Formation of intermetallic compounds at eutectic Sn–Zn–Al solder/Cu interface

2001 ◽  
Vol 16 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Shan-Pu Yu ◽  
Moo-Chin Wang ◽  
Min-Hsiung Hon
Keyword(s):  
Electron Microscope ◽  
Electron Diffraction ◽  
Intermetallic Compounds ◽  
Adhesion Strength ◽  
Heating Time ◽  
Electron Diffraction Analysis ◽  
Cu Substrate ◽  
Transmission Electron ◽  
Kirkendall Voids ◽  
Scanning Electron

The eutectic Sn–Zn–Al solder alloy was used [composition: 91Sn–9(5Al–Zn)] to investigate the intermetallic compounds (IMCs) formed between solder and a Cu substrate. Scanning electron microscope, transmission electron microscope, and electron diffraction analysis were used to study the IMCs between solder and a Cu substrate. The γ–Cu5Zn8 and γ–Cu9Al4 IMCs were found at the Sn–Zn–Al/Cu interface. Thermodynamic calculation can explain the formation of γ–Cu5Zn8 and γ–Cu9Al4 IMCs instead of Cu–Sn compounds. The formation and growth of γ–Cu9Al4 IMC at 423 K resulted in the decrease of adhesion strength at the interface of solder and a Cu substrate, where the Kirkendall voids were severely formed. As the heating time increased up to 1000 h at 423 K, the adhesion strength between the eutectic Sn–Zn–Al solder and a Cu substrate decreased from 7.6 ± 0.7 MPa to 4.4 ± 0.8 MPa.

Electron Diffraction Analysis and Determination of Se Phase Formed by Reduction of Oxoselenium Anions by Iron (II) Hydroxide

1997 ◽  
Vol 3 (S2) ◽  
pp. 755-756
Author(s):  
D. C. Dufner ◽  
R. A. Zingaro ◽  
A. P. Murphy ◽  
C. D. Moody
Keyword(s):  
Aqueous Solution ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Transmission Electron Microscope ◽  
Iron Hydroxide ◽  
Distilled Water ◽  
Electron Diffraction Analysis ◽  
Transmission Electron ◽  
Standard Solution

Since the early 1980s, Se toxicity in wildlife has created a great deal of interest and concern. Reservoirs, marshes, and wetlands in which excessive amounts of Se have been found are considered to be the source of their toxicity problems. Thus, an effective and inexpensive treatment of Se-contaminated waters which significantly lowers the concentration of this element is needed. One such method for removing selenites and selenates from water utilizes iron (II) hydroxide as a reducing agent. In this work, the reduction products are analyzed in the transmission electron microscope (TEM) using electron diffraction and energy-dispersive spectroscopy (EDS) to determine the presence of Se.A “standard” aqueous solution was prepared by the addition of KOH to distilled water to pH 8.8. Sufficient quantities of Na2SeO3 or Na2SeO4 were weighed and dissolved in the “standard” solution to yield SeO3-2 or SeO4-2 ions. A weighed quantity of Fe(NH4)2(SO4)2 was then added to the SeO3-2 or SeO4-2 “standard” solution to form a precipitate of iron hydroxide.

Synthesis of Hollow Carbon Hemispheres in the Magnesium Carbonate-Metallic Li System with the Help of CHBr3

2011 ◽  
Vol 266 ◽  
pp. 106-109
Author(s):  
Jia Fu Chen ◽  
Zhi Min Chen ◽  
Yan Cao ◽  
Qun Xu
Keyword(s):  
Electron Microscope ◽  
Electron Diffraction ◽  
Single Layer ◽  
Magnesium Carbonate ◽  
X Ray Diffraction ◽  
Graphite Phase ◽  
X Ray ◽  
Transmission Electron ◽  
Hollow Carbon ◽  
Scanning Electron

Hollow carbon hemispheres (HCHs) were synthesized at 500 oC in the magnesium carbonate-metallic Li system with the help of CHBr3. The product was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM). XRD and electron diffraction (ED) pattern results showed that HCHs were graphite phase and polycrystalline. By FESEM and TEM observation, the diameters of the HCHs were in the range of 200-900 nm. The shell of the HCHs was single-layer and their thickness was about 31 nm. The formation mechanism of HCHs with the help of CHBr3 was discussed. Besides, the effect of reaction temperature and dosage of CHBr3 on the morphology of HCHs was studied.

Effect of Addition Zr on As-Homogenization Microstructures of 5182 Aluminum Alloy

2013 ◽  
Vol 749 ◽  
pp. 47-53 ◽  
Author(s):  
Bin Hui Jin ◽  
Bao Hong Zhu ◽  
Xi Wu Li
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Electron Microscope ◽  
Optimum Condition ◽  
Intermetallic Compounds ◽  
Dendritic Structure ◽  
Optical Microscope ◽  
Transmission Electron ◽  
The Matrix ◽  
Scanning Electron

The microstructure of 5182 alloys, standard and modified by Zr, before/after homogenizing heat treatment were investigated by optical microscope (OM), scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS) and transmission electron microscope (TEM). The microstructures on optimum condition for homogenizing heat treatment and the effect of Zr were discussed. It is found that the intermetallic compounds formed on the grain boundaries are less in Zr modified 5182 than 5182 alloys for the as-cast structure. After the two alloys homogenized at 475 for 24h, the dendritic structure disappear and intermetallic compounds become discontinuous, Al2Mg3 phases are decomposed, and there are some precipitates of Al6(Mn,Fe) and Al6Mn in the grain interior. In addition, precipitates of Al3Zr distributed in the matrix of Zr modified 5182 alloys.

Application of Scanning Electron Microscopy to Medical Research

1969 ◽  
Vol 27 ◽  
pp. 12-13
Author(s):  
J. D. Hutchison
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Medical Research ◽  
Prosthetic Heart Valve ◽  
School Of Medicine ◽  
Transmission Electron ◽  
Definition Of ◽  
Mechanism Of Failure ◽  
The Brain ◽  
Scanning Electron

When the transmission electron microscope was commercially introduced a few years ago, it was heralded as one of the most significant aids to medical research of the century. It continues to occupy that niche; however, the scanning electron microscope is gaining rapidly in relative importance as it fills the gap between conventional optical microscopy and transmission electron microscopy.IBM Boulder is conducting three major programs in cooperation with the Colorado School of Medicine. These are the study of the mechanism of failure of the prosthetic heart valve, the study of the ultrastructure of lung tissue, and the definition of the function of the cilia of the ventricular ependyma of the brain.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

Resolution of a Transmitted Electron Image Formed by A Scanning Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 386-387
Author(s):  
S. Takashima ◽  
H. Hashimoto ◽  
S. Kimoto
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Objective Lens ◽  
Specimen Thickness ◽  
Probe Diameter ◽  
Transmission Electron ◽  
Electron Image ◽  
Conventional Transmission Electron Microscope ◽  
Scanning Electron

The resolution of a conventional transmission electron microscope (TEM) deteriorates as the specimen thickness increases, because chromatic aberration of the objective lens is caused by the energy loss of electrons). In the case of a scanning electron microscope (SEM), chromatic aberration does not exist as the restrictive factor for the resolution of the transmitted electron image, for the SEM has no imageforming lens. It is not sure, however, that the equal resolution to the probe diameter can be obtained in the case of a thick specimen. To study the relation between the specimen thickness and the resolution of the trans-mitted electron image obtained by the SEM, the following experiment was carried out.

Sign in / Sign up

Export Citation Format

Share Document