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Induction periods and mechanism and kinetics of nucleation of barium tungstate crystal growth from sodium tungstate melts in platinum crucibles
Author(s) -
Roy B. N.,
Roy M. R.
Publication year - 1982
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.2170170207
Subject(s) - tungstate , nucleation , sodium tungstate , supersaturation , crystallization , barium , kinetics , platinum , chemistry , crystal growth , reaction rate constant , thermodynamics , inorganic chemistry , tungsten , crystallography , catalysis , physics , biochemistry , organic chemistry , quantum mechanics
Induction periods ( t ) and mechanism and kinetics of nucleation in barium tungstate crystallization from sodium tungstate melts in platinum crucibles were studied. A theoretical relation has been developed to express the dependence of t on the cooling rates ( R T ) and the rate ( R c ) of development of excess solute concentration. At any crystallization temperature the average rate‐constant ( k n ) for heterogeneous nucleation was related to R c by ( k n /p ) 1/( p +1 ) = 1/( tR c γ ), where γ is a constant and p is the average number of particles in the critical nuclei. The critical temperature ( T ), critical supersaturation ( S ) and γ values were estimated.