Mean Atomic Number Quantitative Assessment in Backscattered Electron Imaging

2012 ◽  
Vol 18 (6) ◽  
pp. 1355-1361 ◽  
Author(s):  
E. Sánchez ◽  
M. Torres Deluigi ◽  
G. Castellano
Keyword(s):  
Atomic Number ◽  
Mineral Phase ◽  
Experimental Conditions ◽  
Backscattered Electron Imaging ◽  
X Ray ◽  
Unknown Sample ◽  
Mineral Phases ◽  
Backscattered Electron ◽  
The Mean ◽  
Electron Imaging

AbstractA method for obtaining quantitative mean atomic number images in a scanning electron microscope for different kinds of samples has been developed. The backscattered electron signal is monotonically increasing with the mean atomic number Z, and accordingly Z can be given as a function of the image gray levels. From results obtained from Monte Carlo simulations, an exponential function is fitted to convert the backscattered registered gray levels into a Z image map. Once this fitting was performed, the reproducibility of the Z determination was checked through the acquisition of backscattered electron images from metal and mineral standards. The developed method can be applied to any unknown sample, always controlling the experimental conditions, as shown here for a thin section of a rock in which several unknown mineral phases are present; the results obtained herein are compared to quantitative assessments performed with X-ray spectra from each mineral phase.

Phase relationships in the Ti–Si–C system at high pressures

1992 ◽  
Vol 7 (6) ◽  
pp. 1473-1479 ◽  
Author(s):  
S. Sambasivan ◽  
W.T. Petuskey
Keyword(s):  
Silicon Carbide ◽  
Electron Probe ◽  
High Pressures ◽  
Kinetic Characteristics ◽  
Experimental Conditions ◽  
Backscattered Electron Imaging ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
Clapeyron Slope ◽  
Phase Relationships

The compatibility of phases in the Ti–Si–C system was studied for pressures from 10 to 20 kbars (1 to 2 GPa) and temperatures from 1200 °C to 1500 °C via an interfacial reaction between titanium and silicon carbide. The interface was characterized by backscattered electron imaging and electron probe microanalysis. Ti3Si was stabilized at high pressures exhibiting an appreciable solubility for carbon (up to 9 at. %). At higher temperatures and lower pressures, it decomposed to Ti5Si3, Ti(Si, C), and TiCx according to the relation Ti3Si (Cz) = (0.70588)TiCx + (0.32437)Ti5Si3 + (0.67227)Ti (Si, C), where the mathematical coefficients were calculated using z = 0.4 and x = 0.5. No detectable quantities of carbon dissolved in Ti5Si3 under these conditions. A clapeyron slope of 0.08 (±0.01) kbar/K was measured for this reaction. The microstructure of the reaction zone and other general thermodynamic and kinetic characteristics are discussed for different experimental conditions.

scholarly journals Phase relationships in the Al-rich region of the Al-Y-Zr system

2017 ◽  
Vol 53 (1) ◽  
pp. 9-12 ◽  
Author(s):  
X. Bao ◽  
L. Liu ◽  
S. Huang ◽  
Y. Jiang ◽  
X. Wang ◽  
...  
Keyword(s):  
First Principle ◽  
Rich Region ◽  
Backscattered Electron Imaging ◽  
X Ray ◽  
First Principle Calculations ◽  
Three Phase ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
Scanning Electron ◽  
Phase Relationships

The phase relations in the Al-Y-Zr ternary system at 873 K have been investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) in backscattered electron imaging (BSE) modes. Six three-phase equilibria are determined and no ternary compound is observed. In the meantime, first principle calculations are used to provide theoretical guidance to understand the experimental results.

scholarly journals Silicon location through backscattered electron imaging and X-ray microanalysis in leaves of Cyperus ligularis L. and Rhynchospora aberrans C. B. Clarke (Cyperaceae)

2012 ◽  
Vol 26 (2) ◽  
pp. 275-280 ◽  
Author(s):  
Maria Emília Maranhão Estelita ◽  
Ana Claudia Rodrigues
Keyword(s):  
Cell Walls ◽  
Colloidal Silica ◽  
Structural Changes ◽  
Epidermal Cells ◽  
Vascular Bundles ◽  
Backscattered Electron Imaging ◽  
X Ray ◽  
Backscattered Electron ◽  
Taxonomic Groups ◽  
Electron Imaging

The Cyperaceae show the ability to incorporate silicon by depositing colloidal silica, which is recorded by the occurrence of projections in the form of cones, in inner tangential walls of some epidermal cells or "silica cells". Leaves of C. ligularis and R. aberrans were analyzed through the technique of electron backscatter. Cyperus ligularis accumulates silica, in addition to "silica cells", in some stomata, trichomes and the cell walls that surround the cavities of the aerenchyma. The silica in the latter occurs in various forms; however, the cells located near the vascular bundles have conical projections, similar to those of the epidermis. Rhynchospora aberrans presents "silica cells" whose projections have tapered "satellites". In this species, silica also occurs in stomata and certain epidermal cells adjacent to them. It appears that the silicon deposition occurs in combination with the wall (with no apparent structural changes), and structures of secretion, or projections of the wall. These structural changes in the species, and location, are probably related to functional and environmental factors, especially the soil, in addition to relation with taxonomic groups.

Sign in / Sign up

Export Citation Format

Share Document