Electron Energy-loss Spectroscopy Characterization of ∼1 nm-thick Amorphous Film at Grain Boundary in Si-based Ceramics

Abstract

In many ceramic systems thin amorphous films of about 1 nm thickness often cover grain boundaries. These amorphous films play a key role not only in the formation of microstructures but also in the thermal-mechanical properties of ceramic materials. However, such thin amorphous layers could not be probed directly by an analytical electron beam. With the recent advances in spatially-resolved electron energyloss spectroscopy technique, chemical and physical parameters of the thin films could be successfully derived using the ''spectrum separation'' approach. Basic characters and behaviors of variations for the inter-granular films are analyzed in a few silicon nitride (Si 3 N 4 ) and silicon carbide (SiC) systems. The combined local chemical-structural information reveal new trends on microstructures and properties, and provides further insights in Si-based ceramic materials.

Measuring Electrostatic Potential Profiles across Amorphous Intergranular Films by Electron Diffraction

“…and/or energy dispersive X-ray~EDX! spectrometers~Gu et al, 1998;Dunin-Borkowski, 2000;Walther, 2003;Gu, 2004! andpossibly even a biprism~Wang &Dravid, 2002!. Structural details are reflected in the signal produced by elastically scattered electrons.…”