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Mass spectrometric analysis of gaseous crystallization medium, growing, and some properties of α‐Al 2 18 O 3 crystals
Author(s) -
Arzumanyan G. A.,
Bagdasarov Kh. S.,
Ryadnov S. N.,
Garnikyan A. V.
Publication year - 1990
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170250104
Subject(s) - crystallization , supersaturation , bubble , crystallography , lattice (music) , analytical chemistry (journal) , indentation hardness , materials science , gas bubble , chemistry , microstructure , chromatography , physics , organic chemistry , parallel computing , computer science , acoustics
Some gas phase processes during the vacuum vertical directed crystallization of α‐Al 2 18 O 3 are studied in this paper. An effect of these processes on the H, C, N concentrations in the crystals is discussed. The detected pulsations of partial H 2 and C 18 O pressures are a result of bubble destruction at the melt‐gas interface. The C 18 O bubbles are formed because of chemical interaction between the melt and carbon‐containing phases of container material. Besides the container wall, the H 2 bubbles can be generated also at the crystallization front supersaturated by H 2 . The perfect α‐Al 2 O 3 and α‐Al 2 18 O 3 crystals grown under the same conditions have noticeable differences of their density, microhardness and lattice parameters. This is explained by an isotopic substitution effect.