Corrosion Of Metallic Structures Research Articles

ПРОГНОЗИРОВАНИЕ СРОКА СЛУЖБЫ АНТИКОРРОЗИОННЫХ ПОКРЫТИЙ МЕТАЛЛИЧЕСКИХ КОНСТРУКЦИЙ ОБЪЕКТОВ ПЕРЕРАБОТКИ, ХРАНЕНИЯ И ТРАНСПОРТИРОВКИ УГЛЕВОДОРОДОВ

Leaks of liquid and gaseous hydrocarbons from pipelines and equipment of transportation, storage and processing facilities lead to fires and explosions. Often the cause of hydrocarbon leaks is corrosion of metal structures, leading to their depressurization. To increase the durability of metal structures, they are protected with anticorrosive coatings. The protective ability of the anticorrosive coating is determined by its continuity (defect). The prediction of the continuity (defectiveness) of the anticorrosive coating is carried out using empirical exponential or power expressions. The disadvantage of these expressions is a large number of hard-to-determine factors and empirical coefficients. An empirical expression is given to assess the defectiveness of the anticorrosive coating at the current time. An empirical expression is proposed for predicting the operational continuity (defectiveness) of an anticorrosive coating, taking into account the production (initial) defectiveness, the permissible service life and the aggressiveness of the environment. It is shown that the aggressiveness of the environment significantly affects the continuity (defectiveness) anticorrosive coating. The results of forecasting the continuity (defectiveness) of the anticorrosive coating are compared according to the currently used expressions and according to the proposed expression.
 The obtained results of forecasting the continuity (defectiveness) of the anticorrosive coating are close. The empirical expression proposed for predicting the continuity (defectiveness) of the anticorrosive coating is promising for practical application.

Sensing System Based on FBG for Corrosion Monitoring in Metallic Structures

As corrosion has slow development, its detection at an early age could be an alternative for reducing costs of structural rehabilitation. Therefore, the employment of structural health monitoring (SHM) systems, sensing configurations collecting data over time allowing for observing changes in the properties of the materials and damage emergence, for monitoring corrosion can be a good strategy to measure the damage and to decide the better moment for intervention. Nonetheless, the current corrosion sensor technology and the high costs of the sensing system implementation are limiting this application in the field. In this work, an optical fiber Bragg grating (FBG)-based sensing system is proposed for monitoring the thickness loss of a 1020 carbon steel metal plate subjected to controlled corrosion. The natural frequency of the plate was collected as a function of the corrosion time over 3744 h. To validate the experimental results, ultrasound measures and electrochemical tests were also carried out under similar conditions. The experimental results show adequate reliability, indicating the suitable functionality of the proposed system for monitoring the thickness loss caused by corrosion in metallic structures, in comparison with traditional methods, as ultrasonic and electrochemical measures.

Microbially induced corrosion impacts on the oil industry.

The numerous structural impacts on oil installations caused by corrosion make this issue a concern in the oil industry. Although chemical corrosion is relevant in this sector, it is indisputable that the microbial corrosion or bio-corrosion plays a preponderant role, with considerable economic losses. Microbial corrosion invariably depends on the formation of a biofilm on the attacked surface. Biofilm structures provide the conditions that favor the development of microbial groups related to corrosion. Despite the several microbial species are described as corrosive, certain groups, such as sulfate- and nitrate-reducing bacteria, acetogenic bacteria, and methanogenic archaea are the most commonly related. In spite of environmental factors influence the prevalence of certain species, it is increasingly accepted that the relationships between different species are determinant in corrosion. Such relationships can be evidenced by several surveys of microbial communities involved in bio-corrosion. Here, the main microbes related to corrosion in metallic structures used in oil installations are presented, as well as their metabolisms involved in the deterioration of metallic surfaces.

Pulse-Modulation Eddy Current Imaging for 3D Profile Reconstruction of Subsurface Corrosion in Metallic Structures of Aviation

Metallic structures of non-ferromagnetic materials such as aluminum alloy, titanium alloy, etc., are widely used in the engineering field of aviation. Owing to harsh and hostile environments, subsurface corrosion manifests itself in the in-service Metallic Structures of Aviation (MSA), and is usually hidden within the structure body, leaving it barely detected. Such defect has been found to be one of the most critical defects posing a severe threat to structural integrity and safety of MSA. Therefore, it is imperative to conduct imaging and quantitative assessment of the subsurface corrosion with effective Non-destructive Evaluation (NDE) techniques. Pulse-modulation Eddy Current technique (PMEC) has been identified to be superior to other electromagnetic NDE techniques in evaluation of corrosion in conductors. In light of this, in this paper PMEC for imaging and 3D profile reconstruction of subsurface corrosion in MSA is investigated. Novel features extracted from testing signals are proposed in a bid to enhance the sensitivity of the PMEC response. An image processing technique based on the modified Theta Map is proposed and utilized for recognition of corrosion opening profile. An efficient inversion method, which is focused on the corrosion-profile reconstruction right within the corrosion region and based on a sectional scanning strategy, is investigated along with the establishment of the database conceiving PMEC responses to regular-shaped corrosion. It has been found from the experimental results that the proposed inversion scheme is feasible and applicable for 3D profiling of subsurface corrosion in MSA with the averaged evaluation accuracy of 95.4%.

Determination of electronic characteristics of tetrahydro pyrimidine derivatives and investigation of usability as anti-corrosion

Corrosion of metallic structures is a serious problem in most industries worldwide. This problem can be controlled by the addition of chemicals capable of adsorption onto the metal surface. The metal can be isolated from the corrosive environment. These chemicals are often selected from groups containing free electron pairs and / or π electrons, which are rich in functional groups. In this study, electronic structures Highest Molecular Orbital (HOMO), Lowest Occupied Molecular Orbital (LUMO), MEP, energy gap (ΔE), ionization potential (I), electron affinity (A), chemical structure of pyrimidine derivative compounds containing unpaired electron pairs, π electrons, functional groups such as N, O and S hardness and softness (S), general electrophilic index (ω), transmitted electron fraction index (ΔN) and recovery (backEback-donation) properties of quantum chemical calculation methods to investigate the properties of the selected compounds in this direction and adsorbed to the surface with the quantum chemical calculation methods. The aim of this study is to determine the efficiency of synthesized compounds as anti-corrosion materials and to provide new gains to the industry in this sense.

Passive Surface Acoustic Wave Sensors for Early Corrosion Onset Detection

Corrosion creates serious safety concerns and economic burden in fuel processing and transportation. Being able to monitor the infrastructures in real time and detect corrosion onset may prevent potential consequences resulting from their failure. Passive wireless surface acoustic wave (SAW) devices are promising passive devices to detect the presence of water and corrosion onset amongst other parameters in natural gas pipelines and wellbore tubes. Here, we present on the possibility of using shear horizontal (SH-) SAW devices for monitoring metal film dissolution in hydrochloric acid of varied pH. 520 MHz SH-SAW reflective delay lines with two reflectors were fabricated on 36°Y-X LiTaO3, of which a channel was coated with 60 nm thick iron film by magnetron sputtering. With the film, the sensor had a center frequency of 529.8 MHz when measured in air. The sensor showed a slight attenuation and small frequency shift in DI water. In HCl solution with pH 2.01, the sensor’s center frequency first decreased with time for the first six minutes to reach down to 521 MHz and then remained almost unchanged. The S11 magnitude also showed similar behavior. After ten minutes immersion into the corrosive solution, no iron film was left under a visual inspection. The decrease in the frequency and attenuation is probably due to the changes in the mass and elasticity and the film surface roughening, respectively. Observed initial results are promising towards the implementation of SAW devices for monitoring corrosion in metallic structures in real time.

A framework for corrosion assessment in metallic structures, from data analysis to risk based inspection

Metallic corrosion is a big challenge affecting many sectors in a nation’s economy. Necessary corrosion prevention actions have to be taken in order to maintain the integrity of engineering assets susceptible to corrosion. This paper proposes a holistic framework to support the management of corrosion in metallic structures. It is a fully automation corrosion assessment process, with risk updated by Bayesian theory. Through analyzing the thickness data measured by non-destructive testing (NDT) techniques, the influence of corrosion on the component can be estimated using statistical methods, which will enable users to make decisions on maintenance based on quantitative information. A case study using corrosion data from a steel bridge is included to demonstrate the proposed framework. It improved the conventional corrosion analysis method by the proposed statistical approach using representative thickness data, which aims to take full use of the remaining life. This model can be adapted to a wide range of metallic structure suffering from corrosion damage.

Smart Cathodic Protection System for Real-Time Quantitative Assessment of Corrosion of Sacrificial Anode Based on Electro-Mechanical Impedance (EMI)

Corrosion of metal structures is often prevented using cathodic protection systems, that employ sacrificial anodes that corrode more preferentially relative to the metal to be protected. In-situ monitoring of these sacrificial anodes during early stages of their useful life could offer several insights into deterioration of the material surrounding the infrastructure as well as serve as early warning indicator for preventive maintenance of critical infrastructure. In this article, we present an Electro-Mechanical Impedance (EMI) measurement-based technique to quantify extent of corrosion of a zinc sacrificial anode without manual intervention. The detection apparatus consists of a lead zirconate titanate (PZT) transducer affixed onto a circular zinc disc, with waterproofing epoxy protecting the transducer element when the assembly is submerged in liquid electrolyte (salt solution) for accelerated corrosion by means of impressed current. We develop an analytical model for discerning the extent of corrosion by monitoring shift in resonance frequency for in-plane radial expansion mode of the disc. The model presented here accurately captures the nonlinearity introduced by partial delamination of the corrosion product (zinc oxide) from the disc, and shows excellent agreement with experimental results. Our work establishes the efficacy of the proposed technique for monitoring the state of health of sacrificial anodes in their early stage of deterioration and could thus be widely adopted for structural health monitoring applications within the internet of things.

Slowing down the corrosion of metal structures using polymeric materials

This article examines the resistance of corrosion-resistant polymeric materials to chemical reagents and the degree of corrosion, taking into account the direction of corrosion processes. One of the main factors that determined the corrosion rate is air humidity and dust released into the atmosphere during industrial emissions. Mixtures based on polymer materials can be used to gum up chemical apparatus and equipment; for corrosion protection, expensive materials are required. The sample is conditioned for 30 months at (23 ± 2) 0С, relative humidity (50 ± 5) %, and the thickness of the sample is determined. Resistance to chemical reagents the change in mass of samples of polymeric materials at a temperature of 35 0C for 3 months was analyzed. It was also found that by determining the corrosion rate (grade St3) by storing steel plates in a different exposure environment for 50 days. As a result, the corrosion rate of steel anti-corrosion coatings is lower than the control sample. According to the data obtained, it was found that the chloro-sulfonated polyethylene compositions are resistant to various organic solvents, acids, alkalis, oxidizing agents, and others.

Influence of structural form of elements on corrosion of metal structures

The article considers the influence of the structural form of elements on the corrosion of metal structures. Corrosion is the spontaneous destruction of metals and alloys as a result of chemical, electrochemical or physical-chemical interaction with the environment. Usually, local corrosion is the result of the concentration of the anode reaction of metal ionization on certain small areas of the metal surface, while the rest of the surface is mainly cathodic reactions. The most typical example of local corrosion due to structural features of metal is intergranular corrosion of stainless steels and aluminum alloys. A high rate of metal ionization along the boundaries of grains or intermetallic compounds leads to the predominant dissolution of these sites, which weakens the bond between individual crystals. When designing the equipment, it is not necessary to cover individual parts of the device with insulating materials, and it is also necessary to exclude the possibility of solid precipitation and scale. The latter is partially achieved by the correct choice of the electrolyte speed and continuous mechanical removal of precipitation.

Highly nonlinear solitary waves for the detection of localized corrosion

This paper investigates the application of highly nonlinear solitary waves as a nondestructive evaluation method to detect localized corrosion in metallic structures. An experiment was conducted by using chains of monoperiodic particles in contact with a steel plate subjected to localized accelerated corrosion. A few damage-sensitive features were extracted from the time waveforms and fed into a multivariate statistical analysis to enhance the sensitivity of the proposed non-invasive monitoring approach. The experiment was complemented by a finite element model to quantify the effects of localized corrosion on certain features of the solitary waves propagating along the chain. Both the numerical and the experimental results show that the solitary waves reflected at the chain-plate interface are affected by the presence and progression of corrosion. Furthermore, the multivariate statistical analysis improved the sensitivity of the proposed approach. In the future, the proposed method may be implemented in those applications in which high temperature or radioactive environments are detrimental for the use of piezoelectric based ultrasonic testing.

Self-healing and superhydrophobic coatings for corrosion inhibition and protection

Corrosion of metal structures and consumer products has been a significant problem since the start of the industrial revolution. However, the inhibition and prevention of corrosion have only been an active area of study in the last century. The need for smart and functional coatings has recently become a large area of interest due to the ability of these coatings to be adapted to a variety of materials, mechanical and chemical conditions, and sporadic environmental conditions. One of the most viable methods by which corrosion can be prevented is through coatings. Self-healing coatings demonstrate a novel method of autonomic repair for microcracks using self-healing polymers encapsulated with polymerizable species into microparticles and nanoparticles. Additionally, these microparticles and nanoparticles can also be loaded with corrosion inhibitors that are released upon mechanical or chemical damage, thereby reducing corrosion. The use of superhydrophobic coatings leads to improved corrosion resistance due to the modification of the wettability of the coating, thereby changing its hydrophilic or hydrophobic response. This review details and provides a new perspective on self-healing and superhydrophobic coatings as well as future outlooks.

ГАЛЬВАНОЗ ПОЛОСТИ РТА

Introduction. Galvanosis of the oral cavity is an important problem in modern dentistry. A small amount of textbooks has been written on this topic. 
 Purpose ― to summarize all knowledge about this pathology: etiology, pathogenesis, feature, differential diagnosis, modern treatment methods, prevention - based on the search and study of original modern monographs, scientific articles. 
 Results. The review describes the etiopathogenesis of the oral galvanosis, which is based on the corrosion of metal structures. Many factors have influence on speed and intensity of the corrosion process in the oral cavity. First, in case when the technology of manufacturing metal structures was broken, the release of metallic inclusions into the oral fluid increases, that provokes the occurrence of corrosion. Secondly, saliva is an electrolyte, and the its composition and pH have a great influence on the electrochemical processes in the oral cavity. Thirdly, it is known that some general somatic diseases, periodontal pathologies and oral mucosa cause changes in the composition of the oral fluid and, as a result, electrochemical processes. The clinical picture of galvanosis is described in scientific articles - patients complain of a burning sensation of the mucous membrane of the tongue, a violation of taste sensitivity (metallic or sour taste in the mouth). During examination the oral cavity, it is possible not to reveal pathological changes, just the presence of structures which made of dissimilar metals makes us wonder about the presence of galvanosis. The main diagnostic criterion for oral galvanosis is the measurement of the magnitude of the potential difference between metal structures. Galvanosis treatment is to replace metal structures in the oral cavity with metal-free ones, i.e. eliminating the cause of the disease. There are several ways to prevent galvanoses - firstly, using electroplating in the manufacture of metal structures, and, secondly, conducting a diagnostic test using a plastic crown with inserts of metal alloys, from which the future prosthesis will be made. A review of the literature has shown that it is necessary to study this topic in depth.

The impacts of human activity on the microorganisms in deep subsurface

In the deep biosphere, there are a large number of microorganisms that are mainly bacteria and archaea. Fungi and viruses are also found in deep subsurface. These microorganisms found in the deep biosphere are functionally and phylogenetically diverse. Different from the microorganisms on the Earth surface where they use sunlight as their primary energy source, the microorganisms in deep subsurface employ the hydrogen gas and methane, which are produced mainly from geochemical interactions between water and rock, as their primary energy and/or electron sources. Human activities impact substantially on the deep subsurface environment as well as the microorganisms living there. This review focuses on the impacts of recovery of shale gas by horizontal drilling and hydraulic fracturing (or fracking), geological storage of nuclear wastes and CO2 capture and geological storage on the microorganisms in the deep biosphere. Shale gas is the natural gas locked within the black shale in deep subsurface. Horizontal drilling and fracking are widely used to recover the shale gas. Research results demonstrate that the structures and functions of microbial community differ greatly at different stages of recovery of shale gas by fracking. Results also find that viruses play crucial roles in influencing the structures and functions of microbial community during different stages of recovery of shale gas by fracking. Among the microorganisms identified, the methanogens in the black shale impact positively on the natural gas recovery by producing methane. In contrast to the methanogens, the acid-producing microorganisms impact negatively on the natural gas recovery by causing reservoir souring and corrosion of metal structures. Thus, the microorganisms in the deep subsurface play dual roles in impacting the natural gas recovery. Nuclear wastes are the materials containing or contaminated with radionuclide. Safe storage of nuclear wastes is the most important factor that determines whether nuclear industry and peaceful use of nuclear energy can be continuously developed. Currently, geological storage in deep subsurface is the only acceptable way for long-term and safe storage of the nuclear wastes whose half-life is long and radioactivity is high. For this reason, underground research laboratories (URL) are constructed to assess potential impacts of the microorganisms in the deep subsurface on the safe storage of nuclear wastes in the geological formation. The results demonstrate that complex of microbial communities reside in the geological formations planned for storage of nuclear wastes. Although structures and functions of these microbial communities vary, the sulfate-reducing bacteria found in these communities may corrode the metal structures, while gas-producing microorganisms may increase the chamber pressure of the storage structure. All of these microbial activities may damage the structure and function of the nuclear waste geological repository. In contrast, the Fe(III)-reducing microorganisms may stabilize nuclear wastes in the repository. CO2 capture and storage could slow down the global warming by reducing CO2 emissions. Research results show that certain group of bacteria live under supercritical CO2 condition in the deep subsurface. Moreover, geological storage of supercritical CO2 acidify the water in deep subsurface, which increases dissolution of rocks and minerals. Consequently, it changes the chemical environment and the structures and functions of microbial community in the deep subsurface. In turn, the responses of microbial communities to the addition of supercritical CO2 may affect the stability of CO2 storage in the geological settings. Over the past decades, our understanding of the impacts of human activity on the microorganisms in deep subsurface has been advanced significantly. A common theme emerging from the results of these studies is that the microorganisms influenced by human activity may have either positive or negative effects in recovery of shale gas and geological storage of nuclear waste and CO2.

Silica-Based Coatings for Corrosion Protection of AA7075 Aluminum Alloy

Abstract The large economic and environmental impact caused by corrosion of metal structures has demanded new types of anti-corrosion coatings. This study proposes the application of silica-based coatings for corrosion protection of AA7075 aluminum alloy in saline environments rich in chloride ions. These coatings were obtained using the sol-gel technique. The samples were dip-coated in two types of solutions: (a) a mix of tetraethyl orthosilicate (TEOS) with 3-(Trimethoxysilyl)propyl methacrylate (TMPM) (Coating 1); and (b) a mix of titanium (IV) isopropoxide (TIP) with TMPM (Coating 2). The cure temperatures of the coatings were of 25°C, 60°C, 100°C, and 130°C, with treatment times of 1 and 3 hours. Characterization of the coatings was done by potentiodynamic polarization in aqueous saline solution (sodium chloride 3.5 %), nanoscratching, and scanning electron microscopy (SEM). The layers produced were uniform with good scratch resistance and with superior corrosion resistance when compared to the substrate.

Electrochemical impedance and electrical resistance sensors for the evaluation of anticorrosive coating degradation

AbstractAnticorrosive coatings are commonly used to protect metal structures from corrosion and thus assure constancy of the metal profile area, and consequently the mechanical stability of the metal structure. Due to environmental factors, corrosion of metal structures is inevitable and is considered during the design process; however, it is very difficult to predict the corrosion rate a priori, and the designer usually relies on empirical data to make an assessment. In an attempt to address this issue, various types of sensors that monitor the state of metallic coatings have been developed. In this study, the abilities of two systems, one based on electrochemical impedance and one using electrical resistance, developed by the authors to allow remote real-time monitoring of bridges are described. A laboratory study is presented in which three different sensor coating configurations were evaluated in three simulated environments: a salt spray chamber, a humid chamber, and an industrial chamber. The corrosion rates were monitored over a 9-month study period. Periodic measurements were made of the sensor output signals, and visual inspections (close-up photographs) were made to compare the visual and monitored response of the sensors. The sensitivity of the sensors is described, and the advantages and disadvantages concerning their deployment for field operations are discussed.

Natural Frequency Changes due to Severe Corrosion in Metallic Structures

Degradation of engineering structures due to corrosion affects their safety by reducing the cross-section of structural components and altering the material’s mechanical characteristics. These parameter changes are observable in the shift of the natural frequencies. In the study presented in this paper, it was demonstrated that the kinetic energy distribution reflects the mass participation, thus being able to predict frequency changes due to mass loss, while the modal strain energy distribution can be properly used to indicate the location of the damage. As a result, two mathematical relations were developed by the authors, predicting the frequency changes due to the main effects of corrosion: loss of mass and loss of stiffness.

Functioning analysis of cathode protection of pipelines for transporting of natural gas through fuzzy logic

The cathodic protection is used to prevent the oc-currence of accidental damages, leaks, generated by the corrosion of metallic structure of tubular material of trans-porting pipelines. Following the proper functioning of the cathodic protection system is made by monitorize of the main parameters: electrical potential pipeline-ground, in-jection parameters (continuous voltage, continuous cur-rent), respectively by measurement of insulating resistance of pipeline. In the case of monitoring of parameters by SCADA, it is constate the fact that are reduce the acciden-tal gases leakeges, generated by corrosion avoid the impact which is produced by the evacuation of hydrocarbons on the envirnment. In this paper is presented an analysis method regarding the functioning of the cathodic protection, the DCVG method coloborated with a fuzzy analysis method, trough which are simultanely operated either the numerical dates, and lexical arguments, prior to locate, in the field, more precisely of the damage. DOI: http://dx.doi.org/10.5755/j01.mech.20.5.6144

Refurbishment of structures on the Manchester Metrolink phase 3

The Metrolink phase 3 project in Manchester, UK, has created around 60 km of new tram lines and has incorporated over 380 structures including 160 bridges and tunnels. Nearly 80 bridges were refurbished, repaired or strengthened to provide a low-maintenance system with a minimum 50-year structural design life. The new tram lines have been built on new dedicated alignments and on former railway corridors, reusing existing structures with an age of up to 140 years. Various contractual and technical approaches were taken to address the risk due to structure condition, including risk-sharing arrangements and phased scope determination. Particular issues encountered by the project include: limited information on structure condition; corrosion of metallic structures; scope risk; strategy for repair versus replacement; vehicle incursion risk; determining appropriate specifications; retention of cast-iron structures and modifications to parapets due to electrification. The conclusions include lessons learned for projects dealing with the renewal and upgrade of legacy structures in an affordable manner.

Study of the Corrosion of Buried Steel Grids of Electrical Power Transmission Towers

The corrosion of metal structures in large facilities such as AC power transmission lines results in economic losses due to the necessary replacement of these structures and the interruption of power supply. To evaluate soil corrosion of the buried part of the structure the corrosion rate of AISI1020 steel samples was determined by weight loss measurements as a function of the exposure time to the soil close to a power transmission tower. The same measurements were made with samples which were connected to the tower while buried in the soil. By comparison of the two measurement series the influence of the AC power signal on soil corrosion can be studied.