Benzotriazole Molecules Research Articles

Molecular Interactions in Copper Chemical Mechanical Planarization: A Phenomenological Study

In this study, the molecular interactions occurring during Chemical Mechanical planarization of Copper in Ferric nitrate–Alumina–Benzotriazole system is investigated. This system is characterized by sudden and dramatic transitions in removal rates when experimental parameters such as downforce and concentrations of the slurry components (Benzotriazole, abrasive, oxidizer) are varied. This behavior is interpreted in terms of the three surface kinetic processes viz. Cu dissolution, film formation and film removal by abrasion, that determine the overall removal rate. A phenomenological model incorporating Frumkin isotherm for the adsorption of Benzotriazole molecules and Langmuir isotherm for the adsorption of surfactants/ions is proposed. Mathematical equations relating the rates of film formation, film removal and metal dissolution to the overall removal rates are derived. The model is validated by comparing the model predictions with experimental data. The non-linear equations describing the sudden transitions are shown to exhibit a cusp catastrophe when the interaction parameter exceeds a certain value.

Exploring the effectiveness of two triazole derivatives as copper corrosion inhibitors in NaCl solution: A combined approach of quantitative chemistry and dynamic molecular simulations

The present study investigates the effectiveness of a novel inhibitor, 2‑hydroxy-5-((4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl) benzaldehyde (STR), in preventing copper from corrosion in a 3.5 wt.% NaCl solution. A comparative study of the inhibition efficiency between our newly synthesized water-soluble triazole STR, and the commercially available Benzotriazole (BTA) was evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) tests. The results revealed a substantial reduction in the rate of copper oxidation with increasing inhibitor concentrations. At 10−3 M, STR and BTA demonstrated inhibition efficiencies of 92.73% and 97.62% respectively. Analysis of the Tafel curves showed that the inhibitors used exhibited mixed type behavior. Langmuir isotherms showed that the STR and BTA molecules are adsorbed on copper surface, following the chemical adsorption process. Theoretical calculations based on density functional theory (DFT) method and molecular dynamic (MDS) simulations, provided valuable insights into the efficacy and mode of action of STR and BTA as copper corrosion inhibitors in a 3.5 wt.% NaCl solution.

The new insights towards smart pH-responsive anticorrosion coating based on HNTs carrying synergistic inhibitors: Experimental and molecular simulation

Corrosion of steel structures in reinforced concrete structures in coastal areas has long been an urgent concern. In this study, a combined corrosion inhibitor, consisting of benzotriazole (BTA) and sodium D-gluconate (SD), was loaded onto halloysite nanotubes (HNTs) using the vacuum negative pressure method. Then, the HNTs were encapsulated with biomass polyelectrolytes sodium alginate (SA) and chitosan (CS) by layer-by-layer self-assembly technique to prepare BTA/SD-HNTs@CS/SA (FHNTs) composite. Furtherly, a functional epoxy coating (FEP) with pH-responsive and long-term service ability was successfully fabricated. It is found that BTA/SD was released in large quantities under alkaline (pH = 11) and acidic (pH = 2) conditions, while essentially no release under neutral condition. The electrochemical impedance spectroscopy (EIS) measurements demonstrate that the corrosion protection ability of FEP was significantly stronger than pure epoxy coating (EP), and the addition of 2 % FHNTs having the most excellent anticorrosion performance with the maximum charge transfer resistance (Rct) value (4.8 × 106 Ω cm2) after 4 weeks of immersion, which was 2 orders of magnitude greater than the pure EP coating. Particularly, molecular dynamics (MD) simulations indicate that FEP coating has better barrier properties than EP, while the fractional free volume (FFV) value of H2O and Cl− in EP was 9.1 % and 5.1 %, respectively, whereas this value decreased by about 15 % to 7.7 % and 4.4 % in FEP. The results of density functional theory (DFT) calculations suggest that the released BTA and SD molecules have a synergistic adsorption effect on the surface, which can form a compact film to hinder the invasion of corrosive species. Overall, this study provides new insights for developing smart pH-responsive and superior anticorrosion coatings.

First-principles and experimental study on the inhibition efficiency of BTA for 20SiMn steel in chloride-containing solutions

The inhibition effect of benzotriazole (BTA) with the increase of concentration for 20SiMn steel in 3.5 wt% NaCl solutions was investigated by electrochemical methods, Scanning Electron Microscope (SEM), X-ray Photoelectron Spectroscopy (XPS) and Density Functional Theories(DFT). Results indicate that BTA could suppress the corrosion of 20SiMn steel through chemisorption but with a limited inhibition efficiency (around 60%). DFT calculated results show that the chemisorption of BTA has noticeable effects on the charge distribution of the whole BTA molecule, as well as that of N atom which bonds with Fe atom, but has little influence on those of Fe atom in N-Fe bond and Fe(110) surface where BTA molecules adsorb. The DFT calculated Density of States (DOS) peaks of N atom in N-Fe and those of BTA molecule become lower after the adsorption, and the location of DOS peaks move far away from the Femi surface, implying a more stable structure. As to Fe atom in N-Fe bond and Fe(110) surface, neither height nor locations of the DOS peaks change,which is crucial for losing electrons of metallic matrix and thus responsible for the limitation of BTA inhibition effect.

Studies of Benzotriazole on and into the Copper Electrodeposited Layer by Cyclic Voltammetry, Time-of-Flight Secondary-Ion Mass Spectrometry, Atomic Force Microscopy, and Surface Enhanced Raman Spectroscopy.

Benzotriazole (BTA) is an important compound that demonstrates the strongest anticorrosion properties of copper and plays a role as a leveler and an additive to the electroplating bath for control of the roughness and corrosion resistance of the electrodeposited copper layer. In this paper, we combined cyclic voltammetry (CV), time-of-flight secondary-ion mass spectrometry (TOF-SIMS), surface enhanced Raman spectroscopy (SERS), and atomic force microscopy (AFM) to study the interaction of BTA with copper surfaces at varied concentrations with and without the presence of chloride ions. We identified the most relevant molecular copper and its complex forms with BTA on the copper electrodeposited layer. BTA is adsorbed and incorporated into the copper surface in monomeric, dimeric, trimeric, tetrameric, and pentameric forms, inhibiting the copper electrodeposition. The addition of chloride ions diminishes the inhibiting properties of BTA. The Cu-BTA-Cl complexes were identified in the forms C12H8N6Cu2Cl- and C6H4N3CuCl-. Coadsorption of chloride ions and BTA molecules depends on their concentration and applied potential. Chloride ions are replaced by BTA molecules. BTA and chloride ions, depending on their concentration and applied potential, control the copper nucleation processes at the micro- and nanoscales. We compared the abilities and limitations of TOF-SIMS and SERS for studies of the interactions of benzotriazole with copper and chloride ions at the molecular level.

Insights into the Molecular Motion of Benzotriazole in the Volatile Corrosion Inhibitor Packaging: A Detection and Mass Transfer Study

A new methodology using microwave extraction, gas-diffusion microextraction (GDME) and high-performance liquid chromatography-mass spectrometer (HPLC-MS) was developed for the analysis of the quantitative detection of gaseous and solid benzotriazole (BTA) and the mass transfer behavior of BTA in volatile corrosion inhibitor (VCI) packaging. The best extraction conditions of BTA in the VCI films were obtained, and the vapor pressure of BTA in the VCI packaging was detected and characterized by a mathematical model using the new methodology. The migration content of BTA in the VCI films and the BTA content on the surface of the films were detected, and the diffusion coefficients at three temperatures were calculated. The vapor pressure and diffusion coefficients of BTA increased with increasing temperature, and the volatilization of BTA promoted the migration of BTA from the VCI films. Moreover, a molecular dynamics (MD) simulation was performed to determine the migration of the BTA molecules within the VCI films at three temperatures; the overall trend of the experimental values was the same and the simulated values were generally within two orders of magnitude of the corresponding experimental values, with the difference likely due to the ignoring of the crystallinity of LDPE.

Synergistic inhibition of azoles compounds on chloride-induced atmospheric corrosion of copper: Experimental and theoretical characterization

Synergistic implementation of corrosion inhibitors is an efficient and economic method for metal protection. The adsorption dynamics and inhibition behavior of 2-phenyl imidazoline (2-PI) and benzotriazole (BTA) are investigated in atmospheric and aqueous environments by electrochemical and quartz crystal microbalance sensors. Moreover, their synergistic mechanisms are illustrated from molecule scales by theoretical calculations. Electrochemical tests show that 2-PI and BTA exhibit promising synergistic effects on the corrosion of copper with inhibition efficiency up to 99.1% in 0.1 mol/L NaCl solution and 94.1% in the atmosphere, respectively. In addition, the adsorption kinetics of inhibitors on copper obey a pseudo-first-order kinetic model characteristic of exponential damping. Quantum chemical and molecule dynamic calculations also suggest that there exists an intermolecular interaction between 2-PI and BTA molecules in a parallel adsorption manner when they are co-adsorbed on the surface of copper.

Application of an optimized alkaline cleaning solution for inhibitor removal during the post-CMP process: Performance evaluation and mechanism analysis

With the continuous miniaturization of the feature size of semiconductor integrated circuits, the development of chemical mechanical polishing (CMP) technology for copper interconnection has been promoted, and at the same time, more stringent requirements and challenges have been put forward for post-CMP cleaning technology. Benzotriazole (BTA), which has been used as an inhibitor to decrease metal corrosion especially in copper CMP process, is the main object to be removed after the CMP process due to its highly hydrophobic nature. However, the current post-CMP cleaning method cannot achieve an effective balance between high removal efficiency of BTA and excellent surface quality after CMP cleaning. Therefore, a novel and efficient alkaline cleaning solution for post-CMP cleaning of copper is proposed, which is based on tetraethylammonium hydroxide (TEAOH), l-glutamate (Glu) and polyvinylpyrrolidone (PVP). The cleaning effect of copper surface was characterized by contact angle measurement, electrochemical system, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The ion exchange of TEAOH and Glu promotes desorption of BTA molecules from the copper surface. The presence of PVP plays a key role in improving the surface quality after cleaning. This cleaning solution was proved to be effective for BTA removal and achieving a nearly defect-free clean surface.

Dissociative adsorption of azoles on Cu(111) promoted by chemisorbed O and OH

Metal surfaces are usually either oxidized or at least covered with species such as O and OH under ambient conditions. We show by DFT calculations that chemisorbed O and OH species promote deprotonation of azole molecules on copper surfaces, as exemplified herein by imidazole, benzotriazole, and Cu(111). Deprotonation involves the N–H bond cleavage, although imidazole can also deprotonate via the C–H cleavage. Calculated deprotonation activation energies are considerably smaller for the cleavage of the N–H bond (0.01 eV for benzotriazole and about 0.1 eV for imidazole) than for the cleavage of the C–H bond (from 0.6 to 0.9 eV for imidazole), although the cleavage of C–H bond is thermodynamically preferred for imidazole. Deprotonation reaction energies do not depend strongly on the coverage of O and OH, and for coverages from 1/16 to 1/4 ML, reaction energies typically alter by about ±0.1 eV. The importance of molecular deprotonation upon adsorption is in higher stability of the resulting adsorption states, which increases the persistence of chemisorbed molecules. In particular, deprotonated benzotriazole molecules are by about 1 eV more stable on O/Cu(111) and OH/Cu(111) compared to an adsorbed intact molecule on bare Cu(111). In contrast, for imidazole, the magnitude of such stabilization is significantly weaker (from 0.3 to 0.7 eV).

Effect of Corrosion Inhibitor BTA on Silica Particles and their Adsorption on Copper Surface in Copper Interconnection CMP

In the process of chemical mechanical polishing (CMP) of multilayer copper wiring of integrated circuits, benzotriazole (BTA) as corrosion inhibitors and silica particles as abrasives are important components of polishing slurry. At the same time, they are also the main objects of post CMP cleaning. Under alkaline conditions (pH 10), the addition of BTA will affect the stability of silica particles, such as particle size and zeta potential, so as to affect the adsorption of particles on the copper surface. The effects of different concentrations of BTA on the adsorption of silica particles on copper surface were characterized by scanning electron microscopy (SEM), and the corresponding adsorption mechanism was also analyzed by X-ray photoelectron spectroscopy (XPS). The adsorption energies of BTA molecule and SiO2 molecule on copper surface were calculated by molecular dynamics simulation. The results show that 3 mM BTA reduces the adsorption capacity of SiO2 particles, and increasing the concentration of BTA will increase the adsorption capacity of SiO2 particles on the copper surface.

Adsorption properties and mechanism of montmorillonite modified by two Gemini surfactants with different chain lengths for three benzotriazole emerging contaminants: Experimental and theoretical study

Two gemini surfactants propylbis (dodecyldimethyl) ammonium chloride (12−3−12) and propylbis (octadecyldimethyl) ammonium chloride (18–3-18) with different chain lengths were used to modify Ca- montmorillonite (Ca-Mt). XRD results showed that the arrangement of surfactants was mainly paraffin-type and with additional minor lateral-bilayer in the interlayer space of montmorillonite. Batch adsorption tests indicated that the modified organo-montmorillonite (G12-Mt and G18-Mt) had better removal effect on three benzotriazole emerging contaminants (ECs) than that of original Ca-Mt, and the sequence of adsorption capacity was 1-Hydroxybenzotriazole (OHBTA) > benzotriazole (BTA) >5-methylbenzotriazole (TTA). Molecular dynamics simulation was carried out to reveal the arrangement, conformation and behavior of Gemini surfactants in the interlayer of Mt. at atomic level. The results suggested that one of the two long alkyl chains was erected in a paraffin-type arrangement, the other long alkyl chain accompanying with the positively charged N head groups & the propyl spacer were parallel to the Mt. (001) plane and was fixed near the top and bottom surfaces with the arrangement of lateral-bilayer, which was agreement with the XRD data. BTA molecules located at the aggregate organic phase formed by the alkyl chain, while Cl− ions preferred to appear in the middle area of the interlayer of montmorillonite. Meanwhile, Multiwfn wavefunction program was applied to quantitatively analysis the molecular surface area in different electrostatic potential (ESP) intervals, the ESP minimum & maximum values on the three ECs molecular vdW surface, integrating with color-filled ESP planar maps and VMD program to insight the electrostatic interaction and magnitude order between Gemini surfactants modified Ca-Mt and three pollutants. The adsorption mechanisms of Gemini surfactants modified Mt. to three benzotriazole emerging contaminants involved electrostatic interaction and hydrophobic partitioning effect.

Chemical anti-corrosion strategy for stable inverted perovskite solar cells.

One big challenge for long-lived inverted perovskite solar cells (PSCs) is that commonly used metal electrodes react with perovskite layer, inducing electrode corrosion and device degradation. Motivated by the idea of metal anticorrosion, here, we propose a chemical anticorrosion strategy to fabricate stable inverted PSCs through introducing a typical organic corrosion inhibitor of benzotriazole (BTA) before Cu electrode deposition. BTA molecules chemically coordinate to the Cu electrode and form an insoluble and polymeric film of [BTA-Cu], suppressing the electrochemical corrosion and reaction between perovskite and the Cu electrode. PSCs with BTA/Cu show excellent air stability, retaining 92.8 ± 1.9% of initial efficiency after aging for 2500 hours. In addition, >90% of initial efficiency is retained after 85°C aging for over 1000 hours. PSCs with BTA/Cu also exhibit good operational stability, and 88.6 ± 2.6% of initial efficiency is retained after continuous maximum power point tracking for 1000 hours.

Detection of corrosion inhibitor adsorption via a surface-enhanced Raman spectroscopy (SERS) silver nanorods tape sensor

In this work, surface-enhanced Raman scattering (SERS) strategy was utilized for the on-site detection of corrosion inhibitors using a silver nanorods anchored transparent tape sensor. SERS detection realized the intense enhancement of Raman signals from inhibitors to characterize their adsorption behavior on metallic surfaces. Benzotriazole (BTA) molecules were employed as corrosion inhibitors for the protection of AA2024-T3 aluminium alloy in 3.5 wt.% NaCl solution. Electrochemical impedance spectroscopy (EIS) measurement and surface characterization confirmed the superior corrosion inhibition performance of BTA. SERS assessment elucidated that the Raman signals of BTA on AA2024-T3 surface increased gradually with the increase of inhibitor concentration and immersion time. By comparing the EIS and SERS results, it is shown that the SERS intensity was positively correlated with the resistance of the inhibitor film (Rf) and inversely correlated with the capacitance of the inhibitor film (Qf), which indicated that the increased BTA adsorption offered superior inhibitive property against the corrosion of AA2024-T3 in saline solution. The SERS tape developed in this study can be used as a versatile sensor to monitor the dynamic adsorption process of corrosion inhibitors with no restriction on substrate materials.

Polyethylenimine wrapped mesoporous silica loaded benzotriazole with high pH-sensitivity for assembling self-healing anti-corrosive coatings

The aim of this work is to develop a self-healing coating doped with pH-sensitive nanocontainers for the active corrosion protection of mild steel. A pH-sensitive carboxyl-functionalized mesoporous silica nanomaterials (MSNs-COOH) was prepared via chemical modification of mesoporous silica nanomaterials (MSNs) which was synthesized in a tetraethyl orthosilicate (TEOS) solution via base catalyzed sol-gel process. Benzotriazole (BTA) molecules were loaded into the internal pores of the prepared MSNs-COOH. Then the BTA-loaded MSNs-COOH were wrapped by the highly branched polyethylenimine (PEI) to obtain the nanocontainers of BTA@MSNs-COOH-PEI. SEM, TEM, DLS, XRD, nitrogen adsorption-desorption isotherms, TGA and FT-IR analyses were employed to characterize the as-prepared nanocontainers. The pH-sensitive releasing property of BTA@MSNs-COOH-PEI was studied using UV–vis spectroscopy, which indicates that the releasing rate of BTA from BTA@MSNs-COOH-PEI can be accelerated under alkaline conditions. Afterwards, a self-healing coating was fabricated based on the epoxy resin primer doped with BTA@MSNs-COOH-PEI which can release BTA inhibitor once localized corrosion occurs. Finally, the active anti-corrosion performance of the as-prepared coating was confirmed by EIS measurements and salt spray tests. The self-healing coating prepared in this work brings a new sight for elaborate design of active anti-corrosion coatings.

On the acid-responsive release of benzotriazole from engineered mesoporous silica nanoparticles for corrosion protection of metal surfaces

• UV-induced degradation lowers the corrosion inhibitor ability of benzotriazole. • Mesoporous silica nanocarriers protect benzotriazole from photodegradation. • High anticorrosion efficacy of nanocomposite coatings even after UV exposure. Corrosion inhibitors are largely exploited for the development of highly performing polymeric active coatings. One of the major drawbacks, however, relies in their UV sensitivity, which may compromise their ability to effectively prevent corrosion processes. This issue is particularly relevant in the field of cultural heritage preservation, in which polymeric active coating which are able to ensure a reliable and long-lasting protection against corrosion are highly needed. Besides proving that UV-induced photodegradation impressively lowers the corrosion inhibition ability of benzotriazole (BTA), in the present work we show that this phenomenon can be largely prevented by exploiting inorganic nanocarriers. More specifically, BTA molecules loaded into functionalized mesoporous silica nanoparticles are preserved from photodegradation and released in the host coating only in the presence of acid-related external stimuli. Accelerated corrosion tests carried out on a commercial acrylic-based coating containing engineered mesoporous silica nanoparticles loaded with BTA demonstrated that the developed system possesses an excellent anticorrosion ability.

Dendrite-Free Lithium Anodes Enabled by a Commonly Used Copper Antirusting Agent.

Li metal is considered the most promising anode for high energy density secondary batteries due to its high theoretical capacity and low redox potential. However, lithium is prone to form dendrites which will not only cause internal short-circuits but also bring accumulation of "dead Li" and result in fast capacity decay, thus its large-scale application is challenging. In this work, we demonstrate that the commonly used metal corrosion inhibitor, benzotriazole (BTA), can be used to modify the Cu foil surface and guide homogeneous Li+ plating/stripping due to the lithiophilic nature of the N atom in the BTA molecule. As a result, the lithium plated on the BTA modified Cu (BTA-Cu) substrate is free of dendrites, and a Coulombic efficiency (CE) as high as 99.0% was achieved for Li+ plating/stripping on the BTA-Cu substrate at a current density of 1 mA/cm2. Furthermore, the BTA-Cu foil can be used as an anode to assemble an anode-free cell (BTA-Cu∥LFP), and ∼73.3% of the initial capacity can be obtained after 50 cycles. Last but not the least, a BTA-Cu@Li electrode prepared by plating of Li+ on the BTA-Cu substrate can serve as a stable Li anode in a BTA-Cu@Li∥LFP cell and display an average cycled CE of 98.5% at a depth of discharge (DOD) of 33%. This simple method of Li+ plating/stripping behavior regulation could inspire researchers on the development of highly stable lithium metal anodes for high energy density batteries.

Исследование коррозии нержавеющей стали 10Х17Н13М2Т в хлорной кислоте

The authors study the corrosion of AISI 316 stainless steel in 1M perchloric acid at 90 °C, including in the presence of the benzotriazole corrosion inhibitor. Electrochemical experiments were carried out in a three-electrode glass cell with a platinum counter electrode and a saturated silver chloride electrode as a reference electrode. The authors carried out the potentiodynamic measurements at the temperature of (90±2) °C and the potential sweep speed of 1 mV/s; the impedance measurements within the frequency range from 20 kHz to 0.1 Hz at the voltage amplitude of ±10 mV. Cyclic polarization curves show that the cathode direction currents are always lower than the anode direction currents of the potential sweep. Consequently, the curves of anode and cathode directions of the potential sweep are analyzed separately. When analyzing, the authors use the modified Tafel equation, which is linear at any overload that allow determining the corrosion currents more accurately. The study shows that with an increase in the inhibitor concentration, the potentiodynamic curves shift to the cathode side, and the cathode currents decrease more strongly than the anode currents. Therefore, benzotriazole in perchloric acid is an inhibitor of cathodic action, i.e. slows down the cathodic reaction of the perchloric acid anion reduction to chloride ions. The authors identified that benzotriazole inhibits corrosion at concentrations of more than 10 -4 mol/L. At the concentration of 1×10 -3 mol/L, the inhibition efficiency is 33±10 %, and at the concentration of 1×10 -2 mol/L, it is 36±13 %. The inhibiting effect of a benzotriazole molecule in the acidic medium is caused by the possibility of its protonated form to be adsorbed on the metal surface. The protonated form of benzotriazole in acidic medium allows explaining the slow-down of the cathode depolarization reaction as the inhibitor is adsorbed predominantly on metal surface areas charged more negatively. The impedance measurements showed that the corrosion process is modeled by the element parallel circuit with the constant phase shift and corrosion resistance.

Triple-Stimuli-Responsive Smart Nanocontainers Enhanced Self-Healing Anticorrosion Coatings for Protection of Aluminum Alloy.

Novel acid/alkali/corrosion potential triple-stimuli-responsive smart nanocontainers (TSR-SNs) were successfully assembled to regulate the release of an encapsulated corrosion inhibitor, benzotriazole (BTA), by installing specially structured bistable pseudorotaxanes as supramolecular nanovalves onto orifices of mesoporous silica nanoparticles. In normal conditions, BTA molecules were sealed in the mesopores. Upon any stimulus of acid, alkali, or corrosion potential, BTA molecules were quickly released because of the open states of the supramolecular nanovalves. TSR-SNs as smart nanocontainers were added into the SiO2-ZrO2 sol-gel coating to fabricate a stimuli-feedback, corrosion-compensating self-healing anticorrosion coating (SF-SHAC). Compared with the conventional pH-responsive smart nanocontainers synthesized for the SHAC, TSR-SNs not only respond to the pH changes occurring on corrosive microregions but also, and more importantly, feel the corrosion potential of aluminum alloys and give quick feedback. This design avoids wasting smart nanocontainers because of the local-dependent, gradient pH stimulus intensities and obviously enhances the response sensitivity of the SF-SHAC. Electrochemical impedance spectroscopy and salt spray tests prove the excellent physical barrier of the SF-SHAC. Through scanning vibrating electrode technique measurements, the SF-SHAC doped with TSR-SNs demonstrates inhibiting rates for corrosive microcathodic/anodic current densities that are faster than other control SHACs. The new incorporated corrosion potential-responsive function ensures the efficient working efficiency of TSR-SNs and makes full use of the preloaded corrosion inhibitors as repair factors.

The Synergistic Effect of BTA-Co System on the Corrosion Inhibition of Mild Steel in 3.5 wt% NaCl Solution

In this study, the synergistic effect of benzotriazole (BTA) molecules and cobalt cations (Co2+ cations) on the corrosion inhibition of mild steel was studied by electrochemical and surface analysis techniques. The considerable corrosion inhibition efficiency of BTA-Co system was proved by open circuit potential measurements, polarization tests, and electrochemical impedance spectroscopy (EIS) results. Field-emission scanning electron microscopy, energy dispersion spectrometer, X-ray photoelectron spectroscopy, and EIS analysis were employed to characterize the inhibition mechanism of the BTA-Co system. The precipitation of BTA-Co chelate on the steel surface was proposed as the main mechanism for corrosion protection of mild steel in the presence of BTA molecules and Co2+ cations. Also, a mixed-type corrosion inhibition effect of BTA-Co system was shown by polarization tests.

Improvement of active corrosion protection of carbon steel by water-based epoxy coating with smart CeO2 nanocontainers

Abstract Water-based epoxy coating containing CeO2 nanocontainers was successfully applied on carbon steel for corrosion protection. CeO2 nanocontainers were loaded with the corrosion inhibitor benzotriazole (BTA). Polyelectrolyte multilayers were deposited on the loaded nanocontainers by layer-by-layer assembly method. Responsive release of BTA molecules were studied in water media at different pH values using UV–vis spectroscopy. The anticorrosive performance of the epoxy coatings doped with 0.5 wt% of smart nanocontainers was tested by immersion of the coated carbon steel in 0.5 M NaCl solution. Electrochemical impedance spectroscopy (EIS) was used to estimate the influence of smart nanocontainers on the passive corrosion resistance. The self-healing performance of the coating with modified CeO2 nanocontainers was studied by scanning Kelvin probe (SKP). From results of EIS and SKP, the addition of pH-sensitive nanocontainers into the epoxy resin inhibited the corrosion activities on the metal surface, showing a promising strategy for developing water-based epoxy coatings with long term protection performance.