Galvanic corrosion mechanism and suppressed solution on Al/Cu pads

2015 ◽  
Author(s):  
Andrew Chang-Yen Ko ◽  
Andy Burnett ◽  
Linker Chen ◽  
Kevin Liu
Keyword(s):  
Galvanic Corrosion ◽  
Corrosion Mechanism

scholarly journals Corrosion Behaviors of the Eutectic Structure in Zn-Al-Mg Alloy Coated Steel in Chloride Containing Aqueous Environment

2020 ◽  
Vol 58 (9) ◽  
pp. 610-616
Author(s):  
Jae-Won Lee ◽  
Se-Young Oh ◽  
Bora Park ◽  
Min-Suk Oh ◽  
Sung Jin Kim
Keyword(s):  
Coating Layer ◽  
Early Stage ◽  
Galvanic Corrosion ◽  
Salt Spray ◽  
Eutectic Structure ◽  
Mg Alloy ◽  
Aqueous Environment ◽  
Corrosion Mechanism ◽  
Coated Steel ◽  
Corrosion Behaviors

To clearly understand the effect of the eutectic structure in the Zn-Al-Mg alloy coating on the corrosion behaviors in chloride containing aqueous environments, a bulk Zn-MgZn<sub>2</sub> sample was fabricated by diffusion bonding process, and a variety of experiments, such as electrochemical polarization and galvanic corrosion measurements, salt spray tests, and cyclic corrosion tests, were carried out. This study revealed that the corrosion potential values of MgZn<sub>2</sub> and Zn samples exposed to a 5 wt.% of NaCl solution were approximately -1.5 and -1 VSCE, respectively, and the MgZn<sub>2</sub> showed a higher corrosion current density than Zn at the early stage of corrosion. The continued dissolution of MgZn<sub>2</sub> phase from the eutectic structure in the coating layer provides not only sacrificial protection, but also environmental conditions for the co-formation of two types of corrosion products (simonkoleite (Zn<sub>5</sub>(OH)<sub>8</sub>Cl<sub>2</sub>·H<sub>2</sub>O) and hydrotalcite (ZnAl<sub>2</sub>(OH)<sub>6</sub>Cl<sub>2</sub>·H<sub>2</sub>O)) which have an inhibiting effect on the outer surface. The formation areas and kinetics of the two products on the coating surface were different, and they were greatly dependent upon the types of eutectic structures in the coating layer. Based on the results, a modified anti-corrosion mechanism of Zn-Al-Mg alloy coated steel sheet in chloride containing aqueous environment was proposed.

Pitting corrosion and crevice corrosion behaviors of titanium alloy overlapped with aluminized PVC film in neutral salt spray

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Longfei Xie ◽  
Wenlong Zhou ◽  
Shiwen Zou ◽  
Xuesong Fu
Keyword(s):  
Crevice Corrosion ◽  
Graphical Model ◽  
Electrochemical Impedance ◽  
Galvanic Corrosion ◽  
Salt Spray ◽  
Corrosion Mechanism ◽  
Neutral Salt ◽  
X Ray ◽  
Pvc Film ◽  
Corrosion Behaviors

Abstract This paper presents a research on the corrosion behavior of Ti-15-3 alloy overlapped with aluminized PVC film in salt spray. It was found that severe corrosion occurred on aluminized PVC film in the coupled regions because of crevice corrosion and/or galvanic corrosion whereas Ti-15-3 alloy in the coupled regions experienced minor corrosion. Scanning electron microscope and Energy-dispersive X-ray spectroscopy analyses demonstrated the corrosion products adhered to the surface of Ti-15-3 alloy within the crevice. To evaluate the effect of aluminized PVC film on the crevice corrosion of Ti-15-3 alloy in salt spray condition, it is necessary to compare with the corrosion resistance of Ti-15-3 overlapped with polytetrafluoroethylene (PTFE) in different neutral salt spray. Further, the tests were performed by electrochemical impedance spectroscopy and potentiodynamic polarization. Combining the graphical model, an in-depth understanding of the crevice and galvanic corrosion mechanism of Ti-15-3 alloy overlapped with aluminized PVC film has been revealed.

scholarly journals Mechanism of Corrosion in Porcelain Insulators and Its Effect on the Lifetime

2020 ◽  
Vol 10 (1) ◽  
pp. 423 ◽  
Author(s):  
Taeyong Kim ◽  
Youn-Jung Lee ◽  
Simpy Sanyal ◽  
Jung-Wook Woo ◽  
In-Hyuk Choi ◽  
...  
Keyword(s):  
Crevice Corrosion ◽  
Galvanic Corrosion ◽  
Zinc Coating ◽  
Industrial Area ◽  
Sea Salt ◽  
Corrosion Mechanism ◽  
Maximum Lifetime ◽  
Geographical Factors ◽  
Porcelain Insulators ◽  
Corrosion Mechanisms

Porcelain insulators should be exchanged periodically, but their lifetime is not clearly defined. One factor that affects service life is corrosion occurring at the pin and cap—each of which is made of iron with a zinc coating. A number of porcelain insulators used for different lengths of time in different locations are gathered, and the corrosion mechanisms of the cap and pin are investigated. The corrosion mechanism of the cap is mainly galvanic corrosion while that of the pin is primarily electrolytic and crevice corrosion as well as galvanic corrosion. Although time is an important factor in corrosion, it is found that corrosion is more influenced by geographical factors. Since the amount of acid rain and sea salt—each of which causes rapid rusting—is dependent on geographical factors, the location of where porcelain insulators are installed should be considered when predicting their lifetime. Theoretically, if there is only galvanic corrosion occurring, the expected lifetime is 56 years in an industrial area when the zinc coating has a thickness of 75 µm. Previous articles dealing with aging have predicted the maximum lifetime of porcelain insulators used in Korea to be approximately 30 years. To prolong the lifetime of porcelain insulators, further study is required in which the use of zinc alternatives, or waterproof coatings (in addition to the zinc coating), could be examined.

Galvanic corrosion of electronic material copper coupled silver-coating in electronic systems

2019 ◽  
Vol 66 (6) ◽  
pp. 730-745
Author(s):  
Hualiang Huang ◽  
Furong Bu
Keyword(s):  
Theoretical Basis ◽  
Immersion Time ◽  
Galvanic Corrosion ◽  
Area Ratio ◽  
Silver Coating ◽  
Corrosion Mechanism ◽  
Electronic Systems ◽  
Galvanic Current ◽  
Protective Measures ◽  
Content Type

Purpose The purpose of this study is to provide a theoretical basis for the study of the galvanic corrosion mechanism of copper coupled silver-coating under a thin electrolyte layer in electronic systems. Design/methodology/approach Electrochemical measurements and surface characterizations. Findings The results indicate that the potential difference between copper and silver electrodes first quickly increases, and then reaches a relatively stable and large value with the extension of the immersion time. With the significant increase in the cathode/anode area ratio in electronic systems, the area ratio effect obviously accelerates the corrosion of copper due to the remarkable promotion of the cathode process. For a large cathode/anode area ratio, the galvanic current density always maintains a large value and exhibits an increasing trend with the extension of the immersion time, which is attributed that the area ratio effect reduces the protection of corrosion products. For the same area of cathode and anode, the galvanic current density always maintains a small value with the extension of the immersion time due to a low galvanic effect and protective corrosion products. Practical implications This work provides some information for the establishment of reliably protective measures for electronic systems in service. Social implications This work not only provides some information for the establishment of reliably protective measures for electronic systems in service, but also provides a theoretical basis for the selection of metal materials in microelectronic systems. Originality/value This work provides not only a theoretical basis for the study of the galvanic corrosion mechanism of Cu/Ag under a thin electrolyte layer, but also provides some information for the establishment of reliably protective measures for electronic systems in service.

scholarly journals Influence of Cerium on the Formation of Micro-Galvanic Corrosion Elements of AZ91

2011 ◽  
Vol 690 ◽  
pp. 381-384 ◽  
Author(s):  
Daniela Zander ◽  
Meredith Heilig ◽  
Norbert Hort ◽  
Gerald Klaus ◽  
Andreas Bührig Polaczek ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Strong Influence ◽  
Volume Fraction ◽  
Galvanic Corrosion ◽  
Intermetallic Phase ◽  
Corrosion Mechanism ◽  
Sand Cast ◽  
Al Content ◽  
Microstructural Parameters ◽  
Average Grain Size

Investigations of AZ91D revealed a strong influence of mainly the following microstructural parameters on corrosion: porosity, the eutectic, the Al-content of the Mg-phase as well as the volume fraction and distribution of gamma-Al12Mg17. Further an improved corrosion resistance was observed by the addition of rare earth elements. The influence of Ce on microstructure and corrosion of sand cast and high pressure die cast AZ91D with 0.5-2.0 wt.% Ce was investigated by SEM before and after potentiodynamic polarization measurements in pH7.5 (bi-distilled water adjusted with KOH). It was observed that Ce significantly improved the corrosion resistance by changing the microstructure. A strong influence of Ce on the average grain size, the fraction of the eutectic, changes in morphology and/or volume fraction of gamma Al12Mg17 and formation of a Ce-rich intermetallic phase was observed. Therefore, not only the chemical composition but also the change of microstructure and the formation of micro-galvanic elements influence the local corrosion mechanism of AZ91D with cerium.

Proposed FAC Mechanism Using a Macro-Cell Corrosion Model

2007 ◽  
Author(s):  
Masanobu Matsumura
Keyword(s):  
Carbon Steel ◽  
Pipe Wall ◽  
Galvanic Corrosion ◽  
Solution Temperature ◽  
Corrosion Mechanism ◽  
Accelerated Corrosion ◽  
Macro Cell ◽  
Wall Thinning ◽  
Laboratory Test Results ◽  
Incident Cases

Wall thinning at unusually high rates (0.5∼1 mm y−1) due to FAC (flow accelerated corrosion) may sometimes occur on the walls of carbon steel piping which transports pure, high-temperature water. FAC generally tends to occur in locations where the solution temperature is 140∼150°C, downstream of pipe fittings and flow-meters. It arises quite accidentally: sometimes occurs and sometimes does not in spite of related parameters such as flow velocity and temperature being identical. In addition, the damage may be drastically reduced, when the material of the pipe tube in which unusual wall thinning had occurred is exchanged with low alloyed steel. The macro-cell corrosion mechanism, which is the principle mechanism for galvanic corrosion as well as for cathodic protection with a sacrificial anode, was modified by taking laboratory test results into consideration, and applied to incident cases to successfully explain the generation mechanism of this unusual pipe wall thinning. It explains the characteristic behavior of FAC described above and the anticorrosive effect of chromium. It was concluded that the unusual wall thinning of carbon steel pipe may be attributed to the formation an active/passive macro-cell on the surface. An active/passive macro-cell occurs due to gaps in the distribution of such passivation affecting parameters as the pipe wall temperature and the dissolved oxygen content, so that the basis of prevention amounts to avoidance to these gaps. Thus, it is recommended that stagnation watershed and localized lowering of temperature should be avoided with pipe lines.

Effect of Anodic Films on Galvanic Corrosion Behavior of TC4 Titanium Alloy and LY12 Aluminum Alloy

2014 ◽  
Vol 998-999 ◽  
pp. 39-42
Author(s):  
Zhi Yong Wu ◽  
Xue Yuan Li ◽  
Li Ning Zhao ◽  
Su Rong Hu
Keyword(s):  
Titanium Alloy ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Anodic Film ◽  
Corrosion Mechanism ◽  
Anodic Films ◽  
Galvanic Current ◽  
Corrosion Morphology ◽  
Tc4 Titanium Alloy

Galvanic corrosion behavior of TC4 titanium alloy coupled LY12 aluminum alloy was investigated in 3.5% NaCl solution. Particular attention was given to the effect of three different oxidation films. Galvanic corrosion test was conducted on TC4 titanium alloy which coupled LY12-sulfuric acid anodic film (LY12/A(S)), LY12-chromic acid anodic film (LY12/A(Cr)), LY12-hard anodic film (LY12/A(S) hd) and bare LY12, respectively. Galvanic corrosion current (Ig) and average galvanic current density (Ig’) were monitored. Corrosion morphology was observed by camera and corrosion mechanism was discussed. The results show that the three anodic films improve the corrosion resistance of the anode in different magnitudes. LY12/A(S) hd is found to be least susceptible to galvanic corrosion when coupled TC4 titanium alloy. LY12/A(S) and LY12/A(Cr) are found to be moderately susceptible to galvanic corrosion. But the bare LY12 is highly susceptible to galvanic corrosion in corrosive environment.

Effect of Zn concentration on microstructure and corrosion resistance of Mg-Zn alloys microalloyed with Ca and Ce

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Cheng Zhang ◽  
Cheng Peng ◽  
Jin Huang ◽  
Yanchun Zhao ◽  
Guangsheng Huang ◽  
...  
Keyword(s):  
Design Methodology ◽  
Electrochemical Impedance ◽  
Galvanic Corrosion ◽  
Second Phase ◽  
Corrosion Mechanism ◽  
Corrosion Performance ◽  
Content Type ◽  
Second Phase Particles ◽  
Zn Concentration ◽  
Optic Microscopy

Purpose The influence of Zn concentration on microstructure and corrosion performance of the Mg–xZn alloys microalloyed with Ca and Ce was investigated through optic microscopy, scanning electron microscopy, hydrogen evolution, dynamic polarization and electrochemical impedance spectroscopy experiments. Design/methodology/approach In this paper, Mg–xZn alloys (x = 0.5∼2.0 Wt.%) microalloyed with Ca and Ce (0.2 Wt.% each) were prepared. Findings As the increase of Zn concentration, the number of second phase particles (Mg-Zn-Ca, Mg-Zn-Ce and Mg-Ce phases) increased, and when the Zn concentration increased to 2.0 Wt.%, the new second phase Mg-Zn phase was precipitated. Originality/value The influence of Zn concentration on corrosion mechanism of Mg-xZn alloys microalloyed with Ca and Ce was revealed. Increasing of the Zn concentration resulted in the intensification of galvanic corrosion. When Zn concentration was 0.5 Wt.%, the alloy showed the lowest corrosion rate (0.61 mm y-1), which was about 1/2 of that of Mg-2.0Zn-0.2Ca-0.2Ce alloy.

Corrosion Behaviour of Lead-Free and Sn-Pb Solders in 3.5wt% NaCl

2013 ◽  
Vol 686 ◽  
pp. 250-260 ◽  
Author(s):  
Asma Kamarul Asri ◽  
Esah Hamzah
Keyword(s):  
Sodium Chloride ◽  
Corrosion Behaviour ◽  
Galvanic Corrosion ◽  
Salt Spray ◽  
Lead Free ◽  
Corrosion Mechanism ◽  
Corrosion Tests ◽  
Lead Free Solders ◽  
Better Than

The current need to produce lead-free solders in the electronic industries makes it necessary for the replacing solders to have properties which are comparable if not better than the conventional Sn-Pb solders. Thus this research was conducted to compare the corrosion behaviour of lead-free solders with composition Sn-4.0Ag-0.5Cu (SAC405), and Sn-3.0Ag-0.5Cu (SAC305) with conventional Sn-37Pb solders. Corrosion tests were conducted using salt spray tests with 3.5% sodium chloride (NaCl) solutions. The samples were characterized after corrosion tests by using SEM, EDS and XRD. The results showed that the elements present in the solders contributed to galvanic corrosion mechanism that affected the overall corrosion behaviour of the solders.

A PROPOSAL FOR MODIFIED GALVANIC CORROSION MODEL: INVESTIGATING EFFECTS OF MICRO-ARC OXIDATION ON Al ALLOY

2019 ◽  
Vol 26 (02) ◽  
pp. 1850147
Author(s):  
YUANHANG YANG ◽  
YANHONG GU ◽  
JIAN LIANG ◽  
WEN YUE
Keyword(s):  
Open Circuit Potential ◽  
Galvanic Corrosion ◽  
Open Circuit ◽  
Al Alloy ◽  
Corrosion Mechanism ◽  
Corrosion Performance ◽  
Before And After ◽  
Micro Arc Oxidation ◽  
Corrosion Behaviors ◽  
Micro Structures

Corrosion is generally an undesirable phenomenon in most engineering applications. The effects of micro-arc oxidation (MAO) coating on Al alloy on the galvanic corrosion performance have been studied. The surface micro-structures were characterized using scanning electron microscope (SEM) and metallographic microscope before and after corrosion. Electrochemical studies on the corrosion behaviors have been reported by using open circuit potential (OCP) and potentiodynamic polarization (PDP) measurements in a slurry solution. All measurements were consistent with each other and showed that the MAO coating can significantly reduce the corrosion rate of Al alloy. A model for elucidating corrosion mechanism and corrosion process of the MAO coating on Al alloy is proposed.

Sign in / Sign up

Export Citation Format

Share Document