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Crystal Growth of Boron Sillenite Bi 24 B 2 O 39
Author(s) -
Burianek M.,
Mühlberg M.
Publication year - 1997
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.2170320803
Subject(s) - crystallization , phase diagram , homogeneous , stoichiometry , boron , homogeneity (statistics) , crystal growth , crystallography , ternary operation , crystal (programming language) , materials science , analytical chemistry (journal) , chemistry , phase (matter) , thermodynamics , chromatography , physics , statistics , mathematics , organic chemistry , computer science , programming language
The Sillenite type Bi 24 B 2 O 39 is an incongruently melting compound at T p = 650 ° C . Single crystals have been grown from non‐stoichiometric melts as well as from high temperature solutions by the Czochralski method and by a top seeded solution growth technique (TSSG), respectively. The main difficulty in the crystal growth of Bi 24 B 2 O 39 arises from the very small field of crystallization in the binary system Bi 2 O 3 –B 2 O 3 . Further problems are caused by the nearly simultaneous formation of the 2:1 compound Bi 4 B 2 O 9 and the 12:1 compound Bi 24 B 2 O 39 . Therefore, a precise thermal reinvestigation of the phase diagram was carried out using DTA‐technique on the Bi 2 O 3 ‐rich side. Additionally, crystal growth runs have been started in the ternary system Bi 2 O 3 –B 2 O 3 –Li 2 O in order to extend the crystallization field. Homogeneous melts were more difficult to prepare because of the high density difference between Bi 2 O 3 (∂ = 9.3 g/cm 3 ) and B 2 O 3 (∂ = 2.46 g/cm 3 ). The homogeneity of the melts were improved, using Bi 2 O 3 and synthesized Bi 4 B 2 O 9 (∂ = 8.25 g/cm 3 ) as starting materials. As a result of this procedure, small crystals of Bi 24 B 2 O 39 were grown from these starting materials and the lattice parameter were determined.