Environmental Scanning Electron Microscope study of SiO2 heterogeneous material with helium and water vapor

The analysis and the structural characterization of heterogeneous materials are usually difficult to perform using conventional techniques and only global information may be obtained. A comparative study in the Environmental Scanning Electron Microscope with different gases is carried out on a heterogeneous and insulating SiO2 material. Electron beam scattering effect on the resolution of microanalysis due to the introduction of two gases: water vapor and helium within the specimen chamber of the Environmental Scanning Electron Microscope is studied. The best results are obtained with helium. The use of this gas enabled a better focusing the electron beam on the micronic zones which led to better distinguish the chemical species present in our material. This study deals with the diffusion of some cations such as Ca2+ and K+ inside the SiO2 aggregate. The results show that calcium and potassium do not belong to the same phase.