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This paper aims to develop an electrochemical dechlorination method for large objects in a short time, which were for a long time in the sea. Traditionally, in conservation, chlorides are extracted from marine iron artifacts using complete immersion of those objects in alkaline solutions with or without electrolysis. However, these techniques are time-consuming and very costly, especially when applied to large marine artifacts such as cannons and anchors.

An appropriate sponge was chosen based on resistance to NaOH and the rate of exacted chlorides. Application of electrochemical dechlorination in situ and removal of chloride were measured by the scanning electron microscope (SEM)-EDAX method on the corrosion products and by titration of the electrolysis solution. X-ray diffraction (XRD) method is used for identification of corrosion products before and after application of electrochemical chloride extraction.

The electrochemical chloride extraction (ECE) method is applied against the corrosion of reinforced concrete. From the authors’ research, it is obvious that ECE can successfully extract chlorides from dried large metallic objects exported from the sea. The method of ECE removes the majority of chlorides from the metal during conservation treatment so that the application of organic coating will allow the object to remain stable over a long period.

A new methodology was developed for dechlorination of metallic objects exported from the sea in a short time and thus the consumption of chemical reagents was cut down.

The evolution of a semi‐open cooling circuit of a nuclear reactor was monitored over a two year period. The work aims to provide orientation elements for preventive procedures against localised corrosion.

The water of the circuit was analysed in stagnation and in circulation, at various sampling points. The rust was analysed by neutron diffraction and the surface quality of the steel was checked by microscopic observations.

The obtained results did not confirm the presence of rust in iron compounds supported by chlorine, such as the Akaganeite, β‐FeOOH. In addition, chemical analysis of water showed that, after two years, the increase of chlorine concentration and water conductivity remained weak. Moreover, the pH was maintained within values favourable rather to the passivation of the steel.

It was deduced through this work that the dosing of the circuit with chlorine was not sufficient that it should require an annual replacement of the water.

The originality of this work resides in the evaluation of a semi‐open coolant circuit in service for ten years and located in an area subjected to seasonal sand winds.

The purpose of this paper is to explore the environment around the rail track at different sites in Nile Delta region, Egypt, through the measurements of the air pollutants and corrosive ionic species present in surface soil and also to investigate the impact of the existing contaminants on the composition of iron rust formed on the rail head surface at these sites and then the durability of rail itself.

The soil characterization was studied by means of sieve shakers, pH meter, conductivity meter and ion chromatography instrument. Scanning electron microscopy, energy dispersive spectrometry, Fourier transform infrared spectroscopy and X-ray diffraction were used to characterize the rust layer formed on the rail head surface.

The results showed the relation between the contaminants and the composition of the rust layer. Magnetite and goethite were the major phases identified in the rust layers. Akaganeite was detected in the marine atmosphere. Iron sulfide and iron oxide nitrate hydroxide were detected in environments rich in H₂S and NO₂ gases, respectively. The appearance of phases like FeCl₂ and FeOCl only at marine atmospheres reflects that the corrosive species in suspended particulate matter like chloride ion have a higher effect on the rust composition of the rail head surface than that in surface soil layer.

This paper revealed the impact of air and soil contaminants on the composition of rust layer on the rail head surface and may provide guidance for the durability of rails and the necessity for their preservation.

When concrete is manufactured, it can be instantaneously contaminated by chloride (Cl⁻) ions or later by their intrusion from the environment. This work aims to study the electrochemical behavior of the passive layer formed on the reinforcing steel surface in the presence of the same Cl⁻ ion concentration, with and without passivation time. This will, undoubtedly, affect the corrosion threshold values thereafter.

Electrochemical polarizations were carried out in two concrete pore solutions. The surfaces of samples immersed for 255 days in saturated Ca(OH)₂ solution were examined with optical and scanning electron microscopy and Raman microspectroscopy.

Cl⁻ ion origins in reinforced concrete lead to different values of corrosion thresholds. The passive layer behaves like a physicochemical barrier, and corrosion occurs at higher NaCl concentration thresholds. The formed passive film on the steel surface shows differences in the chemical composition and the morphology. The results show a rich presence of hematite. Maghemite, lepidocrocite, akaganeite and goethite are also present in much lower concentrations. The Cl⁻ ion presence in fresh concrete at the beginning of the manufacture harms the good formation and the good stability of these oxides, leading to corrosion initiation.

This study contributes to a better understanding of the passive layer role, not only in reducing the corrosion rate value but also in reconsidering new Cl⁻ ion corrosion threshold values.

The application of hydrogen plasma on corroded steel and excavated iron artefacts has been studied. Transformations of the corrosion layer due to the plasma effect were investigated by means of X‐ray diffraction analysis. The reduction of iron oxides to the stable iron oxide, magnetite, was observed for all the samples. In the case of excavated objects, the reduction to magnetite did not occur throughout the whole of the bulk of the oxides, as it does (for example) in the case of steel corroded in the laboratory. Nevertheless, excavated objects, in which a metallic core remained, were stabilised against subsequent corrosion. However, objects that are completely oxidised must be treated carefully, because treatment may result in the formation of a brittle outer layer, and there is a risk of disintegration of such items, if treated using the plasma conditioning and restoration procedure.

The purpose of this paper is to study the ability of commercial tara powder to convert rust into iron tannate and evaluate their use as raw material for the formulation of water based rust converter.

Water-borne acrylic primers were formulated with tara powder and aqueous tara extract and applied on steel rusted by three different methods. The conversion of rusted steel by tara tannins was studied by X-ray diffraction spectroscopy, infrared spectroscopy and scanning electron microscopy. The acrylic primers, containing hydrolysable tannins, were coated with alkyd finish and were evaluated in comparison to commercial systems in accelerated corrosion tests. The corrosion inhibition effects of tara powder on mild steel in 0.1M NaCl were studied by DC electrochemical techniques.

Tara tannin converts rust to ferric tannate and increases the magnetite content of rusted steel. The water-based acrylic primer formulated with aqueous extract of tara, alkyd-coated finish, showed performance equivalent to pure alkyd system.

The chlorides content in the commercial tara powder can be screened the beneficial effect of hydrolysable tannins to convert rust. Furthermore, the water-based rust converter formulated with acrylic resin may be sensitive to salt contamination of rust.

Hydrolysable tannins from commercial tara powder have not been studied yet in its application to the development of rust converters. A water-based primer formulated with commercial tara powder developed for the effective treatment of rusted surfaces can be of interest as an environmentally friendly to current commercial approaches.

The purpose of this study is to evaluate the role of encapsulation pH and iron source on the anchorage mode and performance of iron oxide-encapsulated aluminium pigments.

The coloured waterborne aluminium pigments were prepared at pH 5-7.5 by using FeSO₄ and FeCl₃ as iron source. The anchorage mode of iron oxides on aluminium was characterized using optical microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. Furthermore, the pigmentary performance was characterized through anticorrosion test and multi-angle spectroscopy.

Diaspore and boehmite could form from H₂O₂ oxidizing aluminium. Both low pH and FeSO₄ systems are beneficial for diaspore, inducing green rust anchor on the aluminium to form goethite. Either in FeSO₄ or FeCl₃ system, slightly high pH is beneficial for the formation of boehmite, which occurred together with ferrihydrite to form denser coating with yellowness and excellent anticorrosion property. At pH above 7, the formation of dendritic iron oxide is detrimental to the anticorrosion property and the glossiness.

Only FeSO₄·7H₂O and FeCl₃·6H₂O as iron sources were explored.

The investigation results provide theoretical basis to obtain excellent chromatic waterborne aluminium pigments.

The method for investigation of encapsulation mechanism by surveying the structure of iron oxides on aluminium, which varies with the pH of the system and iron sources, is novel.

The purpose of this paper is to study the influence of temperature on the acceleration and simulation of indoor corrosion tests and the corrosion behavior of Q235 carbon steel.

The indoor corrosion test was carried out by continuous salt spray in a salt spray chamber. Weight loss analysis, X-ray diffraction, cannon 1500 D, scanning electron microscopy and electrochemical techniques are used to analyze the results.

It was found that thickness loss of Q235 carbon steel increases with higher temperature and it can reach 0.095 mm at 50°C. Compared with the Xisha exposure test, the acceleration rate can achieve 230 times. This phenomenon indicates that decreasing the experimental temperature is beneficial to the anti-corrosion of the Q235 carbon steel. It is fascinating to find that acceleration and simulation increase with temperature simultaneously, which shows that β-FeOOH promotes the corrosion rate and α-FeOOH provides high simulation. Meanwhile, electrochemical impedance spectroscopy indicates that the resistance of the rust layer improves with temperature.

Through the study, the authors found that with the increase of temperature, the acceleration and simulation of indoor corrosion test improved, corrosion products and kinetics are the same as those in outdoor exposure test, and which means that the laboratory can achieve the long-term corrosion degree of outdoor exposure in a short time, and the similarity with outdoor exposure is high. This helps to the study of marine atmospheric corrosion, and indoor accelerated corrosion tests can largely eliminate regional differences by adjusting some environmental factors, and lay a foundation for marine atmospheric corrosion.

The effects of temperature on the acceleration and simulation of indoor corrosion tests are discussed. Through laboratory experiments, the long-term service life of Q235 carbon in the Xisha marine atmosphere can be predicted effectively.

The purpose of this paper is to characterize the surface of steel under cathodic protection while submerged in seawater, to understand the mechanism that controls the operation of the protection system.

Steel rods were immersed in seawater and NaCl solution with applied cathodic protection. The experimental methodology included monitoring of corrosion potential (E_corr), galvanic current (I_galv) protection potential (E_protection) and the depolarization potential of steel during the time of exposure. In addition, the chemical composition of the steel surface was assessed using a Scanning Electron Microscope (SEM).

In this research it was determined that the effectiveness of the CP system was mainly attributable to the formation of an iron oxide film on the steel surface.

It is necessary to carry out analysis of the chemical composition of deposits formed on the steel surface, perhaps using X‐ray diffraction (XRD), to verify the presence of a protective oxide.

Deposits on the steel surface have the beneficial effect of reducing the current required for efficient protection. Deposit formation therefore is of economic interest, as it decreases the cost of protection.

A unique feature of cathodic protection in seawater is the formation of calcareous deposits on metal surfaces. Advantageous aspects of these deposits, such as decrease in cathodic current requirement, have been investigated by various authors from various viewpoints. However, very little attention has been paid to the impact of any iron corrosion product films; the present paper contributes useful understanding and explains the importance of the mechanism that controls the operation of the protection system.

This paper aims to reveal the corrosion mechanism and corrosion development regulation of marine engineering structural steel in the marine environment and provide constructive suggestions for marine immersed tunnel engineering.

In this study, marine engineering structural steel’s behavior and corrosion prediction were carried out under the conditions of no cathodic protection and under-protection by artificially adding dissolved oxygen in a simulated seawater solution as a depolarizing agent.

Marine resources are rich in China. With the development of the economy and the improvement of engineering technology, marine engineering structural steel is used more and more widely. Engineering structural steel has a great risk of corrosion failure for long-term service in seawater, as seawater is a kind of corrosive medium containing various salts. At present, there are few projects and research studies available on the corrosion in the seawater environment of Q390C engineering structural steel, which is used in the Shenzhen–Zhongshan Link immersed tunnel steel shell at home and abroad. It cannot guide the corrosion of immersed tunnel steel shells in the ocean.

In this paper, the corrosion mechanism and corrosion development regulation of marine engineering structural steel in the marine environment are studied by accelerated corrosion test in the laboratory, which is of great significance to ensure the long-life durability of the immersed tunnel in marine engineering.