NCJ Number
238072
Journal
Canadian Society of Forensic Science Journal Volume: 44 Issue: 4 Dated: December 2011 Pages: 121-129
Date Published
December 2011
Length
9 pages
Annotation
This technical note reports the unusual appearance of the primer surfacer layer used on Saturn vehicles manufactured at the Springhill, Tennessee, and the Wilmington, Delaware, plants.
Abstract
Shiny, black, opaque, micron-sized, flake-like particles were observed in the primer surfacer layer when it was examined using a stereomicroscope. Microscopically, these particles resemble metallic flakes which are not commonly present in primer layers. These flake-like particles were observed in the primer surfacer layer of 50 different Saturn vehicles manufactured between 1992 and 2006. Scanning electron microscopy - energy dispersive X-ray (SEM-EDX) analysis was used to establish that these particles were non-metallic. These particles were identified as graphite flakes using a combination of X-ray diffraction (XRD) analysis, scanning transmission electron microscopy (STEM), and Raman spectroscopy. Prior to this, graphite flakes have not been observed in casework. However, identification of graphite is not possible using Fourier transform infrared (FTIR) spectroscopy, a standard technique for the characterization of paint samples. This illustrates the importance of using more than one analytical technique to identify the principal components of paint. (Published Abstract)