Abstract The method of oxalate co-precipitation assisted with microwave is used for the synthesis of pure barium titanate (BT) particle with a diameter of 30–50 nm by choosing tetrabutyl titanate Ti(OC4H9)4 (98.0%), barium nitrate Ba(NO3)2 (99.5%), oxalate H2C2O4 (99.5% purity) and nitric acid HNO3 (65 ∼ 68%) as starting materials. Lanthanum oxide is doped in barium titanate powders to prepare ceramics by pelleting, forming, dumping, sintering and other steps. The structure and morphology of ceramics are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The dielectric constant and dielectric loss are obtained by dielectric frequency analyzer. The results show that grain size and tetragonality of the barium titanate ceramics doped by lanthanum oxide sintered at 1270 °C for 3 h are found to decrease with the increase of dopants concentration. Dielectric constant increases at first and then decreases as La2O3 concentrations grow, reaching the maximum value when the concentration is 0.3 mol%. The ceramic samples transform from normal ferroelectric to the ferroelectric with diffused phase transition.

中文翻译：

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氧化镧掺杂钡钛陶瓷的介电性能

摘要 采用微波辅助草酸盐共沉淀法，选择钛酸四丁酯Ti(OC4H9)4(98.0%)、硝酸钡Ba( NO3)2(99.5%)、草酸盐H2C2O4(纯度99.5%)和硝酸HNO3(65～68%)为起始原料。将氧化镧掺杂在钛酸钡粉体中，通过造粒、成型、倾倒、烧结等步骤制备陶瓷。陶瓷的结构和形貌分别通过 X 射线衍射 (XRD) 和扫描电子显微镜 (SEM) 进行表征。介电常数和介电损耗由介电频率分析仪获得。结果表明，氧化镧掺杂钛酸钡陶瓷在 1270 ℃烧结 3 h 后的晶粒尺寸和四方性随着掺杂浓度的增加而减小。介电常数随着 La2O3 浓度的增加先增大后减小，当浓度为 0.3 mol% 时达到最大值。陶瓷样品从普通铁电体转变为具有扩散相变的铁电体。