Structure and Chemistry of Symmetrical Tilt Grain Boundaries in α‐Al ₂ O ₃ : II, Bicrystals with Y at the Interface

Abstract

Symmetrical tilt grain boundaries (STGBs) on the (10¯10), (¯2112), and (01¯18) planes in α‐Al 2 O 3 have been investigated for their behavior with respect to yttrium doping by performing a combined study of high‐resolution transmission electron microscopy and spatially resolved energy dispersive X‐ray analysis. Bicrystals have been produced by diffusion bonding under ultrahigh vacuum; yttrium was introduced before the bonding process. The prismatic twin has a bulklike grain boundary (GB) structure and does not accommodate any yttrium at the GB. The yttrium at the Σ17 (¯2112) GB and the Σ37 (01¯18) GB changes the GB structure and the content of other impurities.