Analytical Sciences

Total Quantification of Magnesium Alloys by X-ray Fluorescence Spectrometry Using the “Standardless” Fundamental Parameter Method

Wataru MATSUDA,* Atsushi MORIKAWA,* Atsushi OHBUCHI,* Takao MORIYAMA,* and Toshihiro NAKAMURA*,**

*Rigaku Corporation, 14-8 Akaoji-cho, Takatsuki, Osaka 569-1146, Japan
**Meiji University, 1-1 Kanda-Surugadai, Chiyoda, Tokyo 101-8301, Japan

X-ray fluorescence spectrometry using the “standardless” fundamental parameter method has been studied for the whole elemental analysis of magnesium alloys. Twelve major elements were determined: Mg, Al, Si, Ca, Mn, Fe, Ni, Cu, Zn, Ag, Sn and Pb. The specimens used were over 30 mm in diameter and greater than 10 mm thick to determine Sn Kα which has the largest analyzing depth (9 mm) through the alloy samples. The surfaces of the specimens were polished with fine alumina abrasive paper (#240) to remove the oxide layer and to avoid the influence of any surface roughness variation on the intensities of Mg Kα, Al Kα and Si Kα which have smaller analyzing depths. The total quantitative values of the 12 elements, determined by the FP calculation, were normalized to 100 mass%. The analytical values obtained by this method were comparable to those obtained by the conventional calibration curves method. The relative standard deviations were 6.6% for 0.0014 mass% of Ni, and 0.005% for 93.82 mass% of Mg in AZ91 series Mg alloys. The validation results of the proposed method for 12 elements were successful for the five CRMs tested.

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