|
Low
Magnification Photography with the SEM
The scanning electron microscope
(SEM) can be used to take good, three dimensional,
black and white photographs of small
objects or subjects. An example that most people are
familiar with are the numerous photographs published
in the news media (when they haven't anything better
to report) of ticks, fleas, bedding mites, etc.
Indeed at high magnifications, these "monsters" are
fearsome.
An example of using an SEM in low
magnification photography is shown in the following
photograph. A piece of debris, presumably left in
the patient's nasal cavity following surgery, is
shown in Photograph A, taken with a digital camera.
Photograph
A
Although the digital photograph
shown in A above is very revealing, a much better
three-dimensional view (although online in black and
white) is shown in Photograph B.
Photograph B
This SEM photograph is at a
magnification of 20x and shows the topography
(shape) of the subject debris in great detail.
Another use of the SEM for low
magnification photography was an investigation
involving fuel clip failures from a truck fuel
injector. An overall macroscopic photograph of a
failed injector clip is shown in Photograph C
Photograph C
An SEM view of the failed end of
the fuel nozzle clip is shown in the SEM scanning
electron micrograph shown in Photograph D.
Photograph D
Even at a magnification of only
35x in Photograph D, it is evident that the fracture
made is intergranular cracking.
|
Dr.
R. Craig Jerner, Ph.D., PE specializes in accident
investigation and metallurgical failure analysis,
with over 30 years experience as a metallurgical
consultant and accident investigator. He has
testified as a metallurgical expert in over 250
depositions and more than 70 court appearances. If you or someone you know should need the services of Dr. Jerner and J.E.I. Metallurgical, please visit our web site at the buttons below, or e-mail Dr. Jerner --- 