Extent Of Corrosion Research Articles

Understanding the process of phosphate removal in Fe0/H2O systems using the methylene blue method

The removal mechanisms of contaminants in Fe0/H2O are still poorly understood, and characterized by contradictory findings. Therefore, the present study aims to improve the understanding of the processes involved in phosphate removal in Fe0/H2O system. Herein, the methylene blue method (MB method) is used to trace the dynamics within the investigated systems. The MB method utilizes the differential adsorptive affinity of MB onto sand and sand coated with iron corrosion products to evaluate the degree of Fe0 corrosion in Fe0/H2O systems. The extent of MB discoloration and phosphate removal in various Fe0-based systems was characterized in parallel quiescent batch experiments for two weeks and two months. Parallel experiments with Orange II (O-II) as a model contaminant allowed an improved discussion of the results. The investigated systems were: (i) Fe0 alone, (ii) MnO2 alone, (iii) sand alone, (iv) Fe0 + sand, (v) Fe0 + MnO2, and (vi) Fe0 + sand + MnO2. Additional experiments were conducted to test the influence of Fe0 type, Fe0 and sand mass loadings on dye discoloration and phosphate removal in Fe0/sand system. Each system was characterized by: (i) pH value, (ii) Fe concentration, (iii) dye discoloration (MB, O-II), and (iv) phosphate concentration. Results showed that the MB method was capable of tracing the extent of iron corrosion in the various investigated systems and clarified the role of in-situ generated iron corrosion products (FeCPs) in the removal of phosphate. The suitability of mixing sand aggregates with Fe0 for efficient phosphate removal is demonstrated through the MB method. Overall, the appropriateness of the MB method to characterize the dynamics of Fe0/H2O systems is validated.

Dynamic Galvanic Corrosion of Working Lithium Metal Anode Under Practical Conditions

AbstractThe practical deployment of lithium metal anodes in rechargeable batteries has been significantly restricted by poor electrochemical performance, which largely stemms from their high susceptibility to corrosion. Inan effort to complete the real picture of Li corrosion pathways, in this contribution, a dynamic galvanic corrosion mechanism under realistic working conditions is described, through which an extended solid electrolyte interphase (SEI) is progressively generated on the successively exposed copper substrate during the dynamic Li removal process. As determined by the titration gas chromatography method, the dynamic galvanic corrosion reaction is unveiled to induce an unfavorable extra Li loss and hence a reduced cell reversibility, especially at sluggish Li stripping rates. Systematic investigations reveal that three critical factors, including total step length of Li stripping, dynamic corrosion current (icorrosion) degradation speed, and SEI chemistry, are responsible form odulating the extent of dynamic galvanic corrosion in practical batteries. This work provides an important complement to current knowledge regarding the corrosion processes of working Li metal anodes, affording fresh insights into the design strategies toward high‐reversibility Li cycling.

A phenomenological and quantitative view on the degradation of positive electrodes from spent lithium-ion batteries in humid atmosphere

The present study deals with the phenomenological observation of the corrosion of the positive electrode foil of lithium-ion batteries containing LiNi0.6Co0.2Mn0.2O2 (NMC) as cathode material. Due to the presence of moisture, localized water accumulation is formed on the NMC surface. The water absorbed by the electrolyte reacts with the NMC under Li+/H+ exchange and the resulting pH increase leads to dissolution of the carrier foil and characteristic salt-like blooms on the NMC surface. With the increase in the relative area occupied by the holes in the aluminum foil per time, a sufficiently suitable parameter was found with which to quantitatively determine the extent of corrosion. The degree of degradation depends on time and ambient humidity. It was shown that functional recycling with the water jet method is no longer applicable for degraded foils, since the mechanical stability of the foils decreases as corrosion progresses. Lithium, aluminum, sulfur and oxygen were detected in the blooms using SEM–EDX and Laser-Induced-Breakdown-Spectroscopy (LIBS). The underlying NMC layer was found to contain mainly aluminum and significantly lower lithium content than the non-degraded material. SEM and Raman microscopy analyses also showed that the active material is also locally degraded and therefore no longer suitable for functional recycling.

Friction and wear behavior of multiple steel wires with different corrosion extents under different lubrication conditions

Corrosion and wear of the steel wires are two major factors in the failure of wire ropes and can greatly reduce their service life as well as the reliability of mine hoists. In this paper, to study the fretting wear behavior of multiple wires with different extents of corrosion under different lubrication conditions, fretting wear tests on corroded wires were conducted on a homemade testing apparatus. The results show that corrosion and lubrication had great influence on coefficient of friction (COF) and fretting state. In addition, the wear resistance of steel wire decreased with increasing corrosion extent. The application of lubricant is beneficial. It could significantly reduce the overall specific wear rate and reduce the difference in degree of wear due to corrosion. In two lubricants specially used for mining wire ropes, lubricating grease (IRIS-400 M) had better anti-wear effect than lubricating oil (IRIS-550A). Furthermore, lubrication condition and corrosion degree affected the wear mechanism between steel wires. This study can provide basic data for the safe use and maintenance of wire rope.

Influence of Saline-treated Wastewater on Properties of Concrete: An Experimental Study

The rapidly growing world population and the accompanying increase in concrete production to meet building and infrastructure needs have led to significant increase in potable water consumption, which resulted in several environmental problems. This paper investigates the feasibility of replacing potable water with highly mineralized treated wastewater in concrete mixing in order to make concrete production more eco-friendly in an arid region. Concrete specimens were prepared using saline treated wastewater (saline-TWW) as mixing water and compared to those mixed with distilled water (DW) and with the performance requirements given by the mixing water quality standards. The results revealed that the concrete mixes produced using saline-TWW exhibited higher early strength and a similar long-term strength than the control mix produced using DW. It was also found that the use of saline-TWW increased the setting times of cement paste but had no remarkable effect on the workability of fresh concrete mixture. Furthermore, the microstructural characteristics of the hardened concrete were assessed by water-permeability test, SEM image analysis, and X-ray diffraction tests. The results revealed that saline-TWW concrete exhibited a more compact microstructure and smaller pore sizes than their counterparts of DW, which means an improvement in the durability of saline-TWW concrete. Moreover, an electrochemical test was conducted to estimate the extent of corrosion of the steel embedded in reinforced mortar specimens prepared using saline-TWW and DW. The electrochemical test results showed that the use of 100% saline-TWW as mixing water of concrete resulted in a high corrosion rate of the embedded steel.

An overview of the Canadian nuclear waste corrosion program

AbstractOver the past decade, the Nuclear Waste Management Organization has conducted a thorough proof test plan (PTP) to evaluate their novel copper‐coated used fuel container and bentonite buffer box underground emplacement concept for use in a deep geological repository (DGR). This PTP has included the development of new technologies as well as feasibility studies related to engineered barrier production, underground emplacement, and safety assessment of the technologies within a DGR. Although the PTP was winding down in 2022, many work packages continue, particularly those associated with the evaluation of the corrosion performance of the used fuel container, the Nuclear Waste Management Organization (NWMO)'s copper corrosion allowance. This work evaluates the extent of corrosion that may result from oxic‐, radiolytic‐, anoxic‐, and sulfide‐induced corrosion which may occur in the Canadian DGR. Particular attention is paid to assessing the potential for localized corrosion phenomena across each project. This article provides an overview of these work packages which support a lifetime corrosion expectation of 270 µm and an extreme upper bound of corrosion of 1204 µm over one million years.

A study on preparation of sulfur-iron compounds and their electrochemical and hydrogen barrier properties

Corrosion and hydrogen damage cause problems to oil and gas industry equipment. FeS (sulfur-iron) compounds generated by H2S causes surface corrosion and covers the surfaces of the equipment where the extent of corrosion and hydrogen damage are influenced by these compounds. Different types of FeS compounds have different crystal structures, and there by influence their corrosion and hydrogen resistance. In this paper, single-structure pyrrhotite and pyrite were synthesized by hydrothermal method, which was controlled by controlling the temperature and Fe, S ratio. Their structures are hexagonal sheet and polyhedron respectively. The interfacial properties and hydrogen barrier properties of FeS were tested and the results show that pyrrhotite possesses anion selectivity. The electrochemistry shows low impedance modulus and high corrosion current density, which indicates low corrosion resistance. Pyrrhotite has the lowest hydrogen permeation current density and has good inhibition of hydrogen permeation ability. For the high impedance modulus and low corrosion current density pyrite possesses cation selective, which shows strong resistance to corrosion. However, its hydrogen permeation current density is high and hydrogen blocking effect is weak.

A review on eminent application and performance of nano based silica and silica fume in the cement concrete

In last few years, the revolution of nanotechnology has escalated great in varied science streams. In the, study of effective utilization of Nano particles in construction industry has become a conspicuous one. While implementing the sustainability in construction, the adoption of nanotechnology has done a greater impact and there is still need more to explore. The Nano particles are usually possess incredible physical and chemical properties that enable it to use as a better constructionmaterials which help to enhance the properties like strength, durability and rheology of concrete and it also helps to counteract the environmental pollution. Additionally, the cement based materials which is prepared along with Nanomaterial helps to assess and examine the resistance towards deterioration in concrete and the extent of rebar corrosion. This paper reviews the literature on the nanotechnology application particularly in the construction industry. At first, the preliminary details of nanotechnology have been discussed and then, it exclusively focuses the effective nanoparticles like Silica fume and Nano silica which are proved as a ready thing to improve the property of concrete.

Investigation of corrosion mechanism of ribbed mild steel bars coated with magnesium potassium phosphate cement paste

This study investigated the anti-corrosion performance of magnesium potassium phosphate cement (MKPC) paste applied to the surface of ribbed mild steel bars – which was exposed to simulated accelerated corrosive environment. Four electrochemical approaches were used including open-circuit potential (OCP), electrochemical impedance spectroscope (EIS), polarization resistance (PR) and potentiodynamic polarization (PDP) over a period of 5376 h (224 days). Moreover, visual inspection, optical microscope, and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were used to assess the extent of corrosion on the samples. To understand the mechanism of corrosion protection of the coating system, X-ray photoelectron spectroscopy (XPS) was employed to characterize the chemical groups on the surface of mild steel, and the chemical changes in the coating layer were characterized using thermogravimetric/differential thermal analysis (TG/DTA) and X-ray diffraction (XRD). The MKPC paste coated bars were compared with not only uncoated bars, but also bars coated with ordinary Portland cement (OPC) that is known to passivate steel due to its high alkalinity. Results indicated that MKPC paste coating layer could effectively protect the ribbed mild steel bars, and its protectiveness significantly surpassed that of OPC. Both the de-passivation effects of chloride ions and carbonation of the OPC resulted in relatively severe corrosion of the OPC coated bars during the long exposure duration; while the anti-corrosion merit of the MKPC paste coating layer could be attribute to a double-protection system– the dense microstructure of MKPC and the formation of an iron (III) phosphate passivation layer between the substrate steel and the MKPC paste coating layer.

Effects of stress, defects, and layer composition on the development of corrosion features on protected silver mirrors.

The long-term environmental durability of protected silver mirror coatings is influenced by numerous factors. Here, accelerated environmental exposure testing of model silver mirror coatings illuminated the effects of stress, defects, and layer composition on the extent and mechanisms of corrosion and degradation. Experiments to reduce stress in the highest-stress layers of the mirror coatings revealed that, while stress may affect the extent of corrosion, coating defects and the composition of the mirror layers have the largest influence on corrosion feature development and growth.

Material properties of Japanese and western wooden nails

The corrosion characteristics of Japanese (J) and Western (W) nails with and without coating the Fe3O4 layer on the nail surface were examined experimentally to understand their mechanical properties and corrodibility. In this study, (i) one of the historical J-nails made by the forging process and (ii) commonly employed commercial W-nails created by extruding were used. Although the grain size and strain value differed depending on the nail and its location(sharpened tip, body, and flattened head), the microstructure of both nails consisted of ferrite and cementite structures. A high internal strain was created in the W-nail due to the nail creation by the extruding process. In particular, a high strain was obtained in the sharpened tip and flattened head areas of the W-nail compared to its body area, caused by severe plastic deformation. A high strain was also obtained in the sharpened tip area of the J-nail owing to the severe forging process. Such a high strain was related to the high hardness. The high hardness of the sharpened tip area of the J-nail (220 HV) was slightly lower than that of the W-nail's tip area. The hardness of the J-nail decreased non-linearly to its head area, which was affected by a low strain and largely grown grains. The corrosion occurred on the J- and W-nail surfaces, where lepidocrocite (γ-FeOOH) was detected due to the weak-acidity oxidation, i.e., acid rain. The corrosion extent was different depending on the nail. Although the corrosion was detected for the J-nail after exposure for 3 months, the corrosion occurred on W-nail after exposure to the atmosphere for a week. Different corrosion extents between J- and W-nails were affected by their microstructural characteristics and strain levels, i.e., different surface energy. The corrosion resistance of both nails was improved by coating the Fe3O4 layer on the nail surface, where the corrosion extent for both J- and W-nails was similar due to the corrosion protection by the Fe3O4 layer. The corrosion characteristics directly affected their mechanical properties: tensile strength and ductility. This work systematically analyzed details of the mechanical properties of the nails after corrosion.

Optimized purification methods for metallic contaminant removal from directly recycled Li-ion battery cathodes.

Metallic contaminants pose a significant challenge to the viability of directly recycling Li-ion batteries. To date, few strategies exist to selectively remove metallic impurities from mixtures of shredded end-of-life material (black mass; BM) without concurrently damaging the structure and electrochemical performance of the target active material. We herein present tailored methods to selectively ionize two major contaminants-Al and Cu-while retaining a representative cathode (LiNi0.33Mn0.33Co0.33O2; NMC-111) intact. This BM purification process is conducted at moderate temperatures in a KOH-based solution matrix. We rationally evaluate approaches to increase both the kinetic corrosion rate and the thermodynamic solubility of Al0 and Cu0, and evaluate the impact of these treatment conditions on the structure, chemistry, and electrochemical performance of NMC. Specifically, we explore the impacts of chloride-based salts, a strong chelating agent, elevated temperature, and sonication on the rate and extent of contaminant corrosion, while concurrently evaluating the effects on NMC. The reported BM purification process is then demonstrated on samples of "simulated BM" containing a practically relevant 1 wt% concentration of Al or Cu. Increasing the kinetic energy of the purifying solution matrix through elevated temperature and sonication accelerates the corrosion of metallic Al and Cu, such that ∼100% corrosion of 75μm Al and Cu particles is achieved within 2.5 hr. Further, we determine that effective mass transport of ionized species critically impacts the efficacy of Cu corrosion, and that saturated Cl- hinders rather than accelerates Cu corrosion by increasing solution viscosity and introducing competitive pathways for Cu surface passivation. The purification conditions do not induce bulk structural damage to NMC, and electrochemical capacity is maintained in half-cell format. Testing in full cells suggests that a limited quantity of residual surface species are present after treatment, which initially disrupt electrochemical behavior at the graphite anode but are subsequently consumed. Process demonstration on simulated BM suggests that contaminated samples-which prior to treatment show catastrophic electrochemical performance-can be recovered to pristine electrochemical capacity. The reported BM purification method offers a compelling and commercially viable solution to address contamination, particularly in the "fine" fraction of BM where contaminant sizes are on the same order of magnitude as NMC and where traditional separation approaches are unfeasible. Thus, this optimized BM purification technique offers a pathway towards viable direct recycling of BM feedstocks that would otherwise be unusable.

Establishment of coverage-mass equation to quantify the corrosion inhomogeneity and examination of medium effects on iron corrosion.

Metal corrosion is important in the fields of biomedicine as well as construction and transportation etc. While most corrosion occurs inhomogeneously, there is so far no satisfactory parameter to characterize corrosion inhomogeneity. Herein, we employ the Poisson raindrop question to model the corrosion process and derive an equation to relate corrosion coverage and corrosion mass. The resultant equation is named coverage-mass equation, abbreviated as C-M equation. We also suggest corrosion mass at 50% coverage, termed as half-coverage mass M corro50%, as an inhomogeneity parameter to quantify corrosion inhomogeneity. The equation is confirmed and the half-coverage massM corro50% is justified in our experiments of iron corrosion in five aqueous media, normal saline, phosphate-buffered saline, Hank's solution, deionized water and artificial seawater, where the former three ones are biomimetic and very important in studies of biomedical materials. The half-coverage massM corro50% is proved to be more comprehensive and mathematically convergent than the traditional pitting factor. Iron corrosion is detected using visual observation, scanning electron microscopy with a build-in energy dispersive spectrometer, inductive coupled plasma emission spectrometry and electrochemical measurements. Both rates and inhomogeneity extents of iron corrosion are compared among the five aqueous media. The factors underlying the medium effects on corrosion rate and inhomogeneity are discussed and interpreted. Corrosion rates of iron in the five media differ about 7-fold, and half-coverage massvalues differ about 300000-fold. The fastest corrosion and the most significant inhomogeneity occur both in biomimetic media, but not the same one. The new equation (C-M equation) and the new quantity (half-coverage mass) are stimulating for dealing with a dynamic and stochastic process with global inhomogeneity including but not limited to metal corrosion. The findings are particularly meaningful for research and development of next-generation biodegradable materials.

A Discrete Partially Observable Markov Decision Process Model for the Maintenance Optimization of Oil and Gas Pipelines

Corrosion is one of the major causes of failure in pipelines for transporting oil and gas products. To mitigate the impact of this problem, organizations perform different maintenance operations, including detecting corrosion, determining corrosion growth, and implementing optimal maintenance policies. This paper proposes a partially observable Markov decision process (POMDP) model for optimizing maintenance based on the corrosion progress, which is monitored by an inline inspection to assess the extent of pipeline corrosion. The states are defined by dividing the deterioration range equally, whereas the actions are determined based on the specific states and pipeline attributes. Monte Carlo simulation and a pure birth Markov process method are used for computing the transition matrix. The cost of maintenance and failure are considered when calculating the rewards. The inline inspection methods and tool measurement errors may cause reading distortion, which is used to formulate the observations and the observation function. The model is demonstrated with two numerical examples constructed based on problems and parameters in the literature. The result shows that the proposed model performs well with the added advantage of integrating measurement errors and recommending actions for multiple-state situations. Overall, this discrete model can serve the maintenance decision-making process by better representing the stochastic features.

Effect of metal fluorides on the corrosion of structural materials in molten LiF-NaF-KF

The corrosion of structural materials in molten fluoride salts is predominantly caused by the presence of impurities in the salt. This study focuses on understanding the corrosion behavior of selected alloys in molten FLiNaK salt with addition of similar quantities of metal fluoride impurities such as CrF2, CrF3, FeF2, FeF3, and NiF2. The results show that the presence of selected metal fluoride impurities increases the extent of corrosion of the selected alloys in molten FLiNaK salt, with the exact effect depending on the thermodynamic stability of the fluoride impurity added as well as the composition of the structural alloy studied.

High-throughput assessment of corrosion inhibitor mixtures on carbon steel via droplet microarray

A high-throughput screening method for rapid laboratory evaluation of corrosion inhibitors was developed based on microarray consisting of up to 200 droplets of corrosion inhibitor solutions on one carbon steel substrate. The extent of corrosion on the steel under each single droplet was studied by tracking the variation of the 3D morphology of the corrosion product. Using this high-throughput screening platform, we evaluated the corrosion inhibition effect of benzotriazole and Ce(NO3)3 mixture and identified their best mixing ratio. The enhanced inhibition of the inhibitor mixture was discussed based on the corrosion experimental data and the molecular dynamic simulation.

Corrosion Compatibility of Stainless Steels and Nickel in Pyrolysis Biomass-Derived Oil at Elevated Storage Temperatures

Corrosion compatibility of stainless steels and nickel (Ni200) was assessed in fast pyrolysis bio-oil produced from pyrolysis of high ash and high moisture forest residue biomass. Sample mass change, ICP-MS and post-exposure electron microscopy characterization was used to investigate the extent of corrosion. Among the tested samples, type 430F and type 316 stainless steels (SS430F and SS316) and Ni200 (~98.5% Ni) showed minimal mass changes (less than 2 mg∙cm−2) after the bio-oil exposures at 50 and 80 °C for up to 168 h. SS304 was also considered to be compatible in the bio-oil due to its relatively low mass change (1.6 mg∙cm−2 or lower). SS410 samples showed greater mass loss values even after exposures at a relatively low temperature of 35 °C. Fe/Cr values from ICP-MS data implied that Cr enrichment in stainless steels would result in a protective oxide layer associated with corrosion resistance against the bio-oil. Post exposure characterization showed continuous and uniform Cr distribution in the surface oxide layer of SS430F, which showed a minimal mass change, but no oxide layer on a SS430 sample, which exhibited a significant mass loss.

Higher Order Mode Cluster ( HOMC) Guided Waves - A novel technique for accurate detection and quantification of hidden corrosion

Corrosion happening at the support regions, under sleeves, in interfaces of the pipes are severe and need reliable assessment. These hidden corrosion vary in nature based on the type of hidden region such as in resting supports, welded sacrificial pads or clamp supports just pipes wrapped in protective wrapping. Ultrasonic NDT plays a major role in the inspection of these supports. Several NDE Techniques exist for such inspection but quantifying the wall loss in an accurate manner depends on the nature and extent of corrosion. A new concept for the improved inspection of corrosion at the support region of pipelines using a short-range ultrasonic guided wave technique that uses a collection of Higher Order Modes Clusters, called here as HOMC* has been developed and verified at several field sites. Ultrasonic guided waves (circumferential or axial modes), once generated will be reflected or transmitted from corrosion and other features on the pipe. Inspection can be carried out from the accessible portion of the pipe . This could be done as an in-service inspection without emptying the pipe. HOMC guided waves are unaffected by the point of incidence of the probe. Accurate Wall loss estimation is possible together with cross sectional profile of maximum thickness loss. Using this information an accurate remaining wall thickness assessment is achieved. The technique has been deployed from pipes 2inches and above and upto 20mm wall thickness.

Electrochemical and weight loss studies of the corrosion profiles of gray cast iron under the influence of water hyacinth plant extract in 0.5 M NaOH

In an alkaline media (0.5 M of sodium hydroxide solution) with and without hot water digested water hyacinth plant extract (DWHPE) as an inhibitor, at various concentrations of 5 g, 10 g, 15 g, 20 g, and 25 g, the extent of gray cast iron corrosion was investigated in this study. The optical micrographs of the least (sample DWHPE-25 g) and most corroded (control) samples were investigated using optical microscopy. The least corroded sample showed minimum localized form of corrosion compare to the control under the micrograph view. With the use of the electrochemical polarization (EP) at a scan rate of 10 mV/s, and the weight loss (WL) method, the rates of corrosion of the working samples were investigated. For the control sample, these values were 3.36456 mmpy (obtained via WL), -543.643 mV (via EP), and 0.054556 mmpy (via EP). The corrosion rate via the WL and EP was, however, significantly reduced at 25 g of DWHPE, with values of 1.27200 mmpy and 0.023731 mmpy, respectively, at a greater corrosion potential of -283.86 mV.

Automated detection and quantification of the onset of undercoating corrosion using pulsed thermography

AbstractCorrosion of metals can occur under coatings making early visual detection almost impossible which enables corrosion to progress undetected. Nondestructive evaluation can be used to inspect parts during their life. Thermography uses the difference in thermal properties between defective and sound areas to locate defects by applying a short pulse of heat and monitoring the surface temperature of the sample with an infrared camera. However, currently, inspection is reliant on highly trained operators to analyze images for defects and in the case of corrosion, judge its growth. The aim of this research was to develop and test a novel algorithm to identify and quantify the onset of corrosion under coatings and monitor the growth. Using this algorithm, the corrosion was autonomously detected in a variety of mild steel samples exposed to three different corrosive environments. The method successfully detected, quantified, and monitored the growth of corrosion under coatings accurately and robustly using thermal images gathered by a microbolometer infrared camera. The extent of corrosion was reported with an accuracy of 3% absolute error when compared to the true extent.