Premium
Differential Thermal Analysis Studies on the Crystallization of Strontium Tungstate from Sodium Tungstate Melts Thermodynamic and Kinetic Parameters
Author(s) -
Roy B. N.
Publication year - 1981
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.2170160606
Subject(s) - sodium tungstate , thermodynamics , tungstate , enthalpy , crystallization , arrhenius equation , strontium , activation energy , diffusion , kinetic energy , chemistry , materials science , inorganic chemistry , tungsten , metallurgy , physics , organic chemistry , quantum mechanics
From the estimated diffusion rate‐constants ( k D1 ) of strontium tungstate crystal growth from sodium tungstate melts in platinum crucibles, energy (E), enthalpy (Δ H a ), entropy (Δ S a ) and free‐energy (Δ G a ) of activation and the pre‐exponential factor ( k 0 ) for the process were estimated using an ordinary Arrhenius equation k Dl = k 0 e − E/RT . These thermodynamic parameters were virtually unaffected by the changes in crystallization temperatures ( T 0 ) and cooling rates ( R ) T . The distance ( r 12 ), between a diffusing species and its host necesary for a successful diffusion, increased with T 0 and T T but there was no direct correlation.