Anticorrosion Function Research Articles

Electro-Enhanced Separation of Microsized Oil-in-Water Emulsions via Metallic Membranes: Performance and Mechanistic Insights.

Conventional separation membranes suffer from evitable fouling and flux decrease for water treatment applications. Herein, a novel protocol of electro-enhanced membrane separation is proposed for the efficient treatment of microsized emulsions (∼1 μm) by rationally designing robust electroresponsive copper metallic membranes, which could mitigate oil fouling and coenhance permeance (from ∼1026 to ∼2516 L·m-2·h-1·bar-1) and rejection (from ∼87 to ∼98%). High-flux Cu membranes exhibit superior ductility and electrical conductivity, enabling promising electroactivity. Separation performance and the fouling mechanism were studied under different electrical potentials and ionic strengths. Application of negative polarization into a large-pore (∼2.1 μm) Cu membrane is favorable to not only almost completely reject smaller-sized oil droplets (∼1 μm) but also achieve antifouling and anticorrosion functions. Moreover, surfactants around oil droplets might be redistributed due to electrostatic repulsion, which effectively enhances the steric hindrance effect between neighboring oil droplets, mitigating oil coalescence and consequently membrane fouling. Furthermore, due to the screening effect of surfactants, the presence of low-concentration salts increases the adsorption of surfactants at the oil-water interface, thus preventing oil coalescence via decreasing oil-water interfacial tension. However, under high ionic strengths, the fouling mechanism converts from cake filtration to a complete blocking model due to the reduced electrostatic repulsion between the Cu membrane and oil droplets. This work would provide mechanistic insights into electro-enhanced antifouling for not only oil emulsion separation but also more water treatment applications using rationally designed novel electroresponsive membranes.

Long-Term Corrosion Behavior of Strong and Ductile High Mn-Low Cr Steel in Acidic Aqueous Environments.

To expand the industrial applicability of strong and ductile high Mn-Low Cr steel, a deeper understanding and mechanistic interpretation of long-term corrosion behavior under harsher environmental conditions are needed. From this perspective, the long-term corrosion behaviors of 24Mn3Cr steel under acidic aqueous conditions were examined through a comparison with conventional ferritic steels using the electrochemical measurements (linear polarization resistance and impedance), and immersion test followed by the metallographic observation of corrosion morphologies. In contrast to conventional ferritic steels, 24Mn3Cr steel, which had the lowest corrosion resistance at the early immersion stages (i.e., the highest corrosion current density (icorr) and lowest polarization resistance (Rp)), showed a gradual increase in corrosion resistance with prolonged immersion. Owing to the slow formation kinetics of (Fe,Cr)-enriched oxide scale, a longer incubation time for ensuring a comparatively higher corrosion resistance is required. On the other hand, conventional ferritic steels had an oxide scale with less densification and a lower elemental enrichment level that did not provide an effective anti-corrosion function. From the results, this study can provide significant insight into the industrial applicability of the high Mn-low Cr steel by providing the mechanistic interpretation of corrosion behaviors in acidic aqueous environments.

Research on Interface Modification and Thermal Insulation/Anticorrosive Properties of Vacuum Ceramic Bead Coating

The thermal insulation effect of the coating was closely related to the content of the thermal insulation filler, but too much filler would cause interfacial compatibility problems of various substances in the coating, micro-defects in the coating, and affect the anti–corrosion performance of the coating. Therefore, solving the interface problem was the key to preparing a coating with heat insulation and anticorrosion functions. In this study, organic–inorganic hybrid polymer was used to modify the surface of vacuum ceramic microbeads, and epoxy–silicone resin was used as the film–forming material to prepare a heat-insulating and anticorrosive coating that can withstand 200 °C. The SEM morphology showed that the interface compatibility of the vacuum ceramic beads modified by the organic–inorganic hybrid agent and the film-forming material were improved, the dispersibility was significantly improved, and the beads were tightly arranged; the thermal conductivity of the coating reached 0.1587 W/(m·K), which decreased by 50% after adding 20% ceramic beads, ANSYS finite element simulation showed that the coating has good thermal insulation performance; after the coating underwent a thermal aging test at 200 °C for 600 h, the microstructure was dense, and the low-frequency impedance modulus was still around 109 Ω·cm2. There was no obvious defect in the microstructure after the alternating cold and heat test for 600 h; the low-frequency impedance modulus was still above 108 Ω·cm2, and the low-frequency impedance modulus of the coating was 1010 Ω·cm2 after the 130d immersion test, indicating that the coating had good heat resistance and anti-corrosion performance.

Surface micro-nano hydrophobic structuring on silver-coated semiconductor substrate by femtosecond laser irradiation

In this paper, the effect of femtosecond laser irradiation on the wettability of semiconductor materials InAs and GaAs coated with silver film was studied. The experimental results show that the semiconductor material can be transformed from hydrophilic to hydrophobic. Laser power and scanning period play a decisive role in the morphology of micro-nano structures, and different micro-nano structures have different hydrophobicity. The higher the surface roughness is, the greater the contact angle is, and the maximum contact angle can reach 143°. The existence of silver film further increases the surface roughness in two different ways. For InAs samples, the existence of silver film does not change the surface morphology of the micro-nano structure, which is fish-scale structure. However, the size of the microstructure is increased, and the hydrophobicity is significantly improved. The contact angle increases from 122.6° to 139.8°. For the GaAs sample, the existence of the silver film changed the surface morphology of the micro-nano structure. The morphology changed from a laser induced periodic structure to the convex structure, and the contact angle increased from 122° to 143°. The process can be used for surface modification of semiconductor materials, which is well applied to optoelectronic devices to achieve self-cleaning and anticorrosion functions of the surface and prolong the service life of optoelectronic devices.

Conducting Poly[N-(4-Methoxy Phenyl)Maleamic Acid]/Metals Oxides Nanocomposites for Corrosion Protection and Bioactivity Applications

Corrosion is considered as the most common cause of steel material property degradation, while coatings are effective and popular corrosion protection methods. Coatings come in a variety of forms, each with its own set of effectiveness, methods and constituents. This study used an electrochemical oxidation approach to make Poly [N-(4-Methoxy Phenyl) maleamic acid] from monomer [N-(4-Methoxy Phenyl) maleamic acid] (NPM) in a 3.5% seawater solution. On a low carbon steel [L.C.S] electrode (working electrode), a polymer film was produced. The polymer was created, according to infrared, SEM and FTIR examinations. Using the electrochemical polarization approach, the anticorrosion function of polymer films on L.C.S was examined. Also, adding nanoparticles (NP), like CuO and ZnO to the monomer solution improved the polymers anticorrosion. The results revealed that there was an increase in the L.C.S corrosion rate with the increase of temperature from 293K to 323K, while the values related to coatings polymer inhibition efficiency improved with NPs addition. For the corrosion of L.C.S in salt medium prior to and following polymeric coating, thermodynamic and kinetic activation parameters were estimated. The impact of preparing polymers on certain bacteria strains was also investigated.

Stacking design in photocatalysis: synergizing cocatalyst roles and anti-corrosion functions of metallic MoS2 and graphene for remarkable hydrogen evolution over CdS

The advantages of stacking design over traditional core–shell and supported photocatalytic structures have been highlighted with CdS firstly supported by rGO and then covered with metallic MoS2 as a model catalyst.

Efficient photocathodic protection enabled by a multi-dimensional quaternary hybrid superstructure

The global annual steel waste associate with interface corrosion represent significant challenges for steel’s lifetime as well as sustainable development of modern society. Herein, we report a unique multi-dimensional quaternary hybrid superstructure for photocathodic protection (PCP) which not only has an intense visible to near-infrared absorptivity for generating ‘hot’ electrons but also can provide time-delay anti-corrosion functions in the dark. We exemplified the PCP performance of this quaternary composite on a typical 304 stainless steel (304SS) which results in its surface potential shifting negatively by about 660 mV compared to its natural corrosion potential under visible light illumination. Besides, time-delay protection without illumination is also demonstrated, which is resulted from the “electron pool” effect associates to the embedded zero-dimensional quantum dots. Based on density functional theory (DFT) simulations as well as comprehensive electron microscopy studies, we elucidate the origin of the enhanced PCP performances are attributed to the improved work per photon using ‘hot’ carriers, which surpass the limit of the state-of-the-art PCP technologies. In addition, we found the use of one-dimensional titanium dioxide nanorods and two-dimensional reduced graphene oxide as a scaffold can structure the metal nanoparticles and forces photoinduced ‘hot’ electrons to transfer to the functionalized 304SS. Various promising functionalities arises from the use of as-proposed multi-dimensional quaternary superstructure as a sustainable anti-corrosion material can be envisioned.

THE ANTI-CORROSIVE REPAIR METHODS FOR DEGRADED WEATHERING STEEL BRIDGES

The existing rust with heavy amounts of salinity or anti-freezing agents on the weathering steel bridge surface can lead to serious durability issues. In the event that the anticorrosion functions of weathering steel bridges do not perform satisfactorily, it is necessary to eliminate the cause or to consider the repair coating and the life extension process. In order to achieve the expected life of the repair coating, it is important to perform the correct surface treatment, appropriate surface preparation (near-white blast cleaning, ISO standard Sa2 1/2 equivalent), and the certain removal of rust containing salinity (50 mg/m2 or below). This study provides state-of-the-art techniques on repair method, which is two repair coating methods and one simple repair method for weathering steel bridges. In 2015, some repair methods, with considerable effectiveness, were carried out to actual weathering steel bridges with undesired rust generation. The investigation of three years after repair coating shows that both repair coating film is confirmed to exhibit good corrosion resistance. The weathering steel surface repaired by simple repair method is also in a good state.

Synthesis of inhibitor-loaded polyaniline microcapsules with dual anti-corrosion functions for protection of carbon steel

In this work, a novel type of two-shell structured inhibitor-loaded polyaniline (PANI) microcapsule was fabricated for efficient corrosion protection of carbon steel. In our strategy, modified SiO2 nanoparticles were used to stabilize an oil phase containing aniline, photo-crosslinkable monomer and crosslinker. Upon UV irradiation, the monomer and crosslinker underwent polymerization and converted into the first shell of microcapsules, which endows sufficient stability and robustness to the microcapsules. The subsequent polymerization of aniline at the oil/water interface contributed to the second layer of the microcapsules shell, which functioned as anticorrosion filler and pH-sensitive gatekeeper of the microcapsules to realize the responsive release of the incorporated inhibitor simultaneously. Corrosion inhibitor (2-mercaptobenzothiazole, MBT) was encapsulated into the prepared polyaniline microcapsules and pH-responsive release of MBT from the microcapsule was demonstrated. The anti-corrosion performance of the epoxy embedded with MBT loaded polyaniline microcapsules was achieved by the combination of the passivation of the steel surface by PANI and the on-demand release of MBT during the corrosion process, thus affording dual corrosion protection for the mild steel. The results showed that MBT loaded polyaniline microcapsules exhibited significantly enhanced corrosion protection of carbon steel than unloaded polyaniline microcapsules as well as MBT, demonstrating a synergistic inhibition effect of MBT and PANI.

Active anti-corrosion of epoxy coating by nitrite ions intercalated MgAl LDH

Layered double hydroxide (LDH) with NO2− intercalation was successfully prepared via acidification oscillation and ion exchange. The nano-fillers were incorporated into the resin to prepare anti-corrosion coatings with the thickness of ca. 50 ± 5 μm. The electrochemical and self-repairing properties of the LDH-doped coatings were studied by EIS and LEIS. Results indicated that the addition of LDH loaded with nitrite induced obvious increased in the impedance of coating (from 4.64 × 108 Ω cm2 to 2.14 × 1010 Ω cm2) and improved the anticorrosion performance of the coating. In addition, the localized corrosion of coatings could be largely inhibited, and the released nitrite ions from LDH interlayers exhibited active anticorrosion functions. When LDH nanosheets were added to the coatings, the lamella structures improved the barrier performances of the coatings. At the same time, the excellent ion exchanges ability of LDH could be used as storage stations for chloride ions, and the release of nitrite ions could play an active anti-corrosion role. Both of them cooperated to synergistically improve the anti-corrosion performance of the coating.

Designing a zinc-encapsulated Feldspar as a unique rock-forming tectosilicate nanocontainer in the epoxy coating; improving the robust barrier and self-healing anti-corrosion properties

For the first time, Feldspar (F) nanocontainer, which is a group of rock-forming tectosilicate minerals with the chemical composition of KAlSi3O8-NaAlSi3O8-CaAl2Si2O8, was used for the construction of an epoxy composite coating with superior barrier and self-healing anti-corrosion performance. Feldspar (F) based nanocontainer with robust corrosion inhibitive activity was fabricated through the encapsulation of zinc cations as a cathodic inhibitor. It was understood from the electrochemical measurements that in the saline solution including F/Zn extract the metal corrosion was significantly retarded (by protection efficiency of 73%) due to the inhibitor release activity of the F/Zn container and protective film generation on the metal surface. The inductively coupled plasma (ICP) analysis results confirmed the Zn2+ cations (5.33 mg/L) release in the chloride solution from the F/Zn container. EIS test results evidenced the significant effect of the F/Zn in the epoxy ester composite coating barrier and self-healing anti-corrosion functions in the intact and scratched forms. In the presence of F/Zn an improvement in the charge transfer resistance (about 83%) of the scratched coating was observed, indicating the active self-healing inhibition effect of the F/Zn nanocarrier. By incorporation of the F/Zn particles into the epoxy ester coating the E′ (at 30 °C), glass transition temperature (Tg), stress, strain and energy at break were significantly enhanced. These results proved that not only the corrosion protection properties but also the mechanical properties of the epoxy ester coating were excellently improved in the presence of F/Zn nanocarrier.

Photocathodic Protection of Cobalt Doped ZnO Nanorod Arrays for 316 Stainless Steel and Q235 Carbon Steel in 3.5 wt.% NaCl Solution

In this work, cobalt-doped ZnO nanorod arrays with anticorrosion function were successfully prepared on fluorine-doped tin oxide (FTO) substrates by a simple aqueous solution method. The XRD patterns and the energy-dispersive X-ray spectroscopy (EDX) analysis indicate the doped Co2+ were successfully incorporated into the ZnO crystal lattice. The photocurrent density and open circuit potential (OCP) results indicate the photocathodic protection performance for 316 stainless steel (316 SS) and Q235 carbon steel in a 3.5 wt.% NaCl solution under a Xe lamp with a power of 300 W was enhanced with the increase of cobalt concentration, and the photoanode with a 15% Co/Zn ratio had the optimal photocathodic protection effect. The mechanism of enhancement may be result from the narrowed band gap, the lower recombination rate of the photogenerated electron-hole pairs, the intermediate impurity level, and the split of the hypo-outer shell of cobalt ions.

Preparation and Photocathodic Protection Properties of ZnO/TiO2 Heterojunction Film Under Simulated Solar Light.

In this work, a novel double layer made of ZnO nanorod arrays and TiO2 nanorod arrays with anticorrosion function were successfully prepared on fluorine-doped tin oxide (FTO) substrate by a simple low-temperature solvothermal method. As compared with the pure TiO2 and pure ZnO film, the combination of the two films presented higher photocathodic protection performance for 316 stainless steel (316 SS) and Q235 carbon steel in 3.5 wt% NaCl solution. The composite film with ZnO nanoparticles layer between ZnO nanorod arrays and TiO2 nanorod arrays exhibited the best photocathodic performance, which lowered the open circuit potential (OCP) of 316 SS and Q235 to −991 mV, −1066 mV, respectively. The results demonstrated that the formation of the uniform heterojunction film and the small difference in band alignment played important roles in the promotion of photocathodic protection performance.

Preparation of pH responsive smart nanocontainer via inclusion of inhibitor in graphene/halloysite nanotubes and its application in intelligent anticorrosion protection

Graphene exhibits great potential as a functional building block in modern protective material aiming to high anti-corrosion performance. Herein, we demonstrate a concept for graphene based integrated intelligent inhibitor nanocontainer (IIIN), which can provide multifunctional anti-corrosion protection when be applied as a modifier in waterborne coating. The synthesis of IIIN was started from the nanocomposite of halloysite nanotubes (HNTs) and reduced graphene oxide (rGO). Then, L-histidine (L-His) was loaded on HNTs-rGO for the formation of ternary nanocomposite via electrostatic adsorption. IIIN has the excellent compatibility with waterborne coatings. Importantly, L-His@HNTs-rGO can provide an integrated anticorrosion function: in addition to the role of “passive protection” of rGO, IIIN not only extends the diffusion distances of the corrosive molecules, interrupts the possible formation of conductive pathways, but also serves an intelligent container to release L-His. The comprehensive result is the effective prolongation on the protection life of the coating from 7, 67 and 22 days of the unmodified waterborne coating, to 42, 116, and 69 days of the IIIN modified coating in H2SO4, NaOH, NaCl solution respectively. The electrochemical impedance spectroscopy (EIS) has been applied to monitor the corrosion process for different coatings, which confirms the synergism effect of IIIN.

A novel technology for the corrosion protection of iron archaeological artefacts using parylene base removable bilayer

Abstract Combinations of different acrylic resins and microcrystalline waxes are most often used for conservation and preservation these days. However, their properties are not sufficient and satisfactory in many ways. A novel barrier coating for the conservation of iron archaeological artefacts composed of parylene C polymer and Laksil lacquer is proposed within this article. Parylene C is a commercial name of poly(chloro-p-xylylene) polymer, and it was prepared via modified chemical vapour deposition. Parylene removability was ensured through the xylene soluble interlayer made of Laksil silicone-acrylic lacquer which was applied between a protected iron model substrate and parylene thin film. The corrosion tests in salt spray showed excellent barrier properties of Laksil/parylene bilayer. The surface roughness measured by the profilometry and the surface morphology shown by the SEM displayed the synergic effect between the Laksil and parylene layer which leads to the exceptional barrier and anticorrosion function of Laksil/parylene bilayer. First, the Laksil layer flattened out rough surface of a substrate; second, thereon deposited parylene film became smooth and defect free and acted as a good diffusion barrier. The colouristic measurements proved that the bilayer does not change the appearance of item, in terms of colour. The EDX and TGA confirmed entirely successful removal of bilayer and thus the reversibility of conservation treatment is enabled. The characteristics of Laksil/parylene bilayer were compared with the conventional conservation coating composed of Paraloid B72 acrylic resin and Revax microcrystalline wax prepared by professional conservators. The Laksil/parylene bilayer demonstrated significantly superior properties in this comparison.

Designing a dual-functional epoxy composite system with self-healing/barrier anti-corrosion performance using graphene oxide nano-scale platforms decorated with zinc doped-conductive polypyrrole nanoparticles with great environmental stability and non-toxicity

Designing a novel epoxy composite system with dual self-healing/barrier anti-corrosion functions using graphene oxide (GO) nano-platforms decorated by polypyrrole (PPy) nanoparticles doped with zinc metal ions is the major objective of this research attempt. GO-PPy-Zn nanoplatform was fabricated via one-pot polymerization of pyrrole monomers on GO and two direct/indirect methods of zinc doping. In order to verify the PPy nanoparticles synthesis on GO sheets several analyses such as UV–visible, XPS, HR-TEM and FE-SEM were performed. The epoxy nanocomposite coatings containing GO-PPy and GO-PPy-Zn nanoplatforms were fabricated and applied on carbon steel. The nanocomposite coatings anti-corrosion capability was examined by electrochemical impedance spectroscopy (EIS), salt spray and pull-off adhesion test methods. The results of XPS analysis and HR-TEM and FE-SEM images demonstrated the zinc doped PPy nanoparticles formation on the GO nanoplatform. The great potency of GO-PPy-Zn on the epoxy coating anti-corrosion performance promotion, self-healing-barrier properties enhancement and cathodic delamination resistance improvement were obtained on carbon steel.

Novel dual-functional coating with underwater self-healing and anti-protein-fouling properties by combining two kinds of microcapsules and a zwitterionic copolymer

Antibiofouling and repairing of the micro-cracked coating on the surface of the facilities in underwater environment are two great challenges in marine industries. This paper prepared a dual-functional coating with underwater self-healing and anti-protein-fouling properties by combining two kinds of microcapsules and a zwitterionic copolymer. First, epoxy resin microcapsules and underwater epoxy hardener microcapsules were prepared. Epoxy resin microcapsules with a poly(urea-formaldehyde) shell and the entrapped mixture of epoxy resin and n-butyl glycidyl ether showed homogeneous spherical morphology with encapsulation ratio of 90.42%. Underwater epoxy hardener microcapsules with a polymethyl methacrylate shell and the entrapped underwater epoxy hardener showed cellular spherical morphology with encapsulation ratio of 78.67%. Both of the microcapsules exhibited pretty thermal stability and acid, alkali and salt resistance. Then, two types of microcapsules were mixed with amine cured epoxy coating system to cast film on steel piece, and subsequently a zwitterionic polymer, ploy(sulfobetaine methacrylate-co-glycidyl methacrylate)(PSG) solution was casted on the surface of the un-cured epoxy coating. Therefore, a dual-functional coating with underwater self-healing and antibiofouling functions was obtained. The self-healing anticorrosion function attributed to the dual microcapsules and the anti-protein-fouling performance provided by PSG layer had been certificated. The facile combination of underwater self-healing and anti-protein-fouling functions may provide a new protection strategy for marine and other underwater facilities.

PH-Responsive zeolitic imidazole framework nanoparticles with high active inhibitor content for self-healing anticorrosion coatings

Zeolitic imidazole framework (ZIF) is an emerging class of functional materials with promising nanostructures and applications in biomedicine and materials science. Herein we present a dynamic protective coating system with self-healing anticorrosion function, based on pH-responsive ZIF nanoparticles. Due to the advantage of high content of corrosion inhibitor in the ZIF-7 nanoparticles and its nature of pH-sensitivity, the ZIF-7 nanoparticles could quickly respond to the surrounding acid environment and release the linker as healing agent, led to a new barrier on scratched metal surfaces. The embedding and homogeneous distribution of the ZIF-7 nanoparticles in polymer coating system improved the corrosion resistance of carbon steel in 0.1 M hydrochloric acid solution in comparison to the control samples, as determined by electrochemical impedance spectroscopy (EIS). The self-healing anticorrosion property of dynamic polymer system was characterized during a simulated corrosion process by scanning electrochemical microscopy (SECM). The concentration of the embedded ZIF-7 nanoparticles was varied (0.5 − 7 wt %) to ascertain the optimum conditions for anticorrosion performance. The important effect of particle size and shape of ZIF-7 nanoparticles is discussed as well. The ZIF-7 based on dynamic protective polymer systems can interact with and adapt to the surrounding acid environment, leading to a new healed barrier on metal surfaces with anticorrosion functions.

Whole pH range anti-corrosion property of aluminium alloy coated with MFI zeolite film

ABSTRACTStrong protection capability of zeolite coating for AA6061 substrate from corrosion in NaCl, H2SO4 and NaOH solution has been demonstrated with reduction of corrosion current by five orders of magnitude. Film resistance was identified as the governing parameter in the formation of a barrier shielding the penetration of aggressive species. For the MFI zeolite film growth on the surface of the AA6061 substrate, while the in situ crystallisation (InC) protocol generated loosely packed film made of large zeolite crystal, the dry-gel conversion (DGC) protocol prepared dense film comprising of nanoparticles. Superior protection ability of DGC-grown film is attributed to the increased film resistance associated with a dense and impermeable zeolite layer. As such, the DGC-grown film requiring thinner film thickness around 5 μm showed better anti-corrosion function than the InC-grown film.This paper is part of a supplementary issue from the 17th Asia-Pacific Corrosion Control Conference (APCCC-17).

Super anticorrosion of aluminized steel by a controlled Mg supply

The current anticorrosion strategy makes use of coatings to passively protect the steel, which faces increasing challenge due to the tightened environmental regulations and high cost. This paper reports a new method for achieving a super anticorrosion function in Al-Si alloys through Mg nano-metallurgy, which was characterized by real-time synchrotron measurements. The unique function is based on the formation of an amorphous and self-charge-compensated MgAl2O4-SiO2 phase between the grain boundaries to help prevent the penetration of oxygen species through the grain boundaries. Through this, the corrosion resistance of pristine aluminized steel could be improved almost 20 fold. An analysis of the phases, microstructures of the Mg-coated aluminized layer and corrosion products consistently supported the proposed mechanism. This charge-compensated corrosion resistance mechanism provides novel insight into corrosion resistance.