水热合成KNbO_3粉体的理论设计与实验研究

以K-Nb-H2O三元体系为研究系统,在Lencka-Riman热力学模型的框架内,对水热法合成KNbO3粉体进行了理论设计,得到了体系稳定产出相图和优化的合成条件包括反应温度、反应物浓度和溶液的pH控制等重要信息.研究结果表明,前驱物浓度和pH调节(矿化剂KOH浓度)是形成纯相KNbO3必需的条件.在此基础上,利用简单的五氧化二铌和KOH做前驱物,在523K反应温度,高强碱性溶液条件下,常规水热法成功合成了纯相的KNbO3粉体.实验研究和理论设计十分吻合.

Theoretical Design and Expeerimental Study of Hydrothermal Synthesis on KNbO3 Powders

In the framework of Lencka–Riman thermodynamic model,we studied on the theoretical design for synthesis of KNbO3 powder by hydrothermal processing in the K-Nb-O system.As the result of the calculations,stability and yield diagrams of the investigated system were obtained.Thus,the optimum conditions(i.e.,temperature,synthesis precursor concentrations,solution pH) for the hydrothermal synthesis of phase-pure KNbO3 were presented.The calculated results suggested that the concentrations of precursors and pH-adj...