On the application of energy filtering TEM in materials science: I. Precipitates in a Ni/Cr-alloy

摘要: Electron spectroscopic imaging (ESI) in the transmission electron microscope (TEM) can be efficiently used to detect nanometer sized precipitates solids. This achieved by processing sequences of energy filtered images recorded at different losses before and after an ionization edge. To demonstrate application method we have investigated a Ni/20%Cr alloy containing variety precipitates: TiN (100–150 nm diameter), Y2O3 (∼ 5 nm) twinned Y2O3Al2O3 (10–50 Cr-metal grain boundaries. We evaluated use jump ratio (two window method) elemental distribution maps (three for precipitate visualization found that most cases provide significant advantages: show contrast similar but with lower noise are nearly free diffraction artifacts (bend contours, thickness fringes). Jump also useful obtaining elements which occur very low concentration, if background subtraction is behindered EXELFS modulations edges overlapping. However, care, because they sometimes susceptible artifacts. One main finding this work image matrix element, case Ni, visualize all occurring regardless crystallographic orientation chemical composition. Furthermore, applied correlation techniques ESI direct phases.