A comparison between conventional macroscopic and novel microscopic scanning electrochemical methods to evaluate galvanic corrosion

2001 ◽  
Vol 43 (7) ◽  
pp. 1203-1216 ◽  
Author(s):  
R Akid ◽  
D.J Mills
Keyword(s):  
Galvanic Corrosion ◽  
Electrochemical Methods

THE RESEARCH OF POSSIBILITY OF GALVANIC CORROSION IN BRAZED CONNECTIONS USED IN AVIATION ENGINE CONSTRUCTION

2021 ◽  
pp. 3-13
Author(s):  
E.N. Kablov ◽  
◽  
A.E. Kutyrev ◽  
A.I. Vdovin ◽  
I.A. Kozlov ◽  
...  
Keyword(s):  
Galvanic Corrosion ◽  
Electrochemical Methods ◽  
Chloride Solutions ◽  
Engine Construction

The article presents the results of researche of galvanic corrosion possibility of brazed connections of steels 13Сr11Ni2W2MoV and 12Cr18Ni10Тi with use of the solders VPr4 and VPr50, which are used in design of aviation engineering engines. The research was carried out by electrochemical methods. Corrosion currents’ density and contact pairs’ potentials in chloride solutions have been determined. It is determined that 13Сr11Ni2W2MoV steel can be exposed to galvanic corrosion in a place of brazed connection. Thus the greatest danger to it is represented by VPr4 solder. The mechanism of corrosion of 13Сr11Ni2W2MoV steel in neutral environments has been examined and recommendations about its protection against galvanic corrosion are made.

Imaging molecules adsorbed onto electrodes under potential control by scanning probe microscopy

1991 ◽  
Vol 49 ◽  
pp. 376-377 ◽  
Author(s):  
N.J. Tao ◽  
J.A. DeRose ◽  
P.I. Oden ◽  
S.M. Lindsay
Keyword(s):  
Surface Charge ◽  
Environmental Effects ◽  
Scanning Probe Microscopy ◽  
Statistical Significance ◽  
Electrochemical Methods ◽  
Surface Structures ◽  
Scanning Probe ◽  
Potential Control ◽  
Afm Imaging ◽  
Special Circumstances

Clemmer and Beebe have pointed out that surface structures on graphite substrates can be misinterpreted as biopolymer images in STM experiments. We have been using electrochemical methods to react DNA fragments onto gold electrodes for STM and AFM imaging. The adsorbates produced in this way are only homogeneous in special circumstances. Searching an inhomogeneous substrate for ‘desired’ images limits the value of the data. Here, we report on a reversible method for imaging adsorbates. The molecules can be lifted onto and off the substrate during imaging. This leaves no doubt about the validity or statistical significance of the images. Furthermore, environmental effects (such as changes in electrolyte or surface charge) can be investigated easily.

Corrosion of Electronic and Magnetic Devices and Materials

1996 ◽  
Vol 451 ◽  
Author(s):  
Gerald S. Frankel
Keyword(s):  
Thin Film ◽  
Failure Modes ◽  
Galvanic Corrosion ◽  
Potential Drop ◽  
Magnetic Devices ◽  
Disk Structure ◽  
Magnetic Layers ◽  
Ohmic Potential Drop ◽  
Corrosion Problem ◽  
Corrosion Susceptibility

ABSTRACTCorrosion of thin film structures commonly used in electronic and magnetic devices is discussed. Typical failure modes are presented, and galvanic corrosion is discussed in some detail since it is one common problem with such devices. A graphical explanation for the determination of the ohmic potential drop during galvanic corrosion is presented. The corrosion problem of thin film disks is shown to have changed during the past ten years owing to changes in disk structure. The corrosion susceptibility of two antiferromagnetic alloys used for exchange coupling to soft magnetic layers is discussed.

Development of corrosion flaws for the production of realistic test specimens

2020 ◽  
Vol 64 (1) ◽  
pp. 23-28
Author(s):  
J. Hodač ◽  
Z. Fulín ◽  
P. Mareš ◽  
J. Veselá ◽  
O. Chocholatý
Keyword(s):  
Power Plants ◽  
Galvanic Corrosion ◽  
Water Solution ◽  
Erosive Wear ◽  
Corrosion Damage ◽  
Water Mist ◽  
Carbon Steels ◽  
Bending Stress ◽  
Solution Flow ◽  
Mechanical Bending

AbstractTo produce realistic test specimens with realistic flaws, it is necessary to develop appropriate procedure for corrosion flaw production. Tested specimens are made from steels commonly used in power plants, such as carbon steels, stainless steels and their dissimilar weldments. In this study, corrosion damage from NaCl water solution and NaCl water mist are compared. Specimens were tested with and without mechanical bending stress. The corrosion processes produced plane, pitting and galvanic corrosion. On dissimilar weldments galvanic corrosion was observed and resulted to the deepest corrosion damage. Deepest corrosion flaws were formed on welded samples. The corrosion rate was also affected by the solution flow in a contact with the specimens, which results in a corrosion-erosive wear. Produced flaws are suitable as natural crack initiators or as realistic corrosion flaws in test specimens.

SEPARATION AND CHARACTERIZATION OF ANTHOCYANINS BY ANALYTICAL AND ELECTROCHEMICAL METHODS

2011 ◽  
Vol 10 (5) ◽  
pp. 697-701 ◽  
Author(s):  
Firuta Fitigau ◽  
Claudia Popescu ◽  
Adina-Elena Segneanu ◽  
Ionel Balcu ◽  
Raluca Martagiu ◽  
...  
Keyword(s):  
Electrochemical Methods

Studies on a Failure Analysis Flow of Surface Contamination, Corrosion, and Underetch on Microchip Al Bondpads in Wafer Fabrication

2005 ◽  
Author(s):  
Hua Younan
Keyword(s):  
Failure Analysis ◽  
Galvanic Corrosion ◽  
Surface Contamination ◽  
Wafer Fabrication ◽  
Tof Sims ◽  
Corrosion Passivation

Abstract A failure analysis flow is developed for surface contamination, corrosion and underetch on microchip Al bondpads and it is applied in wafer fabrication. SEM, EDX, Auger, FTIR, XPS and TOF-SIMS are used to identify the root causes. The results from carbon related contamination, galvanic corrosion, fluorine-induced corrosion, passivation underetch and Auger bondpad monitoring will be presented. The failure analysis flow will definitely help us to select suitable methods and tools for failure analysis of Al bondpad-related issues, identify rapidly possible root causes of the failures and find the eliminating solutions at both wafer fabrication and assembly houses.

PCB Related Field Failures with ImAg Surface Finishes

2007 ◽  
Author(s):  
Anil Kurella ◽  
Aravind Munukutla ◽  
J.S. Lewis
Keyword(s):  
Emerging Markets ◽  
Galvanic Corrosion ◽  
Electrochemical Migration ◽  
Copper Sulphide ◽  
Electronic Components ◽  
Related Field ◽  
Surface Finishes ◽  
Immersion Silver ◽  
Manufacturing Environments

Abstract PCB surface finishes like Immersion silver (ImAg) are commonly used in Pb-free manufacturing environments following RoHS legislation. With this transition, however the numbers of field failures associated with electrochemical migration, copper sulphide corrosion, via barrel galvanic corrosion are on a steady rise. More often than not ImAg surfaces seem to assist these failing signatures. As computers penetrate into emerging markets with humid and industrialized environments there is a greater concern on the reliability and functionality of these electronic components.

Analysis of Al-over-Cu Bond Pad Hillock and Pit Hole Defects

2005 ◽  
Author(s):  
Daniel Cavasin ◽  
Abdullah Yassine
Keyword(s):  
Focused Ion Beam ◽  
Galvanic Corrosion ◽  
Process Analysis ◽  
Ion Beam ◽  
Metal Corrosion ◽  
Process Characterization ◽  
Nucleation Sites ◽  
Hole Defects ◽  
Bond Pads ◽  
Sawing Process

Abstract Bond pad metal corrosion was observed during assembly process characterization of a 0.13um Cu microprocessor device. The bond pad consisted of 12kÅ of Al-0.5%Cu atop 9kÅ of Cu, separated by a thin Ta diffusion barrier. The corrosion was first noted after the wafer dicing process. Analysis of the pad surface revealed pitting-type corrosion, consistent with published reports of classic galvanic cell reactions between Al2Cu (theta phase) particles and the surrounding Al pad metal. Analysis of the bond pads on samelot wafers which had not been diced showed higher-thanexpected incidence of hillock and pit hole defects on the Al surface. Statistically designed experiments were formulated to investigate the possibility that the observed pre-saw pad metal defects act as nucleation sites for galvanic corrosion during the sawing process. Analyses of the experimental samples were conducted using optical and scanning electron microscopy, along with focused ion beam deprocessing and energy dispersive X-ray. This paper explores the relationship between the presence of these pre-existing defects and the propensity for the bond pads to corrode during the dicing process, and reviews the conditions under which pit hole defects are formed during the final stages of the Cu-metallized wafer fabrication process. Indications are that strict control of wafer fab backend processes can reduce or eliminate the incidence of such defects, resulting in elimination of bond pad corrosion in the wafer dicing process.

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