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This study aims to explore the differences in the tourists’ perceived destination image on travel e-commerce platforms (e.g. Ctrip and Fliggy) and social media platforms (e.g. Xiaohongshu and Weibo).

The formation and corrosion processes of a conversion film on the AZ80 Mg alloy with different second phases were compared to clarify the effect of microstructure on the quality of protective coatings.

The size and distribution of second phases in the edge and central regions of the AZ80 cast ingot exhibit a great difference. The film growth processes and their corrosion resistance on the edge and central regions of the AZ80 cast ingot were investigated by scanning electron microscope observations, immersion tests and electrochemical measurements.

The results indicate that second phases act as micro-cathodes and hydrogen evolution reaction occurs on their surface, which is not beneficial for the deposition of the conversion film.

The conversion film formed on the central regions of AZ80 cast ingot with a low volume fraction of second phases exhibits a more uniform surface and higher corrosion resistance than that formed on the edge regions of the sample with a higher volume fraction of second phases.

The purpose of this paper is to optimize a suitable electrochemical method in evaluating the corrosion rate of structural materials of 20# carbon steel, P280GH carbon steel, 17-4PH stainless steel, 304 stainless steel and Alloy 690TT in high-temperature and high-pressure (HTHP) water of pressurized water reactor secondary circuit system.

Weight-loss method has been used to obtain the corrosion rate value of each structural material in simulated HTHP water. Besides, linear polarization method and weak polarization curve-based three-point method and four-point method have been compared in obtaining a sound corrosion rate value from the potentiodynamic polarization curve. Scanning electron microscopy (SEM) and atomic force microscope have been used to characterize the microstructure and corrosion morphology of each structural material.

Although there is deviation in gaining the corrosion rate value compared to weight-loss test, the weak polarization curve-based four-point method has been found to be a suitable electrochemical method in gaining corrosion rate value of structural materials in HTHP waters.

This paper proposes a suitable and reliable electrochemical method in gaining the corrosion rate value of structural materials in HTHP waters. The proposed weak polarization curve-based four-point method provides a timesaving and high-efficient way in corrosion rate evaluation of secondary circuit structural materials and thus has a potential application in nuclear power plants.

The purpose of this paper is to predict the life of a corroding metallic structure in seawater so that uncertain and unpredictable failures of a structure, leading to accidents, can be prevented.

Pitting has been known to show a large scatter in the measurable parameters such as corrosion rate, maximum pit depth, time to perforation and so on. Scatter results from the influence on pit development on metal surface heterogeneity and from variations in the corrosive environment over time. All these facts suggest that randomness is an inherent and unavoidable characteristic of pitting corrosion over time, so that stochastic models have been developed to formulate pit depth as a function of parameters influencing the process. Since chloride penetrates the passive film of the metal surface, Cl ion distribution into the metal has been mapped by finite element method (FEM).

The maximum pit depth which decides the onset of perforation or leakage has been modeled by the following equation: d=36.31(ΔE)^0.68×(Δt)^0.35. Cl ion distribution within a pit and outside has been modeled for better understanding of pit initiation which till today is not fully understood.

Perforation and leakage of a tank, container, or pipeline occur when the depth of pitting reaches the section thickness of the material of which the metallic structures are made. The pitting corrosion is localized and occurs at any spot or site where electrochemical conditions (ΔE Equation (9)) are prone to pitting. This leads to unpredictable failures of the structures which may look polished and undamaged under naked eyes. In most metallic structures, pitting may be present at some spots, but failures occur only when the depth predicted by the model Equation (9) reaches the section thickness of the material. Thus, determining pipe to soil potential gives a guide to go for maintenance before pit depth reaches the material thickness, and thereby unpredictable failure can be prevented. Second, the map generated by FEM showing Cl distribution throws much information and light on movement of Cl ions from passive layer into the pit, which leads to its growth. This helps scientists and researchers to understand the mechanism and gives much insights on finding new methods for protection of structures.

The work will guide the engineers and researchers to prevent unpredictable failures of structures leading to accidents and human and property loss and prevent environment pollution from spilling of oil from tank and pipeline.

This is an original work based on several laboratory-generated simulated experimental data.