EBSD

Uses               Workflow

What is EBSD?

Electron backscatter diffraction (EBSD) is emerging as a valuable analytical tool for materials science and earth sciences. The EBSD technique permits statistical data on grain size and grain texture, both of which are extremely important parameters in determining the strength of crystalline materials. A good general reference on all aspects of EBSD can be found at www.ebsd.com

The reflected signal from the sample surface used in EBSD is generated within the first 10’s nm of the sample surface. Thus it is critical to have a surface that is near perfect, with little or no damage. Broad argon beam tools have historically been used to produce damage-free transmission electron microscope (TEM) samples. The same techniques are now applied for scanning electron microscope (SEM) samples used to produce EBSD signals.

Uses

3D EBSD with broad argon beam tools

This can be done manually by returning the sample to the PECS II instrument and polish removing from 5 – 500 nm simply by varying the time. An example is shown below.

A recent development by Gatan is to automate this process by integrating a PECS II instrument onto a FIB/SEM. The system was installed in November, 2015 and data will be published shortly.

Workflow

Step 1: Prepare the sample

Specimens must be prepared carefully for EBSD applications, as the technique requires a very smooth specimen to avoid shadows on the diffraction pattern. The best way to accomplish this is to utilize a fully automated argon ion polishing system, like the PECS II instrument. By using a PECS II instrument, you can produce damage free surfaces, cross sections, and deposit coatings to protect or eliminate charging. Typical conditions for planar polish in the PECS II are the guns set to 2 – 4° to the surface with a coarse polish at 4 – 6 keV for 1 – 2 h, followed by a lower polish voltage of 1 keV for 30 – 60 min.

Step 2: Transfer to SEM

Step 3: Imaging