Extended structural defects in α-Al2O3 (alumina), a technologically important, complex ceramic material were quantitatively analyzed with respect to grain boundary segregation, atomic and electronic structures using spatially resolved electron energy-loss spectroscopy (EELS), energy dispersive X-ray spectroscopy (EDS) and first-principles local-density-functional (LDFT) calculations. in this study the results of analytical investigations will be compared with the outcome of LDFT calculations.
The analytical measurements were performed with a dedicated scanning transmission electron microscope (TEM) VG HB501UX, operating at 100 kV and with a typical beam diameter of lnm. For the spatially resolved EELS a parallel electron energy-loss spectrometer (Gatan model 666) with an energy resolution of better than 0.8 eV was used. For the chemical analysis an EDS system (Noran-Gresham with a Si(Li) detector and a Norvar window) was applied. The detection limit of the EDX system for measuring interface excess is in the range of 0.3 atoms/nm2.