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Confocal micro‐XRF analysis of light elements with Rh X‐ray tube and its application for painted steel sheet
Author(s) -
Yagi Ryota,
Tsuji Kouichi
Publication year - 2015
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/xrs.2599
Subject(s) - x ray tube , calibration curve , analytical chemistry (journal) , materials science , calibration , confocal , x ray fluorescence , detection limit , x ray , fluorescence , tube (container) , optics , chemistry , anode , physics , composite material , electrode , chromatography , quantum mechanics
A confocal micro‐X‐ray fluorescence (XRF) instrument with a vacuum chamber was applied for analysis of light elements for painted steel sheet. Because this instrument is equipped with a Rh‐anode X‐ray tube, light elements are excited more effectively by the Rh‐L lines. However, it was difficult to analyze Cl, because the energies of the Cl‐K lines are close to those of the Rh‐L lines. Thus, we applied an Al thin film as a primary X‐ray filter to eliminate the Rh‐L lines and confirmed the feasibility of Cl analysis using a Rh X‐ray tube. Rh‐L scattered X‐rays were observed by using an acrylic plate as a sample. The Rh‐L scattered X‐rays were completely absorbed by a 24 µm thick Al filter. A calibration curve of Cl was prepared by using certified reference materials with different Cl concentrations. The limit of detection for Cl was 11.9 ppm as estimated from the calibration curve. Confocal micro‐XRF with a Rh X‐ray tube enables the analysis of low Z elements including Cl by applying an Al filter. This technique was applied for a practical painted steel sheet sample. The elemental image of Cl was successfully observed after corrosion in NaCl solution as well as other light elemental maps. Copyright © 2015 John Wiley & Sons, Ltd.