The kind folks over at Chemistry-Blog.com sent over a stir rod to get scanned under our Scanning Electron Microscopes.
We’ve made a report for you guys, so, here goes:
Stir Rod Analysis
Analysis and reports by:
Ben Abraham, Analyst
babraham@aspexcorp.com
This is what was sent in to us …
SEM parameters used during an analysis:
Instrument: ASPEX eXplorer
Beam Current: 20 KeV
Spot Size: 40%
Working distance: 16.0 mm
Variable Pressure: 0.30 torr
Detector: BSED
Instrument and Software
The Stir Rod was analyzed using the ASPEX PSEM. Chemical composition data was
acquired using a SDD detector with a 30 mmsq- Ultra Thin Window SDD detector.
Reports were prepared using ASPEX imaging reporter.
Testing performed
Backscatter electron detector (BSED) images were collected under variable pressure
conditions (VP set point is 0.3 torr).
Image 1: Image from BSED detector. EDS performed on a particle on the surface.
| Element | Normalized K-Ratio rounded to first decimal |
| C | 4.2 |
| O | 73.9 |
| Al | 16.4 |
| Si | 5.5 |
Image 2: Image from BSED detector. EDS performed on a particle on the surface.
| Element | Normalized K-Ratio rounded to first decimal |
| C | 3.1 |
| O | 30.5 |
| Al | 0.4 |
| Si | 0.5 |
| Fe | 65.5 |
Image 3: Image from BSED detector. EDS performed on a particle on the surface.
| Element | Normalized K-Ratio rounded to first decimal |
| C | 6.7 |
| O | 35.1 |
| Na | 5.1 |
| Mg | 3.5 |
| Al | 2.3 |
| Si | 7.2 |
| S | 12.1 |
| Cl | 10.0 |
| Ca | 4.0 |
| Fe | 3.1 |
| Zn | 11.0 |
Image 4: Image from BSED detector. EDS performed on a particle on the surface.
| Element | Normalized K-Ratio rounded to first decimal |
| C | 4.6 |
| O | 29.3 |
| Al | 1.0 |
| Si | 0.3 |
| Cr | 64.6 |
Image 5: Image from BSED detector. EDS performed on a particle on the surface.
| Element | Normalized K-Ratio rounded to first decimal |
| C | 2.9 |
| O | 33.6 |
| Al | 49.0 |
| Si | 14.4 |
Image 6: Image from BSED detector. EDS performed on a particle on the surface.
| Element | Normalized K-Ratio rounded to first decimal |
| C | 12.1 |
| O | 4.0 |
| F | 80.1 |
| Al | 3.9 |
[...] The results are in, and they are as cool as expected. Analyst Ben Abraham captured several images of our very, very old stir bar, with corresponding chemical composition analysis. The stir bar contains several elements, some expected, some not. At various sampling points around the stir bar, carbon, oxygen, aluminum, silicon, iron, sodium, magnesium, sulfur, chlorine, calcium, zinc, fluorine, and chromium (!) were identified. Clearly, after several good years of wear and tear, the surface of the stir bar becomes irregular and several impurities remain on the stir bar. [...]
I think I have read this post somewhere else but nevertheless it is informative. If you ever need to expand your knowledge about Chemistry, let me know.
Margie
Chemistry Expert
10bomb.com