Heated Stage Scanning Electron Microscope

The use of the ElectroScan Environmental SEM allows the examination of unprepared, uncoated specimens on a heated stage up to a temperature of 1,832^oF (1,000^oC) in a variety of atmospheres. The most recent use of this analytical instrument was for the study of the calcination behavior of limestones. Use of this instrument enable us to observe the development of thermally-induced fractures (TIFs) during calcination. It was observed that the orientation and extent of TIFs that developed varied significantly between limestones that were identified as petrographically different. This was considered significant because the TIFs serve as large feeder pores which permit rapid influx of SO₂, thereby increasing calcium utilization.

Photomicrographs and Description of TIFs

Shown below (left) is a SEM micrograph of a high purity limestone particle and a micrograph of the same limestone (right) after being heated in the ElectroScan Environmental SEM. Magnification 220x.

Before Heat Treatment	After Heat Treatment (Calcined)