Effect of water density on polymorph of BaTiO3 nanoparticles synthesized under sub and supercritical water conditions
Effect of water density on polymorph of BaTiO3 nanoparticles synthesized under sub and supercritical water conditions
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DOI：
10.1016/j.matlet.2004.11.063
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发表时间：
2005-05
影响因子：
3
通讯作者：
Y. Hakuta;H. Ura;H. Hayashi;K. Arai
中科院分区：
文献类型：
--
作者：
Y. Hakuta;H. Ura;H. Hayashi;K. Arai
研究了水密度对亚临界和超临界条件下水热合成的BaTiO3颗粒多晶型的影响。实验采用流动反应系统，在温度300～420℃、压力20～40MPa的范围内进行。这些条件对应于0.15至0.70 g/cm3的水密度。 TiO2 溶胶和Ba(OH)2 溶液用作起始材料。通过粉末X射线衍射、透射电子显微镜和拉曼光谱对产物进行表征。结果发现，产物的晶相不仅取决于温度，还取决于压力。在超临界条件下，当水的密度小于0.5 g/cm3时，得到了具有四方相的BaTiO3颗粒。
The effects of water density on polymorph of BaTiO3particles synthesized hydrothermally under sub and supercritical conditions have been studied. Experiments were performed within the temperature range of 300 to 420 °C and the pressure of 20 to 40 MPa using a flow reaction system. These conditions correspond to the water density of 0.15 to 0.70 g/cm3. Aqueous TiO2sols and Ba(OH)2solution were used as starting materials. Characterization of products was performed by powder X-ray diffraction, transmission electron microscopy and Raman spectroscopy. From the results, it has been found that the crystal phase of products depends not only on the temperature but also the pressure. The BaTiO3particles with tetragonal phase were obtained under the supercritical conditions, when the density of water was smaller than 0.5 g/cm3.