Preparation of Platelike NaNbO3 Particles by Single-Step Molten Salt Synthesis
Preparation of Platelike NaNbO3 Particles by Single-Step Molten Salt Synthesis
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DOI：
10.1111/j.1551-2916.2012.05095.x
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发表时间：
2012-05
影响因子：
3.9
通讯作者：
A. Kikuchihara;Fumito Sakurai;Toshio Kimura
中科院分区：
文献类型：
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作者：
A. Kikuchihara;Fumito Sakurai;Toshio Kimura
本文报道了一步熔盐合成法制备单晶片状NaNbO 3颗粒，而没有Bi 2 O3副产物。在先前的两步熔融盐合成方法中，通过在熔融NaCl中加热Bi 2 O3、Na 2CO 3和Nb 2 O 5的混合物制备了板状Bi 2.5Na3.5Nb5O 18颗粒;然后通过在熔融NaCl中与Na 2CO 3反应将颗粒转化为板状NaNbO 3颗粒。所获得的NaNbO 3颗粒是多晶的，并且Bi 2 O3颗粒作为副产物形成。在本方法中，通过在熔融NaCl中将摩尔比为5：7：10（Bi 2.5Na 3.5Nb 5 O 18的组成）和5：5：8（Bi 2.5Na 2.5Nb 4 O 15的组成）的Bi 2 O 3、Na 2CO 3和Nb 2 O 5的混合物在1225°C下加热12 h来获得没有Bi 2 O 3副产物的单晶片状NaNbO 3颗粒。在加热过程中，首先形成板状Aurivillius（Bi 2.5Na 3.5Nb 5 O 18和Bi 2.5Na 2.5Nb 4 O 15）颗粒，然后这些颗粒与NaCl反应形成板状NaNbO 3颗粒、BiCl 3和Na 2 O。BiCl 3从系统中蒸发，Na 2 O在加热后被洗出。因此，获得单相NaNbO 3。从Aurivillius相到NaNbO 3的浆料转化是形成单晶颗粒的原因。
This article reports single-step molten salt synthesis to prepare single-crystal, platelike NaNbO3 particles without the Bi2O3 byproduct. In the previous method of two-step molten salt synthesis, platelike Bi2.5Na3.5Nb5O18 particles have been prepared by heating a mixture of Bi2O3,Na2CO3, and Nb2O5 in molten NaCl; the particles are then converted to platelike NaNbO3 particles by reaction with Na2CO3 in molten NaCl. The obtained NaNbO3 particles are polycrystalline, and Bi2O3 particles form as a byproduct. In the present method, single-crystal, platelike NaNbO3 particles without the Bi2O3 byproduct are obtained by heating mixtures of Bi2O3, Na2CO3, and Nb2O5 with molar ratios of 5:7:10 (the composition of Bi2.5Na3.5Nb5O18) and 5:5:8 (the composition of Bi2.5Na2.5Nb4O15) in molten NaCl at 1225°C for 12 h. During heating, platelike Aurivillius (Bi2.5Na3.5Nb5O18 and Bi2.5Na2.5Nb4O15) particles are formed first and these then react with NaCl to form platelike NaNbO3 particles, BiCl3, and Na2O. BiCl3 evaporates from the system and Na2O is washed out after heating. Thus, single-phase NaNbO3 is obtained. Sluggish conversion from the Aurivillius phases to NaNbO3 is responsible for the formation of single-crystal particles.