Electron microprobe analysis under conditions of non-normal Electron beam incidence

2000 ◽  
Vol 6 (S2) ◽  
pp. 922-923
Author(s):  
E. Lifshin ◽  
R. Gauvin
Keyword(s):  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Normal Incidence ◽  
Radial Symmetry ◽  
X Ray ◽  
Detection Systems ◽  
Electron Microscopes ◽  
Normal Electron ◽  
Scanning Electron Microscopes

From its inception, electron microprobe analysis was almost exclusively done under conditions of normal electron probe incidence. The radial symmetry of this geometry greatly simplified the development of quantitative equations, and these equations where further refined based on large amounts of data also collected at normal incidence. However, as x-ray detection systems where added to scanning electron microscopes (SEMs), samples were often viewed under conditions of non-normal incidence and attempts were made to modify the various correction procedures to give acceptable quantitative results. Little justification for these methods has ever been published and so the current study was undertaken to compare theoretically calculated x-ray emission from a well characterized sample, in this case NiAl (.685 wt. % Ni, .315 wt. %A1) with experimentally measured results collected as a function of tilt angle. The theoretical calculation where done using a Monte Carlo (MC) program developed by Gauvin and Lifshin.

X-ray Diffraction/Electron Microprobe Analysis of Surface Films Formed on Alloys During Hydrothermal Reaction with Geologic Materials

1984 ◽  
Vol 28 ◽  
pp. 367-375 ◽  
Author(s):  
R. G. Johnston ◽  
M. B. Strope ◽  
R. P. Anantatmula
Keyword(s):  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Hydrothermal Reaction ◽  
Pressure Vessels ◽  
Surface Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Geologic Materials ◽  
Structure Phase

AbstractX-ray diffraction and electron microprobe analysis were used in combination to identify reaction phases that formed on the surfaces of low-carbon steel specimens reacted with a 75% basalt-25% bentonite mixture and anion-doped water in sealed pressure vessels at 100°C and 250°C. Reaction phases on specimen surfaces and in adhering geologic material were identified by conventional X-ray diffraction scans of entire specimens with intact reaction layers. Comparison of results from adhering geologic material and scans of selectively removed layers allowed establishment of approximate reaction gradients in the adhering packing material. Electron microprobe analysis of specimens in cross-section provided quantitative chemical analyses of adhering reaction phases, and identification of reaction layer composition gradients and thicknesses. Magnetite formed on the surface of specimens reacted at 250°C for 4 weeks. Iron-enriched clay was also observed on specimen surfaces and in the adjacent basalt-bentonite mixture. The 100°C experiments yielded surface films of a siderite-structure phase, (Fe,Ca,Mn)CO3, that were not observed in previous experiments with synthetic ground-water. Less extensive iron enrichment of the adjacent clays compared to that seen in the 250°C experiments was observed. The siderite-structure phase generally formed when no carbonate ion was present in the initial solution, implying dissolution of impurity calcite in the bentonite as the controlling factor in the reaction. The results demonstrate the utility of combining X-ray diffraction and electron microprobe analysis for characterization of reaction phases on alloys reacted with complex geologic materials.

Nature of dioctahedral micas in Spanish red soils

Clay Minerals ◽  
1997 ◽  
Vol 32 (1) ◽  
pp. 107-121 ◽  
Author(s):  
J. M. Martin-Garcia ◽  
G. Delgado ◽  
M. Sanchez-Maranon ◽  
J. F. Parraga ◽  
R. Delgado
Keyword(s):  
Powder Diffraction ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
X Ray ◽  
Red Soils ◽  
Mineral Phases ◽  
Composition And Structure ◽  
Structural Formulae ◽  
Coarse Gravel

AbstractStructural formulae and other crystallochemical parameters were used to study different species of dioctahedral micas in clay and coarse gravel fractions of horizons from a red soil (Ultic Haploxeralf) in southern Spain. Mineralogical analyses using X-ray powder diffraction, and measurements of theb0parameter revealed dioctahedral micas, illite and paragonite. Structural formulae established from electron microprobe analysis and energy dispersive X-ray analysis showed the illites to be K mica related in elemental composition and structure to muscovite and phengite. The paragonites were found to be closer to ideal mica. Structural formulae for Na-K dioctahedral micas were obtained with crystallochemical characteristics intermediate between those of Na micas and K micas. The possibilty of these micas representing individual mineral phases or intergrowths of Na and K micas is discussed. In the soil profile, micas from the Bt horizon showed the largest crystallochemical changes induced by pedogenesis.

Monoclinic structure and nonstoichiometry of `KAlSiO4-O1'

2013 ◽  
Vol 69 (4) ◽  
pp. 334-336 ◽  
Author(s):  
Aleksandar Kremenović ◽  
Biljana Lazic ◽  
Hannes Krüger ◽  
Martina Tribus ◽  
Predrag Vulić
Keyword(s):  
Single Crystal ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Monoclinic Structure ◽  
X Ray Diffraction ◽  
Flux Method ◽  
X Ray ◽  
Derivatives Of ◽  
Aluminium Silicate

Crystals of KAlSiO4-O1(potassium aluminium silicate) were synthesized using a flux method and analysed utilizing single-crystal X-ray diffraction and electron microprobe analysis. Both methods confirm that the crystals are nonstoichiometric according to K1−xAl1−xSi1+xO4withx= 0.04 (1). KAlSiO4-O1is closely related to the stuffed derivatives of tridymite, although the topology of the Si/Al-ordered framework is different. Six-membered rings of UUDDUD and UUUDDD (U = up and D = down; ratio 2:1) configurations are present in layers parallel to theabplane. In contrast, the framework of tridymite exhibits UDUDUD rings. The crystals are affected by inversion, pseudo-orthorhombic and pseudo-hexagonal twinning.

scholarly journals The distribution of Cu across three basaltic lava flows from the Faeroe Islands

1982 ◽  
Vol 31 ◽  
pp. 1-10
Author(s):  
Aage Jensen
Keyword(s):  
Spectral Analysis ◽  
Atomic Absorption ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Fluorescence Analysis ◽  
Lava Flows ◽  
Absorption Analysis ◽  
X Ray ◽  
Ti Oxides

The distribution of Cu across lava flows has been investigated by using a combination of several different analytical methods on samples taken along two profiles across each of three flows: one from the lower series, one from the middle series, and one from the upper series of the Faeroe Islands basalts. The profiles comprise 97 samples, all of which have been investigated by X-ray fluorescence analysis, atomic absorption analysis, and microscopic analysis. Furthermore some of the samples have been investigated by microchemical analysis, spectral analysis, and electron microprobe analysis. Spectral analysis has also been carried out on separates from selected samples. The total amount of Cu present in the samples has been determined by X-ray fluorescence analysis. The amount of Cu lattice-bound in Fe-Ti-oxides, pyroxenes and plagioclases has been determined as the difference between total Cu and Cu values obtained by atomic absorption analysis carried out on solutions obtained by using weak solvents which do not dissolve lattice-bound Cu in minerals not having Cu as a major element. Electron microprobe analysis has shown that the amount of Cu lattice-bound in Fe-Ti-oxides, pyroxenes and plagioclases increases with increasing oxidation, with an abrupt increase coincident with the formation of pseudobrookite. Where pseudobrookite is present most of the Cu is lattice-bound, but where the oxidation during initial cooling has not resulted in the formation of pseudobrookite, most of the Cu ends up loosely held in the rock in the same manner as cations in zeolites, but in many of the samples a smaller part of the Cu forms native copper and Cu-bearing sulphides.

Arsenoflorencite-(Ce): a new arsenate mineral from Australia

1987 ◽  
Vol 51 (362) ◽  
pp. 605-609 ◽  
Author(s):  
E. H. Nickel ◽  
J. E. Temperly
Keyword(s):  
Powder Diffraction ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
South Australia ◽  
Stream Sediments ◽  
Space Group ◽  
X Ray ◽  
Conchoidal Fracture ◽  
Simplified Formula

AbstractArsenoflorencite-(Ce) has been found at three localities in Australia—two in South Australia, and one in Queensland. It occurs as colourless to light brown scalenohedral crystals and crystal fragments in stream sediments. Electron microprobe analysis gave Ce2O3 12.97, La2O3 8.62, Pr2O3 3.35, Nd2O3 2.40, Gd2O3 1.38, Sm2O3 0.38, SrO 1.99, Al2O3 28.75, As2O5 27.02, P2O5 4.68, SO3 1.21%; calc, H2O 9.36%; total 102.11%. The simplified formula is REAl3(AsO4)2(OH)6, with Ce as the dominant RE element. Arsenoflorencite-(Ce) is rhombohedral, has space group R3m with αhex. 7.029 and chex. 16.517 Å, and Z = 3. Strongest X-ray powder diffraction lines are: 3.513(6)(110), 2.963(10)(113), 2.201(4)(107), 1.905(5)(303) and 1.753 Å(4)(220). Density is 4.096 (meas.) and 4.091 (calc.) g/cm3. Hardness is VHN10 170. Arsenoflorencite-(Ce) is brittle, breaks with a conchoidal fracture, and has no perceptible cleavage. The mineral is colourless in transmitted light, uniaxial positive, and has ω 1.739 and ɛ 1.745 (λ = 589 nm). Arsenoflorencite-(Ce) is the arsenate analogue of florencite-(Ce), and the name was chosen to indicate this relationship.

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