ISSN:
1551-2916
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
High-spatial-resolution analytical electron microscopy using energy-dispersive X-ray (EDX) and electron energy-loss spectrometry (EELS) of yttrium- and lanthanum-doped Al2O3 has been conducted to ascertain the level of segregation of these impurities to grain boundaries. Line profile analyses indicate that the segregation is confined to a layer thickness of 〈3 nm. Similar amounts of excess solute have been observed in both dopant systems: 4.4 ± 1.5 and 4.5 ± 0.9 at./nm2 for yttrium and lanthanum, respectively. Assuming all the segregant is uniformly distributed within ±0.5 nm of the boundary, this excess corresponds to 9 ± 3 at.% for yttrium-doped Al2O3 and 10 ± 2 at.% for lanthanum-doped Al2O3. For both dopant systems, examination of the spatially resolved electron energy-loss near-edge structures (ELNES) on the Al-L2,3 edge suggests a loss in octahedral symmetry and a slight Al-O bond-length expansion. No significant change is noted in the O-K edge.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1151-2916.1999.tb02169.x
Permalink