Energy Dispersive X-Ray Spectroscopy EDS

Energy-Dispersive X-Ray Spectroscopy, EDS, is a specific technique for the detection and energy distribution determination of X-Ray Fluorescence, XRR XRF is the phenomena where X rays are emitted from a material when bombarded by high energy radiation (electrons, ions, X rays, neutrons, gamma rays). Some of the X-ray energies emitted are characteristic of the atoms present, allowing atomic identification in the material of interest. 

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XRF is closely related to the EPMA, energy-dispersive X-Ray Spectroscopy (EDS), and total reflection X-Ray Fluorescence (TRXF), which are described elsewhere in this encyclopedia. Brief comparisons between XRF and each of these three techniques are given below. 

Film-forming chemical reactions and the chemical composition of the film formed on lithium in nonaqueous aprotic liquid electrolytes are reviewed by Dominey [7], SEI formation on carbon and graphite anodes in liquid electrolytes has been reviewed by Dahn et al. [8], In addition to the evolution of new systems, new techniques have recently been adapted to the study of the electrode surface and the chemical and physical properties of the SEI. The most important of these are X-ray photoelectron spectroscopy (XPS), SEM, X-ray diffraction (XRD), Raman spectroscopy, scanning tunneling microscopy (STM), energy-dispersive X-ray spectroscopy (EDS), FTIR, NMR, EPR, calorimetry, DSC, TGA, use of quartz-crystal microbalance (QCMB) and atomic force microscopy (AFM). 

Linear absorption measurements can therefore give the first indication of possible alloy formation. Nevertheless, in systems containing transition metals (Pd-Ag, Co-Ni,. ..) such a simple technique is no longer effective as interband transitions completely mask the SPR peak, resulting in a structurless absorption, which hinders any unambiguous identification of the alloy. In such cases, one has to rely on structural techniques like TEM (selected-area electron diffraction, SAED and energy-dispersive X-ray spectroscopy, EDS) or EXAFS (extended X-ray absorption fine structure) to establish alloy formation. 

To find the distribution of iron within the nanotube walls an energy dispersive x-ray spectroscopy (EDS) line scan was performed via scanning transmission electron microscopy (STEM), see Fig. 5. 55. The intensity of both the TiK and FeKa lines are maximum at the center of the wall due to its torus shape. Despite the presence of isolated hematite crystallites, a more or less uniform distribution of iron relative to the titanium can be seen across the wall. STEM line scans were performed across a number of walls, and while the average relative intensity of the TiK and FeKa lines varied from wall to wall the relative distribution across a single wall remained uniform. It appears that some of the iron goes into the titanium lattice substituting titanium ions, and the rest either forms hematite crystallites or remains in the amorphous state. 

Local chemical composition from areas less than 1 nm in diameter can be measured by energy dispersive X-ray spectroscopy (EDS) or electron energy loss spectroscopy (EELS). Such spectroscopic information may be presented in 2D maps showing the spatial element distribution in the specimen (13). Furthermore, information about the local density of unoccupied electron states of a specific element can be extracted from EELS data and used to estimate the oxidation state and the local coordination geometry of the excited atoms (14). In some favorable cases, electronic structure information with a resolution of about 1 eV from individual atomic columns has been attained (15,16). Recent developments of monochromators and spectrometers have brought the resolution down to 0.1 eV (17,18), and this capability may offer new opportunities to determine relationships between electronic structure information, the atomic arrangements and the catalytic activities of solids. 

Abstract. Gas interstitial fullerenes was produced by precipitation of C6o from the solution in 1,2 dichlorobenzene saturated by O2, N2, or Ar. The structure and chemical composition of the fullerenes was characterized by X-ray powder diffraction analysis, FTIR spectroscopy, thermal desorption mass spectrometry, differential scanning calorimetric and chemical analysis. The images of fullerene microcrystals were analyzed by SEM equipped with energy dispersive X-ray spectroscopy (EDS) attachment. Thermal desorption mass spectroscopy and EDS analysis confirmed the presence of Ar, N and O in C60 specimens. From the diffraction data it has been shown that fullerite with face centered cubic lattice was formed as a result of precipitation. The lattice parameter a was found to enhance for precipitated fullerene microcrystals (a = 14.19 -14.25 A) in comparison with that for pure C60 (a = 14.15 A) due to the occupation of octahedral interstices by nitrogen, oxygen or argon molecules. The phase transition temperature and enthalpy of transition for the precipitated fullerene microcrystals decreased in comparison with pure Cgo- Low temperature wet procedure described in the paper opens a new possibility to incorporate chemically active molecules like oxygen to the fullerene microcrystals. 

Synthesis of alloyed silver-palladium bimetallic nanoparticles was achieved by /-irradiation of aqueous solutions containing a mixture of Ag and Pd metal ions using different Ag/Pd ratios. The synthesis of alloys implies the simultaneous radio-induced reduction of silver and palladium ions. The nanoparticles were characterized by UV-visible spectroscopy, transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The Ag-Pd nanoparticles display a face-centered cubic (fee) crystalline structure. The lattice parameter was measured for several Ag/Pd ratios and was found to closely follow Vegard s law, which indicates the formation of homogeneous alloys. In order to avoid the simultaneous reduction of silver and palladium ions which leads to alloyed bimetallic nanoparticles. 

Ibe structure, composition, and morphology of the oxidation products were investigated by X-ray diffraction (XRD). energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). 

The brazed Joints were mounted in epoxy, ground, polished, and examined using Field Emission Scanning Electron Microscopy (FESEM) (model Hitachi 4700) coupled with energy dispersive x-ray spectroscopy (EDS). Microhardness scans were made with a Knoop indenter across the joint interfaces on a Struers Duramin-A300 machine under a load of 200 g and loading time of 10 s. Multiple (4 to 6) hardness scans were made across each joint to check the reproducibility. 

FIGURE 6.19 TEM energy-dispersive x-ray spectroscopy (EDS) analysis results. 

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