Corrosion Behavior Of Cu Research Articles

Effect of Nd addition on the microstructure, mechanical properties, shape memory effect and corrosion behaviour of Cu–Al–Ni high-temperature shape memory alloys

The effects of rare earth element Nd on the microstructure, mechanical, shape memory properties and corrosion behaviour of Cu-13.0Al-4.0Ni-xNd (wt.%) high-temperature shape memory alloys were investigated in this paper. It was observed that the grains in Cu-13.0Al-4.0Ni-xNd alloys can be refined by adding Nd, and the grain size decreased from the millimeter scale to several hundred microns. The matrix of the Cu-13.0Al-4.0Ni-xNd alloys, composed of 18R and 2H martensite, was not changed by Nd doping. However, the hexagonal (Al,Ni)Cu4Nd phase was formed as the Nd content increased. The grain refinement led to an improvement in the mechanical properties of the Cu-13.0Al-4.0Ni-xNd alloys. When x = 0.5, the compressive fracture stress and strain increased from 580 MPa to 10.5% to 940 MPa and 18.3%, respectively. The Nd addition also enhanced the shape memory effect of the Cu-13.0Al-4.0Ni-xNd alloys, and a reversible strain of 6.8% was obtained for x = 0.2 under a prestrain of 10% after heating. In addition, the results of electrochemical impedance measurement and polarization measurement showed that the corrosion resistance of Cu–Al–Ni alloy were slightly reduced by Nd addition, and the corrosion behaviour of Cu–Al–Ni alloy was mainly controlled by Cu element.

Investigation of photo-induced corrosion of copper in aqueous solution based on point defect model

The corrosion behaviors of Cu in a chloride-containing borate buffer solution (pH 8.4) with and without visible light illumination were investigated in the present work. Visible light illumination was shown to induce distinct corrosion behaviors during different stages of exposure. In the early stage, visible light illumination facilitated the growth of a less defective Cu2O film which offered higher resistance to corrosion. Whereas in the longer-term visible light illumination was found to destabilize the Cu2O film and hence accelerated the Cu dissolution. The corrosion mechanisms corresponding to the corrosion behaviors during different stages of exposure were discussed based on the point defect model (PDM).

Study of Corrosion Mechanism in Brazed Cu Joints

The mechanism behind corrosion of Cu and Cu alloys has been the subject of extensive studies within their applications in various engineering components. These studies explore the electrochemical mechanisms along with the contributing factors impacting the corrosion behaviors such as pH, temperature, and solution chemistry. Thanks to these studies, the corrosion behavior of Cu and Cu alloys is reasonably well understood to a degree to predict their reliability under conditions that have been a concern of related industries. However, it is noted that studies are very limited to the impact of a microscopic structure that forms a galvanic pair with Cu and Cu alloys. One of the most obvious but least studied examples of such a case is the corrosion located in the joint that is created by brazing material. The Cu or Cu alloy components with a brazed joint is commonly found in water handling devices and facilities (such as a heat exchanger). Since the filler material used for the brazing of Cu and Cu alloys contains a substantial number of elements other than Cu the joint changes chemically and microstructurally different. It then becomes a source of a galvanic couple. In this case, the most corrosion prone part is the area near or at the joint as the corrosion is accelerated by the galvanic potential. While such joints are abundantly placed in various engineering components (and therefore the concern for corrosion should be focused more on those parts), studies on the corrosion mechanism with the brazing joint are extremely limited. This is probably due to sufficient material redundancy in the joint and thus causing immunity to failure by corrosion. However, a recent development of an advanced cooling system, where heat from electronic devices such as a microcontroller is removed by the use of recirculating coolant, the redundancy is no longer valid and the corrosion at the brazed joint becomes a matter of critical and practical concern.Motivated by the growing need to better understand the corrosion mechanism active in advanced cooling system, we have investigated the nature of corrosion in Cu plate with a variation in filler materials (Cu-Ag eutectic alloy, Cu-Ag-P alloys), liquid type (water, water mixed with PG), and temperatures. One of the most challenging part of our investigation is the fact that there are multiple sources of galvanic potential due to the existence of multiple phases in the sample. For example, when a Cu-Ag-P alloy was chosen as a filler material, the joint contained three phases, Cu-rich, Ag-rich and Cu3P intermetallic phases. An example of such a microstructure is shown in Fig.1, where an SEM micrograph of the joint is displayed. In this case, the galvanic potential exists not only between the filler materials as a whole and the surrounding Cu, but also among these three phases. In order to overcome the difficulty of studying corrosion behaviors in such a structure, we adapted two different experimental approaches. The first is to measure the corrosion current under the configuration of ZRA (zero-resistance-analysis). The ZRA uses the Cu and the joint as the counter/working electrode as shown in Fig.2 and measures the galvanic potential and current across the joint. The second is to make a mini-galvanic cell consisting of a pure Cu plate and a Cu plate with the brazed part. Spaced by an O-ring, these two plates are forced to make a galvanic cell with a liquid filled the gap and an external short circuit. We were able to measure the resulting corrosion current, direction and the amount of which can be related to the galvanic corrosion created by the braze.This study presents some of our highlighting findings suggesting that the galvanic corrosion can be better characterized by the use of techniques employed in our study. An example of such evidence can be found in Fig.3 where the ZRA scan signal (voltage and current) in 1M KCl solution is shown with the filler area as the working and surrounding Cu as the counter electrode. Note the instability in the galvanic potential with time, which is attributable to the lack of sustainable passivation layer on top of Cu3P and is responsible for the complex corrosion response of the brazed part to the solution chemistry. A detailed description of such findings along with theoretical explanation will be provide in this paper. Figure 1

Influences of heat treatment on the oxidation and corrosion behavior of Cu–Ni–Fe inert anodes for aluminium electrolysis

Abstract The homogenization heat-treatments were implemented to the experimental as-cast Cux(Ni1.67Fe)100-x alloys with x = 60,52,44 wt%, which have a two-phase structure to obtain a uniform microstructure. Moreover, the oxidation kinetics of the as-cast and as-homogenized Cux(Ni1.67Fe)100-x alloys were investigated by the thermogravimetry at 850 °C under 1atm O2 atmosphere. The thermogravimetry results showed that all the samples approximately follow the parabolic law during oxidation under this condition. The homogeneous alloys have the lower oxidation rate than the as-cast alloys due to the inhibition of outward diffusion of Cu. Furthermore, the as-cast and as-homogenized 52Cu–30Ni–18Fe alloys were tested as inert anode materials in laboratory aluminium electrolysis tests. The as-homogenized 52Cu–30Ni–18Fe alloy anode performs significantly better corrosion resistance due to the formation of NiFe2O4. In the end, there is less impurity contents of Cu in the produced aluminium after electrolysis using the as-homogenized 52Cu–30Ni–18Fe alloy anode than using the as-cast 52Cu–30Ni–18Fe anode.

The Influence of Alloying Elements (Al, Ni and Zn) on the Corrosion Resistance of Some Cu-Ternary Alloys in Na2SO4 Solutions

In this research, the corrosion behavior of Cu–10Al–10Zn, Cu–10Al–10Ni and Cu–10Ni–10Zn alloys was investigated in sulfate solutions. The effects of alloying elements, immersion time, and sulfate ions concentration were also studied. Different electrochemical methods such as open-circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy (EIS) were used. Polarization measurements reveal that Cu–10Al–10Ni alloy possess lower corrosion rate than both Cu–10Al–10Zn and Cu–10Ni–10Zn alloys in this solution. The EIS measurements have shown that a more thicker and resistant passive layer is formed on the Cu–10Al–10Ni alloy surface. Also, the corrosion current density (icorr) decreases with increasing $$ {\text{SO}}_{4}^{ - } $$ ion concentration especially at concentration higher than 0.1 M Na2SO4 solution. The surface analysis (SEM/EDX) has shown the participation of the different alloying elements in the protection according to the alloy constituents. It turned out that presence of Al and Ni increase the corrosion resistance. For industrial applications, the results lead to the recommendation of the Cu–10Al–10Ni alloy for applications in the production of Na2SO4. The stability of the Cu-ternary alloys in SO42− solutions depends on the presence of the alloying elements Al, Ni and Zn.

Corrosion behavior of Cu–Sn bronze alloys in simulated archeological soil media

AbstractThe corrosion behavior of synthetic Cu–Sn bronze alloys with six different Sn contents was examined through an electrochemical test and a synthetic test in a simulated corrosive medium. The mechanism of corrosion and the morphology of the corroded surfaces were characterized through field emission scanning electron microscopy equipped with energy‐dispersive spectroscopy. At the corrosion potential, the corrosion behavior appears to be determined by the charge transfer step and the diffusion process. It was found that the bronze‐IV (Cu–26.8Sn) specimen exhibited the best corrosion resistance, as evidenced by a low corrosion current density and a high impedance. This improvement resulted from an increase in the content of the Cu–Sn solid solution in the alloy, which was conducive to forming a relatively more protective passive film on the surface of the bronze alloy. This finding would be valuable in the anticorrosion protection of archeological artefacts after their excavation.

Influence of chloride ion concentration and temperature on the corrosion of Cu–Al composite plates in salt fog

In this work, the effects of temperature and chloride ion concentration were evaluated for the corrosion behavior of Cu–Al composite plates exposed to salt spray. There were three diffusion layers at the interface between Cu and Al, which were Al4Cu9, AlCu and Al2Cu, respectively. Corrosion only appeared on the diffusion layers and the aluminum, amongst which Al2Cu was the most vulnerable to corrosion, AlCu and Al were the second most vulnerable while the corrosion resistance of Al4Cu9 was second to the Cu. When the concentration of NaCl was lower than 3 wt%, the increased concentration had an obvious effect on the mass loss of the corrosion for the Cu–Al composite plates. The kinetic constant of corrosion increased with the increasing NaCl concentration. When the concentration of NaCl increased from 1 wt% to 3 wt%, the kinetic constant of corrosion increased by 31 times. With the concentration of NaCl increasing to 5 wt%, the kinetic constant of corrosion was 4.6 times that of 3 wt% by weight. In addition, the kinetic constant of corrosion was affected by temperature. With an increase of temperature, the kinetic constant of corrosion initially increased, and then decreased. The kinetic constant of corrosion reached its maximum value at 45 °C. Finally, the results of electrochemical testing showed that an increase of the chloride ion concentration (CIC) accelerated the corrosion of Cu–Al composite plates, and the corrosion attack was the worst under 45 °C.

Mechanical and corrosion behavior of Cu, Cr, Ni and Zn electroplating on corten A588 steel for scope for betterment in ambient construction applications

In this study, copper (Cu), chromium (Cr), nickel (Ni), and zinc (Zn) are deposited onto corten A588 grade steel by electroplating technique. After depositing the coating, microstructure, micro-hardness and surface morphology are studied. This is done through X-ray diffraction (XRD), Vickers hardness and field emission scanning and electron microscopy (FESEM) respectively. The XRD and EDS reveals the presence of Cu, Cr, Ni and Zn elements in the respective coatings and the highest micro hardness of 1918.1HVN is observed in Cr coated corten A588 substrate. Electrochemical impedance spectroscopy (EIS) is studied to find the corrosion behavior of coated and uncoated samples. EIS studies shows that chromium electroplated steel exhibit superior corrosion resistance (Ecorr – 1.742 V; Icorr – 0.334 mA) properties rather than Cu, Ni, Zn coatings and uncoated corten A588 substrate. The weight loss analysis is also performed on coated and uncoated samples with 3.5% NaCl for a week and the results exhibit minimum weight loss in Cr coated corten A588 samples. Hence, the study reveals that the Cu, Cr, Ni and Zn coated corten A588 samples is the suitable candidature for construction applications.

Surface analysis of Cu coated with ALD Al2O3 and its corrosion protection enhancement in NaCl solution: EIS and polarization

Al2O3 was coated on copper substrates with a thickness of 62 nm at 473 K temperature using atomic layer deposition method. The morphology of the produced samples was obtained by scanning electron microscope and atomic force microscope while the latter instrument also provided information on the surface roughness and grain sizes formed on the surface of the samples. Energy dispersive spectroscopy was employed for obtaining abundances of different elements in the samples before and after corrosion tests. Corrosion behavior of Cu and Al2O3/Cu was investigated by means of electrochemical polarization and electrochemical impedance spectroscopy analyses in 3.5% (0.6 M) NaCl solution. The validity of the data obtained from the latter method is investigated by Kramers-Kronig transformations. Also simulation of this data by equivalent electrical circuits resulted in a corrosion inhibition enhancement factor of η = 97.48% which indicates high improvement in corrosion resistance of Cu by Al2O3 coating. Corrosion parameters were also obtained from the polarization curves by fitting the experimental results with Stern-Geary relation near the open circuit potential. Negative shift of corrosion potential for the Al2O3 coated Cu relative to uncoated Cu indicates that Al2O3 coating is blocking the cathodic reaction. Corrosion inhibition efficiency/yield (PE%) obtained from anodic and cathodic branches of polarization curves showed high enhancement with values of 69% and 93%, respectively while the latter is consistent with the corrosion inhibition enhancement factor of η = 97.48% mentioned above. Results are compared with the published data and good agreements are obtained, deviation of those results from the rest is discussed considering all parameters involved in the ALD deposition.

The Synergetic Effect of Flow Velocity and Exposing Time on the Electrochemical Behavior of Cu–Ni 90/10 Alloy in Simulating Conditions of Desalination Plant

A laboratory investigation has been achieved to study the effect of flow velocity on the corrosion behaviour of Cu–Ni 90/10 alloy immersed in synthetic seawater, at 60 °C which simulates the real condition of desalination industry in the south of Tunisia. Flow velocity was one of major parameters influencing the oxidation process of cupronickel pipe, through its effect on mass transport and corrosion rate. This influence has been examined on a laboratory scale by means of electrochemical techniques like: Potentio-dynamic polarization, electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR). Results show that the flow velocity has a significant influence on corrosion rate, compared to static immersion. This effect was confirmed by means of corrosion current density (icorr) increase and polarization resistance Rp decrease with exposure time, as indicated by LPR and EIS measurements. Corrosion was attributed to the film deterioration by the erosion corrosion phenomena, caused essentially by hydrodynamic conditions. Indeed, at stagnant condition, the substrate proves a higher corrosion resistance due to the stability of the protective layer.

Influence of electric current on the corrosion behavior of Cu for the electric contact in the isolation switch

AbstractThe flow of electric current through the conductor has a far‐reaching effect on its corrosion behavior. In this paper, the effect of current on the corrosion behavior of Cu is investigated. The accelerated corrosion test of Cu with various external currents from 1 A to 5 A are carried out in 5% NaCl neutral salt spray environment. The results show that the samples with external current exhibit a faster corrosion rate than those without current. The corrosion kinetics and underlying mechanism are also discussed in this paper.

Corrosion Behavior of Cu–Al–Ni–xCo Shape Memory Alloys Coupled with Low-Carbon Steel for Civil Engineering Applications

Due to the promising mechanical properties of Cu-based shape memory alloys (SMAs), their applications have become essential in many applications. In the present study, the galvanic behaviors of coupled and uncoupled steel bars with Cu–Al–Ni–xCo shape memory alloys were investigated in 3.5% NaCl solution. Thirteen measurement cells were considered for coupled and uncoupled steels and aged/unaged Cu–Al–Ni–xCo shape memory alloys. The electrochemical measurements were carried out three times to ensure the consistency of the corrosion behavior after the samples were immersed in 3.5% NaCl solution. The results revealed that the addition of 1 wt% Cobalt followed by an aging treatment led to an improvement in the corrosion resistance of coupled steel/Cu–Al–Ni–xCo shape memory alloys and a reduction in the corrosion rate by 50% for the steel bars.

Investigation on corrosion behavior of Cu–TiO2 nanocomposite synthesized by the use of SHS method

Enhancing the copper-based composites with oxide nanoparticles attracts more attention and many routes are proposed. In this investigation, stoichiometric Cu–TiO2 nanocomposite is synthesized through the self-propagating high-temperature synthesis, and the effect of additional Cu contents of 10, 20, 30wt% on mechanical and physical features of this composite was evaluated. To investigate the obtained properties of specimens, scanning electron microscopy, X-ray diffractometry (XRD), micro-hardness, electrochemical impedance spectrometry and polarization tests were carried out. XRD results show that the metastable phase is formed within the synthesis. With increasing the Cu content, the amount of this phase is reduced. The maximum obtained Vickers micro-hardness is 369HV for the sample, which contents 20wt% Cu. Results show that the optimum excess copper content is 20wt%. Also, EIS results show that an interaction between CuxO–TiO2 is decisive in the corrosion behavior of samples.

Detection of metal corrosion characteristics in chlorine solution using solid state nanopore

Nanopore structures were originally proposed for detection of biomolecule translocation through nanometer-scale pores that perforate membranes by transient changes in ionic current. In this study, these changes are utilized to detect corrosion of different metals in aqueous chlorine media. The corrosion behaviors of Cu, Al, Ti, and Cr were analyzed by monitoring the changes in ion current resulting from ion concentration variations in solutions due to corrosion of the metals. We observed that the Cu layer passivated by CuOx was severely corroded when a drastic change of ion current was induced, from 10 to 30 nS to the level of 104 nS, as soon as the bias voltage was applied. In the case of Al passivated by thin AlOx, the conductance increased from 10–30 to 166 ± 52 nS and became saturated. Highly localized pitting corrosion was observed on the periphery of the nanopore, where the electrical field was most concentrated. Finally, we observed that Ti and Cr passivated by oxide showed long-term stability without corrosion in 1 M KCl in the pH range of 4–11.

Compression and corrosion behaviour of sintered copper-fly ash composite material

An attempt has been made to reinforce Copper (Cu) with low density material Fly Ash (FA) to form Cu–FA composite material through Powder Metallurgy (P/M) route. Samples of 3, 6 and 9 weight percentage of FA in Cu matrix were prepared. Scanning electron microscopy analysis was used to study the morphology of the composite materials. The x-ray diffraction analysis was used to characterize the elemental composition of composite powder. Energy-dispersive spectroscopy (EDS) mapping was used to find the homogeneous distribution of FA in Cu matrix. Mechanical behavior of the Cu–FA composite material was studied using Vickers hardness and compression test. The mechanism model for decrease in compressive strength of Cu–FA composite material was identified as boundary slip. The corrosion behavior of Cu–FA composite material in acidic (1N HCl) and in sea water media are studied. Electrochemical polarization test was used to carry out the corrosion studies on Cu–FA composite material in acidic media. The increase in Polarization Resistance (Rp = 68.6499 × 10−4 Ω cm2 in acidic media and Rp = 68.75327 10−4 Ω cm2 in sea water) of Cu-9FA evidences that increase in weight percentage reinforcement of FA in Cu matrix decreases the corrosion rate in both acidic and sea water media. The increase in charge transfer resistance (Rct = 1142 Ω cm2) of Electrochemical Impedance Spectroscopy (EIS) test authenticates that the corrosion resistance of Cu-9FA is healthier than pure Cu. It was observed that improved corrosion resistance and good mechanical properties are obtained for 9% FA reinforced Cu composite material.

Corrosion Inhibition from Thiol Self-assembly Layer: A High Pressure Perspective

Taking dodecanethiol as the representative, we investigated the corrosion inhibition performance of SAL in seawater under pressures from 0.1 to 9 MPa. By using scanning Kelvin probe, the dodecanethiol SAL is confirmed to build on Cu surface, and the modification of SAL has positively shifted the surface potential to realize the inertness. Electrochemical techniques, such as electrochemical impedance spectroscopy and potentiodynamic polarization were used to reveal the corrosion behavior of Cu modified by SAL under the different pressure, i e, 0.1, 3, 6, and 9 MPa. It is indicated that the longer modification time affords better corrosion resistance to Cu. Higher static pressure is easier to deteriorate the corrosion inhibition capability due to the penetration effect. A plausible mechanism is proposed to illustrate the degradation process of SAL in the high pressure seawater environment.

Corrosion characteristics of copper in static liquid lithium under high vacuum

Copper (Cu) materials are extensively used as heat sinks and sealing gaskets in fusion devices because they have the properties of good thermal and electrical conductivity and high plasticity. Meanwhile, liquid lithium (Li) is considered as a potential blanket coolant and tritium breeder and/or plasma facing material in fusion devices. Studying the corrosion characteristics of Cu materials by liquid Li under extreme fusion conditions is important because the corrosion of Cu by liquid Li may affect simultaneous application of these materials in fusion devices. The corrosion behavior of Cu in static liquid Li at 620 K for 15 h under high vacuum was investigated. After exposure to liquid Li, the weight loss rate of Cu in liquid Li is 466.1 g m−2 h−1, which is equivalent to 458.7 mm⋅a−1 for the average corrosion depth rate. The entire surface of each specimen was seriously damaged. Visible grain boundary corrosion was observed on the surface of the specimens. Also, Cu debris entered the liquid Li from the corroded surface, resulting in considerable Cu loss from the specimen. These results demonstrate a corrosion protection grade of Cu in liquid Li of 10, Cu cannot withstand the corrosion of liquid Li under the given conditions. Additionally, the corrosion process of Cu in liquid Li at 620 K under high vacuum was studied using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). The results from these simulations indicate that the corrosion of Cu in liquid Li is induced via physical dissolution and intergranular corrosion, where intergranular corrosion is the dominant mechanism.

Effect of Sulfate Reducing Bacteria on Corrosion Behavior of Cu in Circulation Cooling Water System

Effect of Sulfate Reducing Bacteria on Corrosion Behavior of Cu in Circulation Cooling Water System

Galvanic corrosion behaviors of Cu connected to Au on a printed circuit board in ammonia solution

During etching treatments of printed circuit board (PCB) with ammnioa solution, galvanic corrosion occurs between electrically connected gold and copper, and resulting in unexpected over-etching problems. Herein, we determine corrosion of galvanic coupled Cu to Au quantitatively in ammonia solutions, and evaluate factors influencing corrosion of galvanic coupled Cu to Au (i.e., area ratio of anode to cathode and stirring speed). The difference of the corrosion rate (Δi = icouple, (Cu-Au)–icorr, Cu) of Cu connected to Au (117 μA/cm2) and of single Cu (86 μA/cm2) infers the amount of over-etching of Cu resulting from galvanic corrosion in ammonia solution (Δi = 0.31 μA/cm2). As the stirring speed increases from 0 to 400 rpm, the corrosion rate of galvanic coupled Cu to Au increases from 36 to 191 μA/cm2. Furthermore, we confirm that an increase in the area ratio (Au/Cu) from 0.5 to 25 results in a higher rate of corrosion of Cu connected to Au. The corrosion rate of galvanic coupled Cu to Au is approximately 20 times higher when the area ratio of Au to Cu is 25 (1360 μA/cm2) than when the ratio is 0.5 (67 μA/cm2).

Visualizing Nanoscale Distribution of Corrosion Cells by Open-Loop Electric Potential Microscopy.

Corrosion is a traditional problem but still one of the most serious problems in industry. To reduce the huge economic loss caused by corrosion, tremendous effort has been made to understand, predict and prevent it. Corrosion phenomena are generally explained by the formation of corrosion cells at a metal-electrolyte interface. However, experimental verification of their nanoscale distribution has been a major challenge owing to the lack of a method able to visualize the local potential distribution in an electrolytic solution. In this study, we have investigated the nanoscale corrosion behavior of Cu fine wires and a duplex stainless steel by in situ imaging of local corrosion cells by open-loop electric potential microscopy (OL-EPM). For both materials, potential images obtained by OL-EPM show nanoscale contrasts, where areas of higher and lower potential correspond to anodic areas (i.e., corrosion sites) and cathodic areas, respectively. This imaging capability allows us to investigate the real-time transition of local corrosion sites even when surface structures show little change. This is particularly useful for investigating reactions under surface oxide layers or highly corrosion-resistant materials as demonstrated here. The proposed technique should be applicable to the study of other redox reactions on a battery electrode or a catalytic material. The results presented here open up such future applications of OL-EPM in nanoscale electrochemistry.