scholarly journals Pitting Corrosion Behavior and Surface Microstructure of Copper Strips When Rolled with Oil-in-Water Emulsions

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7911
Author(s):  
Xudong Yan ◽  
Jianlin Sun

Copper strips experience severe corrosion when rolled with an oil-in-water (O/W) emulsions lubricant. The effects of rolling reduction on the pitting corrosion behavior and surface microstructure of Cu strips were studied in detail using electrochemical measurements and electron back scattered diffraction (EBSD) analysis. It was found that the corrosion current densities of the rolled Cu strips increased with accumulated reduction, which also lowered the pitting potentials and weakened their corrosion resistances. Therefore, the corrosive tendency of Cu strips under different rolling reductions (ε) followed the order of ε0% < ε20.7% < ε50.6% < ε77.3%. The Cu surface easily reacted with chlorine, sulfur, and carbon components from O/W emulsions to generate pitting corrosion. Under the interactive effect of pitting corrosion and stress corrosion, pits expanded along the rolling direction. The aggregation of anions in surface defects, such as dislocations, metastable pits, and microcracks, further accelerated the pitting corrosion of the surface.

2011 ◽  
Vol 299-300 ◽  
pp. 427-431
Author(s):  
Yun Li ◽  
Shi Zhi Shang ◽  
Ming Cheng ◽  
Liang Xu ◽  
Shi Hong Zhang

The corrosion behavior of Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy in 3.5% NaCl solution was investigated by using potentiodynamic polarization experiments and electrochemical impedance spectroscopy (EIS). The results show that Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy has the better corrosion resistance than its corresponding crystal alloy. During the bath in the 3.5% NaCl solution at 25°C, Zr53.5Cu26.5Ni5Al12Ag3 alloy has the lower corrosion current density than the corresponding crystal alloy. After 100h, the corrosion current densities of Zr53.5Cu26.5Ni5Al12Ag3 and the corresponding crystal alloy are 3.8415×10-8A/cm2 and 5.2827×10-7A/cm2, respectively. The results of EIS test indicate that Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy has the excellent corrosion resistance because passive film with stable structure formed on the surface in 3.5% NaCl solution. With an increase in the immersion time, the passive film becomes thicker. It leads to impedance resistance and corrosion resistance decrease. The surface of Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy in 3.5% NaCl solution for 100h was analyzed by SEM and EDS. The results show that the corrosive pitting can be found at both the amorphous alloy and the corresponding crystal alloy. However, the amorphous alloy has the better corrosive pitting resistance than the crystal one because the corrosion products formed by selective dissolving of Zr and Al elements. Moreover, the addition of Ag element helps to improve the corrosion resistance of the amorphous alloy greatly.


2020 ◽  
Vol 993 ◽  
pp. 747-755
Author(s):  
Bing Hui Ren ◽  
Kang Wang ◽  
Ran Wang ◽  
Jin Feng Leng

The influence of various retrogression and re-ageing (RRA) treatment processes on the hardness, electrical conductivity and corrosion behavior of graphene/7075 aluminum matrix composite were investigated. The results showed that the hardness decreased swiftly at the initial stage and short time to peak value as the retrogression temperature (170 °C, 180 °C, 190 °C, 200 °C) rises. In the RRA 180 °C/120 min process, the electrical conductivity and peak-aging Brinell hardness were 37.9%IACS, 192.8. This RRA treatment possessed excellent pitting corrosion resistance, and the corresponding pitting potential (Epit), the passivation potential (Epit-Ecorr), the pitting corrosion current density (Logicorr) were -0.756V, 0.558V, -1.836A/cm2, respectively. This enhance can attribute that the continuous η phase distributed along the grain boundary became intermittent and coarse in the retrogression stage.


2017 ◽  
Vol 35 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Kenneth Kanayo Alaneme ◽  
Eloho Anita Okotete ◽  
Michael Oluwatosin Bodunrin

AbstractThe corrosion behavior of Cu-Zn-Al alloys modified with Fe, B, and Fe-B was investigated. This was motivated by the need to verify the effect of microalloy additions on the corrosion behavior of Cu-Zn-Al alloys, which, as recent study suggests, impacts microstructural changes other than grain refinement. Cu-Zn-Al alloys were produced by casting method with and without the addition of microalloy elements. The alloys were subjected to thermomechanical treatment before machining of test samples for corrosion and microstructural analysis. Scanning electron microscopy (SEM) and polarization electrochemical technique were used for the study. From the results, increase in grain size and change in grain edge morphology was apparent for the modified Cu-Zn-Al alloys produced. In 3.5 wt.% NaCl and 0.3 m H2SO4 solutions, the corrosion current densities were dependent on the type and concentration of the microalloy addition. Essentially, the corrosion rates for the modified alloys were higher in 3.5 wt.% NaCl solution; in 0.3 m H2SO4 solution, the modified Cu-Zn-Al alloy grades were observed to be more resistant to corrosion. The corrosion mechanisms of the alloys in both solutions were not feasibly established from the SEM images, but the extent of corrosion product deposition was apparent.


2015 ◽  
Vol 817 ◽  
pp. 225-230
Author(s):  
Yan Li ◽  
Jian Lin Sun ◽  
Jing Yue Chen ◽  
Hao Shi

The silicon steel was cold rolled by using an oil-in-water emulsion for lubricating its surfaces. Oil in water (O/W) emulsion is a lubricant composed of oil in the form of droplets suspended in water. This paper mainly researched on the new emulsion which was prepared by changing the compound proportion between antioxidant 2, 6-Di-tert-butyl-p-cresol (T501) and antirust agent petroleum sodium sulfonate (T702). The corrosion behavior of the emulsion was investigated by weight loss and electrochemical methods. The mechanisms for inhibition of corrosion synergism between T501 and T702 in base oil were studied. The results show that the antirust agent (T702) can effectively forming a layer of adsorption film on the rolled strip surface and this adsorption film can segregate strip surface from air and water. The antioxidant (T501) can capture oxygenic free radical (•OH, RO•, ROO•) and carbon free radical and reduces the trend which emulsion occur oxidation reaction under high temperature and high pressure. The antioxidant plays a minor role in inhibition of corrosion synergism. The results show that the best compound proportion content is 4% antioxidant (T501) and 8% antirust agent (T702), which can effectively increase the anticorrosion effect of emulsion. Meanwhile, the self-corrosion potential and self-corrosion current of the sample is minimal and the self-corrosion current is 1.0226×10-7A/cm2.


2015 ◽  
Vol 29 (10n11) ◽  
pp. 1540025 ◽  
Author(s):  
Xiaomin Wang ◽  
Xiaoyao Liao ◽  
Chuanping Ma ◽  
Shufang Zhang ◽  
Yan Liu ◽  
...  

Corrosion behavior of 7N01 Al alloy is sensitive to chemical composition. In this paper, stress corrosion cracking (SCC) and electrochemical behaviors of A7N01S-T5 Al alloys with three different chemical compositions were investigated. The corrosion weight loss and corrosion pits depth statistics showed that Alloy #3 (4.53 wt .% Zn , 1.27% Mg , < 0.001% Cu , 0.24% Cr , 0.15% Zr ) possesses the best anti-SCC property, while Alloy #1 (4.54% Zn , 1.09% Mg , 0.102% Cu , 0.25% Cr , 0.15% Zr ) was the weakest one. The different SCC susceptibility was mainly related to the Cu content as Alloy #3 contains higher Cu than Alloys #1 and #2. Electrochemical test result showed that Alloy #3 has higher corrosion potential and lower corrosion current density than Alloys #1 and #2. It is believed that a trace Cu can significantly improve the SC resistance of Al alloy, mainly because that Cu element can reduce the potential difference between grain inside and grain boundaries.


2011 ◽  
Vol 65 (1) ◽  
pp. 15-21
Author(s):  
Ali Elkais ◽  
Milica Gvozdenovic ◽  
Branimir Jugovic ◽  
Tomislav Trisovic ◽  
Miodrag Maksimovic ◽  
...  

The electrochemical synthesis of polyaniline (PANI) on mild steel, aluminum and copper from the sodium benzoate solutions has been investigated. It has been shown that thin, highly adherent, polyaniline films on the investigated metals could be obtained by anodic oxidation with current densities in the range of 0.5 and 1.5 mA cm-2. The corrosion behavior of mild steel, aluminum and copper with polyaniline coating in 0.5 mol dm3 NaCl (pH 3) solutions, has been investigated by polarization technique. The corrosion current densities, porosity and protection efficiency was determined. It has been shown that polyaniline coating provided corrosion protection of all mentioned metals.


2013 ◽  
Vol 643 ◽  
pp. 33-36
Author(s):  
Wei Ke An ◽  
An Hui Cai ◽  
Guo Jun Zhou ◽  
Yun Luo ◽  
Tie Lin Li ◽  
...  

The corrosion behavior of Cu50Zr40Ti10 (at. %) in HCl and NaCl solutions was investigated. The corrosion current densities icorr in HCl and NaCl solutions increase with increasing Clconcentration when the Cl- concentration is <0.5 molL-1, then continuously increase in the former and decrease in the latter. The icorr is larger in the latter than in the former when the Clconcentration is <0.5 molL-1, while inversely for in 1 molL-1 Cl- solution. The corrosion potential Ecorr decreases with increasing Cl- concentration in HCl. However, the change of the Ecorr vs. the chloride ion concentration in NaCl solution appears down-up-down.


Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1283
Author(s):  
Jingjiu Yuan ◽  
Chaoyi Chen ◽  
Junqi Li ◽  
Bianli Quan ◽  
Yuanpei Lan ◽  
...  

When alumina is produced by the Bayer process with high-sulfur bauxite, the sulfur would strongly corrode the 12Cr1MoV steel made heat exchanger. This study investigated the initial corrosion behavior of the 12Cr1MoV steel exposed to a thiosulfate-containing sodium aluminate (TCSA) solution under the evaporation conditions of alumina production. The obtained corrosion rate equation is V = 6.306·t·exp(−0.71). As corrosion progressed, with the corrosion product film growing, the corrosion current density declines slowly, and the corrosion resistance of the steel is increased. At 1–3 days, the corrosion product film consisted of FeO, Fe2O3, and FeOOH. S2O32− lead to corrosion in local areas of the steel and pits appeared. AlO2− is transformed into Al(OH)3 and filled in the corrosion pits. At 4 and 5 days, Fe3O4 is generated in the outermost layer, and Al(OH)3 is shed from the corrosion pits. The corrosion mechanism of 12Cr1MoV steel in a TCSA solution is proposed based on the experimental results.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Weili Yu ◽  
Changhai Du ◽  
Hongren Shen ◽  
Hao He ◽  
Yong Yu ◽  
...  

Herein, powder metallurgy gas-solid nitriding was used to prepare a high-nitrogen Ni-free austenitic stainless steel with more than 1.0 wt.% N. Study of the microstructures and corrosion resistances of the as-prepared samples revealed that the corrosion weight loss, size, number of corrosion pits, and corrosion depth decreased as the N content increased from 1.19 to 1.37 wt.%. The self-corrosion current densities of the alloys were determined from their potentiodynamic polarization curves. The changes in the capacitive arc radius as demonstrated by the Nyquist curves were consistent with the conclusions of the immersion corrosion analysis; that is, a high N content leads to a high corrosion resistance.


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