Compositions and chemical bonding in ceramics by quantitative electron energy-loss spectrometry

摘要

Quantitative electron energy-loss spectrometry was applied to a range of ceramic materials at a spatial resolution of <5 nm. Analysis of Fe L(sub 23) white lines indicated a low-spin state with a charge transfer of (approximately)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 Co(sub 3)O(sub 4) layers in an oxidized directionally solidified CoO-ZrO(sub 2) eutectic, with the highest O levels near the ZrO(sub 2). The energy-loss near-edge structures were dramatically different for the two cobalt oxides; those for CO(sub 3)O(sub 4) have been incorrectly ascribed to CoO in the published literature. Kinetically stabilized solid solubility occurred in an AlN-SiC film grown by low-temperature molecular beam epitaxy (MBE) on (alpha)(6H)-SiC, and no detectable interdiffusion occurred in couples of MBE-grown AlN on SiC following annealing at up to 1750C. In diffusion couples of polycrystalline AlN on SiC, interfacial 8H sialon (aluminum oxy-nitride) and pockets of Si(sub 3)N(sub 4)-rich (beta)(prime) sialon in the SiC were detected.