Metal Corrosion Research Articles

Metal loss and corrosion attack of FeCrAl overlay welds on evaporator tube shields of a waste‐fired power plant

AbstractThree FeCrAl alloys (APMT, EF100 and EF101) from Kanthal® and the reference Ni‐Cr Alloy 625 were used as weld cladding materials on tube shields in the evaporator tube bank of a waste‐fired combined heat and power plant. For each alloy type, the overlay welded tube shields were placed in both roof and floor positions within the evaporator for 6 months. The metal‐loss rate, the microstructure and hardness of the overlay welds before and after exposure and the corrosion products were analysed. The results showed higher metal‐loss rates in the welds placed in the roof position, confirming heterogeneities in the evaporator bank environment. Alloys were ranked from higher to lower erosion–corrosion resistance as follows: APMT ≈ Alloy 625 > EF101 > EF100. The analysis of the corrosion attacks showed a significant variation among the alloys, from a primarily homogeneous corrosion attack on APMT to intergranular corrosion in EF100 and pit formation in EF101.

Surface Engineering on Zinc Anode for Aqueous Zinc Metal Batteries.

Rechargeable aqueous zinc metal batteries (AZMBs) are considered as a potential alternative to lithium-ion batteries due to their low cost, high safety, and environmental friendliness. However, the Zn anodes in AZMBs face severe challenges, such as dendrite growth, metal corrosion, and hydrogen evolution, all of which are closely related to the Zn/electrolyte interface. This article offers a short review on surface passivation to alleviate the issues on the Zn anodes. The composition and structure of the surface layers significantly influence their functions and then the performance of the Zn anodes. The recent progresses are introduced, according to the chemical components of the passivation layers on the Zn anodes. Moreover, the challenges and prospects of surface passivation in stabilizing Zn anodes are discussed, providing valuable guidance for the development of AZMBs.

Water and Salt Concentration-Dependent Electrochemical Performance of Hydrogel Electrolytes in Zinc-Ion Batteries.

Zinc-ion batteries (ZIBs) are promising energy storage devices with safe, nonflammable electrolytes and abundant, low-cost electrode materials. Their practical applications are hampered by various water-related undesirable reactions, such as the hydrogen evolution reaction (HER), corrosion of zinc metal, and water-induced decay of cathode materials. Polymer hydrogel electrolytes were used to control these reactions. However, salt, water, and polymeric backbones intervene in polymer hydrogels, and currently, there are no systematic studies on how salt and water concentrations synergistically affect polymer hydrogels' electrochemical performance. Here, we used an in situ polymerization method to synthesize polyacrylamide (PAM) hydrogels with varied Zn(ClO4)2 (0.5 to 2.0 mol kg-1) and water (40 to 90 wt %) concentrations. Their electrochemical performances in Zn||Ti half-cells, Zn||Zn symmetrical cells, and Zn||V2O5 full cells have been comprehensively evaluated. Although the ionic conductivity of electrolytes increases with the salt concentration, a high salt concentration of 2.0 mol kg-1 with more Zn2+ solvated H2O would induce more severe HER and Zn corrosion at the electrolyte/electrode interfaces. A narrow window of the water concentration at 70-80 wt % is optimal to balance needs for achieving a high ionic conductivity and restricting water-related undesirable reactions. The chemically more active water counts roughly 64.1-73.1 wt % of the total water in electrolytes. PAM hydrogel electrolyte with 1.0 mol kg-1 Zn(ClO4)2 and 80 wt % water enables 1200 h of stable cycling in a Zn||Zn symmetric cell and 99.24% of Coulombic efficiency in a Zn||Ti half-cell. Due to the water-induced decay of V2O5, the electrolyte with 70 wt % water delivers the best performance in a Zn||V2O5 full cell, which can retain 73.7% of its initial capacity after 400 charge/discharge cycles. Our results show that achieving precise control of salt and water concentrations of hydrogel electrolytes in their optimal windows to reduce the fraction of chemically more active water while retaining high ionic conductivity is essential to enabling high-performance ZIBs.

Enhancement of ammonia corrosion resistance of coatings through improving dispersion and binding site of graphene oxide in silane coatings

Copper metal is essential to our production process, but it is highly corrosive in an ammonia environment and must be highly valued. Anti-corrosion coating is a simple and cost-effective method of preventing metal corrosion. In this study, a composite silane coating was prepared on copper using an impregnation method with mercaptopropyltriethoxysilane (TPTES) as the silane substrate and graphene oxide (GO) modified with isophorone diisocyanate (IPDI) or isocyanatopropyltriethoxysilane (IPTS) as filler to protect the copper from ammonia corrosion. The coating samples were hanging tested against ammonia corrosion by setting up two corrosive environments: ammonia gas and ammonia water. After 20 days of corrosion, the surfaces of the TPTES/IPDI-GO and TPTES/IPTS-GO coatings remained unchanged under both ammonia environments and the corrosion rate was consistently low at 2–3 μm/y. Additionally, the coating exhibited high protective qualities according to the electrochemical impedance spectroscopy (EIS) test in a 3.5% NaCl solution, which is attributed to the good dispersion that improves the densification and regularity of the coating. Meanwhile, IPTS-GO has a greater binding force with the coating matrix due to the increased number of reactive sites, resulting in further improved corrosion protection. This study provides an idea for research on ammonia-resistant coatings.

Solid-like slippery surface for anti-icing and efficient fog collection

Ice accumulation on the surface of aerospace and transportation equipment under extreme weather seriously endangers the safety and efficiency of equipment operation. In recent years, metal corrosion, especially in the marine engineering industry, has become a global concern. The slippery liquid infused porous surface (SLIPS) is a new bionic surface which has caused extensive research in recent years, and has great potential in anti-corrosion and anti-icing. In this study, a multifunctional solid-like lubricated slippery surface (SL-SLIPS) was developed by superhydrophobic modification of the base of copper hydroxide nanoneedles and injection of solid-like lubricant synthesized by embedding oil-stored mesoporous silica nanoparticles on the surface of epoxy resin. At −30 °C, the delayed icing time on the surface of the SL-SLIPS sample was 22.6 times that of the original copper substrate. The ice adhesion was tested on the surface of the sample, and the results showed that the adhesion of the icicle on the SL-SLIPS surface was the smallest, which decreased by 89% compared with the original copper substrate. In addition, SL-SLIPS have excellent corrosion resistance and rapid droplet trapping, nucleation and drop. It has good practical application prospects in corrosion resistance of marine equipment and icing resistance of aerospace and transportation equipment. This study provides new ideas for the design of new slippery surfaces and their application in practical fields, such as anti-corrosion of offshore equipment, anti-icing of equipment in aviation and fog collection engineering in industry.

Under-reporting by surgical pathologists in tissue removed during revision surgery for metal-on-metal arthroplasties.

Although adverse local tissue reactions (ALTR) have been reported for metal-on-metal implants (MoM) requiring early revision surgery, no study has looked at the accuracy of surgical pathologists in diagnosing ALTR. This study aims to investigate the accuracy of reporting adverse local tissue reactions in tissue samples following revision surgery from metal-on-metal implants. The authors reviewed histology glass slides as well as the original pathology reports of tissue processed in revision arthroplasties in 23 cases. These samples were microscopically analyzed for tissue necrosis and cystic degeneration, the presence of metal particles, corrosion byproducts, membrane formation, histiocytic cells, lymphocytic cells, and vascular pathology. The authors' findings were then compared to their corresponding original pathology reports. The authors found consistent under-reporting of the tissue findings. Most importantly, 18 samples showed evidence of metal present compared to 2 samples on original pathology reporting. The authors found that 15 samples showed evidence of pathological membranous tissue compared to just 6 on original pathology reporting. While just 3 of the original pathology reports indicated the presence of areas of predominantly lymphocytic inflammatory cells, the authors found 13 examples of such areas. Although ALTR reactions have been described as a sequala of failed MoM, the authors' data suggest that ALTR may occur more frequently than previously described. Under-reported findings of ALTR deprive both the patient and orthopaedic surgeon of important information that can help guide further follow-up.

Reconstitution of a biofilm adhesin system from a sulfate-reducing bacterium in Pseudomonas fluorescens

Biofilms of sulfate-reducing bacterium (SRB) like Desulfovibrio vulgaris Hildenborough (DvH) can facilitate metal corrosion in various industrial and environmental settings leading to substantial economic losses. Although the mechanisms of biofilm formation by DvH are not yet well understood, recent studies indicate the large adhesin, DvhA, is a key determinant of biofilm formation. The dvhA gene neighborhood resembles the biofilm-regulating Lap system of Pseudomonas fluorescens but is curiously missing the c-di-GMP-binding regulator LapD. Instead, DvH encodes an evolutionarily unrelated c-di-GMP-binding protein (DVU1020) that we hypothesized is functionally analogous to LapD. To study this unusual Lap system and overcome experimental limitations with the slow-growing anaerobe DvH, we reconstituted its predicted SRB Lap system in a P. fluorescens strain lacking its native Lap regulatory components (ΔlapGΔlapD). Our data support the model that DvhA is a cell surface-associated LapA-like adhesin with a N-terminal "retention module" and that DvhA is released from the cell surface upon cleavage by the LapG-like protease DvhG. Further, we demonstrate DVU1020 (named here DvhD) represents a distinct class of c-di-GMP-binding, biofilm-regulating proteins that regulates DvhG activity in response to intracellular levels of this second messenger. This study provides insight into the key players responsible for biofilm formation by DvH, thereby expanding our understanding of Lap-like systems.

High-efficiency graphene/epoxy composite coatings with outstanding thermal conductive and anti-corrosion performance

Although graphene is an ideal thermal conductive and anti-corrosion filler, the thermal conductivity and corrosion resistance of graphene/polymer composite coatings are difficult to improve synergistically. Herein, graphene (rGO) and benzotriazole-loaded hollow mesoporous silica (BTA@HMS) were mixed into epoxy to simultaneously improve its thermal conductivity and anti-corrosion performance. The results show that the thermal conductivity of the prepared rGO-BTA@HMS/epoxy composite coating reaches 1.239 W/(m·K), which is improved by 596 % over pure epoxy. The corrosion protection property of the composite coating is four orders of magnitude higher than that of pure epoxy. Furthermore, BTA@HMS can significantly inhibit the accelerated corrosion of the copper metal coated by rGO/epoxy composite coatings through its self-healing function, and the charge transfer resistance for substrate corrosion is increased from 60 KΩ·cm2 to 3410 KΩ·cm2 due to the introduction of BTA@HMS. The prepared composite coatings have the potential for applications in thermal conductive and anti-corrosion coating fields.

Three anionic surfactants for corrosion inhibition in cobalt CMP: Research on validity and mechanism

Inhibitors are introduced into the slurry to avoid excessive metal corrosion during the chemical mechanical polishing (CMP) process. The anti-corrosion effect of surfactants in CMP was not investigated systematically in past studies. In this paper, three eco-friendly anionic surfactants, potassium laurate, potassium oleate, and dodecyl benzenesulfonic acid, were studied in depth as cobalt CMP inhibitors. Electrochemical experiments demonstrated that the three inhibitors act as anodic inhibitors. Static etching tests and surface morphology analysis proved that they can effectively inhibit the corrosion rate of cobalt and improve surface morphology. XPS results demonstrated that the inhibitor reduces corrosion by inhibiting cobalt oxidation. DFT calculations demonstrated that inhibitors adsorb on the cobalt surface through the O atoms in hydrophilic groups, while the CC double bond and benzene ring can significantly enhance the adsorption. Molecular dynamics simulations showed that the inhibitors are adsorbed on the cobalt surface in parallel. Additionally, all three surfactants improved the solution's wettability on cobalt. This report provides critical insights into the corrosion inhibition specific to cobalt CMP and offers an approach to realize the multi-functionality of a single agent in slurries.

Preparation of Cr-N coatings on 316H stainless steel via pack chromizing and gas nitriding, and their resistance to liquid metal corrosion in early stages

Liquid metal corrosion has become a critical issue in lead-cooled fast reactor when the steel encounters lead–bismuth eutectic (LBE). Although various coatings applied in LBE have garnered interest from many researchers, there are few reports on the compatibility of chrome carbide or chromium nitride coatings in LBE. Thus, Cr carbide and Cr-nitride coatings with thicknesses of 80 μm were prepared on 316H stainless steel (SS) to investigate the corrosion behavior in contact with static liquid LBE at 550 °C for 25, 76, and 207 h. These coatings were synthesized via pack chromizing and subsequent gas nitriding. The results showed that a distinct LBE penetration layer appeared on the surface of the as-received 316H SS after exposure to LBE. Pack-chromized coating and pack-chromized + gas nitride coating did not undergo obvious consumption in LBE in the early stages. Cracks in the pack-chromized coating promoted the preferential diffusion of oxygen and PbBi. The Cr in the pack-chromized + gas nitride coating slightly diffused outward to combine with oxygen to form Cr-oxide scale on the coating surface. These coatings act as a barrier to LBE corrosion, making the surface of the coating impermeable to LBE.

Microbiome analysis of the restricted bacteria in radioactive element-containing water at the Fukushima Daiichi Nuclear Power Station.

In the context of nuclear power station decommissioning, the proliferation of microorganisms within the reactor and piping systems constitutes a formidable challenge. Therefore, the identification of microbial communities in such environments is of paramount importance. In the aftermath of the Fukushima Daiichi Nuclear Power Station accident, microbial community analysis was conducted on environmental samples collected mainly outside the site. However, analyses using samples from on-site areas, including adjacent soil and seawater, were not performed. This study represents the first comprehensive analysis of microbial communities, utilizing meta 16S amplicon sequencing, with a focus on environmental samples collected from the radioactive element-containing water in the torus room, including the surrounding environments. Some of the identified microbial genera are shared with those previously identified in spent nuclear fuel pools in countries such as France and Brazil. Moreover, our discussion in this paper elucidates the correlation of many of these bacteria with metal corrosion.

Coating of ThO2 (111) surface with two–dimensional sheets for potential corrosion protection

ThO2 is an important nuclear fuel that could be used in molten salt reactors, and its corrosion behaviors and anticorrosion mechanisms should be in–depth understood. More emerging two–dimensional (2D) sheets show potentially great corrosion resistance in metal corrosion due to their barrier properties and poor conductivity. In this work, first-principle calculations were performed to assess the potential ability of a series of 2D sheets for the corrosion protection of nuclear material ThO2. The strong binding interaction is found for two MXenes (Mo2C and Ti3C2 sheets) with ThO2 (111) surface revealed by their fairly low binding energy. The high binding strength of Mo2C and Ti3C2 sheets with ThO2 (111) surface originates from the remarkable charge redistribution around the interfaces. The coatings of the semiconducting 2D sheets on the ThO2 surface weaken the interaction with H2O. The one–side passivated MXenes can be efficiently anchored on the ThO2 surface through metal side, and the passivated side shows low adsorption affinity to H2O molecule. Our current work provides the basic understanding of the interaction between 2D nanosheets and ThO2 surfaces.

Specifics and Methods of Inhibiting the Underfilm Corrosion of Carbon Steel.

The process of metal dissolution under a delaminated insulating polymer coating (underfilm dissolution) has been studied. For this purpose, we used an experimental setup that simulates the process of corrosion of underground metal structures in the presence of through defects in the polymer coating and/or extended areas of peeling of the polymer coating from the metal (loss of adhesion)-subfilm cavities partially or completely filled with electrolyte. In particular, the distribution of the protective current under a peeled polymer coating was studied, and a sharp decrease in the value of the protective current was shown at a distance of 1-3 cm from the edge of the defect with a gap between the metal and the coating of 1-6 mm. The localized nature of metal corrosion under the exfoliated polymeric coating has been demonstrated. The ratio of the areas with accelerated corrosion to the total area of the metal can be 1 to 100. It has been established that there are areas of anodic dissolution of the metal during cathodic polarization of the entire sample with a peeled coating. The activating effect of carbon dioxide and hydrogen sulfide on the corrosion and anodic dissolution of steel under the coating was shown. So, it has been established that the dissolution current flowing from the anodic sections on a surface can increase approximately 10 times in the presence of carbon dioxide and hydrogen sulfide. A synergistic effect of these compounds on the process of localized underfilm corrosion of steel was detected. It has been developed a mechanism for the formation of localized corrosion damage to steel under a delaminated polymeric coating, which can be the nuclei of corrosion cracks upon reaching a certain level of mechanical loads, i.e., stress corrosion cracking (SCC) of carbon steel. Possible manners of inhibiting underfilm dissolution of metals are considered, and a method for pre-treatment of the surface with solutions of organosilanes, which ensures the formation of surface self-assembled polymeric siloxane nanolayers responsible for inhibiting underfilm corrosion of steel, is proposed.

Surface adsorption and corrosion resistance performance of modified chitosan: Gravimetric, electrochemical, and computational studies

Two novel chitosan derivatives (water soluble and acid soluble) modified with thiocarbohydrazide were produced by a quick and easy technique using formaldehyde as links. The novel compounds were synthesized and then characterized by thermogravimetric analysis, elemental analysis, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry. Their surface morphologies were examined using scanning electron microscopy. These chitosan derivatives could produce pH-dependent gels. The behavior of mild steel in 5 % acetic acid, including both inhibitors at various concentrations, was investigated using gravimetric and electrochemical experiments. According to the early findings, both compounds (TCFACN and TCFWCN) functioned as mixed-type metal corrosion inhibitors. Both inhibitors showed their best corrosion inhibition efficiency at 80 mg L−1. TCFACN and TCFWCN, showed approximately 92 % and 94 % corrosion inhibition, respectively, at an optimal concentration of 80 mg L−1, according to electrochemical analysis. In the corrosion test, the water contact angle of the polished MS sample at 87.90 °C was reduced to 51 °C. The water contact angles for MS inhibited by TCFACN and TCFWCN in the same electrolyte were greater, measuring 78.10 °C and 93.10 °C, respectively. The theoretical results also support the experimental findings.

Emerging Trends in Smart Self-Healing Coatings: A Focus on Micro/Nanocontainer Technologies for Enhanced Corrosion Protection

Smart self-healing coatings offer a revolutionary approach to mitigating metal corrosion, a problem with significant economic and environmental impacts. Divided into intrinsic and extrinsic types, these coatings autonomously rectify the damage. Intrinsic variants utilize reversible bonds to achieve ongoing repair, while extrinsic ones incorporate micro/nanocontainers that activate upon environmental triggers to mend micro-cracks, their efficacy dictated by the encapsulated healing agents’ volume. This review dissects the rapidly evolving sector of stimuli-responsive self-healing coatings, emphasizing the progress in micro/nano container technology. It discusses the synthesis and encapsulation processes of different micro/nanocontainers and charts the transition from single to multistimulus-responsive systems, which enhances the coatings’ sensitivity and functionality. The addition of multifunctional traits such as self-reporting and anti-microbial actions further broadens their industrial applicability. The review provides a succinct overview of the field’s current state and future potential, envisioning a paradigm shift in corrosion protection through advanced smart coatings.

Deterioration Valuation of Polymer Materials in UV-ozone Generator using Microwave Plasma

Various materials are used to sterilize medical instruments. Rubber and other products deteriorate owing to ozone and UV exposure. Ozone is capable of inactivating bacteria and fungi and is known to be effective in inactivating a wide range of viruses. Silent discharge is the mainstream method of ozone generation. The silent discharge method is also concerned with the generation of nitrogen oxides (NOX) caused by nitrogen molecules in the air, and the deterioration of electrodes during use poses a problem. Furthermore, nitrogen oxides react with water in the gaseous phase to produce nitric acid. Nitric acid reacts with several metals to form nitrates. A sterilization device using high concentrations of ozone has not been put to practical use because of the lack of an efficient method for decomposing ozone and the corrosion of metals. If a medical device is altered, it cannot be used as a sterilizing device. In this study, we exposed polymeric materials, which are often used in medical instruments, to ozone and UV light to determine whether their properties changed. Elution tests were conducted on polymeric medical materials from the viewpoints of their physical and chemical properties, functional decline, and biological safety. This study investigates changes in mechanical strength and surface chemical properties, representing the physical and chemical aspects.

Corrosion Inhibition of Expired Cefazolin Drug on Copper Metal in Dilute Hydrochloric Acid Solution: Practical and Theoretical Approaches.

In this work, we studied the corrosion of Cu metal in 0.5 mol L-1 HCl and the inhibition effect of the expired Cefazolin drug. The inhibition efficiency (IE) of Cefazolin varied according to its concentration in solution. As the Cefazolin concentration increased to 300 ppm, the IE increased to 87% at 298 K and decreased to 78% as the temperature increased to 318 K. The expired drug functioned as a mixed-type inhibitor. The adsorption of the drug on the copper surface followed Temkin's adsorption model. The magnitudes of the standard free energy change (ΔGoads) and adsorption equilibrium constant (Kads) indicated the spontaneous nature and exothermicity of the adsorption process. Energy dispersive X-ray (EDX) and scanning electron microscopy (SEM) techniques showed that the drug molecules were strongly attached to the Cu surface. The electrochemical frequency modulation (EFM), potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS) results were in good agreement with the results of the weight loss (WL) method. The density functional tight-binding (DFTB) and Monte Carlo (MC) simulation results indicated that the expired drug bound to the copper surface through the lone pair of electrons of the heteroatoms as well as the π-electrons of the tetrazole ring. The adsorption energy between the drug and copper metal was -459.38 kJ mol-1.

Oxidation Mechanism and Surface Characterization of Pyrolytic Graphite in Simulated Air for Pyrochemical Reprocessing Application

Accidental air ingress into the containment chamber of pyrochemical reprocessing of spent nuclear fuels can cause severe oxidation of graphite components. Pyrolytic graphite (PyG) coating on conventional high-density graphite (HDG) is proposed for protection against oxidation, molten salt, and molten metal corrosion. The aim of the present study is to evaluate the thermal stability and kinetic parameters and propose a suitable oxidation mechanism of PyG under simulated air using thermogravimetry analysis (TGA). In dynamic oxidation, a linear increase in the oxidation onset, peak, and burnout temperature is observed for PyG synthesized at increasing pyrolysis temperature from 1200 to 2400°C except for 1400°C. The isothermal oxidation study showed a similar trend i.e., a decrease in the linear oxidation rate constant value for any given isotherm with increasing pyrolysis. The Arrhenius plot showed two-stage oxidation regimes operating between 600 to 1000°C. In regime-I, between 600 to ∼800°C controlled by surface chemical reaction kinetics, the activation energy is measured between 100-200 kJ.mol−1. The graphite-oxygen reaction initiates and propagates preferentially along the prismatic planes at the sample edges, where the dangling bonds of stacked graphite layer structures are exposed. In regime-II operating above ∼800°C, the surface reaction rate is infinitely faster, and the diffusional mass transport becomes a rate-limiting factor. In this regime, the graphite-oxygen initiates by pore formation on defective reactive sites on the bulk surface and propagates by pore-widening and pore-coalescence mechanism. The observed differences in the oxidation rates for different pyrolysis PyG attributed to its intrinsic material properties are investigated. This work provides new insights into the oxidation mechanism of the PyG during accidental air ingress in a pyrochemical reprocessing plant.

Unveiling the potent corrosion-inhibiting power of Ammophila arenaria aqueous extract for mild steel in acidic environments: An integrated experimental and computational study

Plant extracts have emerged as potent inhibiting compounds for metallic corrosion, offering numerous advantages including simple accessibility, low toxicity, eco-friendliness, biocompatibility, effectiveness, and renewability. In this study, the potential of Ammophila arenaria extract as a green corrosion inhibitor for mild steel in 1.0 M HCl over the concentration range of 25–700 ppm was evaluated, using various electrochemical analyses such as Open circuit potential (OCP), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Results revealed a notable reduction in the corrosion rate of steel, particularly at 700 ppm, where Ammophila arenaria extract demonstrated its highest inhibition efficiency, reaching 83.67% for polarization and 84.32% for EIS. The cathodic and anodic polarization curves indicated that the aqueous extract of Ammophila arenaria functions as a mixed-type inhibitor. The thermodynamic analysis revealed a negative Gibbs free energy value (∆Gads°), suggesting spontaneous physisorption as the predominant adsorption mechanism. To delve into the inhibition mechanism at the molecular level, the surface morphology of mild steel exposed to 1.0 M HCl solutions, both in the absence and presence of Ammophila arenaria aqueous extract, was scrutinized through Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Theoretical techniques, including Quantum Calculation Theory, Non-Covalent Interaction (NCI), and Atom In Molecule (QTAIM), were concurrently employed, providing valuable insights into molecular-level interactions. Remarkably, the computational studies complemented and corroborated the experimental data. These comprehensive results significantly contribute to the understanding of Ammophila arenaria extract's corrosion inhibiting properties, endorsing its potential as a sustainable and environmentally friendly corrosion inhibitor suitable for diverse industrial applications. The synergistic integration of experimental and computational approaches establishes a robust foundation for future endeavors in the field of green corrosion inhibitors.

An Eco-friendly Mangifera indica Leaves Extract Corrosion Inhibitor for Stainless Steel in Acidic Medium

Corrosion of metals and alloys is one of the most frequent problems encountered in chemical and process industries. Inefficient corrosion control measures typically lead to an increased risk of unplanned downtime, huge economic loss, environmental damage, and health and safety hazards. Hence, it is essential to develop environment-friendly and cost-effective corrosion inhibitors over existing toxic anticorrosive agents. The main objective of this work is to examine the efficacy of eco-friendly ethanolic extract of Mangifera indica leaves (MIL) in different concentrations as a green corrosion inhibitor for stainless steel (SS-316L) under an acidic environment. The inhibition efficiency of Mangifera indica leaves extract in 1 M hydrochloric acid (HCl) was evaluated by conventional weight loss method along with adsorption isotherm analysis. Chemical compounds present in leaf extract and changes in surface morphology of SS-316L samples were assessed using Fourier Transform Infrared spectroscopy (FTIR) and Field Emission Scanning Electron Microscopy (FE-SEM) provided with elemental analysis. The results of the weight loss method revealed that the inhibition efficiency increases with increasing MIL extract concentration due to higher surface coverage. The highest inhibition efficiency of almost 63.43% in 14 days and minimum corrosion rate of 0.433 mm per year was obtained for SS-316 L in 1.0 M HCl with 1000 ppm concentration. The adsorption of MIL extract on SS-316L surface followed Freundlich adsorption isotherm, and the obtained value of free Energy of adsorption (ΔG˚ads = – 9.20 kJ.mol-1) indicates the physical adsorption mechanism. The developed regression-based models can predict the corrosion rate as a function of inhibitor concentration and exposure time with good accuracy (>80%). Thus, the present findings demonstrate that Mangifera indica L. leaves extract can suitably be applied as an inexpensive, non-toxic, biodegradable, efficient green corrosion inhibitor for the protection of stainless steel in acidic media.