Cathodic Disbondment Tests Research Articles

Emerging Mo-doped MgAl-LDH lamellar/carbon nanotubes as 3D sustainable nanohybrid for designing a durable smart anti-corrosion composite

This paper focused on the utilization of 3D hybrid nanocomposites composed of layered double hydroxides (L) containing sodium molybdate (SM), which are chemically bonded with functionalized multi-walled carbon nanotubes (FCN), as nanocarriers for smart corrosion prevention. The SM molecules were loaded into the L, and L/FCN nanocarriers by an anion exchange process, and then the 3 synthesized nanoparticles (L, SM-L, and SM-L/FCN) were characterized. Based on the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD) tests' outcomes, the maximum corrosion prevention efficiency (about 90.88 %) belongs to the SM-L/FCN nano reservoir containing saline extract. Additionally, for the epoxy phase, the EIS results (on the intact and scratched specimens) revealed a significant diminish in the chloride and water penetration into the epoxy coating during 63 days of immersion for intact and 24 h for scratched states. EIS results indicated the enhancement of the charge transfer resistance (Rct) of the scratched coatings, from 17.42 kΩ.cm2 for the EP sample to 72.47 kΩ.cm2 for the SM-L/FCN/EP one in long immersion times, revealing the self-repairing behavior of the designed coating. The results of intact coating revealed that the Log (|Z|0.01 Hz) value reached 10.63 in long immersion time indicating a decreased occurrence of coating disbondment attributed to the electrolyte infiltration and corrosion of the underlying metal substratum. According to the pull-off and cathodic disbonding tests results, there was an enhancement in adhesion (51.5 % decrease in loss of adhesion strength, & a 52 % decline in diameter of cathodic disbondment), and a strong interaction between the interface of epoxy and substratum. According to the mechanical tests (tensile and DMTA) results the incorporation of L and FCN nanoparticles into the SM-L/FCN sample enhanced the nanocomposite's mechanical properties. The tensile test showed an increase in ultimate tensile strength (σUTS) and elongation at break (Ɛb) of 130.61 % and 107.59 %, respectively, compared to the pure epoxy (EP) sample. Additionally, the dynamic mechanical thermal analysis (DMTA) test indicated a 144 % increase in crosslinking density for the SM L/FCN sample compared to the neat epoxy.

One pot synthesis of amino silane grafted cerium phosphate (AS@CePO4) as an effective anticorrosion nanopigment for epoxy coating

This work proposed a facile method to synthesize an effective anticorrosion nanopigment based on amino silane grafted cerium phosphate for epoxy coated steel system. CePO4 nanoparticles were synthesized from Ce(NO3)3 and Na3PO4 precursors, then surface-grafted with a coupling agent N-2-(aminoethyl)-3-aminopropyl trimethoxysilane (denoted as AS) via a one-pot reaction to obtain the AS@CePO4 nanopigment. The effectiveness of this nanopigment on corrosion protection, dry/wet adhesion strength, and cathodic disbondment resistance was thoroughly evaluated on an epoxy-coated steel system. The composition and morphology of pigments as well as epoxy containing pigments were characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) methods. The adhesion strength, cathodic disbondment resistance and corrosion protection performance characteristics of the coatings were evaluated by pull-off test, cathodic disbondment test, electrochemical and salt spray tests, respectively. The synergic effect from stronger bonding of AS coupling agent and excellent inhibitory ability of CePO4 led to strengthened adhesion strength, better corrosion protection performance, and higher cathodic disbondment resistance of epoxy coated steel system.

Trisodium phosphate-loaded magnesium‑aluminum layered double hydroxides/oxidized-multiwalled carbon nanotubes self-assembled 2D-nanohybrid for designing a multifunctional smart epoxy nanocomposite

In this study, a hybrid nanomaterial based on layered double hydroxides (LDH) and multi-walled carbon nanotubes (MWCN) was fabricated using a co-precipitation method. Trisodium phosphate (TP) was loaded into the designed nanocarrier to enhance the corrosion resistance of mild steel in 3.5 wt% NaCl media. Fourier transform infrared (FT-IR) spectroscopy, Raman, and X-ray diffraction (XRD) analyses were carried out to investigate the magnesium‑aluminum layered double hydroxides/oxidized-multiwalled carbon nanotubes (Mg-AL-LDH/O-MWCN) structure and morphology before and after loading of trisodium phosphate. Furthermore, the nanocarrier inhibition capability was evaluated through electrochemical impedance spectroscopy (EIS), polarization, and field emission-scanning electron microscopy (FE-SEM) techniques. Electrochemical impedance spectroscopy (EIS) was also employed to estimate the anticorrosion properties of the epoxy coating loaded with TP-LDH/O-MWCN. The EIS evaluation of the intact coating revealed the impedance at the lowest frequency (|Z|0.01 Hz) of about 109 Ω.cm2 after 42 days of immersion for the trisodium phosphate-layered double hydroxides/oxidized-multi-walled carbon nanotubes@epoxy (TP-LDH/O-MWCN@EP) sample and the lowest value of breakpoint frequency was obtained for this sample (fb = 0.063 Hz). These findings prove the trisodium phosphate-layered double hydroxides/oxidized-multi-walled carbon nanotubes (TP-LDH/O-MWCN) particles' effectiveness in the epoxy coating water/ion barrier function enhancement. EIS results indicated the enhancement of the charge transfer resistance (Rct) of the scratched coatings, from 65.97 kΩ.cm2 for the pure epoxy (EP) sample to 94.87 kΩ.cm2 for the trisodium phosphate-layered double hydroxides/oxidized-multi-walled carbon nanotubes@epoxy (TP-LDH/O-MWCN@EP) sample, revealing the self-repairing behavior of the designed coating. In addition, the adhesion properties of the samples coated with LDH/O-MWCN@EP and TP-LDH/O-MWCN@EP were studied by pull-off and cathodic disbonding tests, leading to a 33% reduction in adhesion loss and a 52.23% reduction in the diameter of cathodic delamination. The tensile test conducted on the samples indicated an increase in the ultimate tensile strength (σUTS), elongation break (Ɛb), and toughness values by 188%, 223%, and 800%, respectively, in comparison with the pure epoxy (EP) sample.

In situ-polymerized and nano-hybridized Ti3C2-MXene with PDA and Zn-MOF carrying phosphate/glutamate molecules; toward the development of pH-stimuli smart anti-corrosion coating

A smart anti-corrosion epoxy coating (EPC) was designed on the basis of polydopamine (PDA), and zeolitic imidazolate framework8 (ZIF8) tailored MXene (Ti3C2) sheets, which were loaded with two different corrosion inhibitors, namely phosphate and glutamate ions. The utilization of these inhibitor-loaded hybrid carriers in EPC yielded self-healing properties and prolonged resistance against corrosion. First, characterization tests including FT-IR, Raman, XRD, XPS, BET, TGA, SEM, and HRTEM were performed to confirm the synthesis of the constructed containers. Then, the inhibition efficiency and mechanism of the container were investigated via ICP and electrochemical (EIS and polarization) analyses. The synthesized PM-ZP and PM-ZG containers loaded with phosphate and glutamate inhibitors were proven to have a promising efficiency in reducing the corrosion of the metal, as the inhibition efficiency in the polarization test was demonstrated to be 42.17 and 60.31 %, respectively. The impedance values in the EIS test regarding solution media showed a considerable increment in PM-ZP (6511.3 Ω.cm2@3h) and PM-ZG (5438.3 Ω.cm2@5h) compared to the unprotected steel (2081.0 Ω.cm2@24 h). The self-healing potential of the nanocomposite containing PM-ZP and PM-ZG samples was manifested through the EIS test, FE-SEM as well as EDX maps of coatings with artificially produced scratches. The intact coatings’ long-term barrier characteristics were also investigated with an EIS test and impedance values > 40 Ω.cm2 and log|Z|10mHz > 10.5 justified the high performance of epoxy composites containing PM-ZP and PM-ZG synthesized carrier after 90 days of immersion in aggressive media. Pull-off, salt spray, and cathodic disbonding tests revealed that coatings containing PM-ZP and PM-ZG carriers outperformed epoxy coatings without corrosion inhibitors.

Comparative Studies of Wear and Corrosion Behaviors of Conventional and Nano Filler Based Solvent Free Tarfree Epoxy-amine Coatings

Tar-free epoxy coatings aid in protecting intact of Mild Steel (MS) substrate immersion condition of atmosphere. From lot of study revised and assorted that tar free (light colour) epoxy amine coating developed which give better performance for protection in long term. By ASTM method, wear behaviors as well as mechanical properties of quartz (micro silica) and organosiliane (nano silica) based tar-fee epoxy coatings were studied. DETA cured epoxy composites coatings were characterized by FTIR spectroscopic technique, powder X-Ray Diffraction (XRD), SEM and FESEM analysis. Transmission Electron Microscope (TEM) confirmed the size of nano particles. The data of wear index of nano fillers based epoxy coating was observed 8.3mg/1000cycles which indicate such an improvement of of abrasion behavior. Corrosion behaviors of the coated MSspecimens were evaluated by Cathodic Disbondment (CD) test immersion in 3.5% NaCl solution. Water absorption and chemical resistance also studied of composite coatings. All over tar-free epoxy-amine nano composite coating shows good result.

Effect of 2-Methylimidazole Composition as Low-Temperature Application in Phenol-Formaldehyde, Glycidyl Ether Epoxy Coating

The addition of materials to pile pipe at low temperatures is very challenging. Thereby, an optimum operating level is needed to produce a quality coating. Furthermore, 2-methylimidazole (2MI) was added into a phenol-formaldehyde, glycidyl ether polymer fusion bonded epoxy (FBE) coating at different concentrations of 1, 2, and 3 %wt. Thermal analysis was then carried out using differential scanning calorimetry (DSC), where the addition of 2MI decreased the curing temperature to 134.76°C due to the reduced activation energy. Potentiodynamic polarization showed the best corrosion rate of 0.00991 mm/year with a current density of 0.847μA/cm2 after adding 1 %wt 2MI. Electrochemical impedance spectroscopy (EIS) was carried out to determine the charge transfer resistance and maximum coating capacitor capacitance after adding 1 %wt 2MI, namely 9.9 kΩ and 8.45×10-5 F, respectively. The cathodic disbondment test (CD-Test) showed that the disbondment radius of the coating under the influence of the cathodic protection current was 4.32mm. Mechanical analysis by pull-off adhesion test showed a value of 7.28 MPa after the addition of 2MI 2 %wt but decreased to 6.63 MPa at 3 %wt. Therefore, the optimum addition is 1 %wt 2MI for low-temperature applications of 170 –175°C in piles with high coating performance and compliance with predetermined standards.

Enhancing Self-Healing and Adhesion Bonding Properties: Investigating the Promising Potential of Ce-ZIF8 MOF Hybrid Thin Films as pH-Responsive Nanocoatings.

Further modification of the pre-treated steel surface with cerium conversion coating was performed using a novel porous coordination polymer (PCP) based on zeolitic imidazole framework-8 (ZIF8) in order to reduce the defect and disorders of the surface. The treated mild steels (MS) with Ce (MS/Ce) and Ce-ZIF8 (MS/Ce-ZIF8) were characterized by the GIXRD, Raman, and FT-IR, and via contact angle and FE-SEM, their surface features were investigated. The protection performance of the samples against corrosion was evaluated in the saline solution media using electrochemical impedance spectroscopy (EIS, in the long term) and polarization tests. The results evidenced that applying the ZIF8 nanoparticles onto the Ce-treated steel surface increased the total resistance value after 24 h of immersion (49.47%). Afterward, the ZIF8-modified coating (MS/Ce and MS/Ce-ZIF8) impact on the epoxy coating protection function was characterized by EIS (in the scratched form), salt spray (5 wt % salts), cathodic disbonding (at 25 °C), and pull-off tests. The EIS outcomes of the scratched coatings proved approximately a 51.29% increase in Rt of the MS/Ce-ZIF8/EC sample compared with the MS/EC sample after 24 h of immersion. The cathodic disbonding test results after 24 h of exposure revealed that the delamination area of the coating decreased in the modified sample, and the delamination radius of the epoxy coating was about 4.78, 2.96, and 2.0 mm for the MS/EC, MS/Ce/EC, and MS/Ce-ZIF8/EC samples, respectively.

Long‐term cathodic disbondment tests in three‐layer polyethylene coatings

AbstractCathodic protection allied to a polymeric coating is one of the most employed techniques to protect buried steel pipelines against corrosion. Nevertheless, cathodic disbondment, a phenomenon associated with such protection in high‐performance coatings such as (three‐layer polyethylene [3LPE]), still concerns the oil and gas segment regarding pipeline integrity. The present work was part of a Program of Integrity Management and studied in field‐like conditions the influence of cathodic potential, type of soil and coating system on the coating disbondment of buried pipelines for 450 days. The coating systems herein studied simulated the patching between aged (coal tar) and new coatings (3LPE), a standard procedure during damaged pipeline repair. Results pointed out that the combination between aged (coal tar) and new coatings (3LPE) in a pipe segment reduced coating disbondment when compared to the systems where 3LPE was the sole type of coating. Moreover, it was shown that more cathodic potentials (<−1100 mV) and the aggressiveness of the industrial soil herein tested induced disbondment diameters as high as 15.5 mm.

Improving the Mechanical/Anticorrosive Properties of a Nitrile Rubber-Based Adhesive Filled with Cerium Oxide Nanoparticles Using a Two-Step Surface Modification Method.

To prepare a nanocomposite adhesive based on nitrile rubber (NBR) with excellent mechanical/anticorrosion properties, cerium oxide (CeO2) nanoparticles were grafted with bis-[3-(triethoxysilyl)propyl]tetrasulfide silane (TESPT) at different concentrations (i.e., 1, 5, 10, and 20 times the stoichiometric content). The surface-modified nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), ζ-potential, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FE-SEM) techniques. The results showed that the steaming process resulted in an increase in the grafting ratio (R g) by 2.35 times. Pure and modified cerium oxide nanoparticles were added at 1.5, 4.5, and 7.5 wt % to a mixture of a phenolic resin and NBR compound to prepare adhesive samples. The prepared adhesives were evaluated for curing behavior and thermomechanical properties. The morphology of the adhesives was also characterized using SEM analysis. The bonding of adhesives to steel plates was measured by a cathodic disbonding test. The adhesive-coated steel plates were evaluated for anticorrosion performances using a salt spray test. It was found that surface-modified hydrothermally steamed CeO2 nanoparticles that had the highest silane grafting ratio enhanced the anticorrosion properties and cathodic disbonding of NBR-based adhesives. The curing rate index (CRI) and crosslinking of the NBR compound were enhanced using the modified and steamed nanoparticles. This also improved the interfacial interactions between rubber chains and nanoparticle surface, resulting in a 6 °C increase in the glass-transition temperature (T g) of NBR compared to the pristine rubber.

Cathodic disbonding tests operating at large cathodic potentials for long periods need current monitoring, pH control and anode isolation

AbstractMetallic structures in service in seawater are protected by coupling cathodic protection and paints, where the former may induce disbondment of the latter. A preliminary evaluation of the cathodic disbondment risk can be made by cathodic disbondment tests (CDTs). Many CDTs use cathodic potentials as large as E < −1400 mV versus saturated calomel electrode (SCE) applied up to 90 days. Only two CDT protocols require contemporary anode isolation, current and pH monitoring, without its correction. These three aspects were considered to develop a hybrid CDT; it consisted of polarizing steel panels at −1500 mV versus SCE for 12 weeks. The chemical effects related to the anodic processes were investigated. A pH acidic shift was observed and was justified by the increasing current demand due to paint damage and brucite precipitation on the panels. The necessity of anode isolating glass to prevent chlorine chemical attack against the paints, potentially affecting the disbondment result, was verified by estimating the virtual chemical attack induced by free chlorine. In conclusion, current monitoring, pH control and anode isolation are highly suggested to correctly conduct and interpret the cathodic disbondment results when CDTs requiring large electronegative potentials are applied for long periods.

Discussion about the Relationship between Coating Life and Cathodic Protection Current Density of Offshore Pipeline

This article studies characteristics of 3LPE external coating material and cathodic protection technology for offshore pipeline firstly, analysis the mechanism of cathodic disbondment and specified properties, carries out cathodic disbonding tests base on different cathodic protection current density applied on coated samples at given temperature, and then analyses the relationship between coating failure life and index of cathodic protection using Arrhenius model and inverse power law model, puts forward a recommended maximal cathodic protection current density for offshore pipeline at a certain design life of coating.

Metal-doped 2D rGO nano-sheets fabrication utilizing plant source bio-molecules and application in the epoxy anti-corrosive coating: Combined experimental and DFT-D modeling investigations

Recently, graphene-filled polymeric composites have been utilized for achieving durable active corrosion protection properties in seawater solutions. The utilization of reduced graphene oxide (rGO) is highly recommended for this purpose. Although the traditional reductants can successfully reduce the GO layers, employing green active agents is far more affordable. In the present study, Mustard seed extract was introduced as a novel cost-effective, and green reductant for GO layers since it includes active agents like arabinose, allyl isothiocyanate, galactose, xylose, diallyl trisulfide, and rhamnose molecules. For boosting the active protection property, the rGO nano-sheets were doped with Zn (II) ions (Zn@rGO) as the inorganic inhibitor. The synthesized nanosheets' anti-corrosion impacts in the solution phase were illustrated by polarization and EIS techniques. The obtained results have proved that the Zn@rGO containing saline solution exposed steel samples resulted in 88% degree of inhibition in mixed mode. The EIS assessments carried out over the scratched epoxy composite reflected that the coating resistance was raised from 12,491 Ω cm2 to 47,480 Ω cm2, affirming the inhibitive corrosion prevention potency of the Zn@rGO/EP composite. The FE-SEM captures have displayed that the inhibitive layer filled the scratched zones successfully. Besides, the intact coating's high resistance (over 30 GΩ.cm2) indicated that the constructed nano-filler could effectively promote the EP coating barrier index. The optical captures after conducting a salt-spray test have demonstrated that after the EP anti-corrosion performance was significantly improved in the presence of Zn@rGO nano-layers. The coating delamination diameter reduction from 28 mm for the neat epoxy to 11 mm for the Zn@rGO loaded coating was recorded in the cathodic disbondment test. In addition, the theoretical findings ensured the affinity of the zinc ions/ME compounds for adsorption on the GO layers.

Cathodic disbonding of self-healing composite coatings: effect of ethyl cellulose micro/nanocapsules

ABSTRACT The effect of ethyl cellulose (EC) micro/nanocapsules containing linseed oil (LO) on the cathodic disbonding of self-healing composite coatings is investigated by cathodic disbonding test and electrochemical impedance spectroscopy (EIS). Results reveal that the presence of EC nanocapsules significantly improves the cathodic disbonding resistance of the coatings so that the rates of disbonded area under the simulated condition of cathodic protection decrease from 3.882 mm2 h for the blank coating to 0.025 mm2 h for the nanocapsules containing coating. It may be ascribed to the releasing LO and filling the defects at the coating/substrate interface by oxidative polymerisation mechanism. EIS test results indicate that the corrosion resistance of the coatings is improved in the presence of EC nanocapsules. In addition, the coating resistance to cathodic disbonding and corrosion increase by decreasing capsule sizes. Finally, a proposed mechanism of ion diffusion through the self-healing coating’s defect is schematically illustrated.

Development of an active/barrier bi-functional anti-corrosion system based on the epoxy nanocomposite loaded with highly-coordinated functionalized zirconium-based nanoporous metal-organic framework (Zr-MOF)

For the first time, the UIO-66, NH2-UIO, and NH2-UIO particles covalently functionalized by Glycidyl Methacrylate (GMA@NH2-UIO), were utilized as the novel functional anti-corrosive fillers. The functionality, high surface area, phase composition, excellent thermal properties as well as chemical stability of the Zr-MOFs were proved by FT-IR, BET, XRD, TGA, and water stability tests, respectively. The smart pH-sensitive controlled-release activity of the corrosion inhibitors (i.e., Zr ions and organic compounds) from the prepared Zr-MOFs was proved by the water stability test of the Zr-MOFs particles in the acidic (pH = 2), neutral (pH = 7.5), and alkaline (pH = 12) solutions containing 3.5 wt% sodium chloride. The active inhibition properties of the Zr-MOFs were obtained in saline solution by two methods of (i) the solution phase and (ii) scratched epoxy coated samples containing Zr-MOFs by Tafel polarization method and EIS analysis. According to the EIS data, the excellent barrier (passive) properties of the composite film filled with GMA@NH2-UIO particles (G-UIN/EP) were proved by the highest impedance level at the lowest f (frequency) (log (|Z|10 mHz = 9.86 Ω.cm2), the lowest value of the breakpoint frequency (log (fb) = −1.42 Hz) and the highest coating undamaged index (85.93%) after 120 h of immersion. The salt spray (accelerated corrosion test) test (SST), pull-off (testing the strength of adhesion), and cathodic disbonding test (CDT) experiments showed excellent interfacial-adhesion properties of the G-UIN/EP sample in two dry (unexposed) and wet conditions. The hardness test showed that through the incorporation of the UIO, UIN, and G-UIN particles into the epoxy coating, the hardness, and scratch-resistance of the coating were notably improved.

Nanoclay dispersion and colloidal stability improvement in phenol novolac epoxy composite via graphene oxide for the achievement of superior corrosion protection performance

In this study, Graphene oxide (GO) nanosheets were studied to improve nanoclay (NC) exfoliation in a phenol novolac glycidyl ether and improve coating performance. Particle characterizations are performed by FT-IR, Raman spectroscopy, and FE-SEM methods. EIS measurements confirmed denotative stability in impedance values, more significant than 1010 ohm·cm2, after prolonged immersion time (18 weeks). Complementary characterizations, salt spray test, pull-off, and cathodic disbondment test, revealed that such enhancement in the clay dispersion has significantly improved the coatings protection function.

IBA-modified gypsum-containing epoxy resin coating for rebar: corrosion performance and bonding characteristics

In this study, epoxy resin-based coating was developed for concrete reinforcement mild steel bar (rebar), and the corrosion behaviors of the uncoated rebar, single-cured epoxy resin-coated rebar, and indole butyric acid (IBA)-modified gypsum-containing epoxy resin-coated rebar were investigated in NaCl, CaCl2, and NaOH solution. Triethylene tetramine was used as curing agent for the epoxy resin, and IBA along with gypsum or silica was used in the composition of epoxy coating as inhibitor. Gypsum or silica was used separately as carrier of the IBA. Assessment was carried out on the basis of the corrosion resistance performance and bonding characteristics of the coated rebar. Corrosion resistance performance of the coating was evaluated using polarization resistance test, cathodic disbonding test, and corrosion-induced cracking study. Electrochemical tests showed that incorporation of IBA significantly improved the corrosion protection capacity of the epoxy coating against rebar corrosion. This was related to its healing effect on surface passivation against attack by a corrosive environment. In addition to corrosion protection capacity, bond strength between concrete and rebar is determined through pullout test. It was found that the coating has no adverse effect on the bond strength between embedded rebar and concrete, and additionally, it contributes to the bond strength due to adhesion properties of the resin.

Synthesis and characterization of hybrid materials based on graphene oxide and silica nanoparticles and their effect on the corrosion protection properties of epoxy resin coatings

This study focuses on the use of tetraethyl orthosilicate (TEOS) as a silica source to decorate the surface of graphene oxide (GO) nanosheets and the use of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (Z-6020) as a coupling agent through a one-step in-situ sol-gel process. The results of the Fourier transform infrared spectroscopy (FT-IR), UV-visible, X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) revealed that fine SiO2 nanoparticles have successfully been synthesized on the basal plane of GO by covalent bonding. The dispersion of GO sheets and GO–SiO2 nanohybrids within the epoxy matrix was studied using XRD and SEM techniques. Then, the effect of incorporating 0.1 wt% GO sheets and GO–SiO2 nanohybrids on the corrosion protection and barrier performance of the epoxy coating was also investigated. The results showed that the incorporation of GO–SiO2 into the epoxy matrix improved its thermal stability. The electrochemical impedance spectroscopy (EIS) test, potentiodynamic polarization and cathodic disbonding test showed that the corrosion protection performance was significantly enhanced by the incorporation of GO–SiO2 hybrids into the epoxy resin compared to epoxy/GO and neat epoxy resin, respectively. The water contact angle (CA) results confirmed the reduction of the hydrophobic nature of the surface after the incorporation of GO–SiO2 hybrids.

Graphene oxide as a potential nanocarrier for Zn(II) to fabricate a dual-functional active/passive protection; sorption/desorption characteristics and electrochemical evaluation

Herein, we demonstrated a facile non-covalent functionalization route to exploit the GO sheets as an efficient carrier for high loading of Zn(II) corrosion inhibitor with the controllable slow release. The Zn(II) intercalated GO exhibited good compatibility with epoxy matrix stemming from the chemical and structural alterations as confirmed by Raman analysis along with XPS, FE-SEM and HRTEM. The kinetics of Zn(II) release from the GO carrier revealed the consistency of experimental data with the Higuchi model. EIS combined with cathodic disbondment tests results proved the dual-function active/passive corrosion mitigation of Zn(II) intercalated GO-Epoxy system.

Active corrosion protection performance of an epoxy coating applied on the mild steel modified with an eco-friendly sol-gel film impregnated with green corrosion inhibitor loaded nanocontainers

In this study the corrosion resistance, active protection, and cathodic disbonding performance of an epoxy coating were improved through surface modification of steel by a hybrid sol-gel system filled with green corrosion inhibitors loaded nanocontainer as intermediate layer on mild steel substrate. The green inhibitor loaded nanocontainers (GIN) were used to induce active inhibition performance in the protective coating system. The corrosion protection performance of the coated panels was investigated by electrochemical impedance spectroscopy (EIS), salt spray, and cathodic disbonding tests. It was observed that the corrosion inhibition performance of the coated mild steel panels was significantly improved by utilization of active multilayer coating system. The inhibitor release from nanocontainers at the epoxy-silane film/steel interface resulted in the anodic and cathodic reactions restriction, leading to the lower coating delamination from the substrate and corrosion products progress. Also, the active inhibition performance of the coating system was approved by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive X-ray (EDS) analysis on the panels with artificial defects. The inhibitive agents were released to the scratch region and blocked the active sites on the metal surface.

The role of post-treatment of an ecofriendly cerium nanostructure Conversion coating by green corrosion inhibitor on the adhesion and corrosion protection properties of the epoxy coating

Abstract This study introduces a green strategy for enhancement of the corrosion protection and adhesion properties of an epoxy coating applied on the steel surface treated by cerium conversion coating (CeCC) and then post-treated by Urtica inhibitor. The corrosion behavior of the coatings was evaluated by electrochemical impedance spectroscopy and salt spray test. Scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and contact angle measurements were adopted for surface characterization. For further investigations, pull-off and cathodic disbondment tests were performed. Results demonstrate the beneficial role of the post-treatment of CeCC by Urtica inhibitor on the enhancement of the epoxy coating performance.