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  • 1
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A matrix effect correction is required to improve the accuracy of quantitative AES analysis. The correction includes terms involving the atomic density (n), electron back-scattering factor (R) and electron escape depth (L). Many schemes have been proposed by various people for corrections of the R and L terms. However, up to now, there have been no systematic investigations of the correction accuracy of the proposed schemes. We have evaluated the correction accuracy, based on measured intensity data for Au—Cu alloys of different compositions. Comparison was made between the observed intensity ratio K (=Iunk/Istd) and the calculated intensity, ratio K′ (= C(nunk/nstd)(Runk/Rstd)(Lunk/Lstd)), where C and I represent the concentration and intensity, respectively. The superscripts ‘unk’ and ‘std’ denote that the parameters are for unknown and standard specimens, here the pure elements. If the correction works well, the error Er (= K′ — K)/(K) will become smaller. Evaluations were carried out on three schemes for the R correction and on seven schemes for the L correction using the Au 239 eV, Au 2024 eV and Cu 920 eV transitions. The root mean square (RMS) of the calculated errors showed several per cent for the best case and 20-30% for the worst case. The RMS error varied a few per cent between schemes for the R correction but it varied ∼30% for the L correction.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The Japanese VAMAS-SCA working group is composed of 19 institutes. Three kind of Au—Cu alloys (Au 75 at.-%-Cu 25 at.-%, Au 50 at.-%-Cu 50 at.-%, Au 25 at.-%-Cu 75 at.-%) were prepared, and these specimens, pure Au and pure Cu were distributed to the members of the VAMAS-SCA working group. The surface concentrations of these alloys were calculated from the Auger peak amplitudes in two ways. One method used the published relative sensitivity factors, and the other used pure Au and Pure Cu as the standard materials. The mean values of the surface concentrations calculated with the published relative sensitivity factors were almost the same as those calculated with the standard materials. This means that the published relative sensitivity factors are reliable to some extent. The error of the surface concentration calculated with pure Au and pure Cu as the standard materials lay between about 3% and 10%, and that with the relative sensitivity factors lay between about 7% and 20%. The calculated surface concentrations of Au were larger than the bulk concentrations of Au when the matrix effect was neglected.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 19 (1992), S. 430-434 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A new method for coating the inner surface of ultrahigh-vacuum (UHV) vessels with an inert material is proposed, namely coating with highly oriented graphite layers which precipitate on the surface of a carbon-doped nickel substrate. By using various surface analytical methods, characterization of the precipitated graphite has been performed. AES measurements at elevated temperatures clarified the surface precipitation process on polycrystalline Ni-C. Low-energy electron diffraction studies on Ni(111) showed that the surface-precipitated graphite grew epitaxially with the substrate and its structure was found to agree with that of highly oriented pyrolytic graphite. Reflection high-energy electron diffraction studies revealed that the basal planes (0001) of precipitated graphite preferentially cover the surface even in the case of polycrystalline Ni-C. AES measurements in an O2 atmosphere showed that the graphite-covered surface was hardly oxidized by prolonged oxygen exposure. Thermal desorption spectroscopy measurements suggested that the desorption of CO after O2 dosing was much smaller from the graphite-precipitated surface than from a stainless steel surface. From the standpoint of applications to problems in engineering, graphite precipitation on metals is found to be a promising method for making an inert and low-outgassing surface for UHV use.
    Additional Material: 6 Ill.
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  • 4
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The Japanese VAMAS-SCA working group is composed of 19 institutes. Three kinds of Au-Cu alloys (Au25 at%-Cu75 at%, Au50 at%-Cu50 at%, Au75 at%-Cu25 at%) were prepared, and these specimens were distributed to the members of Japanese VAMAS-SCA working group and Auger peak amplitude ratios were measured to clarify the correlation factor of different types of spectrometers. The comparison was carried out by using the relative sensitivity factor for Au and Cu. The relative sensitivity factor for lower energy varied from spectrometer to spectrometer, but that for higher energy did not vary so much. Therefore, to carry out the inter-laboratory comparison of the data, the transfer of the data of peak amplitude at higher energy should be recommended.
    Additional Material: 5 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 16 (1990), S. 183-187 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: For the improvement of quantitative surface analysis using Auger electron spectroscopy (AES) we propose an Ni—Co alloy system as a candidate for a ‘primary reference material’ to be used for evaluating the accuracy of quantitative surface analysis. A Ni—Co alloy was chosen for two reasons. Firstly, the concentrations of the alloys (Ni49Co51,Ni75Co25) at the surface and in the near-surface region were found to be homogeneous, i.e. phenomena such as preferential sputtering and ion irradiation-induced surface segregation were no observed with angle-resolved XPS measurements during 1 keV Ar+ ion sputtering. Secondly, the corrections of matrix effects of Ni—Co alloys, such as the atomic density, the back-scattering factor and inelastic mean free path corrections, were calculated and found to be negligibly small.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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