Compositions and Chemical Bonding in Ceramics by Quantitative Electron Energy-Loss Spectrometry

ABSTRACTQuantitative electron energy-loss spectrometry was applied to a range of ceramic materials at a spatial resolution of <5 nm. Analysis of Fe L23 white lines indicated a low-spin state with a charge transfer of ∼1.5 electrons/atom onto the Fe atoms implanted into (amorphized) silicon carbide. Gradients of 2 to 5% in the Co:O stoichiometry were measured across 100-nm-thick Co3O4 layers in an oxidized directionally solidified CoO-ZrO2 eutectic, with the highest O levels near the ZrO2. The energy-loss near-edge structures were dramatically different for the two cobalt oxides: those for Co3O4 have been incorrectly ascribed to CoO in the published literature. Kinetically stabilized solid solubility occurred in an AIN-SiC film grown by low-temperature molecular beam epitaxy (MBE) on α(6H)-SiC, and no detectable interdiffusion occurred in couples of MBE-grown AIN on SiC following annealing at up to 1750°C. In diffusion couples of polycrystalline AIN on SiC, interfacial 8H sialon (aluminum oxy-nitride) and pockets of Si3N4-rich β'sialon in the SiC were detected.