液相直接沉淀法制备钛酸钡纳米粉体的研究

Synthesis of BaTiO_3 nanopowders by direct reactive preciptation method from solution

以Ba（OH）2·8H2O和钛酸四丁酯为原料,用液相直接沉淀法合成了粒径约为17-45nm的Ba-TiO3纳米粉体。研究了合成温度对样品的晶胞参数、晶粒大小和CO^3 2-含量的影响;反应物浓度对样品的颗粒大小和形貌的影响;氢氧化钡与钛酸四丁酯的摩尔比对样品中钡钛摩尔比的影响。用傅立叶变换红外光谱仪、透射电子显微镜、X射线衍射仪对产品进行了表征,并对产品进行了化学分析。结果表明,当反应物Ba（OH）2.8H2O和钛酸四丁酯的摩尔比为1.00-1.02时,产品的钡钛摩尔比约为1.0;合成温度由45℃升至90℃,所得粉体的晶粒尺寸由21nm减少至15nm,晶胞参数a则从0.4037nm增加到0.4059nm;与理想的立方晶体相比,BaTiO3的晶胞产生了膨胀;最佳反应温度为70-80℃;所得钛酸钡为具单一立方相的球形纳米粒子。

BaTiO3 nanopowders with an average particle size of 17-45nm were synthesized from solution by direct reactive preciptation method using Ba（OH）2 · 8H20 and tetrabutyl titanate as starting materials. The effects of synthesis temperature on the lattice parameter,the crystallite size and the content of CO^2- 3 of the prepared samples, the effects of the concentration of reactants on the particle size and morphology, and the effects of the molar ratio of barium hydroxide to tetrabutyl titanate on the molar ratio of barium to titanate of products were studied. The products were characterized by FT-IR, TEM and XRD,and were analysed by chemical method. The results show that the molar ratio of barium to titanate of products is about 1.0 when the molar ratio of barium hydroxide to tetrabutyl titanate is 1.00-1.02 in the reactants. With increase of reaction temperature from 40-95℃, the crystallite size of as-prepared powders decrease about from 21-15nm,and the lattice parameter a-axis increase from 0.4037-0. 4059nm. Compared with idea cubic crystal,the lattice cell of the powders prepared expands. The optimal reaction temperature ranges is 70-80℃. The shape of BaTiO3 nanoparticles with single cubic phase is almost spherical.