Study in a new fabrication method of BaTiO_3 single crystal

BaTiO_3单晶制备新方法的研究

基本信息

批准号：
08455406
负责人：
TAKATA Masasuke
金额：
$ 4.93万
依托单位：
Nagaoka University 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：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

We investigated the conditions in which no secondary recrystallization occurred in TiO_2 added BaTiO_3 ceramics for a new fabrication method of BaTiO_3 single crystal. These conditions were confirmed when the specimens were sintered above the eutectic point, The effect of TiO_2 as a secondary recrystallization inhibitor worked on these conditions remarkably by using a low reactive BaTiO_3 powder that have a comparatively large average grain size. In these conditions, the increase of added TiO_2 gave rise to the increase of amount of generated liquid phase. The secondary recrystallization depended on the amount of generated liquid phase and the sintering temperature. Owing to little amount of diffusion of BaTiO_3 in the liquid phase existing between grains, the rapid grain growth, namely, the secondary recrystallization was restrained.The amount of liquid phase was estimated as the degree of change in electrical conductivity around the eutectic point. The electrical conductivity changed … More gradually in the undoped specimen. On the other hand, a striking change of electrical conductivity occurred around the eutectic point in TiO_2 added specimens, proportionally increasing with the amount of added TiO_1, namely, the generated liquid phase. Accordingly, it was found that the measurement of electrical conductivity around the eutectic point was an effective way to determine the amount of liquid phase during heat treatment.A polycrystalline body that contained a seed crystal was heat-treated to make the seed crystal grow using the above conditions in which no secondary recrystallization occurred. The seed crystal grew in all directions without containing the secondary recrystallized grain. The solution-reprecipitation process was the dominant growth mechanism in this fabrication method. The growth of single crystal was caused by a difference of solubility between the seed crystal and the grains of polycrystalline body. The growth rate of seed crystal embedded in the polycrystalline body increased with decreasing the amount of generated liquid phase and increasing of heat-treating temperature. Pores in the porous polycrystalline area were incorporated into the grown single crystal. However, the growth part of single crystal exhibited similar properties, such as the temperature dependence of relative dielectric constant and the lattice constant. Therefore, a high qualitative BaTiO_3 single crystal might be fabricated by removing pores from the porous polycrystalline body. Less

我们研究了二级重结晶在Tio_2中添加了batio_3陶瓷，用于INGLE晶体。添加的TIO_2产生的液相的增加，取决于生成的液相和烧结温度，二次重结晶被限制为液体。在共晶的电导率周围的电导率中。相位，在热处理期间，在晶体上生长的液体量是在所有方向上生长的，这是在晶体上生长的液相的有效方法 - 原理过程是溶解度的差异，YSTAL的占主导地位。单晶体表现出相对介电疗法和晶格的旋转性能，因此，高性的Batio_3单晶可能会从多孔多晶体中去除毛孔