Natural Corrosion Research Articles

Synergistic Gas Hydrate and Corrosion Inhibition Using Maleic Anhydride: N-Isopropylmethacrylamide Copolymer and Small Thiols.

Kinetic gas hydrate inhibitors (KHIs) are often used in combination with film-forming corrosion inhibitors (CIs) in oilfield production flow lines. However, CIs can be antagonistic to KHI performance. In this study, maleic anhydride-co-N-isopropylmethacrylamide copolymer (MA:NIPMAM) and its derivatives were successfully synthesized and tested for gas hydrate and corrosion inhibition. KHI slow constant cooling (1 °C/h) screening tests in high-pressure rocking cells with synthetic natural gas and CO2 corrosion bubble tests in brine were performed in this study. The results revealed that underivatized MA:NIPMAM in water (as maleic acid:NIPMAM copolymer) showed poor KHI performance, probably due to internal hydrogen bonding. However, derivatization of MA:NIPMAM with 3-(dibutylamino)-1-propylamine (DBAPA) to give MA:NIPMAM-DBAPA gave excellent gas hydrate inhibition performance but only weak corrosion inhibition performance. Unlike some KHI polymers, MA:NIPMAM-DBAPA was compatible with a classic fatty acid imidazoline CI, such that neither the KHI polymer performance nor the corrosion inhibition of the imidazoline was affected. Furthermore, excellent dual gas hydrate and corrosion inhibition was also achieved in blends of MA:NIPMAM-DBAPA with small thiol-based molecules. In particular, the addition of butyl thioglycolate not only gave excellent corrosion inhibition efficiency, better than adding the fatty imidazoline, but also enhanced the overall gas hydrate inhibition performance.

Application of galvanodynamic impedance spectroscopy for studying passive film cracking under mechanical strain

The paper reports the results of simultaneous mechanical and electrochemical investigations on austenitic (18/8) stainless steel in a 2 % solution of sulphuric acid. The measurements were performed using Galvanodynamic Electrochemical Impedance Spectroscopy (GDEIS). Electrochemical analysis of mechanical passive layer cracking and repassivation conditions during a tensile test was carried out. Application of this methodology allowed monitoring of the natural corrosion process without external current (IDC = 0A) nor potential perturbation of the system. The results proved the usefulness of measurements of actual electrochemical systems at zero external current conditions. It was found that a transition to an active state occurred for relatively high strain rates, while the passive layer cracking process did not depend on the strain rate.

Research and Evaluation of Foam-Drainage Corrosion-Inhibition Hydrate Anti-Aggregation Integrated Agent

In natural gas exploitation, foam drainage, corrosion inhibition and hydrate inhibition of wellbore fluid are conventional operations. However, there is often a problem where multiple chemical agents cannot be effectively used together and can only be used separately, resulting in complex production processes. In this study, the final integrated formulation was determined: 0.1% sodium alpha-olefin sulfonate (AOST) + 0.3% dodecyl dimethyl betaine (BS-12) + 0.3% sodium lignosulfonate + 0.5% hydrazine hydrate. The minimum tension of the integrated agent could be reduced to 23.5 mN/m. The initial foaming height of the integrated agent was 21.5 cm at 65 °C, the liquid-carrying capacity was 143 mL, and the liquid-carrying rate reached 71.5%. The maximum corrosion depth also decreased from 11.52 µm without the addition of hydrazine hydrate, gradually decreasing to 5.24 µm as the concentration of hydrazine hydrate increased. After adding an integrated agent, the growth rate of hydrates was slow and aggregation did not easily occur, and the formation temperature was also more demanding. Therefore, the integrated agent has a inhibitory effect on the formation of hydrates and has a good anti-aggregation effect. From the observation of the microstructure, the emulsion is an oil-in-water type, and the integrated agent adsorbs at the oil–water interface, preventing the dispersed water droplets in the oil phase from coalescing in one place. The oil-in-water type emulsion is more likely to improve the performance of the natural gas hydrate anti-aggregation agent.

On-Load Tap Changer Internal Contact Health Assessment Based on Ion Detection in Oil

Internal contact deterioration causes most electrical faults in on-load tap changers (OLTCs), which are difficult to diagnose promptly and accurately by traditional methods. This paper proposes a novel approach for internal contact condition evaluation based on metal ion detection. The variation of metal ions under the action of DC breakdown and natural corrosion for metal contacts with different materials are experimentally studied first. The formation mechanism of metal ions indicates that electric erosion is the primary cause of the short-term increase of characteristic ions. In addition, both chemical corrosion and electrochemical corrosion play a significant role in the long-term growth of metal ions. Based on the assumption of maximum damage to OLTC contacts, the characteristic metal ion concentration when the contacts require mandatory replacement is calculated. An early warning method for the damage condition of the internal contacts is proposed by combining the accumulated metal ion concentration and the relative metal ion growth rate. An on-site fault transformer case demonstrates that the multilevel warning value can well meet the requirements for the health status assessment of OLTC’s internal contacts.

Experimental ultimate strength assessment of stiffened plates subjected to marine immersed corrosion

This study experimentally analyses the impact of marine immersed corrosion degradation on the compressive strength of the stiffened plates where the lower degradation levels were considered. The corrosion degradation test was accelerated by controlling the natural corrosion environmental factors, avoiding applying an electric current. Different groups of corrosion degradation levels and initial plate thicknesses were investigated. The specimens were subjected to a compressive load via a universal testing machine. The estimated force-displacement relationships and lateral displacements as a function of the degree of degradation were analysed. Several analyses and discussions showed that considering only the mean value of the corrosion thickness loss, it is insufficient to evaluate the stiffened plates' ultimate strength correctly, and the type of corrosion degradation needs to be accounted for appropriately.

Probabilistic similarity of non-uniform corrosion pattern between natural corrosion and accelerated experiment

Concrete structures can be seriously deteriorated by the corrosion of steel reinforcement lasting for decades under realistic environment. It is still controversial whether and how the natural corrosion can be reasonably accelerated in experimental simulation. This paper focuses on the probabilistic similarity of corrosion pattern by comparing the normalized configuration of natural corrosion and galvanic accelerated experiment. The former is obtained by conducting the Monte-Carlo simulation of the electrochemical process based on the meso-scale model of concrete, whist the latter is analysed using digital image correlation method. The results indicated that their number and location of corrosion peaks are statistically consistent. The configurations of corrosion are very likely to be similar within the rear region of steel reinforcement in most cases, whereas possibly to be reversed in the front inward region and front outward region. The similarity is affected by the geometry of designed specimen and humidity of simulated environment.

Capillary-Driven Water Transport by Contrast Wettability-Based Durable Surfaces.

Controlling water transport and management is crucial for continuous and reliable system operation in harsh weather conditions. Passive strategies based on nonwetting surfaces are desirable, but so far, the implementation of superhydrophobic coatings into real-world applications has been limited by durability issues and, in some cases, lack of compliance with environmental regulations. Inspired by surface patterning observed on living organisms, in this study we have developed durable surfaces based on contrast wettability for capillary-driven water transport and management. The surface fabrication process combines a hydrophobic coating with hard-anodized aluminum patterning, using a scalable femtosecond laser microtexturing technique. The concept targets heavy-duty engineering applications; particularly in aggressive weather conditions where corrosion is prevalent and typically the anodic aluminum oxide-based coating is used to protect the surface from corrosion, the concept has been validated on anodic aluminum oxide coated aluminum alloy substrates. Such substrates with contrast wettable characteristics show long-term durability in both natural and lab-based artificial UV and corrosion tests where superhydrophobic coatings tend to degrade.

Corrosion rates under charge-conservation conditions

Laboratory and numerical corrosion experiments impose an electric potential on the metal surface, differing from natural corrosion conditions, where corrosion typically occurs in the absence of external current sources. In this work, we present a new computational model that enables predicting corrosion under charge-conservation conditions. The metal potential, an output of the model, is allowed to change, capturing how the corrosion and cathodic reactions must produce/consume electrons at the same rates, as in natural conditions. Finite element simulations are performed over a large range of concentrations and geometric parameters. The results highlight the notable influence of the charge-conservation assumption and pioneeringly quantify corrosion rates under realistic conditions. They further show: (i) the strong coupling between the corrosion rate and the hydrogen and oxygen evolution reactions, (ii) under which circumstances corrosion pits acidify, and (iii) when corrosion is able to become self-sustained lacking oxygen.

Effects of Laser Shock Peening on Corrosion Resistance of Additive Manufactured AlSi10Mg

Mechanical properties of Al alloys make them an ideal candidate for different sections of marine, aerospace, automotive, etc. industries. Recently taking the advantages of additive manufacturing (AM), many complex infrastructures/components can be fabricated with very high design freedom via Al alloys. Although Al alloys have good natural corrosion resistance, however improving this property attracts lots of attention in the past few years. Post-processing methods can play a key role for addressing the issues related to internal and surface anomalies associated with as-built AM parts. Generally, these anomalies have detrimental effects on mechanical properties. In the present study, the effect of laser shock peening (LSP) treatment with different laser pulse overlaps and energies was investigated comprehensively on microstructure, surface texture, porosity, hardness, residual stresses as well as corrosion resistance of laser powder bed fused (L-PBF) AlSi10Mg samples. LSP provides strain deformation on the surface, and the deformation enhances by laser beam energy. LSP1 (laser energy of 1.5 J and 50% overlap) and LSP3 (laser energy of 4.5 J and 50% overlap) introduce maximum local strain of 7.5 and 10.7, respectively. The surface roughness of as-built state µm in terms of Rv was effectively diminished to 16.33 after LSP6 (laser energy of 4.5 J and 75% overlap). The results indicated that due to the modified surface texture, improved hardness and induced high compressive residual stresses in the surface layer. (surface hardness improvement and inducing high surface compressive residual stresses were obtained after LSP6 up to 26% and −289 MPa, respectively); the LSP treated samples exhibited higher corrosion resistance with the corrosion rate decreasing down to 50% as compared to the as-built state.

Review of Corrosion Inhibitors in Reinforced Concrete: Conventional and Green Materials

The corrosion of metals has been a major technical, environmental, and financial challenge for many industries and has become a widespread problem in concrete structures and buildings. Various techniques such as utilization of synthetic corrosion inhibitors have been developed to provide sufficient corrosion protection to reinforcing steel. The application of green corrosion inhibitors, however, has recently attracted increasing attention since these sustainable materials decrease the rate of corrosion and increase the durability and service life of reinforced concrete structures effectively. Considering the emerging field of sustainable corrosion management, many researchers have evaluated various green corrosion inhibitors, reporting scattered results. Consequently, there is a need for a comprehensive study to review, compare, and consolidate their findings in order to identify research gaps and critical trends for further research. This article reviews the properties and effects of various inhibitors including those nontoxic environmentally friendly inhibitors functioning at high pH in concrete. It classifies a broad range of corrosion inhibitors and identifies their advantages and disadvantages. Furthermore, it proposes a set of selection criteria to choose the appropriate inhibitors based on their characteristics and sustainability requirements. It can be concluded that natural corrosion inhibitors show promising potential for extending the service life of reinforced concrete structures as a cost-effective and sustainable solution. Further investigation, however, is demanded for evaluating their technical properties including modelling functional groups for corrosion protection and their effectiveness under combined attack of corrosive ions. The findings of this paper identify the main research trends and can guide researchers to develop further research in the identified gaps towards sustainable progress in the field of civil engineering and corrosion management. It also helps practitioners in all relevant disciplines to gain effective knowledge on emerging green corrosion inhibitors.

Fabrication of robust superhydrophobic–superoleophilic mesh for oil–water separation

Frequent oil spillage at sea and waste oily water draining cause severe harm to the environment and economy. Although various extremely wettable materials are designed to achieve oil–water separation, there are still limitations, such as expensive materials, fluorine-containing reagents and poor robustness of oil–water-separating materials. Here, the authors resolved the aforementioned problems by proposing a simple and low-cost sandblasting plating method with nickel (Ni), phosphorus (P) and 1-octadecanethiol modification to manufacture a robust superhydrophobic stainless steel mesh for separating oily water under harsh environments. The mesh can separate light and heavy oily water with outstanding separating efficiency and high purity. It can be also used to separate hydrochloric acid (HCl) solution–oil, sodium hydroxide (NaOH) solution–oil and sodium chloride (NaCl) solution–oil, with separating efficiency higher than 95%. Moreover, the mesh is still superhydrophobic and has outstanding oil–water-separating efficiency after sandpaper abrasion, tape stripping, simulated seawater corrosion and natural environment corrosion tests. Therefore, the robust superhydrophobic stainless steel mesh proposed in this work can very efficiently separate oily water in harsh environments.

Corrosion Inhibitors: Natural and Synthetic Organic Inhibitors

Corrosion is a major challenge in various industries and can cause significant damage to metal structures. Organic corrosion inhibitors are compounds that are used to reduce or prevent corrosion by forming a protective film on metal surfaces. The present review article focuses on natural and synthetic organic corrosion inhibitors and their classifications, active functional groups, and efficiency estimations. Furthermore, previous studies on the use of natural and synthetic organic inhibitors are discussed, along with adsorption isotherms and mechanisms of organic corrosion inhibitors. The kinetics of corrosion modeling are also discussed, providing insights into the effectiveness of organic inhibitors at reducing corrosion. This review aims to provide a comprehensive overview of the current knowledge on organic corrosion inhibitors, with the aim of promoting their wider use in corrosion protection.

Degradation Mechanisms and Residual Mechanical Properties of Reinforcing Steel Bars Exposed to Natural and Artificial Corrosion – Review & Analysis

Reinforcement corrosion is the most problematic phenomenon and one of the main sources for the degradation of structures and infrastructures all across the world, that leads to their premature deterioration before design life has been attained. Therefore, the structural effects of rebar corrosion are crucial in determining the structural performance and residual strength of impaired structures. In the present work, the corrosion initiation mechanisms, corrosion products, corrosion types, corrosion consequences on structural performance and detrimental factors related to corrosion were presented in brief. Moreover, the propagation period and the main consequences on mechanical properties of steel and concrete are analyzed. Analyses of the available statistical data collected from literature were performed for 443 specimens. The findings are further interpreted from structural point of view, and deterioration equations for the mechanical properties of the corroded reinforcements are developed. The relations are well analyzed, leading to the definition of decay equation for yielding and ultimate stresses, and ultimate strain. It was found that the mass loss of 1% due to the rebar corrosion can cause the strength loss of 1.34%, 1.30%, and 3.54% respectively for yield strength, ultimate strength, and elongation. The suggested formulas can be applied in analytical and numerical structural applications.

Black Pine (Pinus nigra) Essential Oil as a Green Corrosion Inhibitor for Carbon Steel

In this work, the essential oil of black pine (Pinus nigra J. F. Arnold) was used for the first time as a natural, ecological, and sustainable corrosion inhibitor for the acid cleaning of carbon steel. The essential oil was extracted by hydrodistillation using a Clevenger-type apparatus, and the oil was analyzed by gas chromatography–flame–ionization detection (GC–FID) and gas chromatography–mass spectrometry (GC–MS). The most abundant components in the essential oil were α-pinene, germacrene D, (E)-cariophyllene, and β-pinene. The inhibition efficiency was determined by electrochemical methods (electrochemical impedance spectroscopy and potentiodynamic polarization measurements). The results showed that the inhibitory efficiency of the black pine essential oil increases with time, reaching the highest values after 4 h of immersion for all inhibitor concentrations. It was also shown that black pine essential oil is a mixed-type inhibitor. The contact angle measurements confirmed that the black pine essential oil, as a new natural, environmentally safe inhibitor, is able to protect carbon steel from corrosion in a 1 M HCl solution.

Biopolymer sodium alginate based titania and magnetite nanocomposites as natural corrosion inhibitors for mild steel in acidic medium

Green biopolymeric materials and its hybrid nanocomposites, i.e. sodium alginate grafted polymethylmethacrylate based titanium dioxide and iron oxide (SA-g-PMMA/TiO2 and SA-g-PMMA/Fe3O4) have been explored for the prevention of mild steel's corrosion in 15% HCl. It is reflected from the electrochemical impedance data that SA-g-PMMA/TiO2 exhibits maximum inhibition efficiency of 97.28% followed by SA-g-PMMA/Fe3O4 that gives 96.82% efficiency while the unmodified sodium alginate possess merely 84.74% efficiency. The declining trend of inhibition efficiency with rising temperature has been explained through gravimetric studies conducted at 303 K- 333 K. The thermodynamic activation and adsorption parameters revealed the mixed mode of adsorption of inhibitors over mild steel surface which follow Langmuir adsorption isotherm. It has been observed from tafel polarization studies that all studied inhibitors are mixed type in nature. The surface morphological inspection of the mild steel samples was done through FE-SEM and AFM, which revealed the formation of better protective adsorption layer over the exposed metallic surface by the nanocomposites in comparison to sodium alginate alone. In addition to this, the elemental composition of adsorbed film on inhibited mild steel specimens was obtained by XPS technique. Quantum parameters obtained through Density Functional Theory (DFT) further corroborate the experimental outcomes.

The use of methanol extract of Rheum Ribes (Işgın) flower as a natural and promising corrosion inhibitor for mild steel protection in 1 M HCl solution

There is a tendency towards natural products with the increase in sensitivity to the environment, people and other living things around the world. In recent years, there has been a similar trend regarding inhibitors used in the metals protection against corrosion. In this study, the adsorption and protection ability of Rheum ribes (RR) flower extract on mild steel (MS) corrosion in 1 M HCl solution were investigated with the help of many electrochemical techniques. The MS surface after exposing to the test solutions was examined by energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and contact angle measurements. Some thermodynamic parameters corresponding to the adsorption of extract molecules on the MS surface and excess surface charge of the steel in the extract containing solution were calculated and a possible mechanism of the corrosion inhibition process was discussed. The durability of the extract film formed on the MS surface was examined under potentiodynamic and potentiostatic conditions. It was found that an adherent and uniformly distributed extract film formed on the MS surface, which is responsible for the inhibition of corrosion. The flower extract provided 94.7 % and 98.4 % protection efficiencies at 1000 ppm concentration after 1 h and 6 h exposure. RR flower extract mitigated both anodic and cathodic reactions, predominantly cathodic process. The extract molecules interact and bond to the MS surface via physical and chemical interactions. The extract could be suggested as a promising natural corrosion inhibitor for MS protection in 1 M HCl solution.

Study on mechanical properties of corroded concrete columns strengthened with SMA wires.

Ocean crossing bridges suffer from seawater corrosion all year round and their mechanical properties will be substantially diminished. In order to enhance the mechanical properties of reinforced concrete columns corroded by seawater, SMA wire is used to restrain the reinforced concrete columns corroded by seawater to study their mechanical properties. 14 specimens were produced through the test, and the natural seawater corrosion was simulated by preparing a certain concentration of synthetic seawater. The mechanical properties of SMA strengthened specimens and unreinforced specimens are compared and analyzed, including failure mode, hysteresis curve, bearing capacity, ductility, stiffness and energy dissipation; the effects of different synthetic seawater corrosion concentrations on the mechanical properties of reinforced concrete columns are discussed. The results show that the bearing capacity and stiffness of reinforced concrete columns subjected to synthetic seawater corrosion are substantially diminished than those of uncorroded specimens, and the bearing capacity of specimens decreases more with the increase of synthetic seawater corrosion concentration; synthetic seawater corrosion has obscure effect on the ductility and energy dissipation performance of the specimens. The mechanical properties of the corroded specimens strengthened with SMA wire have been substantially enhanced, particularly the energy dissipation performance and bearing capacity have been notably enhanced, and the ductility and stiffness have also been somewhat enhanced. At the same time, based on the test, the finite element model is created according to the test specimen, while the accuracy of the model is verified, and the effects of the spacing and diameter of SMA wire, the strength of concrete and the thickness of protective layer on the mechanical properties of the specimen are analyzed.

Probabilistic Similarity of Non-Uniform Corrosion Pattern between Natural Corrosion and Accelerated Experiment

Probabilistic Similarity of Non-Uniform Corrosion Pattern between Natural Corrosion and Accelerated Experiment

Derivation of Defect Factors and Defect Rates of Fire Doors in Apartment Buildings through Field Investigation

Even a fire door with secured performance may not satisfy existing performance standards and fail to prevent the spread of fire owing to natural corrosion, damage from external force, and deformation associated with high-frequency use after installation. Therefore, it is important to ensure that certain results are maintained over the long term through regular management. However, in Korea, fire doors are often left unattended without repair, owing to insufficient management measures. Therefore, to present basic data for improving fire door maintenance measures, this study conducted field surveys to derive the failure rate and cause of failure owing to the age of fire doors. The results showed that of the fire doors surveyed, 3.7% were aged under five years, 13.4%, under 10 years, 14.8% under 10 years, 22.7% over 20 years, and 27.6% over 20 years. In particular, the failure rate of fire doors exceeded 20% for the first time in 15 years. The main causes of defects were natural aging, holes, opening and closing problems, gaps, gaskets, and wear of accessories, such as door closers.

Sorghum halepense (Zacate Johnson) as a potential natural corrosion inhibitor

Corrosion inhibitors can trigger health and/or environmental problems due to their toxicity. For this reason, it has been suggested to use plant extracts as natural corrosion inhibitors, because they represent a rich source of chemical compounds, they are non-toxic, biodegradable and abundant in nature. Sorghum halepense is a herbaceous weed, commonly known as johnson grass, belongs to the family gramíneae or poaceae, the choice of this plant is due to its zero cost and easy availability. In this systematic review, were used keywords such as Sorghum halepense johnson grass, phytochemistry, phytotherapy, phytoremediation, antidiabetic, antioxidant, cytotoxicity, antifungal, antimicrobial, anticancer, biological activity, medical activity, allelochemicals, among others. To do this, were used databases such as Scielo, Dialnet, Redalyc, Google Scholar, DOAJ, Wiley online library, BioOne, EBSCOHost, Knovel, ScienceDirect, SpringerLink y VirtualPro. Previous studies on this weed have reported its therapeutic potential against cancer, diabetes, prostatitis, hepatoprotective activity, antioxidant, antimicrobial, antifungal, as well as abortifacient and placental delivery in veterinary medicine. In view of the numerous organic molecules present in this plant, this study proposes Sorghum halepense as a potential natural corrosion inhibitor.