiodynamic polarization (PP), and AC electrochemical impedance (EIS)]. The experiments revealed that as the dose of these compounds rose, the inhibition efficacy (IE percent) of C-steel corrosion improved, reaching 80.7–93.1% at dose 25 × 10−6 M for SC1 and SCP2, respectively. IE percent, on the other hand, dropped as the temperature range grew. SC1was adsorbed physically and chemically (mixed adsorption) but SCP2 was adsorbed physically on the surface of C-steel and conformed to the Langmuir adsorption isotherm equation. The PP studies revealed that these compounds act as mixed kind inhibitors. To establish the morphology of the inhibited C-steel surface, scanning electron microscopy (SEM), energy transmitted X-ray (EDX), and atomic force microscopy (AFM) studies were used. All tested experiments were in good agreement. [ABSTRACT FROM AUTHOR]

In this research, the Pistia stratiotes leaf (PSL) extract was evaluated as a green corrosion inhibitor for the corrosion of mild steel in 1 M HCl using electrochemical measurements and surface characterization. Electrochemical impedance spectroscopy (EIS) spectra showed that the inhibitory activity of the phytochemical compounds enhanced with increasing concentration up to 400 ppm, which was reflected in the increase in the charge transfer resistance and double-layer capacitance. Regarding the effect of immersion time, EIS results indicated that the persistence of the PSL extract was between 4 h and 8 h of exposure time. From polarization curve (PCC) results, the best performance of the corrosion inhibitor was achieved at 400 ppm with an inhibition efficiency of 93.7%. The PSL extract acted as a mixed-type corrosion inhibitor. The adsorption of the phytomolecules on the metal surface obeyed the Langmuir isotherm through a mixed mechanism (physical and chemical interactions) dominated by physisorption. Scanning electron microscopy (SEM) examinations and energy-dispersive X-ray spectroscopy (EDS) elemental analysis of the corroded samples confirmed the anticorrosive protection of the PSL extract. Chemical characterization of the PSL extract by GC-MS revealed the presence of phytol, steroids, and aromatic and long-chain unsaturated fatty acid esters, in order of abundance. Chemical quantum calculations by DFT allowed for determining that the phthalic acid, di(2-propylpentyl) ester compound has the most significant potential to act as the main active component in corrosion inhibition activity. [ABSTRACT FROM AUTHOR]

Significant concerns with corrosion might occur in terms of assurance, the natural world, and financial damage. One key piece of innovation toward preventing metallic corrosion includes the application of corrosion inhibitors. The polymer inhibitions of corrosion constitute the most promising areas for advancing of new corrosion inhibitors because they have more excellent adherence locations, higher temperature rebellion, versatility, viscosity, and superior filming capacity than smaller molecule corrosion inhibitors. The present review examines the development of natural and synthetic polymers for anti-corrosion agents. Such polymeric anti-corrosion agents work very well at inhibiting corrosion and do not need a high molecular weight. At this point, we examine the published literature on polymeric corrosion inhibitors and discuss how to improve them for use in the industry. [ABSTRACT FROM AUTHOR]

This study evaluated the corrosion inhibitory effects of Ruta graveolens leaf extract for 304 stainless steel in 1 M HCl. The analysis of the leaf extract using HPLC indicated that the primary compounds present in the leaf extract were rutin, caffeic acid, p-coumaric acid, and apigenin. The inhibition efficiency (IE%) of the extract was studied using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and computational simulation (density functional theory, DFT). The effects of the inhibitor concentration and solution temperature were investigated. The results indicated that the IE% increased for increasing concentrations of the extract, while the reverse was true with increasing temperatures. At 25 °C and a 600 ppm extract concentration, the results indicated a maximum inhibition efficiency of 95%, 98%, and 96% by weight loss, potentiodynamic polarization, and EIS techniques, respectively. SEM observations showed a significant change in the surface morphology of the 304 SS with and without the addition of the inhibitor compound. At all temperatures, the adsorption of the inhibitor components onto the 304 SS surface was found to follow the Langmuir isotherm model, and the inhibition process was governed by physical adsorption. Furthermore, chemical interactions between the inhibitor and the 304 SS steel surface were elucidated via density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

The effects of [Co2 (SCN) 4(hmt)2(H2O)6. H2O] (SC1) and [Co (CN)6 (Me3Sn)3(H2O). (qox)] (SCP2) MOF as corrosion inhibitors on C-steel in 0.5 M sulfuric acid solutions are illustrated utilizing mass reduction (MR), electrochemical [potentiodynamic polarization (PP), and AC electrochemical impedance (EIS)]. The experiments revealed that as the dose of these compounds rose, the inhibition efficacy (IE percent) of C-steel corrosion improved, reaching 80.7–93.1% at dose 25 × 10−6 M for SC1 and SCP2, respectively. IE percent, on the other hand, dropped as the temperature range grew. SC1was adsorbed physically and chemically (mixed adsorption) but SCP2 was adsorbed physically on the surface of C-steel and conformed to the Langmuir adsorption isotherm equation. The PP studies revealed that these compounds act as mixed kind inhibitors. To establish the morphology of the inhibited C-steel surface, scanning electron microscopy (SEM), energy transmitted X-ray (EDX), and atomic force microscopy (AFM) studies were used. All tested experiments were in good agreement. [ABSTRACT FROM AUTHOR]

The present research aimed to investigate the impact of some synthetic derivatives of pyridone (6-amino-1-(4-hydroxyphenyl)-4-(4-methoxyphenyl)-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile (PYR-2) and 6-amino-1-(4-hydroxyphenyl)-2-oxo-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PYR-3))on copper corrosion inhibition behavior in HCl acid solution using electrochemical methods, including potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS). Using FTIR, 1HNMR, and mass spectroscopy methods, the two compounds ((PYR-2) and (PYR-3)) were confirmed and characterized. With the two compounds added to corrosive media, the double-layer capacitance value decreases. In the case of 18 × 10−5 M, they reached maximum efficiency of 91.9% and 90.3%, respectively. Having studied its behavior during adsorption on copper, it was concluded that it follows chemical adsorption and Langmuir isotherm and may be considered mixed-type inhibitors. [ABSTRACT FROM AUTHOR]

The corrosion of metals is very important, both economically and environmentally, and is a serious concern. Since the past decades, traditional (chemical) corrosion inhibitors to prevent corrosion have been and are still being used. Although these inhibitors can be said to be a good choice among other protection techniques because of their good efficiency, the toxicity of many of them causes environmental problems, and, due to the change in the laws on the use of chemicals, many of them are no longer allowed. Hence, during the past years, research on green corrosion inhibitors (GCIs) increased and very favorable results were obtained, and now they are very popular. It can be said that biodegradability and easy preparation are their most important factors. Meanwhile, the use of plants, especially their extracts, has been studied a lot. Plant extracts contain compounds that have anti-corrosion properties. In this review, the use of plants as GCIs is investigated, focusing on recent advances in their use. Also, the phenomenon of corrosion, corrosion protection (including coatings, nanoparticles, and chemical inhibitors), and other GCIs are briefly reviewed. [ABSTRACT FROM AUTHOR]

The effect of Fagonia arabica as corrosion inhibitor for Cu in nitric acid solution was studied utilizing mass loss technique, potentiodynamic polarization measurement, electrochemical impedance spectroscopy method, and scanning electron microscopy (SEM); the inhibition efficiency was found to increase with increase in the concentration of inhibitor; the inhibitive effect of this inhibitor was explained based on adsorption metal surface, the adsorption effect follows Flory‐Huggins adsorption isotherm. The corrosion rate was calculated; the results revealed that F. arabica has good inhibition effect on Cu. The surface morphology of Cu metal was examined by employing various techniques such as atomic force microscopy (AFM) and SEM. The AFM results observed greater inhibition efficiency of F. arabica for Cu dissolution in the acid corrosive environment. The parameters for the corrosion procedure have also been determined and discussed. [ABSTRACT FROM AUTHOR]

Two compound derived from fused Pyrazolo-Triazolo-Pyrimidine (C1 and C2), have inhibitory action against corrosion of Zinc in 1 M HNO3 examined experimentally by electrochemical tests and theoretically by density functional theory (DFT). The findings demonstrate that zinc corrodes in acidic conditions with greater corrosion resistance than C1 and C2. Concentration and corrosion inhibition directly relate to one another. The two Pyrazolopyrimidine-derived compounds had optimum inhibition efficiency of 92.06 and 79.36% for C1 and C2, respectively, at 700 ppm. In accordance to the polarization curves, the antagonists feature a mixed but primarily anodic inhibitor and a Langmuir process. DFT computations validated the compounds apparent antagonistic response. SEM also show the development of a barrier on the zinc surface. In conclusion, these two antagonists, C1 and C2, are successful in avoiding zinc dissolution in HNO3. [ABSTRACT FROM AUTHOR]

The extracts of different parts of plants (leaf, stem, and flower) act as a green, environmentally friendly, economical, and safe corrosion inhibitors. The eco-friendly extracts of plant material provide an excellent alternative that substitutes toxic traditional (organic and inorganic) corrosion inhibitors. The plant extracts are renewable and readily available; thus, they occupy a unique position in the family of green inhibitors. The plant extract contains several bioactive compounds, such as flavonoids, tannins, polyphenols, phenolic acids, glycosides, flavonols, etc., which possess experienced significant interest as anti-corrosive agents. These plant extracts contain several heteroatoms like phosphorus, nitrogen, sulfur, oxygen, etc., which are adsorbed on the metallic surface and form an inert protective layer that protects metal from a corrosive environment. Thus, this article aims to shed light on the efficiency of plant extract in protecting steel in an acidic environment. [ABSTRACT FROM AUTHOR]