Effect of specimen preparation procedures on chromium depletion and precipitation chemistry in alloy 825 by analytical electron microscopy

1996 ◽  
Vol 15 (6) ◽  
pp. 522-524 ◽  
Author(s):  
Y. -M. Pan ◽  
N. Sridhar ◽  
D. S. Dunn ◽  
G. A. Cragnolino
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Precipitation Chemistry ◽  
Specimen Preparation ◽  
Chromium Depletion ◽  
Analytical Electron

AEM and HRTEM Analysis of the Metal-Oxide Interface of Zircaloy-4, Prepared by FIB

2001 ◽  
Vol 7 (S2) ◽  
pp. 250-251
Author(s):  
S. Abolhassani ◽  
R. Schäublin ◽  
F. Groeschel ◽  
G. Bart
Keyword(s):  
Electron Microscopy ◽  
Metal Oxide ◽  
Transverse Section ◽  
Analytical Electron Microscopy ◽  
Specimen Preparation ◽  
Pressurized Water Reactor ◽  
Oxide Interface ◽  
Pressurized Water ◽  
Transmission Electron ◽  
Analytical Electron

The understanding of the mechanism of oxidation of Zircaloy materials provides an important support for the corrosion control of the fuel claddings in the light water nuclear reactors. Many investigations are devoted to the study of the oxidation of these materials. One of the important aspects of these studies, is the analysis of the metal-oxide interface, which produces information about the nature of the oxide formed at the interface, at different stages of oxidation and the influence of the oxide structure and morphology on the formation and growth of the oxide.In the present study, analytical electron microscopy (AEM) and high resolution transmission electron microscopy (HRTEM) are used to examine the metal-oxide interface of an un-irradiated Zircaloy-4 material, oxidized in autoclave, under pressurized water reactor conditions.The TEM specimen preparation for the interface analysis is an important step of the investigation, since the transverse section required for such observation should be sufficiently thin exactly at the position of the interface.

The search for a ‘materials science’ knife in ultramicrotomy

1992 ◽  
Vol 50 (1) ◽  
pp. 390-391
Author(s):  
Tom Malis
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Analytical Electron Microscopy ◽  
Specimen Geometry ◽  
Specimen Preparation ◽  
Hard Materials ◽  
Analytical Electron ◽  
Phase Differences ◽  
Diamond Knife

Specimen preparation problems in analytical electron microscopy relating to phase differences, specimen geometry or microanalytical requirements have spurred increasing usage of diamond knife sectioning. Since many of these materials are quite hard and/or tough, many material scientists assume (hope?) that there must be a knife specifically designed for ‘hard’ materials. The fact that such a knife has not been developed is due to the fact that conventional (biological) knives have performed so well, with somewhat vague recommendations to use a 35° knife angle for reduced section compression, 45° for general usage and 55° for very hard materials such as embedded catalyst particles.

Application of Analytical Electron Microscopy to Ion Implantation and Near Surface Microstructures

1985 ◽  
Vol 62 ◽  
Author(s):  
P. S. Sklad
Keyword(s):  
Electron Microscopy ◽  
Ion Implantation ◽  
Ion Beam ◽  
Analytical Electron Microscopy ◽  
Theoretical Models ◽  
Solute Concentration ◽  
Specimen Preparation ◽  
Second Phase ◽  
Near Surface ◽  
Analytical Electron

ABSTRACTSurface modification using ion beam techniques is recognized as an important method for improving surface controlled properties of metallic, ceramic, and semiconductor materials. Determination of the microstructure and composition in regions located within a few hundred nanometers of the surface is essential to gaining an understanding of the mechanisms responsible for the improved properties. Analytical electron microscopy (AEM), high resolution microscopy, and microdiffraction are ideally suited for this purpose. These techniques are powerful tools for characterizing microstructure in terms of solute concentration profiles, second phase formation, lattice damage, crystallinity of the implanted layer and annealing behavior. Such analyses allow correlations with theoretical models, property measurements and results of complementary techniques. The proximity of the regions of interest to the surface also places stringent requirements on specimen preparation techniques. The power of AEM in examining the effects of ion implantation will be illustrated by reviewing the results of several investigations. A brief discussion of some important aspects of specimen preparation will also be included.

Tutorial: Tem Specimen Preparation in the Physical Sciencestripod Polishing and Ion Milling

1998 ◽  
Vol 4 (S2) ◽  
pp. 876-877
Author(s):  
Ron Anderson
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Specimen Preparation ◽  
Strategic Choices ◽  
Ion Milling ◽  
Thin Specimen ◽  
The Past ◽  
Analytical Electron ◽  
Preparation Techniques ◽  
Modern Analytical

Over the past few decades, the demands of modern analytical electron microscopy have increased the need for TEM specimen preparation techniques with a minimum of misleading artifacts in terms of chemical microanalysis. At the same time, the demands of modern industrial materials, be they semiconductor, polymeric or composite in nature, call for speed, flexibility and high spatial resolution as well. The response from the electron microscopy community, especially that portion in the private sector, have been to devise (or advocate) radically different forms of TEM thin specimen preparation from that of classic replication, electropolishing and ion thinning.This tutorial sets forth the goals of TEM specimen preparation, and the requirements for a "good" TEM specimen. The strategic choices governing which technique to use for preparing a wide variety of specimens will be covered. A TEM Specimen Preparation Flow Chart will be used to plot a course that makes optimum use of the preparation techniques available as a function of the type of specimen to be prepared.

Electron Beam Damage of Biomolecules Assessed by Energy Loss Spectroscopy

1978 ◽  
Vol 36 (3) ◽  
pp. 61-69
Author(s):  
M. Isaacson ◽  
M.L. Collins ◽  
M. Listvan
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Structural Integrity ◽  
Analytical Electron Microscopy ◽  
High Dose ◽  
Dose Rates ◽  
Special Cases ◽  
Analytical Electron ◽  
Atom Migration ◽  
Beam Damage

Over the past five years it has become evident that radiation damage provides the fundamental limit to the study of blomolecular structure by electron microscopy. In some special cases structural determinations at very low doses can be achieved through superposition techniques to study periodic (Unwin & Henderson, 1975) and nonperiodic (Saxton & Frank, 1977) specimens. In addition, protection methods such as glucose embedding (Unwin & Henderson, 1975) and maintenance of specimen hydration at low temperatures (Taylor & Glaeser, 1976) have also shown promise. Despite these successes, the basic nature of radiation damage in the electron microscope is far from clear. In general we cannot predict exactly how different structures will behave during electron Irradiation at high dose rates. Moreover, with the rapid rise of analytical electron microscopy over the last few years, nvicroscopists are becoming concerned with questions of compositional as well as structural integrity. It is important to measure changes in elemental composition arising from atom migration in or loss from the specimen as a result of electron bombardment.

Analytical Electron Microscopy (AEM) of Meningeal Cells Exposed to Particulate Cobalt During Studies of Experimental Epilepsy

1982 ◽  
Vol 40 ◽  
pp. 186-187
Author(s):  
R.G. Frederickson ◽  
R.G. Ulrich ◽  
J.L. Culberson
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Experimental Epilepsy ◽  
Metallic Cobalt ◽  
Experimental Animals ◽  
X Ray ◽  
Brain Surface ◽  
Meningeal Cells ◽  
Analytical Electron ◽  
The Brain

Metallic cobalt acts as an epileptogenic agent when placed on the brain surface of some experimental animals. The mechanism by which this substance produces abnormal neuronal discharge is unknown. One potentially useful approach to this problem is to study the cellular and extracellular distribution of elemental cobalt in the meninges and adjacent cerebral cortex. Since it is possible to demonstrate the morphological localization and distribution of heavy metals, such as cobalt, by correlative x-ray analysis and electron microscopy (i.e., by AEM), we are using AEM to locate and identify elemental cobalt in phagocytic meningeal cells of young 80-day postnatal opossums following a subdural injection of cobalt particles.

Analytical Electron Microscopy Characterization of Electric Arc Furnace Dust

1981 ◽  
Vol 39 ◽  
pp. 134-135
Author(s):  
J. R. Porter ◽  
J. I. Goldstein ◽  
D. B. Williams
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Dust Particles ◽  
Particle Analysis ◽  
Arc Furnace ◽  
Analytical Electron ◽  
Residual Elements ◽  
Industry Practice

Alloy scrap metal is increasingly being used in electric arc furnace (EAF) steelmaking and the alloying elements are also found in the resulting dust. A comprehensive characterization program of EAF dust has been undertaken in collaboration with the steel industry and AISI. Samples have been collected from the furnaces of 28 steel companies representing the broad spectrum of industry practice. The program aims to develop an understanding of the mechanisms of formation so that procedures to recover residual elements or recycle the dust can be established. The multi-phase, multi-component dust particles are amenable to individual particle analysis using modern analytical electron microscopy (AEM) methods.Particles are ultrasonically dispersed and subsequently supported on carbon coated formvar films on berylium grids for microscopy. The specimens require careful treatment to prevent agglomeration during preparation which occurs as a result of the combined effects of the fine particle size and particle magnetism. A number of approaches to inhibit agglomeration are currently being evaluated including dispersal in easily sublimable organic solids and size fractioning by centrifugation.

Application of analytical electron microscopy to the study of partitioning of silicon in a 2 wt% Si eutectoid steel

1978 ◽  
Vol 36 (1) ◽  
pp. 616-617
Author(s):  
N. Ridley ◽  
S.A. Al-Salman ◽  
G.W. Lorimer
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Analytical Electron Microscopy ◽  
Eutectoid Steel ◽  
Minimum Diameter ◽  
Thin Foils ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Transformation Front

The application of the technique of analytical electron microscopy to the study of partitioning of Mn (1) and Cr (2) during the austenite-pearlite transformation in eutectoid steels has been described in previous papers. In both of these investigations, ‘in-situ’ analyses of individual cementite and ferrite plates in thin foils showed that the alloying elements partitioned preferentially to cementite at the transformation front at higher reaction temperatures. At lower temperatures partitioning did not occur and it was possible to identify a ‘no-partition’ temperature for each of the steels examined.In the present work partitioning during the pearlite transformation has been studied in a eutectoid steel containing 1.95 wt% Si. Measurements of pearlite interlamellar spacings showed, however, that except at the highest reaction temperatures the spacing would be too small to make the in-situ analysis of individual cementite plates possible, without interference from adjacent ferrite lamellae. The minimum diameter of the analysis probe on the instrument used, an EMMA-4 analytical electron microscope, was approximately 100 nm.

Analytical electron microscopy of grain boundaries in Al-Cu metallizations

1992 ◽  
Vol 50 (2) ◽  
pp. 1684-1685
Author(s):  
J. R. Michael ◽  
A. D. Romig ◽  
D. R. Frear
Keyword(s):  
Electron Microscopy ◽  
Integrated Circuits ◽  
Failure Mode ◽  
Current Density ◽  
Thermal History ◽  
Analytical Electron Microscopy ◽  
Cu Metallization ◽  
Analytical Electron ◽  
Interconnect Lines

Al with additions of Cu is commonly used as the conductor metallizations for integrated circuits, the Cu being added since it improves resistance to electromigration failure. As linewidths decrease to submicrometer dimensions, the current density carried by the interconnect increases dramatically and the probability of electromigration failure increases. To increase the robustness of the interconnect lines to this failure mode, an understanding of the mechanism by which Cu improves resistance to electromigration is needed. A number of theories have been proposed to account for role of Cu on electromigration behavior and many of the theories are dependent of the elemental Cu distribution in the interconnect line. However, there is an incomplete understanding of the distribution of Cu within the Al interconnect as a function of thermal history. In order to understand the role of Cu in reducing electromigration failures better, it is important to characterize the Cu distribution within the microstructure of the Al-Cu metallization.

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