A new occurrence of vanadium minerals in Leicestershire

1971 ◽  
Vol 38 (296) ◽  
pp. 488-492
Author(s):  
Robert J. King ◽  
John A. Dixon
Keyword(s):  
Electron Probe ◽  
Geological Environment ◽  
Percentage Composition ◽  
Composition Graph ◽  
Scanning Electron

SummaryTwo vanadates, tangeïte and volborthite, new to Britain, their association with vanadiferous nodules, and their geological environment are described. A percentage composition graph for vanadium taken across a vanadiferous nodule, by scanning electron probe, is given.

High Resolution Scanning Electron Microscopy

1991 ◽  
Vol 49 ◽  
pp. 478-479
Author(s):  
David Joy ◽  
James Pawley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Beam ◽  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Electron Probe ◽  
Impact Point ◽  
Interaction Volume ◽  
Scanning Electron

The scanning electron microscope (SEM) builds up an image by sampling contiguous sub-volumes near the surface of the specimen. A fine electron beam selectively excites each sub-volume and then the intensity of some resulting signal is measured. The spatial resolution of images made using such a process is limited by at least three factors. Two of these determine the size of the interaction volume: the size of the electron probe and the extent to which detectable signal is excited from locations remote from the beam impact point. A third limitation emerges from the fact that the probing beam is composed of a finite number of discrete particles and therefore that the accuracy with which any detectable signal can be measured is limited by Poisson statistics applied to this number (or to the number of events actually detected if this is smaller).

scholarly journals The Influence of A Mo Addition on the Interfacial Morphologies and Corrosion Resistances of Novel Fe-Cr-B Alloys Immersed in Molten Aluminum

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 256 ◽  
Author(s):  
Zicheng Ling ◽  
Weiping Chen ◽  
Weiye Xu ◽  
Xianman Zhang ◽  
Tiwen Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Probe ◽  
Molten Aluminum ◽  
Dendritic Structure ◽  
H13 Steel ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Scanning Electron

The influence of a Mo addition on the interfacial morphologies and corrosion resistances of novel Fe-Cr-B alloys in molten aluminum at 750 °C was systematically investigated using scanning electron microscopy, X-ray diffractometer, electron probe microanalysis, and transmission electron microscopy. The results indicated that Mo could not only strengthen the matrix but also facilitate the formation of borides. Furthermore, the microstructures of Mo-rich M2B boride changed from a local eutectic net-like structure to a typical coarse dendritic structure and a blocky hypereutectic structure with increasing Mo addition. This was true of the blocky Mo-rich M2B boride, rod-like Cr-rich M2B boride and the corrosion products, which had a synergistic effect on retarding of the diffusion of molten aluminum. Notably, the corrosion resistance of the Fe-Cr-B-Mo alloy, with an 8.3 wt.% Mo addition, was 3.8 times higher than that of H13 steel.

Scanning Electron Microscopy And Electron Probe Microanalysis Of Extraterrestrial Materials

1999 ◽  
Vol 5 (S2) ◽  
pp. 2-3
Author(s):  
J. I. Goldstein
Keyword(s):  
Electron Microscopy ◽  
Low Temperatures ◽  
Electron Probe ◽  
Iron Meteorite ◽  
The Moon ◽  
Iron Meteorites ◽  
Slow Cooling ◽  
Electron Probe Microanalyzer ◽  
Extraterrestrial Materials ◽  
Scanning Electron

One of the first samples analyzed by Castaing in his electron probe microanalyzer (EPMA) some 50 years ago was an iron meteorite. The Widmanstatten pattern microstructure of iron meteorites can be observed at very low magnifications ( Fig. 1). These meteorites are ideal samples for microanalysis because of the Ni gradient which extends over 10 to 1000 microns in the parent taenite phase of these Fe-Ni samples (Fig. 3). The Ni gradient is the result of very slow cooling of the iron meteorite, in terms of millions of years, within a parent'asteroid.The scanning electron microscope (SEM) has been used to characterize the microstructure of meteorites, as well as samples from the moon and mars. For example, the microstructure of the dark etching taenite areas (T in Fig. 1) of the Carleton iron meteorite is shown in Fig 2. In this example, precipitates are observed along original martensite laths which form during the cooling of the iron meteorite at low temperatures.

A comparative study of the morphology, chemical composition and weathering of rhyolitic and andesitic glass

Clay Minerals ◽  
1980 ◽  
Vol 15 (2) ◽  
pp. 165-173 ◽  
Author(s):  
J. H. Kirkman ◽  
W. J. McHardy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
New Zealand ◽  
Chemical Composition ◽  
Electron Probe ◽  
Volcanic Glass ◽  
Chemical Activity ◽  
Rapid Rate ◽  
Bonding Characteristics ◽  
Scanning Electron

AbstractThe morphology of volcanic glass particles in rhyolitic and andesitic tephra of central North Island and Taranaki areas of New Zealand has been studied by scanning electron microscopy. Electron probe analyses of the glasses are compared with those of the clays to which they weather. Loss of silica characterizes the weathering of both glasses. The rapid rate of weathering of andesitic glass is attributed to its occurrence as fine, soft microlites and extensive substitution of Al for Si in the structure. Rhyolitic glass weathers more slowly because it occurs as hard and brittle particles containing relatively little alumina. It is suggested that the structure, chemical composition and chemical activity of allophane is governed largely by the chemical composition and bonding characteristics of the parent glass.

Oscilloscope Readout of Electron Microprobe Data

1962 ◽  
Vol 6 ◽  
pp. 291-300
Author(s):  
Kurt F. J. Heinrich
Keyword(s):  
Electron Microprobe ◽  
Electron Probe ◽  
Practical Importance ◽  
Data Presentation ◽  
Great Practical Importance ◽  
Microprobe Data ◽  
Scanning Electron

AbstractIn view of the amount of data per time unit the scanning electron probe is capable of producing, time economy in data presentation is of great practical importance. In this paper, the characteristics and advantages of various previously known techniques of data presentation are described, and some novel procedures are proposed.

scholarly journals Conduction Processes in Thick Film Resistors. Part I

1976 ◽  
Vol 3 (3) ◽  
pp. 131-140 ◽  
Author(s):  
M. P. Ansell
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thick Film ◽  
Electron Probe ◽  
Electronic Conduction ◽  
Borosilicate Glasses ◽  
Electron Probe Micro Analysis ◽  
Metal Group ◽  
Micro Analysis ◽  
Scanning Electron

The structures of three families of thick film resistors have been investigated by scanning electron microscopy and electron probe micro-analysis. The two principal components of the resistive glazes, that is the conducting pigment and the glassy binder, have been identified in each case. The pigments were found to be simple or ternary oxides of the Pt transition metal group and Pd/PdO/Ag alloys. The glassy binders were based on lead borosilicate glasses.A model for the electronic conduction processes through the glass and pigments is proposed on the basis of the observed physical structures, the measured electrical properties of resistors and the properties of the component resistor materials.Part I of the total paper is concerned with identifying the phases in various Thick Film Resistors and part II considers the conduction processes that are appropriate.

THICK FILMS OF YBaCuO FROM PRECALCINED POWDERS

1989 ◽  
Vol 03 (05) ◽  
pp. 751-761 ◽  
Author(s):  
L. RAO MADHAVRAO ◽  
RAJ RAJAGOPALAN
Keyword(s):  
Electron Microscopy ◽  
Low Temperatures ◽  
Electron Probe ◽  
Thick Films ◽  
Diffusion Distance ◽  
Electron Probe Microanalyzer ◽  
Colloidal Method ◽  
Structurally Stable ◽  
Substrate Film ◽  
Scanning Electron

Preparation and some of the chemical and microstructural aspects of thick films of the YBa 2 Cu 3 O 7−x superconductors (herein designated as YBaCuO) using precalcined YBaCuO powders and a colloidal method are described. Films on alumina substrates were made from calcined YBaCuO powders dispersed in hexane using a commerical dispersant which acts as a steric stabilizer and binder. The additive decomposes without residues at relatively low temperatures, and structurally stable and uniform films are obtained for proper dosage of the dispersant. Scanning electron microscopy has been used to examine the microstructure, quality and sinterability of the films. An example of the use of other additives to improve sintering and adhesion of the film to the substrate is also described. Substrate/film interaction has been studied by compositional mapping using an electron probe microanalyzer. The results show a substantial reaction layer (1−2μm) of barium aluminate and a significant diffusion distance (of several microns) of aluminum into the film.

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