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To study flow‐induced corrosion mechanisms for carbon steel in high velocity flowing seawater and explain corrosive phenomena.

An overall mathematical model for flow‐induced corrosion of carbon steel in high velocity flow seawater was established in rotating disk apparatus using both numerical simulation and test methods. By studying the impact of turbulent flow using the kinetic energy of turbulent approach and the effects of the computational near‐wall hydrodynamic parameters on corrosion rates, corrosion behaviour and mechanism are discussed here. It is applicable to deeply understand the synergistic effect mechanism of flow‐induced corrosion.

It is scientific and reasonable to investigate carbon steel corrosion through correlation of the near‐wall hydrodynamic parameters, which can accurately describe the influence of fluid flow on corrosion. The computational corrosion rates obtained by this model are in agreement with measured corrosion data. It is shown that serious flow‐induced corrosion is caused by the synergistic effect between corrosion electrochemical factor and hydrodynamic factor. While corrosion electrochemical factor plays a dominant role in flow‐induced corrosion.

The corrosion kinetics and mechanism of metals in high velocity flowing medium is discussed in this paper. These results will help someone who is interested in flow‐induced corrosion to understand in depth the type of issue.

This paper aims to investigate the electrochemical corrosion rate of galvanized steel wires for bridge cables.

The electrochemical corrosion test and response surface analysis of galvanized steel wires were carried out, and the variety of polarization curves of galvanized steel wires under different corrosion parameters was discussed. The expression of corrosion rate of galvanized steel wires under the action of single and multi-factor coupling was established.

The polarization curves of galvanized steel wires under different Cl- concentrations, pH value and temperature were basically similar, but all show different degrees of deviation and some anodic polarization curves had inflection points. For example, when the Cl- concentration reached 3.5%, the corrosion rate of galvanized steel wire was four times that of pure water.

The influence relationship of single and multi-factor coupling on the corrosion rate of galvanized steel wires was as follows: RCl > RT * Cl > RT > RpH > RpH * T > RpH * Cl.

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.

This paper aims to study flow‐induced corrosion mechanisms for carbon steel in high‐velocity flowing seawater and to explain corrosive phenomena.

An overall mathematical model for flow‐induced corrosion of carbon steel in high‐velocity flow seawater was established in a rotating disk apparatus using both numerical simulation and test methods. By studying the impact of turbulent flow using the kinetic energy of a turbulent approach and the effects of the computational near‐wall hydrodynamic parameters on corrosion rates, corrosion behavior and mechanism are discussed here. It is applicable in order to understand in depth the synergistic effect mechanism of flow‐induced corrosion.

It was found that it is scientific and reasonable to investigate carbon steel corrosion through correlation of the near‐wall hydrodynamic parameters, which can accurately describe the influence of fluid flow on corrosion. The computational corrosion rates obtained by this model are in good agreement with measured corrosion data. It is shown that serious flow‐induced corrosion is caused by the synergistic effect between the corrosion electrochemical factor and the hydrodynamic factor, while the corrosion electrochemical factor plays a dominant role in flow‐induced corrosion.

The corrosion kinetics and mechanism of metals in a high‐velocity flowing medium is discussed here. These results will help those interested in flow‐induced corrosion to understand in depth the type of issue.

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.

The uniformity of electrodeposition is the key to successful application of pattern plating because the quality of electrodeposited copper layer has a huge impact on the performance of printed circuit boards (PCBs). The multi-physics coupling technology was used to accurately analyze and forecast the characteristics of electrochemical system. Further, an optimized plating bath was used to achieve a uniform electrodeposition.

A multi-physics coupling numerical simulation based on the finite element method was used to optimize electrodeposition conditions in pattern plating process. The influences of geometric and electrochemical factors on uniformity of current distribution and electrodeposited layer thickness were discussed by multi-physics coupling.

The model results showed that the distance between cathode and anode and the insulating shield had a great impact on uniformity of electrodeposition. By numerical simulation, it had been proved that using an auxiliary cathode was an effective and simple way to improve uniformity of electrodeposition due to redistributing of the current. This helped to achieve more uniform surface of the copper patterns by preventing the edge effect and the roughness of the copper layer was reduced to 1 per cent in the secondary current distribution model.

The research is still in progress with the development of high-performance computers.

A multi-physics coupling platform is an excellent tool for quickly and cheaply studying the process behaviors under a variety of operating conditions.

The numerical simulation method has laid the foundation for the design and improvement of the plating bath.

By multi-physics coupling technology, we built a bridge between theoretical and experimental study for control of uniformity of pattern plating in PCB manufacturing. This method can help optimize the design of plating bath and uniformity of pattern plating in PCB manufacturing.

The corrosion behaviour of titanium alloy surface when fluid with different flow rates flows through welded joints with different residual heights was explored.

The experiment uses a combination of array electrodes and simulation.

It is found that when the weld reinforcement exists, the corrosion tendency of both ends of the weld metal is greater than that of other parts of the welded joint due to the influence of high turbulence kinetic energy and shear stress. The presence of weld reinforcement heights makes the fluid behind it fluctuate greatly. The passivation films of both the base metal (BM) at the rear and the heat-affected zone (HAZ) are more prone to corrosion than those of the front BM and HAZ, and the passivation film is rougher.

The combination of test and simulation was used to explore the influence of electrochemical and hydrodynamic factors on the corrosion behaviour of titanium alloy-welded joints when welding residual height existed.

The 1980s and 1990s have seen the development of new and interesting soldering flux formulations. Many of these fluxes exhibit improved soldering performance or are favoured because of their reduced environmental impact. In order to further the understanding of these new fluxes and their interaction with the metallisation on the printed wiring board, as well as the substrate itself, one needs to examine test methods carefully and begin to correlate the data among the existing test methods. At Georgia Tech a variety of data have been collected on a number of fluxes including water soluble, low solids and activated rosin fluxes. Test methods for flux characterisation include surface insulation resistance testing, corrosion test measurements and recently impedance spectroscopy at low frequencies. This paper will review the variety of fluxes available, report on results of testing these fluxes using the techniques mentioned above and will define the important information related to soldering flux interactions which each test method uncovers.

The purpose of this paper is to study the corrosion rate for X52, X60, X65, X70 and X80 steel immersed in Mexican oilfield produced water. For the electrochemical characterization of the five steels rotating disk electrodes, 20°C, 30°C and 45°C of experimental temperature and 0, 500, 1,000 and 2,000 rpm of rotation speed were taken into account. The temperature dependence was analyzed using Arrhenius law. Thus, Rct values obtained from EIS data in comparison with the corrosion rate obtained from polarization curves data were taken into account. Hydrodynamic effects were analyzed by Rct and corrosion rate data.

Electrochemical impedance spectroscopy and potentiodynamic polarization techniques were used to assess the electrochemical behavior for five pipe steels steel immersed in a natural solution.

The resistance and corrosion rate taken from electrochemical tests decreased as temperature and hydrodynamic condition also decreased. In addition, the Arrhenius parameter revealed that the natural solution increased the corrosion rate as the activation energy decreased. Typical branches related to reduction-oxidation reaction (dissolution-activation process or corrosion products dissolution) on steel surface were discussed. Optical images analysis shows that corrosion products for X65 steel exposed to oilfield produced water can be attributed to more susceptibility to corrosion damage for this steel grade (Quej-Ake et al., 2018), which is increased with the temperature and rotation speed of the working electrode.

Corrosion process of the five steels exposed to oilfield produced water could be perceptive when Arrhenius analysis is taken into account. This is because oilfield produced water is the most aggressive condition (brine reservoir and sour water) for internal pipelines walls and storage tanks (brine tanks). Thus, stagnant condition was considered as a more extreme corrosive condition because produced water is stored in atmospheric stationary tanks as well as it is transported under laminar condition in zones where oilfield produced water is maintaining in the bottom of the pipe during the production, transporting and storing of the crude oil. In addition, a brief operational process for Reynolds number and the flowrate of the stock tank barrel per day (Q in STBD) using field and Reynolds number data is discussed.

The purpose of this paper is to investigate and explain thermal oxide effect on electrochemical corrosion resistance anodized stainless steel (SS).

Electrochemical corrosion resistance of thermal oxides produced on anodized 304 SS in air at 350°C, 550°C, 750°C and 950°C in 3.5 wt.% NaCl solution have been investigated by dynamic potential polarization, EIS and double-loop dynamic polarization. Anodized 304 SS were obtained by anodization at the constant density of 1.4 mA.cm^-2 in the solution containing 28.0 g.L^-1H₃PO₄, 20.0 g.L-1C₆H₈O₇, 200.0 g.L^-1H₂O₂ at 70°C for 50 min. SEM and EDS had been also used to characterize the thermal oxides and passive oxide.

Interestingly, anodized 304SS with thermal oxide produced at 350°C displayed more electrochemical corrosion and pitting resistance than anodized 304 SS only with passive oxide, as related to the formation of oxide film with higher chromium to iron ratio. Whereas, anodized 304SS with thermal oxide formed at 950°C shows the worse electrochemical corrosion and pitting resistance among those formed at the high temperatures due to thermal oxide with least compact.

When thermally oxidized in the range of 350°C–950°C, electrochemical corrosion and pitting corrosion resistance of anodized 304 SS decrease with the increase of temperature due to less compactness, more defects of thermal oxide.