Auger electron spectroscopy compounds

These experiments also show the value of NEXAFS as a technique for following the kinetics of surface processes. We have shown that experiments can be tailored so a specific reaction can be studied, even if gas evolution is not involved. This represents an advantage over thermal desorption experiments, where several steps may be required in order to desorb the products to be detected. Another advantage of NEXAFS is that rates are measured isothermally, so the kinetic parameters can be determined with accuracy. Finally, NEXAFS is not a destructive technique, so we need not to worry about modifying the surface compounds while probing the system, as would be the case with other techniques such as Auger electron spectroscopy. 

The performance of the V-Mg oxide catalyst was found to depend on its composition and the method of preparation. As to the composition, it was found that catalysts containing very small or very large amounts of vanadium were not selective. The better catalysts in terms of both activity and selectivity consisted of from about 10 to 60 wt% V2O5 (35). Analyses of these catalysts by X-ray diffraction, Auger electron spectroscopy, and infrared spectroscopy showed that they contained only two identifiable phases Mg orthovanadate (Mg3(V04)2) and MgO. Since MgO had low activity and poor selectivity under the reaction conditions employed, it was concluded that the active phase was Mg orthovanadate (Mg3(V04)2). Indeed, it was later shown that this compound was a selective catalyst (26). 

The chemistry of polymer surfaces and their wear can be measured in situ with Auger electron spectroscopy, X-ray photoelectron spectroscopy and secondary ion mass spectrometry. These tools provide elemental, compound analysis and distinguish among a series of homologs respectively. 

Besides the chemical and radiochemical composition, other properties of the collected materials are also often of interest, such as the natine of the chemical compounds present in these substances. For example, the structure of oxide compounds after isolation from the base material or from the coolant is analyzed by X-ray diffractometry or by Mdssbauer spectrometry. Other microanalytical techniques can be directly applied to oxide layers deposited on surfaces, e. g. of steam generator tube sections. Examples in this field are Auger electron spectroscopy for the determination of element concentrations in micrometer areas and X-ray induced photoelectron spectroscopy for the determination of the chemical states of the individual elements. In order to obtain depth profiles over the thickness of the oxide layer, these techniques often are combined with an argon sputtering process (e. g. Schuster et al., 1988), which removes nanometer fractions from the swface prior to the next analysis step. By y spectrometry of the specimen after each sputtering step, the profile of the radionuclides in the oxide layer can also be determined. 

Mg and possessed a superior corrosion resistance than a couple of Mg alloys and another amorphous alloy Mg65Cu2sYio (Fig. 6.6). Interestingly, the Auger electron spectroscopy (AES) analysis showed that there was no trace of Ga compounds in the passive layer and that it was enriched only with aluminium oxide. However, AES depth profiles suggested the deposition of metallic Ga below the corrosion layer, whieh was further confirmed by the XRD results. It appears that the euhaneed eorrosion resistance was only due to the aluminium oxide enrichment at the surfaee of this alloy. These researeh findings opened up avenues for the development of amorphous alloys with higher aluminium eontent that eould provide not only an improved electrochemical behaviour but superior meehanieal properties as well. 

Al-rich compoations of this compound. Auger electron spectroscopy has shown that, for compounds with the Al-rich compositions, the aluminum concentration at the grain boundary is greater than its bulk composition. 

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