Forensic Comparison of Automotive Aluminum Wheel Fragments Using Synchrotron Radiation X‐ray Fluorescence with 18‐ and 116‐keV Excitation X‐rays

摘要

Abstract The performance of synchrotron radiation X‐ray fluorescence ( SR ‐ XRF ) spectrometry for nondestructive discrimination of small fragments of automotive aluminum wheels was studied. Fragments ( 500 × 500 μm 2 ) of 45 kinds of wheels were first analyzed by scanning electron microscopy–energy dispersive spectroscopy ( SEM ‐ EDS ) and then by SR ‐ XRF . Despite the Mg/Al intensity ratio being a useful identification index, SEM ‐ EDS was not efficient enough because of the absence of other meaningful indicators of comparison. Conversely, pairwise comparison was conducted and a 92.9% identification was achieved via SR ‐ XRF using 18‐keV X‐rays. Trace heavy elements in the high‐energy region were detected by SR ‐ XRF using 116‐keV X‐rays, and an 82.9% identification was obtained. Combined use of 18‐ and 116‐keV X‐rays allowed 98.2% identification. Hence, SR ‐ XRF is a powerful tool for nondestructive discrimination of automotive aluminum wheels with high precision using trace elements in a wide energy region.