TEM characterization of grain boundaries in Al{sub}2O{sub}3/LaAl{sub}11O{sub}18 composites

摘要

Liquid formation during sintering of alumina is known to cause exaggerated anisotropic grain growth. High resolution electron microscopy (HREM) and Auger electron spectroscopy (AES) were used in the characterization of grain boundaries ofSiO{sub}2 doped alumina/La-aluminate composites. Controlled addition of SiO{sub}2 (300ppm) to produce composites with desirable microstructures is shown to play an important role in the local formation of a transient liquid at sintering temperatures which modify alumina grains surface and render a glass-free grain boundary.