Protective Film Research Articles

Corrosion inhibitive performance of Kopsia teoi extracts towards mild steel in 0.5 M HCl solution

This study investigates the capacity of Kopsia teoi (K. teoi) to inhibit corrosion, employing its stem extracts to prevent mild steel (MS) corrosion in 0.5 M HCl. In this study, three distinct extracts: dichloromethane alkaloid (KTDAE), dichloromethane non-alkaloid (KTDNAE), and methanol (KTME) were employed to investigate their corrosion mitigation performance, involving electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD) techniques. EIS results demonstrated a significant increase in inhibition efficiency with concentration for each extract, reaching 87.04, 90.62, and 93.51 % for KTDAE, KTDNAE, and KTME, respectively. According to PD analysis, Kopsia teoi extracts (KTEs) functioned as mixed-type inhibitors. Surface analysis through scanning electron microscopy-energy dispersive X-ray spectroscopy exhibited notable improvements in the morphology of treated MS plates, revealing the establishment of a protective surface film. Langmuir isotherm confirmed that KTEs formed a monolayer on MS surface, and the calculated free energies of adsorption were −25.924, −26.809, and −27.687 kJ mol−1 for KTDAE, KTDNAE, and KTME, respectively. This suggests effective adsorption through both physisorption and chemisorption mechanisms. Consequently, the results of this study highlight the encouraging effectiveness of KTEs as corrosion inhibitors for MS in acidic environments.

Insight into the hot corrosion behavior of GH4251 high-temperature superalloy fabricated by selective laser melting

In this study, the GH4251 high-temperature superalloy was fabricated using selective laser melting (SLM) and hot isostatic pressing (HIP) post-treatment. The hot corrosion behavior of the SLMed and SLM-HIPed GH4251 was systematically investigated and compared with the as-forged one in a mixed salt of 75 % Na2SO4 and 25 % NaCl at 900 °C. The results indicated that three GH4251 superalloys rank in order of superiority for high-temperature corrosion resistance as follows: SLMed > SLM-HIPed > as-forged. The hot corrosion resistance of the alloy is closely related to its microstructures. A high density and a high proportion of small-angle grain boundaries effectively prevent substrate corrosion from molten salts. High dislocation densities and fine grains can increase the elemental diffusion channels and promote the formation of dense protective oxide films, thereby enhancing the hot corrosion resistance. The SLMed superalloy has high densities, high dislocation densities, a high proportion of small-angle grain boundaries, and an appropriate grain size. This is the reason why the SLMed alloy exhibits the most superior hot corrosion resistance. In addition, the hot corrosion mechanisms of the GH4251 superalloy were also discussed in depth.

High temperature oxidation behavior at 1250 °C: A new multilayer modified silicide coating design strategy on niobium alloys

Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy. However, the long-term protective property of single silicide coating remains a long-time endeavor due to the deficiency of oxygen-consuming phases, as well as the self-healing ability of the protective layer. Herein, a silicide-based composite coating is constructed on niobium alloy by incorporation of nano-SiC particles for enhancing the high-temperature oxidation resistance. Isothermal oxidation results at 1250 °C for 50 h indicate that NbSi2/Nb2O5-SiO2/SiC multilayer coated sample with a low mass gain of 2.49 mg/cm2 shows an improved oxidation resistance compared with NbSi2 coating (6.49 mg/cm2). The enhanced high-temperature antioxidant performance of NbSi2/Nb2O5-SiO2/SiC multilayer coating is mainly attributed to the formation of the protective SiO2 self-healing film and the high-temperature diffusion behavior of NbSi2/substrate.

Preparation of high performance calcium oxalate protective film by multifunctional organic molecule on carbonate stones in dry environment

Preparation of calcium oxalate film has been widely adopted in the protection of carbonate stone. However, the solution of oxalate acid or its derivative brushing on the carbonate stone usually evaporates quickly in dry environment, resulting in the inability to form a complete covering calcium oxalate film. Although expensive and difficult to operate, water retention procedures such as surface poultice and plastic wrap are often needful in this case. A novel method for the preparation of the calcium oxalate film with no need of water retention procedures was developed in this paper. The morphology, structure and performance of the calcium oxalate film prepared by above method were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), infrared spectroscopy (IR), X-ray diffraction (XRD), wetting angle, acid resistance, surface strength, porosity, water absorption and color difference. The experimental results showed that a calcium oxalate film with high performance can be prepared in dry environment when ethylene glycol was added into the oxalate acid solution as water retention agent even and the traditional water retention procedures are not necessary. This new method is of great enlightening significance for the protection of the immovable carbonate stones in the dry environment.

MgNiO2 as a Ceramic Additive To Improve the Durability of Lithium Metal Anode.

Ceramic materials are the most popular additives to regulate the reinless interfacial reaction between lithium and the electrolyte by strengthening the SEI layer or tuning lithium deposition. Here, we propose an exceptional material, MgNiO2, abbreviated as MN, which can improve the durability of lithium metal anode. Since it is undecomposed up to 0 V vs Li/Li+, the MN's particles give some semiconductive characteristics to the SEI layer to tune the interfacial reactions. The addition of MgNiO2 in the protective films lowers interfacial resistance, which is responsible for the improved durability of Li|Cu cells: ∼210 cycles, which is 4 times longer than that of the control. Furthermore, this ceramic is used to modify the carbon film woven with carbon nanofibers (CNF @ MN). The cells with this modified 3-D host present excellent operational lives, as high as ∼2400 h in Li|Li symmetric cells and ∼280 cycles in the Li|NCM811 cells. Our approaches demonstrate that MN is an effective ceramic for stabilizing the lithium anode. It also indicates that the inert nature of the semiconductor to lithium is worth exploring thoroughly.

Component regulation and high-entropy engineering for enhanced antioxidant and high-temperature mechanical properties of protective films

Transition metal nitrides (TMNs) have gained widespread application in protecting structural components due to their high strength and hardness. However, TMNs still have the challenge of structural instability and mechanical deterioration caused by oxidation under harsh high temperature conditions. Herein, we present a strategy combining component regulation with high-entropy engineering to develop an advanced high-temperature Al-containing high-entropy nitrides (HENs) material. To prevent the phase decomposition of AlN within the (NbMoTaWAl)N, theoretical simulations were employed to determine a critical atomic percent of 25.0% Al for maintaining the stability of the high-entropy structure. Ensuing experimental synthesis creates three NbMoTaWAlN films with varying Al content: a high-entropy film with 0.0% Al (HEN), a high-entropy film with 21.2% Al (HEN-Al), and an amorphous transition metal nitride film with 30.2% Al (a-TMN-Al), validating key high-entropy engineering benchmarks. It is found that the unique HEN-Al film exhibits excellent oxidation resistance and high-temperature hardness, attributed to the uniform distribution of Al atoms in the robust high-entropy structure, which creates conditions for forming a dense and continuous Al2O3 barrier layer, effectively hindering the diffusion of oxygen into the film interior. This study provides new insights to develop a new generation of high-temperature protective materials.

Constructing surface protective film of V-Se-O to promote zinc ion storage by surface oxygen implantation strategy

Interfacial chemical modification is an effective strategy to adjust the strong Coulombic ion-lattice interactions with high valence cations experienced by electrode materials, facilitating the reaction kinetic. In this paper, a simple and fast surface oxygen implantation strategy was designed to adjust the electronic structure of stainless steel (SS) supported vanadium diselenide (VSe2) nanosheets and form a surface protective film, which effectively accelerates the reaction kinetics of Zn2+ and extends the cycle life of the battery. It is demonstrated that the conductivity, pseudocapacitance and specific capacity can be tuned by selectively introducing oxygen species to the surface, which provides an important reference for the design of electrodes with controlled surface chemistry. Density functional theory (DFT) calculations also confirm that the electronic structure can be adjusted by surface oxygen injection strategy, which not only improves the conductivity, but also adjusts the adsorption energy, thus providing favorable conditions for zinc ion storage. Benefiting from the selenium vacancies and pores generated by the removal of part of selenium, and the oxide film formed on the surfaces, the VSe2-xOx-SS-30 electrode showed higher specific capacity (188.4 mAh/g at 0.5 A g−1 after 50 cycles), better rate performance (107.1 mAh/g at 4 A g−1) and more satisfactory cycling stability (83.1 mAh/g at 5 A g−1 after 1800 cycles) than VSe2-SS electrode. Importantly, the flexible quasi-solid-state VSe2-xOx-SS-30//Zn battery also exhibits high specific capacity and excellent environmental adaptability. Furthermore, the zinc (de)intercalation and transformation reactions mechanism was revealed by some ex-situ/in-situ techniques.

Amelioration of protective organic layer using acenaphthene-based inhibitor responsible for excellent anti-corrosion performance: Experimental and computational perspectives

Despite the engineering promise offered by the co-existence of organic substances in protecting vulnerable metallic materials from corrosive environments, the interaction and formation mechanisms that induce the development of new materials with improved structural properties remain less understood. This study investigated the corrosion inhibitory properties of two acenaphthene derivatives, acenaphthylene-1,2‑dione (ACP) and 1,2-dihydroacenaphthylen-1-ol (DCP), as inhibitors for N80 steel in a 15 % HCl solution. The anticorrosive effectiveness of ACP and DCP compounds was evaluated through multiple research methods, including weight loss analysis, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and surface characterization using scanning electron microscopy (SEM). The experimental findings demonstrate that ACP exhibits superior inhibition performance compared to DCP, with an inhibition efficiency of 93.54 % for ACP and 73.12 % for DCP at an optimum concentration of 5 × 10–3 M. EIS data show that the charge transfer resistance increases with higher concentrations of both compounds. PDP results indicate that ACP and DCP act as mixed-type inhibitors without altering the corrosion mechanism. The kinetic parameters of corrosion adsorption follow the Langmuir isotherm, highlighting a competition between physical and chemical interactions. To investigate how the geometric structures resulting from functional groups influence their interaction with the metal surface, theoretical calculations employing density functional theory (DFT), molecular dynamics (MD), and density-functional tight-binding (DFTB) were conducted. These calculations were aimed at gaining insights into the adsorption behavior of ACP and DCP on the metal surface and their interfacial mechanism. The calculations demonstrate that the molecule possessing twin donor atoms along with p-type orbitals of aromatic rings significantly influenced the formation of a protective film with a uniform distribution. This configuration exhibited superior corrosion performance compared to a molecule containing only one hydroxyl group (—OH). Theoretical calculations further suggest that ACP exhibits stronger adsorption ability, with the two oxygen atoms identified as the most reactive sites, indicating their tendency to donate electrons to the iron surface. The robust resonance-stabilized structure of ACP enhances the stability of the molecules, facilitating its interaction and adsorption onto the metal surface compared to the DCP inhibitor. Overall, the superior inhibition performance of ACP is attributed to the close bonding of twin donor fragments within the ACP molecule, forming a more compact adsorbed inhibitor film on the steel surface.

Effect of Sn addition on the microstructure and corrosion behavior of dilute wrought Mg-Zn-Ca series alloys

The effect of Sn alloying (0.5, 1.0, 2.0 wt%) on microstructure and corrosion behavior of dilute Mg-2Zn-xSn-0.5Ca rolled sheets is illuminated. The corrosion resistance first increases and then decreases with raising Sn content. The alloy with 1 wt% Sn shows the lowest corrosion rate of ∼2.1 mm/y, decreased by ∼63 % compared with Sn-free alloy. Although nobler MgSnCa phase is formed after alloying, more protective oxide film containing SnO2 is also formed, which effectively hinders localized corrosion. However, at 2 wt% Sn addition, detrimental effect of MgSnCa overwhelms positive effect of Sn on film, thus deteriorating corrosion resistance.

2-Benzylsulfanyl-1H-benzimidazole and its mixture as highly efficient corrosion inhibitors for carbon steel under dynamic supercritical CO2 flow conditions

2-Benzylsulfanyl-1H-benzimidazole(2B1BI) was synthesized and used to inhibit the corrosion of carbon steel in supercritical CO2 brine at various rotation speeds. Thiourea (TU) can improve the inhibition of 2B1BI. The corrosion inhibition mechanism and adsorption process were investigated by electrochemical techniques and theoretical calculations. The results show that 2B1BI-TU mixed corrosion inhibitors exhibit increased adsorption with strong bonds on steel, forming a denser and more persistent protective film. This film can effectively inhibit corrosive particles, slowing down both general and localized corrosion. This study explores the potential of the new inhibitor as an efficient corrosion inhibitor in challenging environmental conditions.

Electrochemical corrosion behavior of nanostructured BCC-Al0.5CoCrFeNi0.4 high-entropy alloy in sodium chloride solution

The electrochemical corrosion behavior of Al0.5CoCrFeNi0.4 high-entropy alloy (HEA) in 3.5 wt.% NaCl solution was investigated by electrochemical measurements coupled with comprehensive characterization of its surface films. The results demonstrate that the Al0.5CoCrFeNi0.4 HEA primarily consists of (Al,Ni)-rich B2 phase and (Cr,Fe)-rich A2 phase. When subjected to electrochemical polarization, an ultrathin passive film rich in Cr is homogeneously formed on the surface. As the applied potential increases, the protective film tends to break down at the interface of two phases, followed by the preferential dissolution of B2 phase. Finally, the surface film with a triple-layer structure is formed on the HEA surface. Specifically, the inner layer and the middle layer are enriched in Cr and Fe, respectively, due to the high stability of Cr species and the selective dissolution of Fe. The (Al,Ni)-rich corrosion products are found to deposit at the outmost position ascribed to the dissolution of B2 phase.

Impact of multi-factor coupling on the corrosion behavior of 254SMo stainless steel in an aggressive oilfield environment containing CO2 and H2S

The passivity and corrosion behavior of 254SMo stainless steel in aggressive oilfield environments containing both carbon dioxide (CO2) and hydrogen sulfide (H2S) were investigated using weight-loss and surface analyses. The results indicated that the corrosion rate increased with the increase in temperature, CO2/H2S partial pressures, tensile stress and flow rate. Compressive stress led to a reduction in sulfide compound contents and promoted the formation of protective oxide films, while tensile stress had an opposite effect. Furthermore, a synergistic effect of stress and flow was observed.

UV‐photopolymerized acrylic pressure‐sensitive adhesives with semi‐interpenetration structure: Effect of plasticizer structures on adhesion properties

AbstractAcrylic pressure‐sensitive adhesives (PSAs) were synthesized using a solvent‐free ultraviolet‐induced polymerization method. The monomers n‐(isobutoxymethyl) acrylamide, 2‐ethylhexyl acrylate, 2‐hydroxyethyl acrylate, and methyl methacrylate and an initiator, hydroxy dimethyl acetophenone, were used to prepare acrylic copolymers as prepolymers. A multifunctional monomer, trimethylolpropane triacrylate, was added to form a semi‐interpenetrating network, leading to an increase in the modulus and elasticity of the prepolymer. This decreased the peel strength, which is suitable for temporary protective films. Rheological data from small‐amplitude oscillatory shear measurements also revealed consistent results suitable for removable PSAs. The plasticizers, such as dioctyl phthalate and dioctyl terephthalate, possessing favorable interactions with the main resins were found to exhibit transparency, clear debonding, and ultralow release, which are essential features for temporary protective films.

P‐87: Research on the Influence Factor of Tearing Static Electricity Based on Display Module

This article analyzes and studies the generation, disappearance, and influencing factors of static electricity during the removal of protective film from the module screen, and confirmed the influence trend. To solve the problem of module abnormal display caused by excessive static electricity during film tearing.

Polyethyleneglycol bisphenol A epichlorohydrin copolymer (PEG-BEC) as a highly efficient inhibitor for mild steel corrosion in 1M HCl solutions

In this work, the corrosion inhibition performance of polyethyleneglycol bisphenol A epichlorohydrin copolymer (PEG-BEC) against mild steel in 1 M HCl was studied by electrochemical and weight loss techniques. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX) were applied to characterize the surface morphology of the mild steel samples. The corrosion mitigation efficiency was observed to rise as the concentration of PEG-BEC rises in the corrosive medium while increasing the temperature (25 °C -65 °C) resulting in a drop in the inhibition ability. Furthermore, under hydrodynamic conditions, the corrosion of the mild steel was found to deteriorate both in the absence and presence of PEG-BEC. Just with 10 ppm, an inhibition efficiency (IE) of 97.6% was obtained at 25 °C by EIS. PEG-BEC acts as a mixed-type inhibitor as observed by potentiodynamic polarization (PDP) technique. The observed corrosion inhibition action of PEG-BEC could be ascribed to the adsorption of the molecules and the formation of a protective film on the steel surface as evidenced by static water contact angle (WCA). Langmuir isotherm best describes the PEC-BEG-metal adsorption with large Kads values indicating a thermodynamically stable nature inhibition process. The obtained ∆G°ads = -35.138 to -39.522 kJ/mol indicate that the PEG-BEC spontaneously adsorbed onto the steel with strong tendency to provide protection to the mild steel surface via combination of chemisorption and physisorption processes. The ΔHads -53.07 kJ/mol and ΔSads= +0.048 kJ/mol-k, respectively, suggests an exothermic reaction accompanied by relatively increase in entropy of the PEG-BEC adsorption on the mild steel surface.

CORROSION INHIBITION BEHAVIOUR OF CUSTARD APPLE LEAVES AND ACACIA CONCINNA EXTRACT ON MILD STEEL IN ACIDIC MEDIA: ADSORPTION AND THERMODYNAMIC STUDY

Custard apple leaves extract (CALE) was tested to evaluate corrosion inhibition efficiency for mild steel under acidic medium. The test metal substrate was collected over a period of 24 hr of contacting with acid to determine the corrosion inhibition efficiency (CIE) and corrosion rate (CR) using the Gravimetric analysis. The findings of the study were applied to examine the adsorption behavior and thermodynamic characteristics for CALE as a potential corrosion inhibitor in acidic environment. Mild steel exhibited the highest corrosion rate in the absence of a corrosion inhibitor in a 0.5 M sulphuric acid solution. However, the rate of corrosion was observed to decrease gradually with increase in CALE concentration (0.4–2.0 g/l). The similar trend was noted at the experimental temperature range of 298-328 K. Adsorption behavior was investigated using the Langmuir, Temkin, Freundlich, and Flory Huggins adsorption isotherm models. The Temkin adsorption isotherm model provides the best fit to the experimental data. Besides, the negative values of Gibb’s free energy of adsorption (ΔGad) reveal strong evidence for the spontaneous nature of CALE adsorption on mild steel surface. The increase in activation energy (Ea) from 35.05 kJ/mol in the blank test solution to 68.03 kJ/mol at 2.0 g/l concentration of CALE indicates the formation of a protective film of inhibitor molecules on the metal surface. Adsorption enthalpy values (∆H=31.28-73.79 kJ/mol) over the concentration range (0-2.0g/l of CALE) implies physical adsorption, whereas negative entropy values (ΔS) suggests free movement of inhibitor molecules in the bulk solution. Additionally, a synergistic effect was demonstrated in lowering the corrosion rate by combining Acacia concinna extract (ACE, 0.1-0.3 g/l) with CALE, thereby enhancing the overall corrosion inhibition efficiency. For citation: Jitendra Kisan Shinde, Ravindra Gulab Puri, Pawan Devidas Meshram, Rajkumar Shankarrao Sirsam Corrosion inhibition behaviour of Custard apple leaves and Acacia concinna extract on mild steel in acidic media: adsorption and thermodynamic study. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 119-126. DOI: 10.6060/ivkkt.20246707.7038.

Conformal Low‐Temperature Molecular Layer Deposited Coatings as Interface Modifications to Support Ceramic Protective Films on Macroscopic Flexible Devices

Flexible devices often need a protective coating when operating in harmful environments, ranging from mild ambient conditions to a biologically active environment of the human body. The flexibility poses a problem for traditional encapsulation solutions, as those make the device bulky and limit functionality by applying an external casing. Alternatively, fully conformal encapsulation of a device of arbitrary shape can be realized with thin‐film encapsulation (TFE) without altering device dimensions. Yet, TFE is susceptible to fail under mechanical stresses, especially when a hard ceramic coating is applied on a polymer. Reliability of TFE can be enhanced by altering the elasticity of the hard and brittle thin films, by adding softer layers in between sample and barrier. Herein, molecular layer deposited (MLD) metal‐linked trioxysilylheptanoate (M‐TOSH) films are studied for coating of large devices to conformally and uniformly tune the interface between polymer and atomic‐layer‐deposited protective film. The results show that M‐TOSH process scales to large chambers; parameter optimization leads to superior film quality and lowers elastic modulus. Conformality, tested with home‐built macroscopic test device, finds the process suitable for 3D parts. Final testing reveals that ten cycles of MLD interlayer double the crack‐onset‐strain from 0.26% to 0.51%.

Enhancing high-temperature tribological properties in a detonation-sprayed CoCrNiAl0.3Ti0.3 medium-entropy alloy coating via in-situ formed Al2O3-type oxides and rich-Ag phases

Heterogeneous high-entropy/medium-entropy alloy coatings have the potential of being advanced tribo-components for service in demanding environments. We incorporate dual-heterostructure (Al2O3-type oxides and Ag-rich phases) into the deposited CoCrNiAl0.3Ti0.3 medium-entropy alloy coating employing in-situ flight oxidation and solute addition during detonation spraying. Such heterostructures improve the coating quality and serves twofold, through deposition densification and solid-solution strengthening, contributing to an ultra-low porosity of < 0.6 %, a high bond strength of 61 MPa, and a hardness of 7.6 GPa. The self-organized tribo-layer activated by the heterostructures inhibits abrasive wear at room-temperature, but struggles to resist surface softening and adhesion at 600 ℃. Heterostructures govern the formation of protective glaze-layers and Ag transfer films at 800 ℃ and 1000 ℃, minimizing adhesion and delamination between the tribo-pairs.

Exploring Ginkgo biloba extract's green corrosion inhibition effects on Q235 steel in H2SO4 environments

The corrosion inhibition properties of Ginkgo biloba extract on Q235 steel in 0.5 M H2SO4 solution were comprehensively investigated using weight loss measurements, electrochemical techniques, surface characterization, and quantum chemical calculations. The results demonstrate that Ginkgo biloba extract acts as an effective green corrosion inhibitor, with inhibition efficiencies reaching up to 96.54% at a concentration of 0.7 g/L. The inhibition efficiency increased with increasing extract concentration and temperature. FTIR and LC/MS analyses revealed that the extract contains various phytochemical constituents, including flavonoids, terpenoids, and other polyphenolic compounds, which contribute to its corrosion inhibition properties. The adsorption of the extract compounds on the steel surface followed the Langmuir adsorption isotherm, with a negative value of the standard free energy of adsorption, indicating a spontaneous and stable adsorption process involving both physisorption and chemisorption. SEM and XPS analyses confirmed the formation of a protective film by the adsorbed extract compounds, which acts as a barrier, preventing the direct contact between the aggressive solution and the steel substrate. The film also alters the wettability of the metal surface, making it more hydrophobic and further enhancing the corrosion inhibition efficiency. Quantum chemical calculations showed that flavonoids, particularly quercetin, contribute significantly to the corrosion inhibition performance due to their high reactivity, strong dipole moment, and stable adsorption on the Fe(110) surface. These findings provide valuable insights into the development of sustainable and eco-friendly corrosion inhibitors for the protection of metal structures in acidic environments.

A novel AlCo1.2Cr0.8FeNi2.1 eutectic high entropy alloy with excellent corrosion resistance

A novel AlCo1.2Cr0.8FeNi2.1 eutectic high entropy alloy (EHEA) was designed and prepared. The microstructure of the as-cast alloy was characterized that a fine lamellar structure composed of FCC (L12) phase and B2 phase. The mechanical of the EHEA was studies by the tensile tests, and the corrosion properties of the EHEA in 3.5 wt% NaCl solution at room temperature was investigated. The results shown that the alloy exhibits synergistic effect of strength- plasticity with a high tensile strength of 1048.42 MPa and an excellent elongation of 18.92%. Potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) indicated that the EHEA exhibits spontaneous passivation in 3.5 wt% NaCl solution, forming a protective passive film that exhibits p-type and n-type semiconductor properties, with the main components of Al2O3, CoO, Cr2O3, Fe(OH)3, and NiO. Furthermore, the corrosion mechanism of EHEA was discussed.