Thermodynamic evaluation and hydrothermal preparation of KxNa1-xNbO3
- Zhang Ci
- Lv Haijun
- Guo Min
- Zhang Mei
- Wang Xidong
DOIAbstract
The Gibbs free energies of reaction A,GT of KNb03 and NaNb03 were calculated and then that of K,Nal_,Nb03 was estimated. On the basis of the thermodynamic calculation results, the hydrothermal temperatures were designed at 100, 160, and 230'C respectively. However, NaNb03 was prepared when the heating temperature was higher than 160'C, and KNb03 and KNal-,Nb03 were obtained at 230'C, suggesting that only at a higher temperature the kinetic requirement is satisfied. According to the X-ray diffraction results, both the solid solutions, NaNb03-based solid solution, Nal_KNb03, and KJO03-based solid solution, K1_,Na+,Nb03, were hydrothermally synthesized in 6 mol/L alkali (NaOH and KOH) solution at 230 degrees C.http://gateway.web...
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