Corrosion Inhibitor Benzotriazole Research Articles

Improving activity and barrier properties of epoxy modified polyurethane coating with in-situ polymerized polypyrrole functionalized graphene oxide

The limited dispersibility and lack of active anti-corrosion properties of graphene oxide (GO) have hindered its application in corrosion resistance. In this study, we graft the corrosion inhibitor benzotriazole (BTA) on the surface of GO to achieve pH response release, providing active corrosion protection for epoxy modified polyurethane (EP-PU) coating. An environmentally friendly composite material with a sandwich-like structure was synthesized by in-situ polymerization of pyrrole to improve GO dispersion and prevent rapid release of BTA. The electrochemical impedance spectroscopy (EIS) shows that adding 0.15% GBP enhances the coating's anti-corrosion performance. The dual functions of passive and active corrosion enable the GBP/EP-PU coating to provide long-term corrosion protection for metal substrates.

A smart acid-responsive GO/MS/BTA hybrid epoxy-based anti-corrosion coating for Mg alloy

Conventional surface coatings exhibit poor self-healing ability, especially under the acid corrosion conditions, which is regarded as a huge challenge for the effective protection of Mg alloy. In this study, a smart self-healing hybrid coating is facilely fabricated, providing an excellent long-term anti-corrosion performance for Mg alloys within the harsh environments. Mesoporous silica (MS) loaded with corrosion inhibitor benzotriazole (BTA) is grafted onto the surface of graphene oxide (GO), to synthesize GO-based nanomaterials, which can be uniformly dispersed in the epoxy (EP) coating through ring opening reaction and form the covalent bonds. Electrochemical Impedance Spectroscopy (EIS) results show that the modulus of the EP-GO-MS-BTA hybrid coating remains at 2.57 × 1011 Ω cm2 after immersion in 3.5 wt% NaCl solution for 15 days. In contrast to previously reported works that achieved the self-healing ability in acidity, the current EP-GO-MS-BTA coating represents an ultra-high self-healing efficiency of 1.2 × 108 Ω cm2 h−1 under acid 3.5 wt% NaCl condition (pH = 3). Due to the labyrinth effect, the impermeability of epoxy coating is enhanced by the ameliorative dispersity of GO sheet. In addition, the as-prepared GO-based nanomaterial can be used to load corrosion inhibitor BTA and possess H+ ion-responsive release property, leading to an improved corrosion protection. Combining the dual effects of superior GO dispersion and smart self-healing, it will provide a green and convenient synthetic method for constructing self-healing coatings with the excellent anticorrosion resistance.

Active and passive corrosion protection coating based on NaY zeolite

The coating of a surface with organic material is the simplest and most effective method to prevent metal materials from corrosion. However, pure resin coatings are prone to corrosion, as corrodents can penetrate the metal surface via micropores. Moreover, passive corrosion resistance, achieved by adding a filler to a coating to lengthen the penetration path of the corrodent, is not sufficient to prevent corrosion. Therefore, the development of coatings with active and passive corrosion resistance properties is necessary to extend the lifetime and enhance the performance of coatings. Herein, a coating with active and passive corrosion resistance properties was designed by loading a NaY zeolite nanocarrier with the corrosion inhibitor benzotriazole (BTA), with a NaY zeolite nanocarrier loading capacity of 7.22 %. The release properties of the resulting NaY@BTA and the corrosion inhibition of BTA released under different pH conditions were investigated. The adhesion strength, contact angles (CAs), and water absorption of the composite coatings were evaluated. The coating with 0.5 % nanocarrier exhibited an adhesion strength of 4.68 MPa, a CA of 84.78°, and the lowest absorbed water content of 1.28 %. The corrosion resistance of composite coatings with different amounts of NaY@BTA was compared, with the electrochemical impedance spectroscopy data of intact and scratched coatings displaying their excellent active corrosion resistance and self-repair properties. After immersion in 3.5 % NaCl solution for 60 days, the low frequency Z0.01 Hz value of EP–PU-0.5%NaY@BTA was 1011 Ω.

Effect of potassium persulfate on chemical mechanical planarization of Cu/Ni microstructures for MEMS

Electrochemical FABrication (EFAB) can fabricate complex metal microstructures. Planarization is crucial in EFAB in terms of flatness and surface quality. Accordingly, chemical mechanical polishing (CMP) was employed to planarize Cu/Ni microstructures. The oxidant K2S2O8 is critical in regulating the material removal rate (MRR) selectivity between copper and nickel. In the presence of the complexing agent ethylenediamine sulfate and corrosion inhibitors benzotriazole and sodium dodecyl benzene sulfonate, the MRR selectivity of 1 (∼47 nm/min) and satisfactory surface quality can be achieved by tuning the K2S2O8 concentration to 20 mM. A two-step planarization method was proposed. After lapping for 7 min and CMP for 21 min, the step height of the Cu/Ni microstructures rapidly decreases from 251 μm to −46 nm on average, and the surface roughness Sa of copper and nickel are significantly improved to 8.7 nm and 2.9 nm, respectively. For the CMP mechanism, as the K2S2O8 concentration increases, the copper corrosion is enhanced, and thus the copper MRR quickly increases; The nickel surface film gradually transforms from Ni(OH)2 to NiOOH, and the intermediate state can be removed relatively easily, and thereby the nickel MRR increases and decreases. This study may provide a feasible high-precision planarization method for EFAB.

Corrosion inhibitor distribution on abrasive-blasted steels

HypothesisAbrasive-blasted steel surfaces exhibit a complex, multi-substrate environment. Adsorption to contaminant substrates can reduce the amount of available corrosion inhibitor and decrease its efficiency. Knowledge of where inhibitors preferentially adsorb is required. ExperimentsThe quantitative extent and strength of adsorption of the representative corrosion inhibitor benzotriazole (BTAH) from toluene to particular substrates is given, including corrections for solution self-association, and complemented by X-ray photoelectron spectroscopy (XPS), sum-frequency generation spectroscopy (SFG), and quartz crystal microbalance (QCM) measurements. FindingsAll substrates show adsorbed BTAH layers. Based on the adsorption strength, preferential adsorption is found to be in the order steel > iron oxide > calcium carbonate and garnet > silica – this is relevant when there is limited BTAH. However, with ample BTAH, the amounts adsorbed in the plateau regions of the isotherm are more relevant and the order is calcium carbonate and silica > iron oxide > garnet > steel. Although the contaminant substrates deplete the BTAH concentration, the steel should still have a complete monolayer of BTAH inhibitor. This work is part of a larger initiative developing novel methods of corrosion inhibitor delivery via the blasting process, to prevent corrosion between blasting and repainting.

Protective treatments for copper alloy artworks: preliminary studies of sodium oxalate and limewater effectiveness against bronze disease

Nantokite (CuCl) locked inside subsurface micro-pits has been recognised as the driving force to the form of corrosion called bronze disease. The use of the traditional corrosion inhibitor benzotriazole is questioned because of toxicity. So there is a need for alternative conservation treatments. This work is focused on the experimental design to test the effectiveness of sodium oxalate followed by treatment with limewater to face bronze disease on outdoor bronzes. A number of foundry bronze coupons were exposed to weathering at Genoa Experimental Marine Station (GEMS) exposure site and sprayed twice a week with a 5% NaCl solution for the first 124 days. After 562 days of natural weathering, the patinas on coupons were characterised with non-destructive techniques (NDT) and the presence of nantokite was verified. We designed a workflow, as similar as possible to conservation treatments on real artworks, to test a 3% w/v sodium oxalate treatment with two different application times, with or without limewater, on the coupons. The effectiveness of the treatments was analysed by comparison of surface properties by several NDT measurements. A statistical approach and XRD measurements directly on the corroded bronze surfaces are suggested as an effective way to characterise and compare the overall behaviour of bronze disease treatments for conservation.

Facile Fabrication of Dual Functional Graphene Oxide Microcapsules Carrying Corrosion Inhibitor and Encapsulating Self-Healing Agent.

Dual functional graphene oxide (GO) microcapsules were fabricated through self-assembly in Pickering emulsions, carrying corrosion inhibitor benzotriazole (BTA) on the microcapsule shells and encapsulating a self-healing agent epoxy monomer. The formation of the GO microcapsules was assisted by the interaction between BTA and GO, which provided robust encapsulation for the epoxy monomer. The loading capacity of BTA and epoxy monomer reached 90.5%. The addition of the GO microcapsules simultaneously promoted the corrosion protection and self-healing properties of the waterborne epoxy composite coatings. The healing efficiency of the composite coatings reached over 99.7% when the content of the microcapsules was 10 wt%. Meanwhile, the corrosion current density of the intact coatings was decreased for around 50 times.

Fabrication of BTA-loaded mesoporous silica-encapsulated ZSM-5 molecular sieve for enhancing anti-corrosion performance of waterborne epoxy coatings

Anti-corrosion coatings have been widely applied to protect metals against corrosion attacks. To improve the corrosive resistance, it is an effective way to employ porous materials loaded with corrosion inhibitors as fillers of coatings. One of the critical challenges is to advance the inhibitor loading capability of porous fillers. In this study, the mesoporous silica encapsulation is introduced on the ZSM-5 molecular sieves through the hydrolysis-condensation of tetraethyl orthosilicate (TEOS), followed by calcinated for removing the residual templates. The porous SiO2@ZSM-5 particles are used as micro-nano containers to load corrosion inhibitor benzotriazole (BTA). The morphologies, structures and BTA releasing behaviors are thoroughly investigated. Subsequently, the as-prepared BTA-SiO2@ZSM-5 particles serve as fillers for waterborne epoxy resin (WER) to fabricate BTA-SiO2@ZSM-5/WER composite coatings with long-term anti-corrosion property. The corrosive resistance behavior and mechanism are emphatically tested and analyzed. The results demonstrate that the introduction of mesoporous silica on the ZSM-5 molecular sieves significantly increases the specific surface area and pore volume, which is highly beneficial for improving the BTA loading capability of fillers as well as the anti-corrosion performance of coatings. Moreover, the great dielectric, mechanical and UV light-shielding properties of the composite coatings are confirmed. This study presents an effective and practical route for fabricating long-term anti-corrosive composite coatings.

Adsorption of the prototypical organic corrosion inhibitor benzotriazole on the Cu(100) surface

The interaction of benzotriazole (BTAH) with Cu(100) has been studied as a function of BTAH exposure in a joint experimental and theoretical effort. Scanning tunnelling microscopy (STM), X-ray photoelectron spectroscopy (XPS), high resolution electron energy loss spectroscopy (HREELS) and density functional theory (DFT) calculations have been combined to elucidate the structural and chemical characteristics of this system. BTAH is found to deprotonate upon adsorption on the copper surface and to adopt an orientation that depends on the molecular coverage. Benzotriazolate (BTA) species initially lie with their planes parallel to the substrate but, at a higher molecular coverage, a transition occurs to an upright adsorption geometry. Upon increasing the BTAH exposure, different phases of vertically aligned BTAs are observed with increasing molecular densities until a final, self-limiting monolayer is developed. Both theory and experiment agree in identifying CuBTA and Cu(BTA)2 metal-organic complexes as the fundamental building blocks of this monolayer. This work shows several similarities with the results of previous studies on the interaction of benzotriazole with other low Miller index copper surfaces, thereby ideally completing and concluding them. The overall emerging picture constitutes an important starting point for understanding the mechanism for protection of copper from corrosion.

Corrosion Resistance of the GO/ZIF-8 Hybrid Loading Benzotriazole as a Multifunctional Composite Filler-Modified MgAlY Layered Double Hydroxide Coating.

A composite coating with good load-carrying and controlled release capabilities for the corrosion inhibitor benzotriazole (BTA) was prepared while providing active and passive corrosion protection for magnesium alloy systems. In this paper, the organic corrosion inhibitor BTA was loaded into the ZIF-8/GO hybrid (GZB), and then, the GZB composite was coated with hexadecyltrimethoxysilane (HDTMS). Then, the GZB composites carried by HDTMS were made to adhere a ternary MgAlY layered double hydroxide (LDH) coating based on microarc oxidation (MAO) coating by electrophoresis (Si-MgAlY LDH coating). The successful loading of BTA by GZB composites was verified by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Meanwhile, the Si-MgAlY LDH coating was characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The potentiodynamic polarization curves show that the corrosion current density of the Si-MgAlY LDH coating reaches (2.08 ± 0.49) × 10-9 A/cm2, which means that the Si-MgAlY LDH coating greatly improves the corrosion resistance of magnesium alloy AZ31. The Si-MgAlY LDH coating can also achieve self-healing function in harsh environments, which is attributed to the synergistic effect of passive and active protection. The composite coating is of great significance to expand the potential applications of magnesium alloys.

Influence of the Operating Conditions on the Release of Corrosion Inhibitors from Spray-Dried Carboxymethylcellulose Microspheres

Sodium carboxymethylcellulose (CMC-Na) microparticles, containing corrosion inhibitor benzotriazole (BTA), were prepared using different spray drying processing parameters, with the purpose of future application in protective coatings for the delivery of corrosion inhibitors. The effects of the processing parameters, such as inlet temperature and spray flow rate, are discussed herein. The biopolymeric CMC-Na microparticles obtained were characterized morphologically by SEM and TEM, and their release profile studied by UV-Vis. The results show that the prepared microparticles (microspheres) were homogeneous, spherically shaped and of a matrix-type nature. Additionally, it was observed that the inlet temperature and spray flow rate significantly influenced the release profiles and process yields. From the different process parameters tested, it was found that the best conditions to achieve higher process yields, higher encapsulation efficiencies and better release properties, were an inlet temperature of 170 °C, a pump rate of 2.5 mL/min, and a drying air-flow rate of 440 L/h.

Double-Ligand Strategy to Construct an Inhibitor-Loaded Zn-MOF and Its Corrosion Protection Ability for Aluminum Alloy 2A12

A promising double-ligand strategy for the delivery of active corrosion inhibitors by a Zn(II)-based metal-organic framework (Zn-MOF) is developed. Zn-MOF compounds were synthesized by a facile one-pot solvothermal method and characterized. The Zn-MOF is based on the corrosion inhibitor benzotriazole (BTA) and 2,5-furandicarboxylic acid (H2FDA) ligand, which is a promising renewable building block alternative to terephthalic or isophthalic acid. The crystal structure and morphology are characterized by single-crystal X-ray diffraction analysis, powder X-ray diffraction analysis (PXRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The synthesized MOF crystallites are in the trigonal space group R3c with the cell parameters in a three-dimensional (3D) anionic framework. Their ability to inhibit the corrosion process of aluminum alloy 2A12 in NaCl solution was also evaluated by immersion tests in solutions with and without a MOF. The postcorrosion analysis was performed by SEM and X-ray photoelectron spectroscopy (XPS). Additional information about the inhibition efficiency was obtained by electrochemical impedance spectroscopy (EIS). The results suggest that the as-synthesized MOF can release the inhibitors and form protective layers effectively on the surface of the aluminum alloy. The use of inhibitor-loaded MOF nanocontainers provides promising opportunities for the smart delivery of inhibitors and effective corrosion protection of 2A12 aluminum alloys.

Performance Evaluation of Layered Double Hydroxides Containing Benzotriazole and Nitrogen Oxides as Autonomic Protection Particles against Corrosion

Layered double hydroxides (LDH) are lamellar structures with positively charged laminates and charge-compensating interlayer anions. The ion-exchange capacity of LDHs makes them as promising hosts for corrosion inhibitor anions with stimulus-responsive release and self-healing anticorrosion. In the current work, LDHs loaded with two different corrosion inhibitors (nitrogen oxides and benzotriazole) were evaluated for their ion-exchange capacity and autonomic protection against corrosion on carbon steel. Studies on nitrogen oxide-loaded LDH (NOx-LDH) showed that nitrogen oxides were successfully intercalated in LDH structure, which were released in chloride media. Open Circuit Potential (OCP) results showed that NOx-LDH extract shifted OCP to nobler values, indicating the protection of metal. For benzotriazole-loaded LDH (BTZ-LDH), the results indicated the presence of benzotriazole in the structure, but its release was not observed. OCP results showed no significant increase of carbon steel protection, corroborating with the conclusion that benzotriazole ions did not migrate to metal surface. Considering these results, the insertion of NOx-LDH in an automotive primer was proceeded, under three different concentrations (0.2. 1.0, and 3.0%). Electrochemical impedance spectroscopy (EIS) showed that the more effective NOx-LDH concentration on corrosion delay was 0.2%, which better balanced protection level conferred by LDH with a possible loss on effectiveness of coating due to increase in porosity.

PH-sensitive microcapsules based on biopolymers for active corrosion protection of carbon steel at different pH

Dual-functional poly(urea-formaldehyde) microcapsules, containing the healing agent linseed oil in the core and the corrosion inhibitor benzotriazole (BTA) in the multilayer shell, were synthesized by in situ polymerization. A layer-by-layer assembly technique was applied using the biopolymers alginate and chitosan as oppositely charged polyelectrolytes. The microcapsules were characterized concerning their composition, surface charge, and morphology, using FTIR, TG, zeta potential measurements and SEM. The capsules are spherical, with an average diameter of 0.99 ± 0.15 μm. The encapsulation of linseed oil was confirmed by FTIR and TG. The adsorption of the multilayers was monitored by zeta potential measurements. The release of BTA, in a solution of NaCl and at different pH values, was studied by UV–Vis spectrophotometry, showing the stimulus-responsive behavior of the microcapsules. The corrosion protection performance was investigated by electrochemical impedance spectroscopy (EIS), using a carbon steel substrate coated with epoxy resin loaded with 5 wt% microcapsules. The EIS results showed that the presence of microcapsules provided better protection compared to the pure resin coating, with average RP three times higher.

Cooling tower water treatment using a combination of electrochemical oxidation and constructed wetlands

A substantial part of the freshwater used in the industry is consumed in cooling towers. Cooling towers discharge saline cooling tower blowdown (CTBD), and the reuse of CTBD in the cooling tower can lower the industrial freshwater footprint. This reuse requires CTBD desalination and a pre-treatment that removes organic chemicals before physico-chemical desalination technologies to be applied efficiently. In the present study, the pre-treatment of CTBD by a combination of electrochemical oxidation (EO) with a boron-doped diamond (BDD) or mixed-metal oxide (MMO) anode and a vertical flow constructed wetland (VFCW) was assessed in both possible configurations. The integrated VFCW-EO systems removed more organic chemicals, such as COD, TOC, and the corrosion inhibitor benzotriazole than the EO-VFCW systems. However, the EO resulted in highly toxic effluent to Vibrio fischeri and the plants in the VFCW. This toxicity was the result of the production of unwanted chlorinated organic compounds and ClO3− and ClO4− by both the BDD- and MMO-anode during EO. These toxic EO by-products were removed substantially in the VFCW during EO-VFCW treatment but did impact the removal efficiency and viability of the VFCW. Moreover, significant water loss was observed in the VFCW due to evapotranspiration. In conclusion, the negative impact of EO effluent on the VFCW and evapotranspiration of the VFCW should be considered during application.

Porous polystyrene nanoparticles as nanocontainers of inhibitors for corrosion protection of low-alloy steel

PurposeThis paper aims to investigate effect of porous polystyrene microspheres encapsulated inhibitor on the protection performance of epoxy resin coating.Design/methodology/approachPorous polystyrene (PS) microspheres were synthesized by soap-free emulsion polymerization. The morphology of microspheres was observed by scanning electron microscopy and transmission electron microscopy. Corrosion inhibitor benzotriazole was encapsulated into porous PS microspheres. The protection performance of epoxy resin coating with different contents of PS microspheres was tested by polarization curve.FindingsThe findings of electrochemical impedance spectroscopy and scanning vibrating electrode technique showed that addition of corrosion inhibitor to porous PS microspheres further improved the protection performance of the coatings.Practical implicationsPorous PS microspheres could be used as nanocontainer to encapsulate corrosion inhibitor.Originality/valueAddition of porous PS microspheres with corrosion inhibitor improved the protection performance of the coatings.

P.412 Gallic acid, chlorogenic acid, ferulic acid and quercetin improve learning and memory processes in olfactory bulbectomized rats

Polymeric nanocontainers (NCs) impregnated with corrosion inhibitor benzotriazole are formed using layer-by-layer deposition of poly(acrylic acid) and poly(diallyldimethylammonium chloride) onto hematite particles in the presence of 0.1 M NaCl. Electric light scattering and electrophoresis are employed to control the formation and the size of NCs, as well as the stability of their suspensions. The inhibitor loaded NCs are incorporated into the volume of the galvanized coating during the electrodeposition of zinc on the steel substrate to ensure additional self-healing effect in the case of corrosion attack. The surface morphology and the uniformity of this composite coating as well as the lack of aggregation of the nanocontainers is demonstrated by scanning electron microscopy. The influence of NCs present in the zinc electrolyte on the cathodic and anodic processes is investigated by cyclic voltammetry. The corrosion behavior of the composite coatings at conditions of external cathodic and anodic polarization is tested with potentiodynamic measurements and the results are compared to pure zinc coatings. The composite coatings with embedded NCs revealed enhanced corrosion protection of low carbon steel in comparison with the pure zinc coatings in neutral corrosion medium.

Benzotriazole encapsulation in spray-dried carboxymethylcellulose microspheres for active corrosion protection of carbon steel

Biopolymeric microspheres containing corrosion inhibitor benzotriazole (BTA) were prepared by a spray-drying technique using carboxymethylcellulose (CMC-Na) as encapsulating material. The resulting microspheres were characterized by FTIR, TGA, SEM and TEM analysis. Microspheres containing BTA have an average diameter of 1.1 μm. FTIR analysis confirmed the presence of the core and encapsulating components. The release studies by UV−Vis spectrophotometry showed that the mechanism of inhibitor release from CMC-Na biopolymeric matrix is based on a hydrogel-swelling-driven mechanism triggered by water presence. Electrochemical impedance spectroscopy (EIS) measurements on bare carbon steel in NaCl solution revealed that the presence of CMC-Na does not affect the corrosion inhibition mechanism associated with BTA. Furthermore, the microcapsules were added to an epoxy coating and its active corrosion protection performance was also investigated by EIS. The results obtained indicate that capsules loaded with BTA do not affect negatively the barrier properties of the coating, and contribute for the enhancement of the corrosion protection of the metallic substrate. Therefore, this work shows the potential application of carboxymethylcellulose microspheres for development of new environmentally-friendly microcontainers for corrosion inhibitors.

Resistance to Pit Formation and Pit Growth for Different Tempers of AA2024 Aluminium Alloy in Presence of Benzotriazole

The paper analyses the corrosion behaviour of both naturally and artificially aged AA2024 aluminium alloy in NaCl solution in the presence of the corrosion inhibitor benzotriazole (BTA). The differences between these two aging tempers in terms of resistance to general corrosion are explained as well as the differences in terms of pit formation and pit growth. Based on the values of the polarisation resistance and the corrosion current density, the general corrosion resistance of the alloy is determined in the absence and in the presence of BTA. The resistance to pit formation and pit growth is determined on the basis of the polarisation measurements results. Scanning electron microscopy confirmed the expected differences in the appearance and size of the pits formed in naturally aged and artificially aged alloy. In the presence of the corrosion inhibitor BTA, for both aging tempers of the alloy, the corrosion resistance is significantly higher compared to the resistance in the solution without the inhibitor. The value of the polarisation resistance for both aging tempers increases over time. However, at the same time, the value of the constant phase element increases as well. An explanation for this phenomenon is provided. The calculated average value of the thickness of the adsorbed inhibitor layer on the surface of the aluminium alloy is in accordance with the inhibitor protective ability for both aging tempers.

Enhancing corrosion protection properties of sol-gel coating by pH-responsive amino-silane functionalized graphene oxide-mesoporous silica nanosheets

Amino-silane functionalized graphene oxide-ordered mesoporous silica nanocontainer was synthesized to load corrosion inhibitor benzotriazole, and the synthesized two-dimensional composite was named as fGS-BTA. Its compatibility and dispersion stability in sol solution was prominently reinforced by amino-silane functionalization. Meanwhile, amino-silane as pH-driven “nanogate” suppressed the premature leakage of inhibitor, which endowed fGS-BTA nanocomposite the stimuli-responsive release under alkaline condition. Electrochemical impedance spectroscopy of intact and scratched sol-gel coating filled with fGS-BTA nanosheets showed the enhanced barrier property and the active protection capacity.