[B._Beckhoff,_et_al.]_Handbook_of_Practical_X-Ray_(b-ok.org).pdf

8 philips 1400 sequential rh de jonghs theoretical

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8 Philips 1400 (Sequential) Rh de Jongh’s theoretical correction coefficients 7 [85] 9 RigakuZSX100e (Sequential) Rh Confrontation method between measured and calculated intensity based on FP 12 -
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24 T. Arai of 26.2 wt% and for chromium it was 0.023 wt% at 14.5 wt%. They are one- fifth of the RMS-differences in Table 1.3. It was noted that no matrix correc- tions were required for specimens with only small concentration variations. Lucas-Tooth and Pyne discussed a formula where the correction factor was a constant plus the sum of products of the individual X-ray intensities of the constituent elements with correction coefficients. RMS-differences of 0.07 wt% in chromium and 0.032 wt% in manganese were reported [77]. A third report sponsored by the ASTM committee in 1964 was presented by Gillieson, Reed, Milliken, and Young [78]. Simultaneously, a report about spectrochemical analysis of high temperature alloys by spark excitation was presented. Referring to the matrix correction methods by Lucas-Tooth and Price [79] and Lucas-Tooth and Pyne, they applied a correction on the basis of X-ray intensities of the constituent elements. The measured intensities of aluminum and silicon constituents should be added in order to improve the matrix correction, thereby increasing the accuracy. Lachance and Traill studied simple matrix correction equations that were one plus the sum of products of the weight fraction of constituent elements and correction coefficients [63]. Based on the analysis of high nickel alloys that were selected from the application report, RMS-differences were calculated and are shown in Table 1.3. On the basis of the Lachance–Traill equations, Caldwell derived two kinds of correction equations [38]. The first one was a fixed correction coefficient equation and the second one was a variable correction coefficient equation for wider concentration applications, on which the third or fourth constituent elements exerted reform. RMS-differences of major constituents in variable correction coefficient calculations improved those of the fixed correction coef- ficient method. Ito, Sato, and Narita [82] studied the JIS correction equations that con- sisted of the product of a factor containing a quadratic polynomial of the intensity of the measured X-rays, and a matrix correction factor which was authorized by the JIS Committee. The coefficients of the intensity part were determined by least-squares algorithms from binary alloys with known chem- ical composition or from mathematical models, and the second factor was one plus the sum of products of the weight fractions of the constituent elements and correction coefficients, in which the terms containing the base component and the analyzing elements were excluded. In practical applications for nickel base alloys the correction coefficients of light and heavy elements from iron- based alloys were used; for the analysis of the major constituent elements, chromium, iron, and cobalt in nickel base alloys, the correction coefficients were determined experimentally.
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