Electron dispersive spectroscopy analysis

Figure 12.17 (a) Scanning electron micrograph of a cross-section of a carbon/carbon composite (b) energy-dispersive spectroscopy analysis showing location of silicon. 

X-ray dii action spectra of the samples were recorded with a PW 1050 Philips spectrometer with Co Ka incident radiation. Transmission electron micrographs and electron dispersion spectroscopy (EDS) analysis were obtained with a Philips CM 12 instrument equipped with Philips 9100 attachment. 

SEM analysis was carried out to examine the fracture and bond characteristics of hardened concretes produced from different sandstone aggregates. The concrete samples for SEM analysis were dried at 105 C for 24 h. The dried concrete samples were carefully broken. Ereshly fractured surfaces were coated with gold in a vacuum evaporator. They were examined by a Scanning Electron Microscope (SEM) to determine morphological and minera-logical features. SEM images were also fitted with Electron Dispersive Spectroscopy (EDS). 

Figure 8.6 (a) Electron dispersive spectroscopy (EDS) spectra with elemental analysis for the... 

A scanning electron microscope can also be equipped with additional instmmentation for electron-excited x-ray analysis (9). In many systems, this is performed in the mode known as energy dispersive x-ray analysis (edx). Other common acronyms for this method are eds for energy dispersive spectroscopy or edax for energy dispersive analysis of x-rays. 

The incoming electron beam interacts with the sample to produce a number of signals that are subsequently detectable and useful for analysis. They are X-ray emission, which can be detected either by Energy Dispersive Spectroscopy, EDS, or by Wavelength Dispersive Spectroscopy, WDS visible or UV emission, which is known as Cathodoluminescence, CL and Auger Electron Emission, which is the basis of Auger Electron Spectroscopy discussed in Chapter 5. Finally, the incoming... 

Chong et al. [742] have described a multielement analysis of multicomponent metallic electrode deposits, based on scanning electron microscopy with energy dispersive X-ray fluorescence detection, followed by dissolution and ICP-MS detection. Application of the method is described for determination of trace elements in seawater, including the above elements. These elements are simultaneously electrodeposited onto a niobium-wire working electrode at -1.40 V relative to an Ag/AgCl reference electrode, and subjected to energy dispersive X-ray fluorescence spectroscopy analysis. Internal standardisation... 

Although a number of secondary minerals have been predicted to form in weathered CCB materials, few have been positively identified by physical characterization methods. Secondary phases in CCB materials may be difficult or impossible to characterize due to their low abundance and small particle size. Conventional mineral identification methods such as X-ray diffraction (XRD) analysis fail to identify secondary phases that are less than 1-5% by weight of the CCB or are X-ray amorphous. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM), coupled with energy dispersive spectroscopy (EDS), can often identify phases not seen by XRD. Additional analytical methods used to characterize trace secondary phases include infrared (IR) spectroscopy, electron microprobe (EMP) analysis, differential thermal analysis (DTA), and various synchrotron radiation techniques (e.g., micro-XRD, X-ray absorption near-eidge spectroscopy [XANES], X-ray absorption fine-structure [XAFSJ). 

This chapter summarizes results obtained during the past 5 years, on the design, preparation and study of titanium and vanadium compounds as candidate precursors to TiC, TiN, VC, and VN. The study of the precursor molecules was conducted through several steps. After their synthesis, thermoanalytical studies (TG-DTA), coupled to simultaneous mass spectroscopic (MS) analysis of the decomposition gases, were carried out to determine their suitability as precursors. CVD experiments were then conducted and were followed by characterization of the deposits by scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and electron microprobe analysis with wavelength dispersion spectroscopy (EPMA-WDS). 

The thickness of the deposits was determined by the ball cratering method or SEM measurement of cross-sections. The elemental composition was determined by electron microprobe analysis with wavelength dispersive spectroscopy (EPMA-WDS) on a Camebax Cameca equipment and by X-ray photoelectron spectroscopy (XPS) on a VG Escalab MK2 apparatus... 

Effects of Chemical Purity. Zirconia tubes from five different sources were analyzed at Pennsylvania State University using scanning electron microscopy, plasma emission spectroscopy, energy dispersive X-ray spectroscopy, and electron beam microprobe analysis. The sources for the tubes included several commercially available tubes as well as tubes fabricated by the Pennsylvania State University Ceramics Department. 

It is evident from the above discussion that catalyst characterization is an activity important for scientific understanding, design, and troubleshooting of catalyzed processes. There is no universal recipe as to which characterization methods are more expedient than others. In the opinion of the writer, we will see continued good use of diffraction methods and electron microscopy, surface analysis, IR spectroscopy, and chemisorption methods, increased use of combined EM and ESCA analyses for determining the dopant dispersion, increased use of MAS-NMR and Raman spectroscopies for understanding of solid state chemistry of catalysts, and perhaps an increased use of methods that probe into the electronic structure of catalysts, including theory. 

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