机械力化学合成BaTiO_3纳米晶TEM及HR-TEM研究

STUDY ON MECHANOCHEMISTRY SYNTHESIS FOR NANO-CRYSTALLINE BaTiO_3 BY TEM AND HR - TEM

采用XRD,TEM及高分辨电子显微镜(HR-TEM),研究了高能球磨BaO、锐钛矿型TiO2混合粉体,机械力化学法合成BaTiO3纳米晶的反应机制。研究表明:机械力的作用使混合物粉体粒度减小,晶格畸变,转变为无定形,具有较高的反应活性,提高固相反应的扩散系数,降低了活化能,从而使本该在较高温度进行的反应也可在较低的温度下进行。晶体形成经过成核和生长两个阶段,但生长到一定程度时达到动态平衡,合成的BaTiO3纳米晶体颗粒尺寸为10～30 nm。

The synthesizing process and mechanism of nano-crystalline BaTiO3 by mechanochemistry that ground the mixture powder of BaO and anatase TiO2 was studied by XRD, TEM and HR- TEM. The results show that mechanical treatment leads to the particle size of the mixture decreased, the lattice distorted, transferred into amorphous and higher reaction activity of the mixture. In the meantime, it increases the diffusion coefficient and decreases potential energy of solid reaction so that the reaction can be induced in the lower temperature that used to be in higher temperature. The formation of crystal by mechanochemistry includes two stages of nu-cleation and growth. The particle size of synthesized BaTiO3 by mechanochemistry has a saturation value about 10 nm to 30 nm.