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Preparation of the smallest ferroelectric particle of barium titanate and the investigation of its transformation temperature

最小钛酸钡铁电粒子的制备及其转变温度研究

基本信息

批准号：
13450360
负责人：
IKAWA Hiroyuki
金额：
$ 8.45万
依托单位：
Kanagawa Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13450360/
关键词：
barium titanate ferroelectric twin phase transformation size effect small particle Raman spectrum 強誘電体微粉子

项目摘要

The following commercially available barium titanate powders were investigated with the intentions t find the size of the smallest tetragonal particle. Those were hydrothermal barium titanate made by Sakai Chemical Industry Co., Ltd ; BT-01 and BT-006 with respective nominal sizes of 100 nm and 6 nm, respectively. Another powder of KCM Corp., was made by a solid state reaction with a nominal size of 700 nm.The latter powder was CIPed under 1GPa repeatedly at room temperature to characterize by powder X-ray diffraction, TEM and heat capacity measurements. The tet-cub transformation enthalpy of the CIPed once powder was 1/15 of that of the normal. However, it was tetragonal after CIPed for 60 times although the crystallite size was decreased to 47 nm. Further, tweedy and /or squeezed texture was revealed by TEM to comprise collapsed boundary zones and modulated lattice arrays.Some papers have reported about cubic barium titanate of BT-01. However, this research made it clear that all the … More powders were tetragonal for as received BT-01 ad BT-006, and their heated specimens. This conclusion was derived from following results, however, even very careful electron diffraction examinations failed to detect any tetragonalty on as received powder of BT-01. The half height widths of 113 and 400 diffractions were monitored as functions of temperature to find their reversible changes. These results said that the half height widths of the two diffractions were wide at room temperature because of their tetragonal splittings, and those became smaller at higher temperature that Tc.Systematic measurements of Raman spectrum as functions of temperature supported the tetragonal barium titanate of hydrothermal powders. We had detected on specimens the inhibited spectra for cubic barium titanate at 150℃. That is the inhibited spectra are no use to identify the point group of the crystals. However, we had monitored the sharp reversible changes in intensities of inhibited spectra at transformation temperatures to conclude the specimens were tetragonal barium titanate at a room temperature. Less

研究了以下市售钛酸钡粉末，目的是找到最小的钛酸钡颗粒的尺寸。这些是由Sakai Chemical Industry Co.制造的水热钛酸钡，Ltd ; BT-01和BT-006，其各自的标称尺寸分别为100 nm和6 nm。KCM公司的另一种粉末，采用固相反应法制备了标称粒径为700 nm的纳米TiO 2粉体，并在室温下于1GPa压力下对该粉体进行了多次化学共沉积，通过粉末X射线衍射、透射电镜和热容测量等手段对粉体进行了表征。经一次CIP处理的粉末的tet-cub转变焓为正常粉末的1/15。然而，在CIP 60次后，虽然晶粒尺寸减小到47 nm，但其为四聚体。透射电镜观察到立方相钛酸钡晶体中存在着由边界塌陷区和调制点阵组成的挤压织构。有关BT-01立方相钛酸钡晶体的研究已有报道。然而，这项研究清楚地表明， ...更多信息将粉末原样四次加热形成BT-01和BT-006，以及它们的加热样品。这一结论是由以下结果得出的，然而，即使非常仔细的电子衍射检查也未能在收到的BT-01粉末上检测到任何四方晶系。监测113和400衍射的半高宽度作为温度的函数，以发现它们的可逆变化。结果表明，室温下两个衍射峰的半高宽较宽，这是由于它们的四电子分裂所致，当温度高于Tc时，半高宽变小.系统的拉曼光谱随温度变化的测量结果支持了水热法制备的四电子钛酸钡粉体.我们在样品上检测到立方钛酸钡在150℃时的抑制谱。这就是说，抑制谱不能用来识别晶体的点群。然而，我们已经监测到在相变温度下抑制光谱强度的急剧可逆变化，从而得出样品在室温下为四钛酸四钡的结论。少