This month’s material is a cross-sectioned sandpaper sample. This particular paper is used routinely to polish samples for imaging and elemental analysis in the scanning electron microscope (SEM/EDS). So why is this unique? On one side it has a soft adhesive, for sticking the paper to a spinning platen. The adhesive is attached to a support layer bonded to a paper layer, on which sits the abrasive silicon carbide (SiC) particles that are embedded in a support polymer.

Anyone who has polished, cut, or otherwise prepared samples for cross-sectional analysis knows that the MOST DIFFICULT samples to prepare are those that have very mismatched materials or inclusions. Hard inclusions in a soft matrix tend to pull out, remain fully intact and un-sectioned (see below), and/or move causing distortions in the matrix. But here we see a smooth-faced cross-section through gooey adhesive, paper, polymer, and SiC particles. How did they do that?

Broad Ion Beam (BIB) Milling! Here are full cross-section views for comparison:

SiC paper cross-section, cut using razor blade
(Adhesive layer on top, with smearing)

SiC paper cross, using BIB milling
(adhesive layer contained under glass mask)

 

 

Which method may yield more information? To see more examples showing the wonders of BIB milling, visit our Webinars page and watch the recorded version of our latest Lunch and Learn Webinar.

If you’d like to receive notices about our upcoming Webinars, or if you’d like to discuss an analysis that might be easier using BIB milling to prepare your sample, contact us at answers@analyticalanswersinc.com, or fill out the contact information in the form on our homepage or webinars page.