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This paper aims to explore the transformation process and transformation mechanism of carbon steel under the marine environment.

In this paper, the transformation and rust layers corrosion products on 0Cu2Cr carbon steel with different cycles coupon test was investigated and deeply explored by scanning electron microscope, energy dispersive spectrometer, X-ray diffraction.

The results showed that the thickness of rust layers grew from 71.83 µm to 533.7 µm with increasing duration of corrosion. The initial corrosion product was γ-FeOOH, then part of the γ-FeOOH continued growing, and under the capillary action, the other part of the γ-FeOOH transformed to α-FeOOH.

To the best of the authors’ knowledge, this paper puts forward for the first time a new viewpoint of the development of corrosion products of low-carbon steel in two ways. This discovery provides a new idea for the future development of steel for marine engineering.

The purpose of this paper is to study, under laboratory conditions, the corrosive effect of sulfur dioxide (SO₂) present in the atmosphere of urban and industrial areas on various construction materials.

Iron, copper and brass metals were exposed to SO₂ gas at different relative humidities that were obtained using analytical grade glycerol and water mixtures. The corrosion rates (mdd) of the samples were determined over 120 h using the weight‐loss method under fixed relative humidity (rH) conditions. The change of galvanic current was measured as a function of exposure time over 196 h. Nyquist diagrams were obtained in 10⁻³ M Na₂SO₄ solutions with a pH value of 7.2, which was assumed to correspond to 100 percent rH conditions.

The obtained data showed that the corrosion rate of the studied metals increased with increasing rH. The corrosion rate of the metals decreased with exposure time, due to accumulation of corrosion products over the surface of the metals. However, the surface films of corrosion products on the metal surfaces were not stable and the corrosion rate increased again with time when the surface film disappeared.

The atmospheric corrosion of the industrial materials is dependent upon the rH and SO₂ concentration. The corrosive effect of SO₂ present in the atmosphere of urban and industrial areas on various construction materials can be tested under laboratory conditions.

The effects of SO₂ and NH₃ on the atmospheric corrosion of galvanized iron and the effect of rH on the atmospheric corrosion of defective organic coating materials were reported in literature. In this study, the corrosive effect of SO₂ present in the atmosphere of urban and industrial areas on various construction materials (iron, copper and brass) under laboratory conditions was studied.

This paper aims to present a correlation study on general and accelerated corrosion of the welded structure of aluminum alloy 2219 in N₂O₄.

Corrosion experiments of the Tungsten Inert Gas (TIG)-welded aluminum alloy structure were conducted under both mild and accelerated corrosion conditions by changing the water content in N₂O₄.

The experimental results indicated that both general and accelerated corrosion processes of the TIG-welded structure of aluminum alloy 2219 in N₂O₄ followed the linear equation ΔW = A + Bt, and the corrosion products were unchanged regardless of the water content in the N₂O₄ solution.

The weight loss comparison method is used to identify the structure of the conventional aluminum welding and aluminum welding structure corrosion dinitrogen tetroxide in nitric acid accelerated corrosion relationship.

This paper aims to introduce a method to reduce corrosion caused by acidic-oxidized polymer degradant through subsection injection with different inhibitor.

This paper introduced a method to reduce corrosion caused by acidic-oxidized polymer degradant through subsection injection with different inhibitor.

The experimental results indicated that the influence of pre-corrosion status on corrosion rate and effectiveness of corrosion inhibitor are significant. The corrosion inhibitors in both injection stage inhibited the corrosion process by preventing the contact of corrosive medium and steel surface through formation of a protective film on the surface of N80 steel. The corrosion rate of polymer degradant can be reduced to 0.63 g/m 2 h through subsection injection with different inhibitor.

This result will increase the production of polymer injection plugging wells through expanding the application of acidic-oxidized polymer degradant.

The purpose of this paper is to evaluate the effect of seawater temperature on the corrosion behaviour of 90‐10 cupronickel alloys. Also, to investigate the effect of thiosulphate additions (one of the major sulphide oxidation products in seawater) on the alloy corrosion rate in seawater.

Potentiodynamic polarization measurement (DC) was used to estimate the corrosion rate of the cupronickel alloy in seawater with and without thiosulphate species (50‐650 ppm).

It was observed that the cupronickel alloy suffered accelerated corrosion as the seawater temperature was raised from 25 to 50 or 80°C. The increase in the corrosion rate was found to correspond well with the negative shift in the free corrosion potential. Thiosulphate addition was found to depend on the test temperature. At 25°C, thiosulphate activated the alloy dissolution rate and the higher were the thiosulphate concentrations, the higher was the corrosion rate. At 50 or 80°C, however, thiosulphate promoted the dissolution rate at early stages, but seemed to interfere with the surface film formation later on, producing a black film that effectively decreased the alloy corrosion rate. At higher potentials, however, the film became non‐protective, leading to accelerated corrosion once again.

This paper explains the corrosion behaviour of 90‐10 cupronickel alloys in seawater as a function of test temperature and thiosulphate additions.

This paper aims to quantify atmospheric corrosion by image analyses. The corrosion extent, form and distribution of corrosion product on Q235B and T91 steels exposed to a Zhoushan marine atmosphere over one year are characterized by image analysis.

Image analysis of corrosion images were achieved using the gray value, wavelet analysis and fuzzy Kolmogorov–Sinai (K–S) entropy.

As corrosion becomes extensive, the gray value of corrosion images decreases, and the energy value of nine subimages after wavelength decomposition decreases. Fuzzy K–S entropy increases as localized corrosion propagates but decreases as uniform corrosion spreads.

The methods proposed in this work open a new way for fast corrosion evaluation of metallic materials exposed to atmospheric conditions.

This study aims to investigate the salt spray corrosion (SSC) and electrochemical corrosion of obtained Zn–Al coating, which provided a basis for comprehensive analysis of corrosion behavior of Zn–Al coating.

A Zn–Al coating was fabricated on Q235A steel using a Dacromet method. The SSC and electrochemical corrosion performances in 3.5 Wt.% NaCl solution were investigated using an SSC chamber and electrochemical workstation, respectively, and the corrosion mechanism of Zn–Al coating was discussed.

The Dacromet fabricated Zn–Al coating is primarily composed of Zn and Al phases, its residual stress of −11.1 ± 4 MPa is compressive stress, which is beneficial to improve its corrosion resistance. In the SSC process, the corrosion product of Zn5(OH)8Cl2H2O enhances the corrosion resistance of Zn–Al coating, which provides sufficient cathodic protection for the substrate. The corrosion potential of Zn–Al coating is lower than that of substrate, which provides sufficient cathodic protection to the substrate, the Zn–Al coating in the immersion periods is protected by the corrosion product and Zn–Al sheets.

In this study, a Zn–Al coating was first fabricated on Q235A steel using a Dacromet method.

The purpose of this paper is to determine the long‐term corrosion behavior of cast iron coupons in the Jubail Industrial City (JIC), Saudi Arabia.

The samples were exposed under atmospheric, underground, and splash zone conditions, at Khaleej Mardumah Test Station (KMTS) in Jubail. Soil, groundwater, seawater and air particulate samples were collected at the exposure sites and were analyzed. Secondary electron microscopy (SEM), X‐ray diffraction (XRD) and X‐ray fluorescence (XRF) were used to examine the surface morphology of the test coupons and identify the corrosion products developed on the surface of the metals. The corrosion rates of the coupons were determined by weight loss method.

The results showed that the atmosphere, underground and splash zone conditions all were very corrosive to cast iron, due to temperature and humidity variations as well as the high chloride and sulfate concentrations in the region. The splash zone was the most corrosive regime of the three test zones. The main corrosive ions in the environments were identified as chloride and sulfate. The maximum chloride and sulfate concentrations were measured to be 8.94 and 49.65 μg/m³ in atmosphere, 8,040 and 1,410 ppm in soil, and 29,500 and 5,770 mg/l in seawater, respectively. The corrosion rates of cast irons were found to be 343‐536 μm/y in splash zone, 90‐214 μm/y in underground, and 22‐27 μm/y in atmosphere. Compared to other parts of the world, the soil, marine and atmospheric environments at the selected test site are very corrosive.

In this paper, corrosion of cast iron is presented in atmospheric, soil and splash zone conditions along the eastern coast of the Arabian Gulf.

The purpose of this work is to design the wire beam electrode (WBE) of P110 steel and study its corrosion behavior and mechanism under high temperature and pressure.

Packaging materials of the new type P110 steel WBE and high pressure stable WBE structure were designed. A metallurgical microscope (XJP-3C) and scanning electron microscopy (EV0 MA15 Zeiss) with an energy dispersive spectrometer were used to analyze the microstructure and composition of the P110 steel. The electrochemical workstation (CS310, CorrTest Instrument Co., Ltd) with a WBE potential and current scanner was used to analyze the corrosion mechanism of P110 steel.

According to the analysis of Nyquist plots at different temperatures, the corrosion resistance of P110 steel decreases with the increase of temperature under atmospheric pressure. In addition, R_p of P110 steel under high pressure is maintained in the range of 200 ∼ 375 Ωcm², while that under atmospheric pressure is maintained in the range of 20 ∼ 160 Ωcm², indicating that the corrosion products on P110 steel under high pressure is denser, which improves the corrosion resistance of P110 steel to a certain extent.

The WBE applied in high temperature and pressure environment is in blank. This work designed and prepared a WBE of P110 steel for high temperature and pressure environment, and the corrosion mechanism of P110 steel was revealed by using the designed WBE.

This paper aims to study the effect of chloride ions concentration on the corrosion behavior of carbon steel in methyldiethanolamine (MDEA) aqueous solution in the sight of different process parameters of purification plant.

Due to the decrease of filtration efficiency and separation efficiency, the chloride ion in the desulfurization solution is enriched. The corrosion behavior of carbon steel under chloride ion enrichment environment was studied by weight-loss method, electrochemical impedance spectroscopy, cyclic polarization curve, X-ray photoelectron spectroscopy and scanning electron microscopy.

The results show that temperature and hydrogen sulfide loads are the main factors of corrosion in CO2-MDEA-H2O-H2S environment. The enrichment of chloride ions reduces the corrosion rate at low temperature but promotes the corrosion rate at high temperature. The chloride concentration should be controlled below 3000 mg/L, and no pitting corrosion was found under the experimental conditions.

The effect of chloride ion enrichment on MDEA solution corrosion shows that at low temperature, the increase of chloride ion will reduce the acid gas load and increase the density of corrosion products, so as to reduce the corrosion; on the contrary, at high temperature, the density of corrosion products will decrease and the corrosion will be intensified as well. It is believed that the chloride ion should be controlled below 3000 mg/L according to the results of the tests.