Quantitative electron probe microanalysis of carbon in binary carbides. I—principles and procedures

Bastin, GF Giel; Heijligers, Hjm Hans

doi:10.1002/xrs.1300150212

Cited by 80 publications

(63 citation statements)

References 11 publications

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“…Contrary to our previous studies on quantitative EPMA of carbon 1 and Boron 2 which were completed in one year and less than a year, respectively, the present work on Nitrogen has taken considerably more time. As a matter of fact the micro probe measurements were carried out over a period of approx.…”

Section: Introductionmentioning

confidence: 69%

Quantitative electron probe microanalysis of nitrogen

Bastin

Heijligers

1991

Scanning

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Quantitative electron probe microanalysis of nitrogen has been performed on 18 nitride specimens in the voltage range of 4–30 kV. A conventional lead stearate and a new W/Si multilayer analyzer crystal (2d = 5.98 nm) were used simultaneously. The net peak count rates on the latter crystal were approximately 2.8 times higher than on the lead stearate crystal. In addition, significant improvements in the peak to background ratios were achieved, which proved critical when dealing with difficult nitrides such as ZrN, Nb2N, and Mo2N. A most conspicuous feature of the new crystal, however, is its effective suppression of higher‐order reflections in the wavelength range of N‐Kα. As a result, backgrounds are free of interfering lines and spectral artifacts, which facilitates accurate background determination. Two procedures for the analysis of nitrogen in the presence of titanium are also discussed. One procedure is based on the assumption that the area–peak factor (APF, integral k‐ratio/peak k‐ratio) of the N‐Kα peak in Ti–N compounds relative to a nitrogen standard (Cr2N) has a fixed value which can be used in order to separate the Ti‐ll peak from the N‐Kα peak. Extensive tests on a number of compositions in the Ti–N system have shown that it is possible to do quantitative analysis of nitrogen in Ti–N compounds with a relative accuracy of better than 5%. For very low levels of nitrogen (below 15 at%) the APF method was found unsuitable. In such cases, however, the well‐known multiple least‐squares digital‐fitting techniques appeared to do an excellent job. In order to account for the effects of peak shape alterations in the N‐Kα peak, all nitrogen spectra were recorded in integral fashion and compared with those of the Cr2N standard. The shape alterations for the N‐Kα peak were much smaller than for B‐Kα and C‐Kα radiations: The observed values for the area–peak factor relative to Cr2N differed less than 5% from unity. The present work has resulted in a database containing 144 integral k‐ratios for N‐Kα and 149 peak k‐ratios for the x‐ray lines of the metal partners in the nitrides. Our own Gaussian ϕ(pz) matrix correction procedure “PROZA,” used in conjunction with a set of improved mass absorption coefficients, yielded excellent results for the nitrogen data: An average value of kcalc/Kmeas of 1.0051 and a relative root mean square deviation of 3.99%.

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Section: Introductionmentioning

confidence: 69%

Quantitative electron probe microanalysis of nitrogen

Bastin

Heijligers

1991

Scanning

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“…The measurements were performed at 4, 6,8,10,12,15,20,25 and 30keV. In order to avoid excessive dead-time corrections for the metal lines (see Part I), the metals and carbon were measured separately.…”

Section: Methodsmentioning

confidence: 99%

Quantitative electron probe microanalysis of carbon in binary carbides. II—data reduction and comparison of programs

Bastin

Heijligers

1986

X-Ray Spectrometry

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The performances of four current matrix correction programs have been tested on a data file of measurements on 13 binary carbides between 4 and 30 kV. Both the metal lines as well as the carbon Kα line have been measured, which resulted in 145 k ratios for the metals (relative to elemental standards) and 117 integral k ratios for carbon Kα (relative to Fe3C). Evidence is presented that the existing sets of mass absorption coefficients for carbon Kα radiation are perhaps not fully consistent and a new set is therefore proposed, which is in better agreement with the experimental results. Finally, it is shown that the modified Gaussian ϕ(ρz) approach, when used in conjunction with the new set of mass absorption coefficients, leads to unexpectedly good results, with a relative root‐mean‐square value of 3.7%. This demonstrates that even for carbon very good accuracy can be obtained, provided that proper care is exercised in the measurements and the proper procedures are followed.

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“…the atomic number and the absorption corrections, the latter are likely to be responsible for the systematic deviations. Of course also the errors introduced by the fundamental parameters must be considered; Bastin and Heijligers [51] and Sevov et al [4] showed remarkable changes of the k'/k-values resulting from even small uncertainties of the mass absorption coeh'icients. [1].…”

Section: Primary Ionization Intensitiesmentioning

confidence: 99%