Controlled atmosphere electron microscopy of gas‐solid interactions

Abstract

Abstract From a chemist's point of view, the main limitation of a conventional electron microscope is that materials can only be observed in a vacuum environment, effectively precluding dynamic studies of any structural changes which accompany reactions. Early attempts at overcoming this restriction were pursued independently by several workers,1–4 who devised various techniques to enable specimens to be viewed at room temperature in gaseous environments. These approaches, coupled with experience obtained from heating stages5, led to the development of a single unit that allowed specimens to be heated while exposed to a gas atmosphere. Although several such stages have been developed,6–8 the relative lack of reported data from their use makes it impossible to assess the merits of any one particular design. Without doubt, the most successful stage is that developed by Hashimoto and co-wrkers,9–11 which has been commercially available for some time (JEOLCO JEM AGI). Other approaches to this problem—less ambitious, but quite effective—have been t o simply inject gas into the microscope column at a point close to where a specimen is being heated, and t h s operation has enabled qualitative information to be obtained from some low-pressure systems.12–15