中文摘要：

采用水热法，以硝酸钡和四氯化钛的酒精溶液为原料，在不同反应温度下制备了具有钙钛矿结构的钛酸钡（BaTiO3）粉体，然后在不同烧结温度下得到钛酸钡陶瓷，研究其电学性能．结果表明，陶瓷内部的气孔会影响介电常数随频率变化的特性．所得样品的介电常数、居里温度和介电损耗都随着反应温度的增加，呈现先增大后减小的趋势，并且晶粒尺寸的减小会降低钛酸钡的居里温度．在介电温谱中，240。C和270℃水热合成的样品出现明显的损耗峰，这是由于在高温烧结过程中产生的氧空位导致的．点缺陷会影响样品的极化强度一电场（P-E）回线，出现双电滞回线．

英文摘要：

Nanocrystalline BaTiOa with different crystal sizes were hydrothermally synthesized at different reacting temperature. Then the BaTiO3 nanopowders were sintered at various temperatures and BaTiOa ceramics with different grain sizes. The dielectric constant, temperature and polarization were analyzed. Our experimental results showed that ceramic internal pore can influence stability of dielectric constant with frequency. Dielectric constant, dielectric loss and Curie temperature increase first and then decrease with reacting temperature. Small grain size of BaTiOa ceramic reduce the Curie temperature. The dielectric loss peak was observed in the sample reacted at 240 ℃ and 270 ℃. This is mainly due to the oxygen vacancies in BaTiOa sintered in a high temperature. The point defect also affected ferroelectric characteristics of the samples and lead double hysteresis loop.