Resin-embedded sections vacuum embedding

Figure 2 shows STEM images of a 8%wt Pd/2%wt Pt catalyst which is supported on charcoal. The sample was prepared for microscopy by embedding in epoxy resin and sectioning with a diamond knife in an ultramicrotome, and was examined in a Vacuum Generator s Ltd HB5 STEM, with a 5A probe. The sample thickness is about 500A. 

Because the particles of raw feed are small, several fractions of the feed can be separately contained in the same thin section, thereby saving much time and money. The making of thin sections, therefore, begins with a plastic embedding mold or other suitable container divided into two chambers with a properly cut business card. The >45-pm insoluble residue and >125-pm sieve fractions of the feed are placed wifh a few drops of epoxy resin in the chambers of the mold and a partial vacuum is drawn for a few minutes. Then the container is filled with the remaining resin, small labels inserted in each chamber, and the preparation allowed to harden on a slide warmer set at approximately 40 to 50 C. 

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