The chips corresponded to 5 squares, 1 circle and 2 ellipsoid items. All 5 square chips appeared essentially identical with respect to size and physical appearance. All 5 weighed 160 mg. The diameter of the circular chip and the smaller diameter of the ellipsoid chip were similar in size to the lengths of the sides of the square chips. The circular chip weighted 119 mg. and the two ellipsoid chips weighed 168 mg. (These measurements are all within plus or minus one mg for each type.)
At this point, analyses have been conducted only on the square chips. Using a micrometer, a representative square chip had the dimensions: 6.368 mm x 6.361 mm x 1.596 mm. This gives a volume of 64.65 mm^3. Using a weight of 160 mg, this would correspond to a density of 2.47 mg/mm^3. The squares had two distinguishable sides: a "top" side with rounded edges, and a "bottom" side that was squared off --as if they had possibly been "punched out" from the top. Using a scanning electron microscope (SEM), photographs of the top side (photo 1) and the bottom side
(photo 2) were generated.
The SEM was configured for energy dispersive spectroscopy (EDS) which allows determination of the elemental content of the area being scanned by the electron beam. The bombardment of electrons results in the release of X-rays whose wavelengths are characteristic of the elements being targeted. A detector is able to translate this information into specific "peaks" which are then recorded. The analyses showed that over a broad (averaged) area on the surface of the top and bottom of the square chips (
Figure 1 and Figure 2), only aluminum (Al) could be detected. It was also noted that despite the differences in apparent texture on the sides of the chips, the EDS spectra were essentially identical (not shown) -- i.e. only aluminum was detected in both the rougher and smoother portions. The density of aluminum is 2.7 and thus close to the value of 2.47 determined from our calculation. The curved top edges might contribute to the small difference.
High magnification showed small granular particles embedded in the surface of the squares (
photo 3 and
photo 4). These had sizes of just a few microns (um). EDS showed that these contained silicon (Si) (Fig. 3).
A square chip was embedded in epoxy, cut through the middle and polished in order to obtain a good cross section for SEM and EDS analyses. The SEM was done using a "backscattering" configuration which allows heavier elements to look brighter than less-heavy elements. Photo 5 shows that there are white (i.e. brighter) particulate flake-like materials scattered through the aluminum. These particles had a high iron (Fe) content as indicated in Fig.5 where the area measured was within a single particle. Small amounts of silicon (Si) and manganese (Mn) were also evident. The elements in these particles were not detectable when EDS was measured over a broad area of the chip cross-section (Fig. 4), presumably because of their small respective areas.
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