QUANTITATIVE CHEMICAL-PHASE IMAGING BY MEANS OF ENERGY-FILTERING TRANSMISSION ELECTRON-MICROSCOPY

Electron spectroscopic imaging (ESI) in the transmission electron micr oscope (TEM) is a powerful method to produce 2-dimensional elemental d istribution maps. These maps show in a clear way the chemical situatio n of a small specimen region. In this work we used a Gatan Imaging Fil ter (GIF) attached to a 200 kV TEM to investigate a Ba-Nd-titanate cer amic. The three phases occurring in this material could be visualized using inner-shell ionization edges (Ba M(45), Nd M(45) and Ti L(23)). We applied different image correlation techniques to the ESI elemental maps for direct visualization of the chemical phases. First we simply overlaid the elemental maps assigning each element one colour to form an RGB image. Secondly we used the technique of scatter diagrams to c lassify the different phases. Finally we quantified the elemental maps by dividing them and multiplying them by the appropriate inner-shell ionization cross-sections which gave atomic ratio images. By using the se methods we could clearly identify and quantify the various phases i n the Ba-Nd-titanate specimen.