Energy dispersive X rays spectroscopy

Micrographs showing distribution of Fe and Al amounts across the diffusion boundary formed at (a) 450°C and (b) 600°C. 

An SEM equipped with EDS and ultra-thin window SiLi detector was used for X-ray measurement of electrodeposited hydroxyapatite coatings on Ti6Al4V substrates [57]. X-ray spectra were acquired at a primary beam energy of 30 kV, a current of 5nA and an acquisition time of 180 s. The stoichiometric molar ratio for pure hydroxyapatite is 1.67. X-ray spectra captured in this work showed CaP ratios of 1.51 corresponding to a Ca-deficient hydroxyapatite. 

An Au-catalysed chemical vapour transport and condensation (CVTC) process was used to produce ZnO nanorods and nanowires on Si02 and Si substrates [58], ZnO nanorods with a wide band gap (3.37eV) are regarded as promising candidates for the fabrication of nanoelectronic devices. In this work, EDX spectra of the tip and the body of ZnO nanorods were captured which indicates that Au-Zn alloyed droplets were present at the tips of the fabricated nanorods pointing to a nanorod growth via a vapor-liquid-solid (VLS) mechanism. 

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Energy-dispersive X-ray spectroscopy has been used for quality control and test analysis in many industries including computers, semiconductors, metals, cement, paper, and polymers. EDS has been used in medicine in the analysis of blood, tis-... 

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. 

Before the development of semiconductor detectors opened the field of energy-dispersive X-ray spectroscopy in the late nineteen-sixties crystal-spectrometer arrangements were widely used to measure the intensity of emitted X-rays as a function of their wavelength. Such wavelength-dispersive X-ray spectrometers (WDXS) use the reflections of X-rays from a known crystal, which can be described by Bragg s law (see also Sect. 4.3.1.3)... 

Fig. 4.21. Schematic diagram of spectrometer arrangements for wavelength-dispersive and energy-dispersive X-ray spectroscopy (WDXS/EDXS) in electron microscopy.

The combined use of energy-dispersive X-ray spectroscopy and TEM/STEM is a routine method of analytical electron microscopy enabling both qualitative and quantitative chemical analysis of interfaces and interlayers with high lateral resolution. Reso-... 

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. 

Hill, A. D., A. H. Lehman, H. Arm, and M. L. Parr (2007), Using scanning electron microscopy with energy dispersive x-ray spectroscopy to analyze archaeological materials, J. Chem. Educ. 84(5), 810-813. 

The Atomic emission spectrometry (ICP-AES) results on the solids confirm the chemical purity of Py, Cp, Qz, Cal and Dol samples. The Po sample contains calcium which, after conversion into calcite, gives approximately 10wt% of this mineral. Sid sample contains 10.3 wt% Mn and 1.86 wt% Mg, in agreement with measurements using a Scanning Electron Microscopy coupled to Energy Dispersive X-Ray Spectroscopy (SEM-EDS) analysis again this explains the difference between the measured and theoretical density of the Sid powder. 

In HRTEM, very thin samples can be treated as weak-phase objects (WPOs) whereby the image intensity can be correlated with the projected electrostatic potential of crystals, leading to atomic structural information. Furthermore, the detection of electron-stimulated XRE in the electron microscope (energy dispersive X-ray spectroscopy, or EDX, discussed in the following sections) permits simultaneous determination of chemical compositions of catalysts to the sub-nanometer level. Both the surface and bulk structures of catalysts can be investigated. 

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