Cathodic Protection Research Articles

The influence of microstructure on corrosion mechanism for brazed sheet of AA4045/AA3003mod/AA4045 laminated composites at different depths

The depth profiling of the element content and precipitation phase distribution of the AA4045/AA3003mod (Al-1.5Mn-0.35Cu alloy)/AA4045 brazed sheets were investigated by optical microscope observation, electron probe microanalysis (EPMA), focused ion beam-scanning transmission electron microscopy (FIB-STEM). The electrochemical test and sea water acetic acid test (SWAAT) were performed to obtain the evolution of electrochemical responses and corrosion forms of brazed sheet. EPMA results showed that a diffusion layer with the thickness of approximately 50 μm existed between the clad layer and core layer, where the Cu diffused from the core layer and Si diffused from the clad layer. It was found that brazing led to a significant low elements solid solution area at the end of the Si diffusion path, where the open circuit potential was lower by 25 mV comparing to the unaffected region. Thus the diffusion zone can provide effective cathodic protection to the unaffected region as sacrificial anode by the potential gradient. The SWAAT analysis revealed the corrosion mechanism of the residual cladding was pitting and intergranular corrosion. This area with high density of intermetallic compounds and Si particles increased sensitivity to localized attacks. These results demonstrated the successful application of the FIB-STEM system in illustrating the electrochemical responses and corrosion propagation by an accurate in-depth characterization of intermetallic particles and the matrix solid solution.

Analytical Review of Conductive Coatings, Cathodic Protection, and Concrete

The principal and most expensive type of degradation that currently affects the performance of reinforced concrete bridge constructions is the corrosion of steel reinforcement. Strong financial losses result from the corrosion of reinforced concrete structures. One popular technique for preventing corrosion in reinforced concrete structures is cathodic protection. Since it can give necessary current in a situation where reinforced concrete buildings have high resistance, impressed present cathodic protection (ICCP) provides strength and adaptability. Conductive coatings, discrete anode systems, titanium-based mesh in cementitious overlay, conductive overlay with carbon fibers, and flame-sprayed zinc are examples of anode materials that are often used for impressed current cathodic (ICC). Chloride ions, in particular, are exceedingly difficult to permeate through a continuous epoxy coating on steel, making an epoxy coating a very effective barrier to these hostile chemicals. Epoxy resins are a great option for shielding metal surfaces from the environment and hostile environments because of their outstanding anti-corrosion qualities, good adherence to a variety of surfaces, and chemical resistance. In this work, the cathodic protection, ICCP, various conductive coatings, and epoxy coating as anode material are reviewed.

Failure Mechanism and Control Measures of Cu-CuSO4 Electrode in Saline Soil Environment

Saline soil environment is widely distributed in western China, especially in Qaidam Basin. High salinity soil in Qaidam Basin has higher corrosion risk to metal pipelines. The Cu-CuSO4 electrode is used as the long-term reference electrode in the cathodic protection system of oil and gas pipeline. In saline soil environment, the Cu-CuSO4 reference electrode generally has a problem of excessive drift, which seriously affects the normal operation of cathodic protection system. The failure mechanism of the Cu-CuSO4 reference electrode in saline soil environment was demonstrated: soil ion pollution and drain drying caused potential drift. In view of the main factors affecting Cu-CuSO4 reference electrode drift in saline soil environment, measures such as adding packing material and setting up maintenance device were developed, and the field application effect was good. It provides a technical idea for prolonging the life of cathodic protection system in saline soil environment.

Research and Application of Digital Monitoring System for Pulse Current Cathodic Protection of Oil Pipeline

The transportation of crude oil mainly relies on long-distance buried oil pipelines, which are generally made of steel pipes. Oil leakage often occurs due to corrosion, causing environmental pollution and unsafe accidents. A digital monitoring system for pulse current cathodic protection of oil pipelines was studied, with a focus on the composition and functions of the digital monitoring system for pulse current cathodic protection of oil pipelines. In 2022, the system was applied on two oil pipelines in Tongzhai operation area of the Third Oil Production Plant of Changqing oil field. The system realized the pulse current cathodic protection of oil pipelines to prevent corrosion. At the same time, it can digitally monitor the pulse current cathodic Conservation status status and adjust the working state of the potentiostat, and cooperate with the pulse current cathodic protection monitoring expert system for auxiliary analysis, which has received good economic and social benefits.

Optimization of the cathodic protection system for the main pipelines

This study investigated the multi-criteria task of optimizing the operating modes of cathodic protection stations (CPS), considering monitoring data, geological conditions at the pipeline installation site, climatic or seasonal changes, and other factors. The relevance of this research is associated with a comprehensive solution to the problem of increasing the durability and reliability of trunk pipelines to reduce accidents at their facilities by ensuring the efficiency of electrochemical protection (EChP) systems. The problems of existing EChP systems are analyzed, where the elimination of anode zones ("lack of protection") due to cathodic polarization is carried out without operational consideration of environmental conditions, as a rule, with a margin in terms of protective potential, which often leads to "overprotection", resulting in increased power consumption, gas formation on the metal surface, and detachment and wear insulation of pipelines. The aim of this research is to create a method for optimal regulation of the operation modes of the main pipelines and an adaptive electrochemical protection system that provides control and parameter management of cathodic protection stations, considering changes in external conditions on individual linear sections of main pipelines. Tasks: to develop an adjustment method for finding the effect of the CPS on the value of potentials at control points along the pipeline route; to develop a multicriteria optimization model for regulating the operation modes of the CPS; and to provide an example of testing the method of optimal regulation on the objects of the linear part of the existing main gas pipeline. The following results were obtained. A method is proposed for determining the effect of CPS operating modes on the value of potentials at control points in the mode of interrupting the protection current of other stations. An optimization model was formed according to the criterion of uniformity of the distribution of the protective potential "pipe-ground" along the pipeline route and according to the criterion of the minimum total protective current of all CPSs on a given section of the main pipeline. Conclusions. The scientific novelty of the results obtained is associated with the development of an original optimization method that allows scientifically determining the operation modes of the CPS to ensure the protection of the main pipeline both in time and length with reduced operating costs and adaptability to changes in climatic, seasonal, and geological conditions at the pipeline installation site. The effectiveness of the proposed approach is illustrated by the regulation of the parameters of the CPS based on the monitoring data of the section of the main gas pipeline of the oil and gas complex of the Republic of Kazakhstan.

Cathodic protection of UNS S31600 with Al A96061 alloy sacrificial anodes for molten quaternary amine transportation

Cathodic protection of UNS S31600 with Al A96061 alloy sacrificial anodes for molten quaternary amine transportation

AC corrosion of steel pipeline under cathodic protection: A state‐of‐the‐art review

AbstractBy the advancement of the oil, electricity, and transportation industries, an increasing number of oil and gas pipelines were buried alongside high‐voltage alternating current (AC) transmission lines and electrified railways. This resulted in a growing issue of AC interference in buried pipelines. Previous studies have shown that the presence of AC interference can result in severe corrosion damage to metallic structures, even when cathodic protection (CP) is available. This paper provides a state‐of‐the‐art review on AC corrosion of cathodically protected pipeline steel. Specifically, attention is paid to research areas including influencing factors in AC corrosion for pipelines under CP, existing AC protection criteria, corrosion risk assessment based on probability of failure, numerical simulation in AC corrosion, and mitigation of AC corrosion. Each area of research is reviewed in detail and the corresponding technical gaps and future research opportunities are identified and discussed.

Analysis of hydrogen embrittlement and applied potential of 1670, 1770, and 1860 MPa ultrahigh-strength steel wire for impressed current cathodic protection on cables and hangers

The hydrogen embrittlement and applied cathodic potential of three ultrahigh-strength steel wires were analyzed. Results show that in the simulated rainfall environment, the suitable protection potential range for 1670 and 1770 MPa wires is from the corrosion potential to −1150 mVSCE, and to −1050 mVSCE for 1860 MPa wire; the protection efficiency can reach 22% compared with unprotected steel wire at the recommended potential. The hydrogen diffusivity decreases with the strength, and are 0.636 × 10−6, 0.577 × 10−6 and 0.409 × 10−6 cm2ꞏs−1 for the three steel wires. The 1860 MPa wire has the highest HE susceptibility compared to the 1670 and 1770 MPa wires.

Development of a novel virtual reality-enabled remote monitoring device for maintenance of cathodic protection systems on oil and gas pipelines

Periodic inspections are required for oil and gas pipelines equipped with cathodic protection systems (CPS) to prevent corrosion. This inspection takes time and requires money, mobilisation of specialised staff, and accessibility of pipeline right of way which is often hindered by security issues, and bad terrain. A novel virtual reality-enabled remote monitoring device, developed using the NACE SP0169 standard, which measures the pipe-to-soil potential (PSP) reading, transmits the measured data to an IoT server, and a virtual environment for analysis and feedback while providing an immersive experience to the user, all in real-time, is presented. The hardware and software components are developed using Sensors, Arduino Mega 2560 board, AWS Sumerian 1.2.0 software, ThingSpeak IoT server, Blender modelling software and AutoCAD. When implemented on real test posts of oil and gas facilities and compared with the traditional methodology, the system showed consistency of data measurement and analysis, with real-time feedback to users, and a Spearman rank’s correlation coefficient of 0.998944. The study is significant as it provides the oil industry with an expert, easy-to-understand tool which helps to reduce the rate of oil spillage and losses through corrosion.

Investigating electrochemical charging conditions equivalent to hydrogen gas exposure of X65 pipeline steel

AbstractIn this study, we systematically investigate electrochemical hydrogen charging conditions equivalent to hydrogen gas pressures relevant for hydrogen transportation in X65 pipeline steel. By performing hydrogen gas permeation, a relationship for Sieverts' law was established, which was used in combination with electrochemical hydrogen permeation to determine the equivalent hydrogen pressure. The results revealed that cathodic protection simulated condition at –1050 mVAg/AgCl was equivalent to a hydrogen pressure of 12.3 bar. The addition of thiourea, a hydrogen recombination poison, and changing the applied potential in the cathodic direction increased the equivalent hydrogen pressure. In this way, an electrochemical charging condition equivalent to a potential hydrogen gas pressure for hydrogen transportation (200 bar) was determined.

Standalone power system with photovoltaic and thermoelectric installations for power supply of remote monitoring and control stations for oil pipelines

During the operation of oil pipelines, accidents with oil spills may occur, which can cause severe damage to the ecological situation in the region and disrupt many processes in nature. The oil pipeline’s remote monitoring and control systems (RMCS) are used to prevent such situations. In areas remote from the centralized power supply, it is necessary to use a standalone power system (SPS) to provide electricity to RMCS facilities. Examples of such facilities are remote monitoring and control (RMC) stations, including systems for monitoring the state of the oil pipeline and its parameters, leak detection systems, and the pipeline’s cathodic protection. The paper proposes a methodology for sizing SPS with a photovoltaic plant, an on-pipe thermoelectric generator, and batteries for the power supply of the RMC station. The idea of the work is to use energy sources that are most efficient at opposite seasons of the year. Particle swarm optimization is used to optimize the sizing of SPS components. The technical optimization criterion is the loss of load probability. The economic optimization criterion is the levelized cost of electricity. The impact of the oil temperature at the point of the RMC station on the efficiency of the thermoelectric generator is estimated. The calculations carried out in this work were made for the climate region of the Vankorsk oil and gas field in the north of Russia. The methodology proposed in this paper can also be used for northern territories, such as Canada, Norway, and the USA.

Improving the anti-corrosive performance of epoxy/zinc composite coatings with N-doped 3D reduced graphene oxide

Three-dimensional reduced graphene oxide (3DRGO) doped with N heteroatoms was innovatively incorporated into a Zn-containing epoxy (EP/Zn) composite coating. Comprehensive investigations that introducing 3DRGO significantly improved the anti-corrosion performance of the coating, and the optimal 3DRGO content was only 0.05 wt%. The effects of both the spatial structure and chemical doping of graphene on the surface protection performance of their EP/Zn coating were revealed for the first time. Compared with the conventional 2-dimensional reduced GO (RGO) sheets and 3D graphene (3DG) with similar 3D structures, 3DRGO exhibited superior effect on promoting the corrosion resistance of its composite coating. This can be attributed to not only the unique 3D porous strut structure of 3DRGO, but also its N-doping, which plays important roles in increasing its interaction with the epoxy matrix, preventing 3DRGO agglomeration, improving the barrier property of the coating, facilitating the construction of an electrical conduction network between Zn particles, and exploiting the cathodic protection function of Zn more efficiently.

Studying and Realizing the Based-Intelligent IoT System for Pipeline Cathodic Protection

Cathodic protection (CP) emerges as the optimal approach for mitigating metal corrosion in pipeline networks. To ensure the continued efficiency of the CP system, monitoring the potential distribution throughout the network is crucial. In distribution networks, the pipeline potential is influenced by time-varying environmental factors, making it challenging to estimate the potential at locations away from the measurement point. This paper presents a proposed CP system for pipelines, utilizing an intelligent IoT system. The sensor nodes of the system designed based on the STM32 microcontroller perform the measurement of voltages from the reference electrodes, process the signal as well as perform wireless communication about the control stations via LoRa (Long Range Radio) communication. Besides, the control stations are designed to implement voltage compensation control through autotransformer and to communicate with the server through the GPRS communication. The objective is to deploy an affordable system capable of effectively monitoring and regulating the potential of the pipeline at a designated measurement location in industrial plants.

The Corrosion of Mn Coatings Electrodeposited from a Sulphate Bath with Te(VI) Additive and Influence of Phosphate Post-Treatment on Corrosion Resistance

Manganese coatings are excellent for the cathodic protection of steel against corrosion. Although manganese is more electrochemically active than widely used protective coatings of zinc, the exceptional resistance of manganese coatings in neutral and basic media is determined by the film of insoluble corrosion products, which forms on the surface of manganese and greatly suppresses its further corrosion. It is known that the electrodeposition process of Mn coatings from sulphate electrolytes is positively affected by some additives of chalcogenide (S, Se and Te) compounds in the electrolyte. However, a more detailed study on the corrosion properties of Mn coatings electrodeposited from sulphate bath with Te(VI) additive is lacking. In this work, the measurements of free corrosion potential and potentiodynamic polarization in a neutral NaCl solution, as well as the corrosion resistance properties of obtained Mn coatings, were evaluated in a salt spray chamber. It was obtained that the best corrosion resistance was shown by Mn coatings, electrodeposited at the cathodic current density of 15 A⋅dm−2 and at higher temperatures (60 and 80 °C). Meanwhile, the corrosion resistance of phosphated Mn coatings, obtained from a room temperature bath, increased about 5 times and reached up to 1000 h until corrosion of the steel substrate occurred.

MAXIMIZING ALLOY PIPELINE LIFESPAN IN ENERGY INFRASTRUCTURE: A REVIEW

Energy infrastructure systems’ efficient and reliable operation relies heavily on alloy pipelines’ integrity and lifespan. These pipelines serve as vital conduits for transporting various energy resources, and ensuring their longevity is crucial for maintaining sustainable and safe energy practices. This research paper presents a comprehensive review of strategies to maximize the lifespan of alloy pipelines in energy infrastructure. The paper begins with an introduction highlighting the significance of alloy pipelines in the energy sector and the importance of extending their operational lifespan. A thorough literature review explores existing research on alloy pipelines, corrosion, erosion, stress, and temperature factors that influence their degradation. The selection of appropriate materials and alloys for pipeline construction is analyzed, considering their mechanical, chemical, and corrosion-resistant properties. Corrosion is identified as a major challenge affecting the durability of alloy pipelines. Various corrosion mitigation strategies, such as protective coatings, cathodic protection, and inhibitors, are discussed in detail. The role of advanced monitoring and inspection techniques, including ultrasonic testing and predictive maintenance, in identifying potential issues and ensuring timely repairs is examined. Operational and maintenance best practices are emphasized to avoid premature pipeline failure. Case studies are presented to demonstrate successful implementations of strategies that have prolonged the lifespan of alloy pipelines in energy infrastructure projects. Additionally, the paper discusses future directions and challenges, identifying areas that require further research and development. The findings of this research highlight the importance of proper alloy selection, corrosion management, and regular maintenance in maximizing the lifespan of alloy pipelines in energy infrastructure. The proposed strategies and insights are expected to contribute to the sustainability and efficiency of the energy industry while addressing the pressing need to minimize environmental impacts and ensure a secure energy supply.

Studies of zinc content reduction using flake zinc powder in epoxy zinc-rich coatings

Purpose Epoxy zinc-rich coatings are widely used in harsh environments because of the long-lasting cathodic protection of steel surfaces. The purpose of this paper is to use flake zinc powder instead of the commonly used spherical zinc powder to reduce the zinc powder content. Design/methodology/approach In this paper, the authors have prepared an anticorrosive zinc-rich coating using a flake zinc powder instead of the conventional spherical zinc powder. The optimal dispersion of scaly zinc powder in zinc-rich coatings has been explored by looking at the surface and cross-sectional morphology and studying the cathodic protection time of the coating. Findings The final epoxy zinc-rich coating with 35 Wt.% flake zinc powder content was prepared using sand-milling dispersions. It has a similar cathodic protection time and salt spray resistance as the 60 Wt.% spherical zinc-rich coating, with a higher low-frequency impedance modulus value. Originality/value This study uses flake zinc powder instead of the traditional spherical zinc powder. This reduces the amount of zinc powder in the coating and improves the corrosion resistance of the coating.

In2S3@TiO2/In2S3 Z-Scheme Heterojunction with Synergistic Effect for Enhanced Photocathodic Protection of Steel.

In this work, a TiO2/In2S3 heterojunction film was successfully synthesized using a one-step hydrothermal method and applied in the photocathodic protection (PCP) of 304SS. The octahedral In2S3 and In2S3@TiO2 nanoparticles combined and coexisted with each other, with In2S3 quantum dots growing on the surface of TiO2 to form In2S3@TiO2 with a wrapping structure. The composite photoelectrode, which includes TiO2 with a mixed crystalline phase and In2S3, exhibited significantly enhanced PCP performance for 304SS compared with pure In2S3 and TiO2. The In2S3@TiO2/In2S3 composites with 0.3 g of P25 titanium dioxide (P25) showed the best protection performance, resulting in a cathodic shift of its OCP coupled with 304SS to -0.664 VAgCl. The electron transfer tracking results demonstrate that In2S3@TiO2/In2S3 forms a Z-scheme heterojunction structure. The enhanced PCP performance could be attributed to the synergistic effect of the mixed crystalline phase and the Z-scheme heterojunction system. The mixed crystalline phase of TiO2 provides more electrons, and these electrons are gathered at higher energy potentials in the Z-scheme system. Additionally, the built-in electric field further promotes the more effective electrons transfer from photoelectrode to the protected metals, thus, leading to enhanced photoelectrochemical cathodic protection of 304SS.

Balanced Anti-Corrosion Action of Reduced Graphene Oxide in Zn-Al Coating during Medium-Term Exposure to NaCl Solution

Considering the electronegativity and shielding anti-sepsis characteristic of reduced graphene oxide (G), we design a Zn-Al coating with embedded G (Zn-G/Al) on low-carbon steel using the low-pressure cold spray (LPCS) method. In this method, G-coated Al powders (G/Al) prepared using in situ reduction and Zn powders were mixed as a raw material for spraying. Embedding G could boost the cathodic protection performance of Zn-Al (70 wt.% zinc and 30 wt.% aluminum) coating, as has been confirmed in previous work. In this work, the microstructure, composition and electrochemical parameters of Zn-G/Al coating during full immersion were measured to investigate G’s effect on the corrosion protection properties of the Zn-Al coating. The test results showed that embedded G could facilitate the generation of many corrosion products and pile on the coating surface to form a corrosion product film during full immersion. The corrosion product film on the Zn-0.2 wt.%G/Al coating surface demonstrated an excellent protective property, which reflects the fact that the Ecorr and icorr values for Zn-0.2 wt.%G/Al after 20d immersion (Ecorr = −1.143 Vvs.SCE, icorr= 49.96 μA/cm2) were lower than the initial value (Ecorr = −1.299 Vvs.SCE, icorr = 82.16 μA/cm2). It can be concluded that adding an appropriate amount of G to the coating can balance the cathodic protection and shielding property of the coating. The equilibrium mechanism was also analyzed in this work.

Biogalvanic cathodic protection of reinforced concrete structures in marine environments

Cathodic protection is an efficient solution that is implemented on reinforced concrete structures to address corrosion issues and prevent further deterioration. However, it has significant drawbacks in terms of sustainability. This paper explores a new biological CP technology for reinforced concrete structures in marine environments, where a bioanode is buried in marine sediments, and electrons are supplied through the oxidation of various substrates by electro-active micro-organisms. The issue was addressed both numerically and experimentally, with a first-of-a-kind experimental verification on a laboratory specimen. This new solution offers three fundamental advantages: autonomous operation, green solution, and free current supply.

Autonomous IoT for Condition Monitoring, Assessment and Predictive Maintenance ‐ Advances

AbstractRocket NG is a startup with experts in civil engineering, electronics, and network engineering. We offer and operate a self‐developed end‐to‐end IoT system for condition monitoring, condition assessment and predictive maintenance. The system is reliable and ease to apply.In this paper the autonomous monitoring system is discussed regarding security, reliability, ease of use and artificial intelligence on the edge (smart algorithms used on the nodes). Additionally, the importance of an easy installation and an intuitive data representation are on discussion.Five applications will be presented. The first application is a crack monitoring on a cantilever bridge. There, different data acquisition modes will be shown for the assessment of static loads, dynamic loads and temperature induced displacements. The second application shows the crack width opening due to heavy transport. The third application addresses the wetting and drying of chloride contaminated water in a concrete wall beside a motorway. The fourth is a monitoring of a passive cathodic protection system. Finally, a digitalization of an analog legacy Extensometer is shown.