固相反应法研究BaTiO3粉末的相变和微观结构的转变

Investigation of the Phase and Microstructural Transformation on BaTiO3 Powder by Solid-State Reaction

摘要:

以国产亚微米级BaCO₃和TiO₂为原料,采用砂磨固相法合成尺寸小、四方性高的BaTiO₃粉体,同时研究煅烧温度、升温速率及保温时间对BaTiO₃平均粒径和四方性的影响。结果表明,通过固相反应合成BaTiO₃的反应机理可分为两个阶段：当煅烧温度低于900 ^_oC,BaCO₃和TiO₂首先形成立方相的BaTiO₃,当煅烧温度升至900 ^_oC,立方相BaTiO₃开始向四方相转变。在煅烧温度为900 ^_oC,升温速率为5 ^_oC/分钟,保温5 h,制备出粒径为180.7 nm,四方性为1.0086的超细BaTiO₃粉体。该工作为制备超薄层MLCC用高性能BaTiO₃粉体提供了较好的研究思路。

Abstract:

As the miniaturization of multilayer ceramic capacitors (MLCCs) is a major trend, well-fabricated ferroelectric materials such as barium titanate (BaTiO₃, BTO) with small grain and well crystallinity are increasingly in demand. Compared with other synthetic routes, solid-state reaction (SSR) is a more feasible route to prepare BaTiO₃ nanoparticles without lattice imperfections. In contrast to other researches about SSR that mainly focus on exploring improved processes to obtain BaTiO₃ nanoparticles with high tetragonality, investigations on the phase, microstructural transformation and reaction mechanism of BaTiO₃ nanoparticles were made in this study. Experiments results reveal that the reaction mechanism of forming tetragonal BaTiO₃ via SSR can be ascribed to two main reaction stages, including the formation of cubic BaTiO₃ and the cubic-tetragonal transformation of BaTiO₃. Finally, BaTiO₃ powders with a tetragonality of 1.0086 (c/a) and average particle size of 180 nm was acquired after optimizing the calcination parameters.