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The purpose of this paper is to quantitatively assess the pit growth rate on AISI 304L and AISI 316 austenitic stainless steels in natural seawater and 3.5 wt.% NaCl solutions through electrochemical measurements during the potentiostatic growth of pits.

A quantitative characterisation was carried out based on chronoamperometric measurements. The volume of dissolved metal per pit was calculated from the charge registered and Faraday's law, considering both, hemispherical and semi‐elliptical pit shapes and the density of the steels. Empirical growth laws for maximum pit depth as a function of polarisation time were obtained and compared with pits volumetric profile obtained from optical microscopy analysis and mechanical removal of material on both steels.

Electrochemical‐based calculations of localised metal dissolution per pit present acceptable fit with the real volume of dissolved metal on hemispherical pits.

The paper presents the quantitative relationship of the corrosion pit growth rate of stainless steels in chloride containing solution determined by chronoamperometry (electrochemical technique) through the Faraday law's, with the mechanical removal of material (pit profile) through the density of metal.

The aim of this paper is to study and analyse the advantages and limitations of the scanning reference electrode technique (SRET) to detect and assess localised electrochemical activity based on an evaluation of the influence of the principal test parameters on the sensitivity and resolution of the technique.

Measurements of Ohmic potential gradients induced by ionic flux close to a point current source (PCS) were carried out using a scanning reference electrode technique (SRET) instrument, which comprised a vertical rotating working electrode and a scanning probe formed by a pair of platinum electrodes of approximately 200 μm of diameter. Ionic flux was induced by anodic polarisation applied to a gold micro‐disc electrode, which acted as the PCS. Measurements were conducted in electrolytes of ten different conductivities, using different scanning probe tips to sample surface distance and different working electrode rotation rates. The range of conductivities used included most of the possible electrolytes to which metallic materials can be in contact under real service conditions.

The SRET signal sensed from a polarised PCS showed a strong dependence on the rotation rate of the working electrode for electrolytes of low conductivity but a minimal effect on electrolytes with conductivities higher than 50 mS/cm.

This work presents the effect of wide variations on the electrochemical and operational conditions on the sensitivity and resolution of SRET signal response and discusses the limitations of the technique to assess localised electrochemical activity due to the effect of high conductivity electrolytes, large separation distance between the SRET scanning probe and developing dissolution and scanning rate of a the localised site.

To study the corrosion resistance of the novel alloy Al‐12.6La (wt%) manufactured using directional solidification.

Samples fabricated using the Bridgman growth technique at three different withdrawal velocities were subjected to total immersion tests in distilled water and in 3.5 per cent NaCl solution and to DC polarisation tests in distilled water. XPS analyses conducted on samples after polarisation indicated the presence of an La compound in the non passive corrosion products film formed.

Anodic polarisation induced dissolution of the alloy with the formation of a non passive corrosion product film. During potentiodynamic polarisation, a sudden current increment occurred at a potential value that was more positive for samples solidified at higher rates. The corrosion resistance of this Al‐12.6%La alloy decreased as the solidification rate increased.

The results presented in this work are an insight to the understanding of the corrosion resistance and electrochemical behaviour of this alloy for future engineering applications and development.

The complexity of atmospheric corrosion, further compounded by the effects of climate change, makes existing models inappropriate for corrosion prediction. The commonly used kinetic model and dose-response functions are restricted in their capacity to represent the non-linear behaviour of corrosion phenomena. The application of artificial intelligence (AI)-driven machine learning algorithms to corrosion data can better represent the corrosion mechanism by considering the dynamic behaviour due to changing climatic conditions. Effective use of materials, coating systems and maintenance strategies can then be made with such a corrosivity model. Accurate corrosion prediction will help to improve climate change resilience of the social, economic and energy infrastructure in line with the UN Sustainable Development Goals (SDGs) 7 (Affordable and Clean Energy), 9 (Industry, Innovation and Infrastructure) and 13 (Climate Action). This chapter discusses atmospheric corrosion prediction in relation to the SDGs and the influence of AI in overcoming the challenges.

The purpose of this paper is to assess the serious corrosion problems of the water injection system on the offshore oil field and to study the type, and effect factors and mechanisms of corrosion on the offshore oil field in order to develop an effective corrosion inhibitor for the sea water injection system.

The corrosion of metal in a water injection system was studied by weight‐loss and electrochemical methods.The effect factors and mechanisms of corrosion on the offshore oil field were proposed from the trend of corrosion.

FeCO₃ is the main corrosion product in the water injection system of the Chengdao Offshore Oil Field. The corrosion rate of coupons in sea water injection systems reaches a maximum peak at a temperature of 50‐60°C. The corrosion rate of coupons exposed in all three water samples increased with an increase in the dissolved oxygen concentration. When the mixed ratio of sea water and produced water and well water is 1:3:1 or 1:2:2, the corrosion rate of carbon steel is lower than is the case in pure water. The electrochemical mechanism of corrosion indicates that corrosion in the well water, produced water, and sea water samples were all controlled by the oxygen absorption process, which controlled the cathodic reaction. The corrosion rate of coupons followed the ranking order: well water; produced water; sea water.

This paper provides the main corrosion product in the water injection system of the Chengdao Offshore Oil Field, and provides new information on the effect factors and mechanisms of corrosion on the offshore oil field.

The aims are to investigate the influence of different environmental parameters on atmospheric corrosion of carbon steel and to further emphasize the feasibility and importance of atmospheric corrosion monitor (ACM).

The experiment includes outdoor exposure test and laboratory simulation test. ACM as an electrochemical method was adopted in order to research the effects of the environmental parameters on the atmospheric corrosion of carbon steel.

The corrosion current of ACM can respond satisfactorily to the corrosion of carbon steel caused by different environmental factors, especially relative humidity. Sulfur dioxide can greatly accelerate the corrosion of carbon steel and the importance of sulfur dioxide is closely related to its concentration and relative humidity. Copper‐accelerated acetic acid salt solution is more aggressive than neutral salt solution, which may be due to sub acidity and copper ion in the former solution.

Recently, ACM seems to be ignored in the research of atmospheric corrosion when some new methods come up, but in practical applications it is a simple, direct and effective method that should be attached importance. This paper further verified the feasibility and effectiveness of ACM used in monitoring atmospheric corrosion and exploring the relationship between corrosion rate and environmental parameters.

This paper aims to investigate the corrosion behaviour of carbon steel in the Mauritian atmosphere over a three-year period. Atmospheric corrosion is a serious problem in Mauritius.

Carbon steel samples were exposed outdoors at various sites. Mass loss analysis was performed to determine the corrosion behaviour of the metal over the exposure period. Scanning electron microscopy and Raman tests were performed to investigate the formation of the corrosion products on the carbon steel surface.

It was found that the corrosion loss at two of the sites considered did not vary clearly according to the bilogarithmic law. Time of wetness was found to be a main factor affecting atmospheric corrosion in Mauritius. The corrosivity of the atmosphere was found to lie between categories C3 and C4, according to ISO 9223.

The results can be of essential help to the construction industry, especially as steel buildings are becoming very common in Mauritius. Moreover, as Mauritius is a tropical island, the results obtained can be useful in other tropical islands.

The purpose of this paper is to obtain the environmental factor, which has the greatest effect on the corrosion rate of Q235 carbon steel under thin electrolyte layer, and to analyze the effect of this factor on the corrosion morphology, corrosion products and polarization process of Q235 carbon steel.

An electrochemical device, which can be used under thin electrolyte layer is designed to measure the corrosion current in different environments. Response surface methodology (RSM) is introduced to analyze the effect of environmental factors on corrosion rate. Scanning electron microscope (SEM) and X-ray diffraction (XRD) technique are used to analyze the results. The Tafel slopes of anode and cathode in different humidity and solution are calculated by least square method.

The three environmental factors are ranked according to importance, namely, humidity, temperature and chloride ion deposition rate. In a high humidity environment, the relative content of α-FeOOH in the corrosion product is high and the relative content of β-FeOOH is low. The higher the humidity, the lower the degree of anodic blockage, whereas the degree of cathodic blockage is independent of humidity. The above experiments confirm the effectiveness and efficiency of the device, indicating it can be used for the screening of corrosive environmental factors.

In this paper, an electrochemical device under thin film is designed, which can simulate atmospheric corrosion well. Subsequent SEM and XRD confirmed the reliability of the data measured by this device. The introduction of a scientific RSM can overcome the limitations of orthogonal experiments and more specifically and intuitively analyze the effects of environmental factors on corrosion rates.

This paper aims to study the corrosion behavior of D32 steel suffered to marine splash zone. Type D32 structural steel has good mechanical properties and is commonly used for offshore oil platform construction in China. To ensure the safety of marine steel structure, it is important to study the corrosion process of D32 steel in the splash zone.

The corrosion behavior of D32 steel in splash zone environments was studied using polarization curves and electrochemical impedance spectroscopy. The electrochemical results were obtained from the corroded steel samples exposed in the splash zone of a bespoke simulate device, while corrosion morphologies and corrosion products of the steel samples were characterized using scanning electron microscopy and X-ray diffraction.

In wet–dry cyclic exposure, the reaction was a self-perpetuating process of chemical oxidation and electrochemical reduction. The rust itself took part in the reduction processes and, hence, increased the corrosion rate of the steel samples.

Finally, the corrosion process of D32 steel in splash zone is considered.

The purpose of this paper is to draw up an atmospheric corrosion map for an industrial zone to determine the best coating system for each location.

The outdoor atmospheric corrosion rate was measured at eight locations distributed in an oil refinery during a year. Corrosion rates were measured by weight loss of carbon steel coupons, according to ISO Standard 9223. Weathering conditions, including temperature, time of wetness, and atmospheric pollution such as chloride precipitation and sulfur content also were measured. The results were analyzed using “Surfer 8” software and the corrosion map of the refinery was derived.

An atmospheric corrosion map was derived for the oil refinery. By this approach, coating system for equipment can be selected based exactly on where the plant item is located.

Exterior coating systems for equipment now can be selected based on their application, regardless of their position in any refinery. In this article, an atmospheric corrosion map was developed for a refinery for the first time. The position of equipment on the corrosion map is a new parameter that should be considered for coating system selection.