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Low‐Angle Grain‐Boundary Macrostructure in Large‐Diameter Czochralski White Sapphire
Author(s) -
YIP V. F. S.,
BRANDLE C. D.
Publication year - 1978
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1978.tb09218.x
Subject(s) - sapphire , materials science , annealing (glass) , crystallography , grain boundary , impurity , seeding , czochralski method , optics , condensed matter physics , crystal growth , microstructure , composite material , chemistry , physics , laser , organic chemistry , thermodynamics
Large‐diameter Czochralski sapphire crystals grown in several orientations were occasionally found to contain complex networks of low‐angle grain boundaries. The subboundaries lie in major low‐index crystallographic planes which are uniquely determined by the gowth orientation. The major subboundary planes were the (11¯00) and (011¯0) for crystals gro_wn_in the direction normal to the ( r )‐(1¯012) plane and the (1¯21¯0) and (21¯1¯0) planes for crystals grown in the 90°‐[1120] direction. The formation of the subboundary macrostructure was attributed to an excessive temperature gradient during seeding and is not related to growth rate, impurity content, or annealing.