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The aim of this paper was to clarify the influence of tensile stress on the electrochemical behavior of X80 steel in a simulated acid soil solution and attempt to understand mechanistic aspects of the corrosion behaviors of X80 under these conditions.

The electrochemical behavior of X80 steel at various tensile stresses was investigated in a simulated acid soil solution using electrochemical impedance spectroscopy, potentiodynamic scan measurements and surface analysis techniques.

The results show that as tensile stress was increased, the open-circuit potential decreased, the reaction activity increase, the reaction resistance (Rct)value became smaller by degrees, the corrosion product film resistance (Rf) first decreased and then increased and polarization current densities changed conversely. The corrosion product film was compact and continuous under the low stress, whereas it was relatively loose under high-stress conditions. Tensile stress promotes the movement of dislocations, which become active points when they move to the steel surface. The increase in the number of active points enhances the anodic dissolution rate and promotes the formation of corrosion product film whose blocking effect can decrease the dissolution rate. The corrosion rate of the specimen is determined by these two effects.

This research provides an essential insight into the mechanism of the electrochemical behavior of X80 steel in acid soil environments.

The purpose of this investigation was to study the erosion-corrosion behavior of ZHMn55-3-1 copper alloy in seawater (flow velocity from 0 to 0.8 m/s, sediment content from 0 to 0.15 percent), to analyze the effects of the flow velocity and sediment content on the erosion-corrosion process.

A simulated erosion-corrosion test system was set up. Weight loss determinations and electrochemical measurements (such as potentiostat square wave (PSW), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests) were used to study the erosion-corrosion behavior of ZHMn55-3-1 copper alloy in stagnant and flowing seawater with different sediment contents.

Under the test conditions, ZHMn55-3-1 copper alloys had good corrosion resistance to stagnant clear seawater, while increasing the flow velocity and sediment content reduced the corrosion resistance of the material. The difference in the erosion-corrosion mechanism between flow velocity and sediment content was that the former affected both the cathode process and the anode process of electrochemical corrosion, while the latter essentially affected only the anode process.

This paper explains the effects of flow velocity and sediment content on the erosion-corrosion behavior of ZHMn55-3-1 copper alloy in flowing seawater.

High temperature oxidation and hot corrosion behaviour of some ceramic‐based coatings, e.g. borate, silicate‐chromate and carbide‐oxide on mild steel has been investigated in the temperature range of 400–850°C. The coated steel in general shows much better oxidation and hot corrosion resistance than the uncoated steel specially at higher temperatures. The borate coating has better hot corrosion resistance performance between 700 and 800°C whereas silicate‐chromate is suitable at temperatures above 800°C. The coated steels show parabolic behaviour during oxidation. In presence of Na2SO4, the corrosion rate increases with increasing salt concentration till a maxima is reached. The amount of Na2SO4 corresponding to the maximum corrosion rate decreases with increasing temperature. A self‐sustained fluxing cum sulphidation mechanism has been proposed to explain hot corrosion behaviour of uncoated or coated mild steel.

The purpose of this paper is to investigate the void coalescence and corrosion behaviour of titanium Grade 4 sheets during single point incremental forming (SPIF) process with various spindle rotational speeds. The development of corrosion pits in 3.5 (%) NaCl solution has also been studied during SPIF process.

In this current research work, the void coalescence analysis and corrosion behaviour of titanium Grade 4 specimens were studied. A potentio-dynamic polarization (PDP) study was conducted to investigate the corrosion behaviour of titanium Grade 4 processed samples with various spindle speeds in 3.5 (%) NaCl solution. The scanning electron microscope and transmission electron microscope analysis was carried out to study the fracture behaviour and corrosion morphology of processed samples.

The titanium Grade 4 sheets obtained better formability and corrosion resistance by increasing the CNC spindle rotational speeds. In fact that, the significant plastic deformation affects the corrosion rate with various spindle speeds were recorded.

The spindle rotational speeds and vertical step depths increases then the titanium Grade 4 sheets showed better formability, void coalescence and corrosion behaviour as the same is evidenced in forming limit diagram and PDP curves.

This paper aims to investigate the effect of alternating current (AC) on corrosion, it is not yet clear about the exact mechanism of the corrosion induced by AC. Previous reports indicated that AC corrosion was similar to the effect of continuous cathodic and anodic polarization on the corrosion process of the metals. Wan et al. studied the effect of negative half-wave AC on stress corrosion cracking behavior and mechanism of X80 pipeline steel in near-neutral solution.

This study attempted to understand the AC-induced corrosion by imposing the half-cycle AC on the X80 pipeline steel in an acid bicarbonate solution. The AC corrosion mechanism was determined by weight loss and potentiodynamic polarization curve measurements, as well as surface characterization.

The results show that the positive half-cycle AC accelerated the uniform corrosion in the NaHCO3 solution, the negative half-cycle AC would decrease the uniform corrosion and local corrosion was increased and some Ca and Mg deposited on the surface of X80 steel, so the corrosion rate decreased by negative half-cycle AC. The corrosion product was composed of α-FeOOH under the application of positive half-cycle AC. The oxygen reduction led to a local increase of pH near the electrode surface and led to the formation of α-FeOOH, which enhanced the protectability of corrosion products.

Researchers studied the effect of negative half-wave AC on stress corrosion cracking behavior and mechanism of X80 pipeline steel in near-neutral solution. However, the AC behavior and corrosion mechanism in acid solution are unknown. So to make clear about the corrosion behavior of metals in different polarization states and the mechanism involved, diode technology was used to research the AC corrosion, half-wave AC was applied on the metals after the full-wave rectified.

This paper aims to explore the influence of CO₂ partial pressure, flow rate and water cut on N80 steel corrosion behaviors in the displacement process of oil in glutenite reservoir by CO₂ injection.

A self-made 3 L high-temperature and high-pressure autoclave was used to conduct corrosion simulation experiments of N80 steel in different CO₂ partial pressures, flow rates and water cut (the independently developed oil and water mixing approach can ensure the uniform mixing of oil and water in experiments). Techniques like weight loss and surface analysis were used to analyze the corrosion behaviors of N80 steel under different conditions.

Results showed that the average corrosion rate of N80 steel accelerated at varying degrees with the increase of CO₂ partial pressure, flow rate and water cut. Excluding that the samples showed uniform corrosion under the two conditions of 0.5MPa CO₂ partial pressure and static corrosion, they displayed mesa attack corrosion under other conditions. Besides, with the increase of CO₂ partial pressure, the pH value of solution dropped and the matrix corrosion speed rose, hence leading to the increased Fe²⁺ and CO₃²⁻ concentration. Meanwhile, a lowered pH value improved the FeCO₃ critical supersaturation, thereby leading to an increased nucleation rate/growth rate and ultimately causing the decrease of the dimension of FeCO₃ crystallites formed on the surface of the samples.

The results can be helpful in targeted anti-corrosion measures for CO₂/oil/water corrosive environment.

The main purpose of this study was to investigate the corrosion behaviour of simulated archaeological iron in Cl⁻, NO₃⁻ and HSO₃⁻ bearing pollutants.

Periodic wet‐dry test, potentiodynamic polarization experiments and surface tension tests were used to study the rule of corrosion rate. Scanning Electron microscopy with EDAX, stereoscopic microscopy and X‐ray diffraction were also used to identify the corrosion products and mechanism. Weight loss measurement, electrochemical theory, as well as ions adsorption theory and penetration theory were used to explain the different corrosion behaviour.

The experimental results demonstrated that the attack of anodic ions to the metal at the initial corrosion stage showed great agreement with their surface activity. However, as corrosion progressed, the different reaction mechanisms and the penetration effect of anions as well as the characteristics of the corrosion products (intermediate products and final products) begin to control the corrosion process.

The initial corrosion rate was found to show agreement with the surface activity of anions. From a new viewpoint, this paper explains the different corrosion behaviour of Cl⁻, NO₃⁻ and HSO₃⁻ anions to simulated archaeological iron and offers reference to the individual who pursues in corrosion and protection of metal.

The purpose of this paper is to investigate the effects of incorporating SiC nanoparticles into ZA-27 alloy on the corrosion behavior of the produced nanocomposites.

The nanocomposites were fabricated by a double-step stir casting technique. The corrosion behavior of the produced ZA-27 nanocomposites was investigated using potentiodynamic polarization test in a 3.5% NaCl medium. The surfaces of the fabricated metal matrix nanocomposites (MMNCs) before and after corrosion tests were imaged and analyzed using an optical microscope and scanning electron microscope (SEM) to examine the microstructure of the produced MMNCs and morphology of its surface before and after corrosion.

The corrosion test results reveal that the fabricated nanocomposites have an improved uniform corrosion resistance when compared with the corresponding monolithic matrix alloy. On the other hand, the base monolithic alloy is less susceptible to the pitting phenomenon than the nanocomposites. The electrochemical results are consistent with the pits morphology of the corroded MMNCs.

This study highlights the use of SiC nano-particulates for controlling of ZA alloy corrosion behavior and enhancing its anti-corrosion characteristics which will open a new route for industrial applications. The corrosion behavior of ZA-27 alloy-based composite reinforced with different weight fractions of nano-SiC particles have an improved uniform corrosion behavior as compared with the corresponding matrix alloy.

This paper aims to investigate the corrosion behaviour of heat-treated and cryorolled Al 5052 alloys in different Cl⁻ ion concentrations.

NaCl solutions with concentrations of 0, 0.5, 3.5 and 5.5 per cent were selected. Samples were subjected to pre-heat treatment (annealing at 300 °C and solution treatment at 540 °C) and cryorolling up to 30 per cent reduction before undergoing corrosion tests. The corrosion behaviour of the samples was then investigated by potentiodynamic polarization. The microstructure of the corroded samples was evaluated under an optical microscope, and the percentages of pits on their surfaces were calculated.

The cryorolled samples had a lower corrosion rate than the samples that were not cryorolled. The cryorolled sample that underwent solution treatment showed the highest corrosion resistance among all the samples tested.

The commercial impact of the study is the possibility of using the cryorolled Al alloy in various ion chloride environment.

The obtained results help in understanding the corrosion behaviour of cryorolled samples under different heat treatment conditions.

The purpose of this paper is to study corrosion behavior and corrosion mechanism of carbon steel in natural freshwaters with humic acid (HA).

The weight‐loss method, electrochemical measurements and surface analysis technique were used to study the corrosion behavior of carbon steel in freshwaters with HA.

General corrosion occurred when carbon steel was exposed to test solutions (fresh lake water with and without HA). The presence of HA in test solution can accelerated the corrosion rate of carbon steel.

There have been few reports on the effect of HA on the corrosion behavior of carbon steel. In this study, it is clearly shown that the presence of HA in fresh lake water can accelerate the corrosion rate of carbon steel. This research not only can offer theoretical guidelines for the prevention of pipelines and facilities from corroding, but also can provide a reference for suitable material selection and the further protection of carbon steel in hydraulic engineering.