Scanning Electron Microscopy

The scanning electron microscope (SEM) is little more than a large camera. Instead of using light (to expose a film) the SEM uses a focused beam of electrons. The electrons interact (strike, bounce around, bounce back and undergo a variety of events) with and within the surface being examined. The electrons resulting from this interaction are processed by the SEM electronics and a resulting, real time, black/white image is displayed. The resulting image has the appearance of the object in 3-D. The sample to be examined in the SEM must be examined and contained in a vacuum to facilitate passage of the beam of electrons from the electron source to the sample. Sample size is therefore limited to a size that can be accommodated in the SEM sample chamber. A photograph (scanning electron micrograph) from scanning electron microscopic examination is shown below in Photograph A.

Photograph A  Scanning electron micrograph of a fracture surface at a magnification of 14x.

Photograph B  Dr. Jerner at SEM. Photograph courtesy of Anderson & Assoc., Houston, TX.

Cases requiring the use of a Scanning Electron Microscope (SEM):
Aluminum Fitting Failure
ATV Rollover
Chain Failure
Corrosion Failure Analysis