Differential Thermal Analysis Studies on the Crystallization of Strontium Tungstate from Sodium Tungstate Melts Thermodynamic and Kinetic Parameters

✍ Scribed by Dr. B. N. Roy

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 218 KB
• Volume: 16
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.2170160606

✦ Synopsis

Thermodynamic and Kinetic Parameters

From the estimated diffusion rate-constants ( k D J of strontium tungstate crystal growth from sodium tungstate melts in platinum crucibles, energy (E), enthalpy (AH,), entropy (AS,) and free-energy (47,) of activation and the pre-exponential factor (k,) for the process were estimated using an ordinary Arrhenius equation k D , = k a e -E / R T . These thermodynamic parameters were virtually unaffected by the changes in crystallization temperatures (To) and cooling rates ( R ) T . The distance (rI2), between a diffusing species and its host necessary for a successful diffusion, increased with To and RT but there was no direct correlation.