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Life cycle assessment of repair variants according to TR‐IH depending on the degree of damage The aim of this publication is the life cycle assessment of repair measures acc. to TR‐IH (Technical guideline Maintenance of concrete structures) on the basis of a case study. Here, a fictitious two‐storey underground car park is considered, the floor slab of which is uncoated and whose false ceiling has numerous separation cracks. On the basis of common chloride diffusion models, the temporal chloride penetration into the floor slab and thus the temporal development of the degree of damage can be estimated. Depending on the degree of damage, permissible repair methods are selected acc. to TR‐IH and their necessary individual measures are defined, which in turn are linked to Global Warming Potential (GWP). Thus, depending on the age of the component at the time of repair, the GWP for various repair procedures can be determined. In a further step, practical assumptions for operation and maintenance are made so that the GWP of the repair procedures can be determined over the remaining service life depending on the time of repair. The calculation results show that early repairs lead to a low GWP. In addition, careful repair procedures without major interventions in the structure (methods 7.7, 7.8 or 8.3) lead particularly to low GWP. If one compares Cathodic Protection (CP) with method 7.2, CP is linked to a significantly lower GWP for crack repair, or if electricity from renewable energies is used during service life. [ABSTRACT FROM AUTHOR]

Corrosion is one of the most significant problems in irrigation systems, and fertigation may increase its damage. One of the solutions to mitigate this phenomenon would be using cathodic protection combined with piping coating, so it is essential to evaluate the type of sacrificial anodes and the cathode/anode area ratio, variables that change the performance of cathodic protection and its application cost. Thus, this study aimed to validate the effect of Al anodes on the protection against the mass loss of galvanized steel used in fertigation with white KCl solution at 10 g L−1 and verify the influence of the cathode/anode area ratio on the galvanized steel protection and anode consumption. Thus, we conducted immersion tests by simulating 10 years of fertigation to determine the mass loss of the galvanized steel and Al anodes. The results showed that Al anodes significantly reduce the mass loss in galvanized steel exposed to KCl solution, but there is no significant difference in its mass loss with the increase in the cathode/anode area ratio. Regarding the Al anodes, there was also no significant difference in mass loss with the increase in the cathode/anode area ratio. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is considered an ideal material for applications involving corrosion resistance due to its excellent properties. However, the structure, surface functional groups, and distribution of GO in zinc-rich coatings (ZRCs) have a remarkable influence on coating properties. GO was reduced in a hydrochloric acid environment using spherical zinc powder, and the resulting products were subsequently dried and incorporated into waterborne inorganic ZRCs. Results show that zinc powder effectively reduces oxygen-containing functional groups on the GO surface, and reduced GO (rGO) is deposited on the surface of zinc powder. This improves the electron migration efficiency of rGO and decreases its surface energy. The electrochemical impedance spectroscopy (EIS) and salt spray test results demonstrate that among the coatings, the ZRC containing 0.2 wt.% rGO (40Zn–0.2rGO) exhibits the highest impedance modulus at the low frequency end. Its impedance modulus reaches 1 × 104 Ω∙cm2 after 216 h immersion. Furthermore, 40Zn–0.2rGO exhibits no signs of corrosion at the marked areas even after 216 h of the salt spray test. The good dispersion effect of the added 0.2 wt.% rGO in the coating, coupled with its exceptional electrical conductivity, facilitates the enhanced contribution of zinc powder to cathodic protection, thereby mitigating the matrix erosion caused by corrosive media. Following zinc powder corrosion, the surface of the coating can still be adorned with insoluble corrosion products such as ZnO or Zn5(OH)8Cl2, thereby offering shielding protection to the substrate. [ABSTRACT FROM AUTHOR]

This study compared the advantages and disadvantages of various corrosion protection methods for steel rebars and clarified the advantages of the cathodic protection (CP) method in the application of corrosion protection in marine structures. The advantages and disadvantages of sacrificial anodes and impressed current technology for the CP of steel rebars in marine structures were further discussed in detail, and the feasibility of CP applications in practical engineering was evaluated. [ABSTRACT FROM AUTHOR]

Environmentally assisted cracking can significantly affect the performance of high strength alloys and limit material selection to minimize the risk of subcritical crack growth in service. UNS N07718 is widely used in marine service applications and under a variety of conditions, such as: alternate immersion, different levels of cathodic protection, and freely corroding galvanic couples, because of its demonstrated corrosion and fracture resistance in these environments. In this work we developed a representative model of the material microstructure including the metal grains, the material texture, and the precipitates along the grain boundaries and within the grains. The microstructural model was subjected to the boundary conditions identified at the notch root of a fracture mechanics sample and the results are used as input for a simulation of hydrogen diffusion from the surface of the notch, assuming the material has been introduced to a hydrogen producing environment. The diffusion of hydrogen was modeled by Fick's law and included both hydrostatic stress and mobile dislocation velocity as driving forces. The influence of immobile dislocations was also modeled to account for the irreversible trapping. The results show that hydrostatic stress and immobile dislocation trapping can significantly alter the highest concentration of hydrogen and its location within the microstructure towards the fracture process zone. Mobile dislocation velocity has a small influence in determining the hydrogen distribution near the fracture process zone. [ABSTRACT FROM AUTHOR]

ABSTRACT Evaluating the cathodic protection (CP) effectiveness of horizontal directional drilling (HDD) pipe is a significant technical challenge, due to the feasibility of testing only in shallow buried areas at entry/exit extremities, and not in deeply buried areas or the crossing section of the pipe. Numerical simulation provides a method to evaluate the CP effectiveness of HDD pipes. To improve the accuracy of potential distribution along the HDD pipe, it is necessary to adopt appropriate boundary conditions of the HDD pipe and accurate holiday models of coating. A specialized deep well polarization test device was designed and employed in the field to obtain the actual polarization characteristics as the boundary condition of the HDD pipe at buried depths ranging from 2 to 25 m. The result revealed that the polarization characteristics of HDD pipe in various depths were different and the potential distribution of the actual situation was greatly different from the potential distribution of the shallow aerobic soil. The potential distribution along the HDD pipe was analyzed in two types of holiday models. The results could be used as a reference for the CP effectiveness evaluation of HDD pipes. [ABSTRACT FROM AUTHOR]

ABSTRACT As an important infrastructure for oil and gas transportation, the safe and stable operation of long‐distance pipelines is significant for guaranteeing national energy security and economic development. However, pipelines are susceptible to corrosion due to various factors. Therefore, it is crucial to take effective corrosion protection measures. Pulse current cathodic protection technology, as an advanced pipeline corrosion protection technology, is superior to traditional cathodic protection technology. This paper mainly summarizes the research progress of pulse current cathodic protection technology for long‐distance pipelines in recent years. It briefly discusses the protection mechanism, characteristic parameters, challenges, and development trends of pulse current cathodic protection technology, which provides a useful reference for the further promotion and application of pulse current cathodic protection technology for long‐distance transport pipelines. [ABSTRACT FROM AUTHOR]

ABSTRACT Unlike the stable AC interference caused by AC transmission lines to buried pipelines, high‐speed railways cause dynamic AC interference to nearby buried pipelines. The dynamic fluctuation characteristics of AC interference parameters of buried pipelines near high‐speed railways with different traction power supply modes were obtained through the statistical analysis of field test data. The dynamic AC corrosion simulation experiments were conducted with different interference cycles and levels, as well as cathodic protection (CP) levels. The results show that the dynamic AC corrosion rate increases with the extension of the interference time within each interference cycle. After the JAC ≥ 100 A/m2, the dynamic AC corrosion rate shows a three‐stage change with a negative shift of CP potential, that is, first decreasing, then increasing, and then decreasing again. On the basis of the experimental results, the dynamic AC corrosion risk assessment criteria were proposed, which comprehensively considers the CP level and the proportion of interference time with different AC current densities. [ABSTRACT FROM AUTHOR]

According to the corrosion problems of the gathering and gas piprlinc, thc pipeline material, cx・ trmal corrosion and internal corrosion were analyzed; the chemical corrosion mechanism and electrochemical corrosion mechanism of pipeline corrasion were summarize*! chemical corrosion was often accompanied by electrochemical corrosion, electrochemical corrosion was more common, and the harm was ako more serious; multi pic protective measures including pipeline material selection, coating protection cathode protection and corrasion inhibitor protection mrasurcs were systematically introduced, and pointed that joint protection technology combined of corrosion technologies was the fiiturc

Two-month experiments were carried out with carbon steel electrodes buried in an artificial sand wetted at 50–55% of saturation with a 0.07 mol L−1 Na2SO4·10H2O solution. Various protection potentials (corrected from the ohmic drop) were applied from −0.60 to −1.13 V/Cu-CuSO4. In each case, the behavior of the electrode protected by cathodic polarization was compared with that of an unprotected electrode. The electrochemical study was performed using voltammetry, linear polarization resistance measurements, and EIS. Surface characterization of the coupons was carried out using optical microscopy and X-ray diffraction. First, cathodic protection was observed to induce a spreading of the electrolyte on the metal surface because of electrocapillary effects. The active area, or more precisely the wet area, of the electrode increased, leading to a decrease in soil electrolyte resistance Rs measured using EIS. This phenomenon was experimentally confirmed via visual observations of the surface of the coupons at the end of the experiments. Secondly, cathodic protection induced a passivation of the steel surface. The passive state persisted for 35 to 85 h after cathodic protection was stopped and could be studied during various periods of interruption of the protection. In each case, the OCP of the previously polarized coupons reached high values, actually 200–250 mV higher than those measured for the unprotected coupons, and was associated with high polarization resistance Rp values (~40 kΩ cm2). Depassivation of the metal finally occurred, a phenomenon revealed by simultaneous important drops of both OCP and Rp. [ABSTRACT FROM AUTHOR]

Free-spanning subsea pipelines subjected to vortex-induced vibrations (VIVs) are particularly prone to fatigue failure. Existing flume observations indicated that the VIVs of a near-bed cylinder may be triggered effectively in moderate shear flows. This may imply that the vibration cycles of a spanned pipeline could be up to tens of millions. As such, very high cycle fatigue (VHCF) can occur during engineering service. The free span length is a key parameter for determining the structural natural frequency and the corresponding reduced velocity (Vr). On the basis of the dimensionless vibration amplitude A/D–Vr curve and the recommended S-N curves for high-strength steel pipelines with cathodic protection under seawater environments, a prediction method is proposed for the fatigue life of a free span undergoing VIVs. A parametric study is then performed to evaluate the fatigue life of the spanned pipelines with a focus on VHCF. It is indicated that the minimum fatigue life emerges at certain flow with a moderate velocity for a given span length. With a further decrease or increase in the flow velocity, the fatigue life would be enhanced correspondingly, which could be within the VHCF regime. Such nonlinear variation of the fatigue life with the span length and the flow velocity is attributed to being involved in various VIV branches of the A/D–Vr curve. [ABSTRACT FROM AUTHOR]

Corrosion is a phenomenon that occurs on pipes, reinforced concrete structures, and storage tanks and causes a major impact on the facility structures and can have a major impact on a facility's structural integrity. This can result in a serious failure in the system and lead to substantial economic losses. One of the solutions widely used to eliminate the corrosion effects is by applying cathodic protection, which depends on direct current as the supply potential. The technique of cathodic protection is used to control corrosion in the utilisation of reinforced concrete structures, pipelines, storage tanks, etc. A photovoltaic cathodic protection system is normally used as an energy source to supply the system. This research reviews the technique utilised for applying solar photovoltaics in powering systems of cathodic protection. Subsequently, it highlights the methods of cathodic protection systems, sacrificial anode cathodic protection and the impressed current cathodic protection. Finally, it is indicated that applying solar photovoltaics in powering cathodic protection systems has great efficacy in controlling the corrosion in the facility's equipment in a smarter, controlled way. Furthermore, this study provides significant insight into the designing and operating the domain of solar photovoltaic systems that power cathode protection systems. [ABSTRACT FROM AUTHOR]

This study reports a combined electrochemical method for preparation of a titanium dioxide–suboxide composite with an electrochemically deposited non-continuous platinum layer on the surface, which can be used for cathodic protection of metal structures. Platinum significantly modifies the properties of TiO2, stabilizes the surface, and prevents the formation of a passive non-conductive layer. The coating has significant advantages compared to Ti/Pt, traditionally used for electrochemical protection, as the platinum content in the composite is significantly reduced. Unlike a continuous precious metal layer, this method of composite formation, particularly thermal treatment in an air atmosphere at 5000 C, allows protecting the platinum, which is encapsulated in titanium oxides, and avoiding the creeping passivation typical of traditionally used materials. The surface of the coatings was investigated using X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, and X-ray microanalysis. Studies of the electrocatalytic properties, especially concerning the oxygen evolution reaction, revealed deviations of the Tafel slope from the theoretical value, which is explained by structural heterogeneity and the presence of a semiconductor component. The stability and corrosion resistance of the composites were studied. It was found that the properties remain unchanged even after prolonged exposure to a corrosive environment. [ABSTRACT FROM AUTHOR]

The paper analyzes the problem of protection of underground metal pipelines using active cathodic protection. Shortcomings and emergency situations of active defense complexes are given. Analytical dependences of determining the levels of the protective potential in the conditions of a heterogeneous environment, various variations of the topology of laying the pipeline system are generally presented. The results of comprehensive monitoring of the operation modes of electrotechnical complexes of electrochemical protection allowed to develop a universal methodology for creating energy-efficient and reliable systems of cathodic protection of pipelines. [ABSTRACT FROM AUTHOR]

This paper introduces an innovative improvement to impressed current cathodic protection (ICCP) systems by integrating a pulse-feeding technique designed to address metal protection degradation during off-potential periods, a common issue in conventional systems. The proposed system enhances the overall effectiveness and reliability of ICCP, providing consistent corrosion protection for critical metal structures. A notable advantage of this method is its simplicity, utilizing a cost-effective microcontroller for pulse feeding. This approach simplifies integration processes and enhances cost-effectiveness, making it an attractive solution for improving cathodic protection system performance without substantial additional costs. The method addresses conventional ICCP weaknesses by applying a high-frequency pulse current during off-potential periods. This reduces excessive negative charge buildup on metal surfaces during interruptions, boosting the system's effectiveness and stability. Research laboratory experiments were conducted using pulse width modulation (PWM) on an ATmega328P microcontroller to demonstrate the method's effectiveness. Additionally, an IoT-monitored ICCP system was developed using an ESP32 microcontroller and the Blynk application. Results highlight the superiority of a 50 kHz pulse feeding frequency in preventing corrosion compared to lower frequencies. Overall, this advancement significantly enhances ICCP systems, providing improved corrosion protection and durability in harsh environments. [ABSTRACT FROM AUTHOR]

Two-month experiments were carried out with carbon steel electrodes buried in an artificial sand wetted at 50–55% of saturation with a 0.07 mol L−1 Na2SO4·10H2O solution. Various protection potentials (corrected from the ohmic drop) were applied from −0.60 to −1.13 V/Cu-CuSO4. In each case, the behavior of the electrode protected by cathodic polarization was compared with that of an unprotected electrode. The electrochemical study was performed using voltammetry, linear polarization resistance measurements, and EIS. Surface characterization of the coupons was carried out using optical microscopy and X-ray diffraction. First, cathodic protection was observed to induce a spreading of the electrolyte on the metal surface because of electrocapillary effects. The active area, or more precisely the wet area, of the electrode increased, leading to a decrease in soil electrolyte resistance Rs measured using EIS. This phenomenon was experimentally confirmed via visual observations of the surface of the coupons at the end of the experiments. Secondly, cathodic protection induced a passivation of the steel surface. The passive state persisted for 35 to 85 h after cathodic protection was stopped and could be studied during various periods of interruption of the protection. In each case, the OCP of the previously polarized coupons reached high values, actually 200–250 mV higher than those measured for the unprotected coupons, and was associated with high polarization resistance Rp values (~40 kΩ cm2). Depassivation of the metal finally occurred, a phenomenon revealed by simultaneous important drops of both OCP and Rp.

In order to clarify the mutual interference law and interference protection measures of the cathodic protection system of double-pipe pipelines laid in the same trench, a double-pipe same trench laying pipelines(D219 and D457) in Xinjiang oilfield was taken as a model, the coating breakage rate of D219 pipeline was set to 0.1%, and the coating breakage rates of D457 pipelines were set to 0.1%, 0.5%, 1.0%. Numerical simulation methods were used to evaluate the effectiveness and applicability of different cathodic protection designs and cathodic protection interference protection measures. Results showed that mutual interference of cathodic protection systems existed in the pipeline laying in the same trench with shallow buried anode separate cathodic protection. The interference degree of parallel D219 pipelines was enhanced as the breakage rate of the D457 anti-corrosion layer of the interfering pipeline increased, and equalizing line measures could be applied to reduce the interference effectively. The joint cathodic protection measures with shallow buried anode and equalizing line could eliminate the mutual interference of cathodic protection systems for the same trench laying pipelines. The improvement of cathodic protection effect was more significant when the difference in the breakage rate of the anti-corrosion layer of the same trench double-pipe pipelines was large(0.1% of D219 and 1.0% of D457). For the same trench pipelines under joint cathodic protection measures with deep well anode, the cathodic protection effect was poor when the breakage rate of the D457 anti-corrosion layer was large(1.0%) and the soil resistivity was high(50 Ω·m). The improvement of cathodic protection effect was not significant by equalizing line and sacrificial anode measures. Increasing the output current of the deep well anode combined with equalizing line measures could significantly improve the cathodic protection effect of pipelines laid in the same trench.

Corrosion failure of sacrificial anodes in extreme deep-sea environment is a key problem in metal protection technology. This study investigated the failure mechanism of the Al-Zn-In sacrificial anode under the synergic action of water pressure and fluid flow, by microstructure characterization and finite element analysis. The results exhibit that water pressure promotes the dissolution of Al-Zn-In alloy near the precipitates that are enriched at the grain boundaries. The flow amplifies the promoting effect of the pressure on anodic dissolution by inhibiting the formation of corrosion layers, and it accelerates the mass loss by mechanically aggressing the aluminum matrix. The synergic effect of water pressure and fluid flow results in a rapid degradation in the extreme deep-sea environment.

Cathodic protection is widely employed to prevent the corrosion of steel in marine environments. However, an inappropriate cathodic potential may lead to the generation of hydrogen and consequently induce cracking. Therefore, this study investigates the relationships between cathodic deposition potential, calcareous deposits, hydrogen evolution, and hydrogen permeation. Combining scanning electron microscopy, Raman spectroscopy, coupled focused ion beam lithography, and energy dispersive X-ray spectroscopy, it is observed that all calcareous deposits formed in artificial seawater at the potential range of −1.0 to −1.3 V SCE have calcium-rich inner and magnesium-rich outer layers, respectively. The thickness and compactness of each layer of the double-layer deposits vary with the cathodic deposition potential. Combining potentiodynamic polarization, hydrogen permeation experiments, and the morphology of calcareous deposits, we can find that the deposits formed at the cathodic deposition potential of −1.1 V SCE exhibit a thin inner layer and a condensed outer layer, which is effective in balancing hydrogen recombination and absorption, thus, inhibiting hydrogen entry. This study provides guidelines for the cathodic protection of steel materials in marine environments. • Addresses hydrogen-induced cracking in cathodic-protected steel in seawater. • Studies the correlation between cathodic potential and calcareous deposits in steel. • Q460 Steel specimens were applied with a potential in the range −1.0 to −1.3 V SCE. • Double-layer deposits with Ca- and Mg-rich inner and outer layers, respectively. • Deposits under −1.1 V SCE are most effective in preventing hydrogen permeation. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) cathodic protection technology based on new energy harvesting represents a promising strategy owing to the low cost, low environmental pollution and simple installation. However, converting alternating current to pulsed direct current through a rectifier reduces the cathodic protection efficiency. Here, a multi-phase coupling TENG (RD-TENG) energy harvesting device with rotating disc is proposed for metal cathode anticorrosion. Through the rotation of the disk, high density current is generated to form a DC power supply. The current output pulse interval is reduced after full wave rectification, and the effect of a constant and stable direct current (DC) power supply can be achieved. The highly coupled superposition RD-TENG (3P5E) demonstrates a short-circuit current density (Isc) of 1.86 μA, an open circuit voltage (Voc) of 120 V, and a transferred charge (Qsc) of 50 nC. At low speeds, RD-TENG (3P5E) can effectively power up to six LED bulbs without any noticeable flickering. Furthermore, when 304 SS connected to RD-TENG (3P5E), the open circuit voltage and corrosion potential decreased by 102 mV and 122 mV respectively, indicating superior corrosion protection compared to systems without RD-TENG. In general, this advancement provides an important practical significance for TENGs in expanding the application of cathodic corrosion protection in the Marine industry. [ABSTRACT FROM AUTHOR]

Steel monopile support structures for offshore wind turbines require protection from corrosion and consideration with respect to biofouling on their external and internal surfaces. Cathodic protection (CP) works effectively to protect the external surfaces of monopiles, but internally, byproducts from aluminum sacrificial anode CP (SACP) and impressed current CP (ICCP) induce acidification that accelerates steel corrosion. Through an 8-week sea water deployment of four steel pipes, this project investigated the effect of perforations on internal CP systems. Additionally, marine growth on the internal and external surfaces of the pipes was assessed. SACP and ICCP systems inside perforated pipes performed similarly to external systems at a lower current demand relative to internal systems in sealed pipes. The organisms that grew inside of the perforated SACP and ICCP pipes were similar, suggesting that the CP systems did not affect organism recruitment. The results of this study demonstrate the potential benefits of designing perforated monopiles to enable corrosion control while providing an artificial reef structure for marine organisms to develop healthy ecosystems. [ABSTRACT FROM AUTHOR]

Calcareous deposits are a consequential outcome of cathodic protection in marine environments, exerting significant influence on the cathodic protection process and current density prerequisites. This study investigates the process of calcium deposition and its impact on the cathodic protection current density of carbon steel under the influence of a rust layer in different corrosion periods. This was investigated using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). The results demonstrate that the formation processes of calcareous deposits vary after exposure to the corrosive environment for 0, 7, and 30 days. While a longer corrosion period leads to thicker rust layers on the metal surface and a higher initial cathodic protection current, the presence of these rust layers facilitates the deposition of calcium and magnesium ions, resulting in a rapid decrease in cathodic protection current density after a certain period. Meanwhile, long-term cathodic protection facilitates the thickening and densification of the oxide layer, thereby enhancing its protective efficacy, effectively reducing the corrosion rate of the metal surface and stabilizing the cathodic protection current density at a lower level. This study provides theoretical data and experimental evidence to support the maintenance of corroded marine engineering equipment. [ABSTRACT FROM AUTHOR]

Developing low-cost and high-efficiency non-precious metal cocatalysts is the key to the practical application of photocatalysis technology. Here, nickel sulfide (NiS) nanoparticles were synthesized on the surface of strontium titanate (SrTiO 3) via a hydrothermal method, identifying the optimal loading molar concentration of NiS as 10 %. The solar-to-hydrogen efficiency (STH) of 10%NiS/SrTiO 3 :Al was enhanced by 97 times compared to SrTiO 3 :Al and by 1.62 times compared to RhCrCoO x /SrTiO 3 :Al. This improvement is primarily attributed to the metallic-like properties of NiS, which enhance the photocatalyst's light absorption capacity and charge transfer capability. Additionally, the STH value of samples loaded with both NiS and RhCrCoO x reached 0.436 %, indicating a positive synergistic effect in photocatalysis between NiS and RhCrCoO x. Their photocathodic protection capability was also studied in simulated seawater conditions, showing a reduced self-corrosion potential (−0.31V) and a low interface charge impedance (5962 KΩ). This work reveals the potential of NiS as an alternative to precious metal cocatalysts, offering new possibilities for developing cost-effective and high-performance materials for photocatalytic water splitting and photocathodic protection. [ABSTRACT FROM AUTHOR]

This paper presents the methodology developed for underwater measurements using electrochemical impedance spectroscopy (EIS) technique, aimed at determining the resistance of an epoxy coating applied in seawater to the legs of an oil production platform. Performing such underwater tests in an offshore environment was technically challenging. The results of measurements obtained on the platform were confronted with comparative results obtained in the laboratory, where the properties of the coating applied in water collected from the Baltic Sea (thickness, hardness, adhesion, and electrical resistance) were examined. This made it possible to conclude about the correctness of the paint coating application by divers on the legs of the platform. The single-layer epoxy coating applied by brush to the platform legs had a resistance above 10 kΩ∙cm2 and thus met the assumed minimum resistance of the protective coating cooperating with cathodic protection as the anti-corrosion protection system of the platform legs. The synergy of these two technologies ensures full protection of offshore structures against corrosion. Measurements of the potential of the platform legs confirmed this. Before painting, the potential value at a depth of 0–15 m was 310 ÷ 320 mV versus the zinc reference electrode, while after painting the potential value decreased to 220 ÷ 240 mV, which means that the effect of full cathodic protection was achieved and the platform legs were protected from corrosion. The developed methodology for underwater EIS measurements on the high seas can be applied to any underwater metal structure to assess the quality of protective coatings. [ABSTRACT FROM AUTHOR]

In this work, the stress corrosion cracking (SCC) behavior of X90 steel was investigated at various cathodic protection potentials by slow strain rate tensile tests, crack growth tests, electrochemical measurements and scanning electron microscope. The results show that the crack growth behavior of X90 steel in high pH soil environment is controlled by the microenvironment-electrochemical interaction at the crack tip. Under the combined action of anodic dissolution and hydrogen embrittlement, the SCC susceptibility decreases at first and then increases with the negative shift of cathodic protection potential. The pH value and Cl- concentration at the crack tip are affected by the potential outside the crack. Crack growth rate (CGR) is fundamentally affected by the cathodic protection potential, and the minimum CGR is − 850 mV/SCE. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate the corrosion inhibitor effect of migrating corrosion inhibitor (MCI) on Q235 steel in high alkaline environment under cathodic polarization. Design/methodology/approach: This study investigated the electrochemical characteristics of Q235 steel with and without MCI by polarization curve and electrochemical impedance spectroscopy. Besides, the surface composition of Q235 steel under different environments was analyzed by X-ray photoelectron spectroscopy. In addition, the migration characteristic of MCI and the adsorption behavior of MCI under cathodic polarization were studied using Raman spectroscopy. Findings: Diethanolamine (DEA) and N, N-dimethylethanolamine (DMEA) can inhibit the increase of Fe(II) in the oxide film of Q235 steel under cathodic polarization. The adsorption stability of DMEA film was higher under cathodic polarization potential, showing a higher corrosion inhibition ability. The corrosion inhibition mechanism of DEA and DMEA under cathodic polarization potential was proposed. Originality/value: The MCI has a broad application prospect in the repair of damaged reinforced concrete due to its unique migratory characteristics. The interaction between MCIs, rebar and concrete with different compositions has been studied, but the passivation behavior of the steel interface in the presence of both the migrating electric field and corrosion inhibitors has been neglected. And it was investigated in this paper. [ABSTRACT FROM AUTHOR]

The appearance of triboelectric nanogenerators (TENG) provides a promising energy technology for harvesting abundant water wave energy. Here, the design and fabrication of a swinging origami‐structured TENG (SO‐TENG) tailored specifically for water wave energy harvesting are presented. The design incorporates an oscillating structure weighted at the bottom, inducing reciprocating motion propelled by the inertia of passing water waves. This reciprocating motion efficiently converts mechanical into electrical energy through the origami structure. By employing origami as the monomer structure, the surface contact area between friction layers is enhanced, thereby optimizing output performance. the swinging structure, combined with the placement of heavy objects, enhances the folding and contact of the origami, allowing it to operate effectively in low‐frequency water wave environments. This configuration exhibits robust power generation capabilities, making it suitable for powering small electronic devices in water wave environments. Furthermore, when applied to metal corrosion protection, the SO‐TENG demonstrates notable efficacy. Compared to exposed Q235 carbon steel, Q235 carbon steel protected by SO‐TENG exhibits a significant reduction in open‐circuit potential drop, approximately 155 mV, indicative of superior anti‐corrosion properties. It lays a solid foundation for water wave energy collection and self‐powered metal corrosion protection in marine environments. [ABSTRACT FROM AUTHOR]

In this article, the carbon nanotube-carbon fiber (CNT-CF)/cement-based composite served as a novel auxiliary anode in the form of overlay for the cathodic protection of reinforced concrete (RC) was proposed. The effect of CNT content and age on the conductivity of CNT-CF/cement-based composite was firstly analyzed. After applying the CNT-CF/cement-based composite, the effectiveness of cathodic protection on the reinforcement was evaluated by the corrosion potential and corrosion current, respectively, as measured by Tafel polarization and half-cell potential methods. For comparison, finite element simulation was adopted to calculate the corrosion potential and corrosion current. It showed that the resistivity of CNT-CF/cement-based composite monotonously decreased with increasing content of CNT up to 2 wt.%. When the CNT content was 0.5 wt.%, the resistivity of the composite reached the minimum value of 22.3 Ω·cm. The resistivity for all the groups decreased with increasing age in the first 7 days. Both the experimental and simulated results showed that the CNT-CF/cement-based auxiliary anode improves the cathodic protection effectiveness for RC. [ABSTRACT FROM AUTHOR]

In this study, the functionality of self‐formulated carbon‐based conductive coatings (CBCCs) with incorporation of graphite as the anode in an impressed current cathodic protection system is studied. The anode materials are tested and evaluated for long‐term durability and performance by an accelerated durability test method. The results show that the functional time is highly dependent on the acceleration factor, and thus the charge passed through the material during testing, as well as the material composition. From the results, there are also indications that the addition of graphene into the CBCC matrix has a positive effect on the homogeneity of the material, but without any major influence on the conductivity and performance. [ABSTRACT FROM AUTHOR]

Cathodic protection is a significant approach utilized to avoid the electrochemical corrosion of pipelines. This is accomplished by supplying an electric current to the structure that requires protection, such as a pipeline, from an external source. study aims to enhance the cathodic protection system by minimizing potential fluctuations along the pipeline hence preventing corrosion. It also aims to achieve economic feasibility by decreasing the number of anodes utilized. These objectives were accomplished by employing meta-heuristic optimization techniques. The present study involves formulating a mathematical model for a pipeline that provides fuel to the Al-Hilla 2 power plant in Iraq to assess the effectiveness of cathodic protection. Utilizing numerical simulation techniques, Multiphysics COMSOL, diverse scenarios are examined, resulting in the acquisition of substantial data. Subsequently, a neural network model is constructed using MATLAB. The primary factors influencing the distribution of cathodic protection potential are the numbers and positioning of the anodes and the output current. Subsequently, the optimization objectives involve determining the optimal anode number, position, and output current value by utilizing the Particle swarm organization (PSO) algorithm. The obtained results provide evidence that the proposed method holds a certain level of significance in guiding the design of cathodic protection systems. [ABSTRACT FROM AUTHOR]

Cathodic protection (CP) in combination with organic coating is applied as a secondary technique to mitigate corrosion of buried steel in an effort to prolong the lifespan of the buried steel pipeline. This study was aimed at developing and applying an adequate technique for monitoring the electrochemical behaviour of buried steel in the presence of CP. A modified voltammetry procedure was applied on carbon steel immersed in simulated soil solution for four days under open circuit potential (OCP) before applying CP for further ten days. Electrochemical impedance spectroscopy (EIS) was also applied at various time intervals to investigate the electrochemistry at the steel/solution interface. The voltammetry experiments revealed that the corrosion rate peaked at 680 µm/yr after three days of being subjected to OCP and then decreased to 411 µm/yr on day four as a result of a passive layer development on the steel surface. The corrosion rate was reduced from 411 µm/yr to 8 µm/yr as result of CP application before fluctuating between 21 and 40 µm/yr. The examination of steel surface via x-ray diffraction revealed the presence of calcareous deposit which resulted due to the application of cathodic protection.

The current study introduces a novel technique to handle electrochemical localized corrosion in certain limited regions rather than applying comprehensive cathodic protection (CP) treatment. An impressed current cathodic protection cell (ICCPC) was fabricated and firmly installed on the middle of a steel structure surface to deter localized corrosion in fixed or mobile steel structures. The designed ICCPC comprises three essential parts: an anode, a cathode, and an artificial electrolyte. The latter was developed to mimic the function of the natural electrolyte in CP. A proportional-integrated-derivative (PID) controller was designed to stabilize this potential below the ICCPC at a cathodic potential of −850 mV, which is crucial for protection efficacy. The controller of the protection system was designed to automatically activate the ICCPC when the environment of the steel structure is exposed to humidity. At a temperature range from 27 °C to 35 °C, the protection potential, current, and power showed an increase in percentage by 411 %, 688.74 %, and 2842.3 %, respectively when the humidity level rose from 10 % to 100 %. The intended spraying of sodium chloride (NaCl) solution on the structure at different concentrations from 1.5 % to 5 % showed excellent protection against corrosion, notable improvements in electrical conductivity, and reduction in resistance between the anode and cathode. The energy dispersive spectroscopy and scanning electron microscopy (SEM-EDS) analyses confirm effective corrosion inhibition under ICCPC coverage compared to unprotected areas. These tests revealed an absence of oxidation beneath the ICCPC compared with areas outside of its coverage. The areas outside of ICCPC protection showed a reduction in iron and carbon contents from 57.1 % to 47.0 % and 41.4 %–22.4 %, respectively, and an increase in oxygen from 1.6 % to 30.6 %.

Corrosion is a degradation process on metal that happen naturally. Corrosion is one of the most common problems in the industry, resulting the corrosion prevention much needed to increase the lifetime of a material. One of the methods of corrosion prevention is cathodic protection using a sacrificial anode. This research was conducted to analyze the effect of ytterbium rare earth to the corrosion rate of sacrificial anode aluminium in seawater environment. In this research, the ytterbium rare earth used using variety of 14%, 21%, and 22%. The alloy was made using a casting process with a mini furnace, and was characterized using XRF, XRD, SEM-EDX, and Metallographic Tests. Then an immersion test was carried out for 10 days and a tafel test using the Corrtest tool and the CS Studio5 application. The electrolyte solution used is 3.5% NaCl and SCE as a reference electrode. The results show that as the element Ytterbium(Yb) increases, the grain size becomes smaller and finer. This is because Ytterbium(Yb) has a role as a grain refiner. Based on the results of the corrosion rate calculation, the lowest corrosion rate value was sample B with a Yb percentage of 21%, which had a corrosion rate value of 0.005 mm/year on the tafel test. Whereas for the 10-day immersion test, the lowest corrosion rate value was also obtained from sample B with a Yb percentage of 21%, namely 1.030 mm/year. The addition of the element Ytterbium(Yb) decreases the potential value of the sacrificial anode in seawater at room temperature with 22% Al-Yb alloy which has a potential value of the criterion of -821mV, so that only 22% Al-Yb alloy can protect the cathode.

Cathodic protection (CP) is the most effective method for protecting petroleum facilities against corrosion. As part of this protection, care should be taken to continuously evaluate the existing system in order to maintain the system in favorable conditions. The subject of the paper’s research is an oil plant for the transportation of oil derivatives located at the Brega company in Tobruk, Libya. In the present work, a case study on how to evaluate the CP system for an existing company for petroleum transportation is considered. The procedure was planned in three steps. The first step is a historical survey of the CP system from when the company started. The second was a diagnostic analysis study of the problem and how to fix it along the system. The third is the conclusions and recommendations regarding the measures for evaluating the CP system without stopping production.

An effective method for the formation of a Zn-doped Ru liner is demonstrated that realizes a self-forming barrier to achieve low resistivity interconnects for future back-end of line interconnect nodes. The "Ru–Zn" exhibits significantly improved adhesion to the dielectric and better electrochemical nucleation as compared to those of pristine Ru. In addition, time-dependent dielectric breakdown (TDDB) measurements indicate the inhibition of Cu ions drifting into the dielectric that precedes the TDDB failure. Complementary analysis using x-ray absorption spectroscopy, transmission electron microscope, and energy dispersive spectroscope suggests that the "Ru–Zn" forms an interfacial Zn–Si–O compound, and Zn, being more electronegative than Cu, protects the latter from oxidation. Calculation using density function theory also indicates that the Zn–Si–O compound adopts an intercalated structure at the interface of Ru/dielectric in which Zn occupies the interstitial sites within the Si–O lattice. We propose a twofold mechanism for improved TDDB performance: (1) the intercalated Zn atoms effectively block the diffusion of Cu ions through the dielectric and (2) Zn provides the cathodic protection of Cu that prevents the generation of mobile Cu ions that accelerate the TDDB. [ABSTRACT FROM AUTHOR]

The corrosion problem of the tank floor of the oil depot tank area becomes more and more serious with the extension of the operation time. At present, how to determine the potential distribution of the storage tank floor and how to judge the cathodic protection effect of the storage tank floor is the bottleneck of technological development. In this paper, by constructing a mathematical model of cathodic protection in the tank area, influence of deep well anode on potential distribution of tank bottom is calculated by boundary element method (BEM) with computer programming, to study the potential distribution of the tank floor under different anode parameters. The results show that the calculated results are in good agreement with the field measured results, which verifies the accuracy and reliability of the calculation. [ABSTRACT FROM AUTHOR]

Sulfate-reducing bacteria (SRB) is a bacterium that can cause microbial corrosion. SRB often leads to corrosion and perforation of oil and gas pipelines. Cathodic polarization is usually used for pipe external corrosion protection, while cathodic polarization may influence the growth and reproduction of SRB on the pipe wall. Based on 14-day electrochemical experiments and morphological characterization of corrosion product, SRB corrosion on L360N under different cathodic polarization potentials was analyzed. Under the action of cathodic protection potential, − 0.85 VSCE stimulated SRB metabolism and accelerated corrosion due to a large amount of electron supply. At − 0.95 VSCE and below, the SRB adsorption process was interrupted, which could play a protective role. The conclusions of this study could provide basic guidance for the corrosion prevention of L360N steel with SRB corrosion environment and reduce the economic losses caused by microbial corrosion. [ABSTRACT FROM AUTHOR]

In this study, a new anticorrosion method combining impressed current cathodic protection (ICCP) with coatings that can be applied to marine atmospheric environments is proposed. As the corrosion medium fills the cracks and pores of the coating, an electrolyte film layer is inevitably formed on the metal surface. Therefore, a graphene conductive coating with excellent chemical inertness and shielding performance is selected as the intermediate coating to form an electrolytic cell system with a metal substrate serving as the cathode and a graphene coating serving as the auxiliary anode. By studying the surface corrosion morphologies and electrochemical signals of the coating samples at different protection potentials and coating thicknesses, the optimal potential is determined to be 0.6 V, and the optimal coating thickness is determined to be 20 μm. The samples protected by the joint method have lower corrosion rates and better anticorrosion performance than those protected by the coatings alone. [ABSTRACT FROM AUTHOR]

In Iraq, an extensive network of pipelines is of vital importance for the transportation of hydrocarbon products, drinking water, and crude oil through the pipelines. The underground infrastructures experience corrosion processes, which therefore requires keeping up with the application of protective measures. This is a simulation survey that takes into account the cathodic protection optimization to reduce such hazards. Employing the Wenner four-terminal method enabled assessment of elements that affect cathodic protection such as environmental factors and soil resistivity across selected sites for the surveys. Soil pH ranges within the range of 7-8, together with anode voltage and current readings were the basis of the simulation models. These models played a crucial role in predicting the best anode locations, operating voltages and currents for various conditions and by comparing the results with empirical data from field experiments it is easy to evaluate the results. The analysis of rectifier voltage, the number of anodes, the anode resistance, and the pipeline current led to the production of the most cost-efficient designs for pipeline protection. Thus, as a result, a segment at station number 2 requires 2.5A current for its protection over the same length and a segment at station number 4 needs 12A current for its protection. Through the integration of simulation outcomes with the field observation the study highlights the accuracy and efficiency of the modeled cathodic protection systems that substantiate their fundamental role in the sustainable management of the pipeline. The results reached in this study add a great deal to this body of knowledge on the subject of subterranean structure preservation, showing this paradigm for the design and optimization of cathodic protection systems against corrosion and erosion which ensures the durability and reliability of pipeline networks. [ABSTRACT FROM AUTHOR]

Summary: A novel, monolithic DC‐magnetron sputtered TiN+MgGd coating, only 3to5 μm thick, effectively protects steel substrates from corrosion. This achievement is due to alloying of TiN with MgGd, which not only maintains the renowned wear resistance of TiN coatings, but potentially improves it through optimized deposition parameters. The key to the enhanced corrosion resistance lies in the addition of magnesium (Mg) and gadolinium (Gd). It reduces the coating's free corrosion potential, thereby mitigating the driving force for galvanic corrosion between coating and substrate. Moreover, at specific Mg to Gd ratios, a cathodic protection effect can be observed. Crucially, the presence of Gd is essential for this performance. It imparts hydrophobicity to the coating surface, reinforces a passivating layer and significantly enhances defect tolerance. This discovery paves the way for a sustainable alternative to electroplated chromium or combined electroplating and PVD, offering superior corrosion protection with minimal coating thickness. [ABSTRACT FROM AUTHOR]

The dual‐function retrofitting system that uses the carbon‐fabric reinforced cementitious matrix (C‐FRCM) as both the anode of impressed current cathodic protection (ICCP) system and the structural strengthening (SS) material, that is, an ICCP‐SS system, is investigated. The experimental program mainly focused on the shear behavior of C‐FRCM strengthened reinforced concrete (RC) continuous beam under the dual‐function retrofitting system. The influence of anode polarization on the shear strengthening of RC continuous beams is analyzed. Shear tests were conducted on a total of 14 corroded RC continuous beams to investigate the influence of key parameters, including anode polarization degree of prefabricated C‐FRCM plate, layer of carbon fiber mesh and side‐wrapping. The failure modes, shear capacities, and load‐deflection curves of the shear‐strengthened RC continuous beams are reported. Based on the test results, the applicability of relevant design codes was evaluated and found to provide rather conservative predictions for the shear capacity of the examined C‐FRCM strengthened RC continuous beams. [ABSTRACT FROM AUTHOR]