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1 – 10 of over 6000Zhuolin Li, Dongmei Fu and Zibo Pei
This paper aims to discover the mathematical model for Q235 carbon steel corrosion date acquired in the initial stage of atmospheric corrosion using electrical resistance probe.
Abstract
Purpose
This paper aims to discover the mathematical model for Q235 carbon steel corrosion date acquired in the initial stage of atmospheric corrosion using electrical resistance probe.
Design/methodology/approach
In this paper, mathematical approaches are used to construct a classification model for atmospheric environmental elements and material corrosion rates.
Findings
Results of the experiment show that the corrosion data can be converted into corrosion depth for calculating corrosion rate to obtain corrosion kinetics model and conform corrosion acceleration phase. Combined with corresponding atmospheric environmental elements, a real time grade subdivision model for corrosion rate can be constructed.
Originality/value
These mathematical models constructed by real time corrosion data can be well used to research the characteristics about initial atmospheric corrosion of Q235 carbon steel.
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Yanjie Liu, Meng Xu and Yumei Cao
Wafer transfer robots play a significant role in IC manufacturing industry and the end effector is an important component of the robots. The purpose of this paper is to improve…
Abstract
Purpose
Wafer transfer robots play a significant role in IC manufacturing industry and the end effector is an important component of the robots. The purpose of this paper is to improve transfer efficiency of a wafer transfer robot through study of its end effector, and at the same time to reduce wafer deformation.
Design/methodology/approach
Finite element method is adopted to analyze wafer deformation. For wafer transfer robot working in vacuum, for the first time, the authors apply the research of microfiber arrays inspired by gecko to the design of robot's end effector, and present equations between robot's transit acceleration and parameters of microfiber arrays. Based on these studies, a kind of micro‐array bump is designed and fixed to a structure optimized end effector. For wafer transfer robot working in atmospheric environment, the authors have analyzed the effects of different factors on wafer deformation. The pressure distributions in absorption area and calculation formula of maximal transfer acceleration are put forward. Finally, a new kind of end effector for atmospheric robot is designed according to these studies.
Findings
The experiments results show that transfer efficiency of wafer transfer robot has been significantly improved through application of the research in this paper. Also wafer deformation under absorption force has been controlled.
Practical implications
Through experiments it can be seen that the research in this paper can be used to improve robot transfer ability and decrease wafer deformation in the production environment. Also the studies of end effector lay a solid foundation for further improvement.
Originality/value
This is the first application of the research of gecko‐inspired microfiber arrays to vacuum wafer transfer robot. This paper also carefully analyzes effects of different factors on wafer deformation through finite element method.
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Wei Su, Wangyan Lv, Zhengchun Liu and Zengguang Zhang
The aim of this paper was to study the initial corrosion behavior of copper in the substations of Zhanjiang and Zhuhai.
Abstract
Purpose
The aim of this paper was to study the initial corrosion behavior of copper in the substations of Zhanjiang and Zhuhai.
Design/methodology/approach
The copper exposed at the substation of Guangdong coastal region in southern China for up to 12 months. The rust layer formed on the copper has been examined by scanning electron microscopy, X-ray energy spectrum, X-ray diffraction and electrochemical polarization techniques.
Findings
The corrosion weight loss of copper at Zhanjiang exposure site is a little more serious than that at Zhuhai exposure site in every exposure period. The corrosion products of copper have different changes in color and composition at the two exposure sites. The tensile strength of copper has a slight decrease after one-year exposure.
Originality/value
The atmospheric exposure experiments of copper in the substations of Zhanjiang and Zhuhai have been adopted for the first time. The corrosion behavior of copper was investigated, and it can provide reference for material selection of the substation.
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Zaki Ahmad, I.M. Allam and B.J. Abdul Aleem
The eastern coast of Saudi Arabia has one of the most corrosive environments in the world. Dhahran is therefore an ideal location for the study of atmospheric corrosion. One out…
Abstract
The eastern coast of Saudi Arabia has one of the most corrosive environments in the world. Dhahran is therefore an ideal location for the study of atmospheric corrosion. One out of every seven cars in the region is corroded. The atmosphere is contaminated by SO2 and a high concentration of suspended particulate matter (SPM) containing sand, salt and carbon particles, exceeding the World Health Organization (WHO) and Middle East Environmental Protection Agency (MEPA) limits most of the time. Corrosion proceeds in the Dhahran atmosphere at a R.H. as low as 40 per cent. At locations close to the sea (1.5 Km), β‐FeOOH is the major corrosion product and α‐ and γ‐FeOOH with some aluminates, silicates and hydrocarbons the minor products. At a location remote from the sea α‐ and γ‐FeOOH are found to be the major corrosion products as shown by XRD and FTIR spectroscopy. The concentration of hydrogen ions, chloride ions and SO2 appears to control the corrosion process during the initial exposure period up to one year and the adsorption of anions on the corrosion product films in the later period.
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Xianlong Cao, Hongda Deng, Wei Lan and Pengjun Cao
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…
Abstract
Purpose
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).
Design/methodology/approach
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.
Findings
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.
Originality/value
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.
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Qingqing Song, Xudong Wang, Boyang Pan and Lei Wan
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…
Abstract
Purpose
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.
Design/methodology/approach
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.
Findings
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.
Originality/value
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.
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L. Maldonado, M.A. Pech‐Canul and Safaa Alhassan
Reinforcing steel bars in concrete structures exposed to tropical marine atmospheres experience very high corrosion rates due to several environmental factors. The aim of this…
Abstract
Purpose
Reinforcing steel bars in concrete structures exposed to tropical marine atmospheres experience very high corrosion rates due to several environmental factors. The aim of this research was mainly to elucidate if zinc‐coated rebars may delay the onset of corrosion and/or extend the service life of infrastructure in the tropics, as the approach is promising in other atmospheres.
Design/methodology/approach
Hot‐dip zinc‐coated and plain steel rebars were embedded in concrete cylinders made with local aggregates and having four different water‐to‐cement ratios. Samples were exposed during 24 months at the marine breeze in a coastal site in the Gulf of Mexico. The corrosion behaviour of zinc‐coated and uncoated rebars was monitored by means of corrosion potential and linear polarization resistance techniques. Also, carbonation penetration and the chloride ingress were measured and correlated with the corrosion behaviour.
Findings
Only under the worst case conditions (concrete with 0.7 w/c ratio) did galvanized steel experience corrosion initiation. It was shown to resist higher chloride levels than uncoated steel and extended the onset of corrosion.
Originality/Value
The effectiveness of the zinc‐coated bar for corrosion control is controversial and its use mainly is supported by accelerated tests or application in cold or subtropical environments. This research showed the corrosion behaviour in an extremely corrosive tropical zone.
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Chunhui Kang, Decheng Kong, JiZheng Yao, Chunyun Guo, Li Wang, K. Xiao and C.F. Dong
This paper aims to investigate the corrosion behavior of zinc in a typical hot and dry atmosphere. It proposes the dynamic corrosion for different exposure periods. Results can…
Abstract
Purpose
This paper aims to investigate the corrosion behavior of zinc in a typical hot and dry atmosphere. It proposes the dynamic corrosion for different exposure periods. Results can provide the basic data and corrosion mechanism of zinc in such environment.
Design/methodology/approach
In this paper, the authors investigated the corrosion behavior of pure zinc exposed in the typical hot and dry environment in Turpan for one-four years, which has never been studied. Scanning electron microscopy, laser scanning confocal microscopy, electron probe micro-analyzer (EPMA), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were conducted to measure the corrosion morphology and products of zinc. Finally, combining electrochemical impedance spectroscopy and scanning Kelvin probe techniques, the corrosion mechanism of zinc in Turpan was examined.
Findings
The thickness loss of the zinc followed an exponential law with respect to exposure time: D = 3.17 t0.61, and both of the rust layer resistance and the charge transfer resistance increased with exposure time. The corrosion products mainly comprised ZnO, Zn(OH)2, Zn5(CO3)2(OH)6, Zn4SO4(OH)6·5H2O and Zn12(SO4)3Cl3(OH)15·5H2O. The Kelvin potentials shifted toward the positive direction from −0.380 to −0.262 V (vs saturated calomel electrode [SCE]) when the exposure time extended from one to four years and the distribution of the corrosion products became more and more uniform.
Originality/value
The corrosion behavior of pure zinc in the typical hot and dry environment in Turpan has not been studied. The dynamic corrosion for different exposure periods was obtained. The corrosion products were systemically investigated via energy-dispersive X-ray spectroscopy, EPMA, XPS and XRD.
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