【作者】 李世春；

【导师】 吴顺华；

【作者基本信息】 天津大学 ， 微电子学与固体电子学， 2012， 硕士

【摘要】 片式多层陶瓷电容器（MLCC）是目前电子信息技术中非常重要的电子元器件之一。其中以BaTiO₃为基的X8R的研究较为广泛，其产品已经用于电子通讯、汽车电子、航天航空等行业。但现在多数的X8R瓷料中均含重金属Pb，其对人体和环境有着极大的危害。本论文在无铅的前提下，以BaTiO₃陶瓷为基础，研究了三种添加剂以及制备工艺对陶瓷介电性能的影响。一方面，在体系中掺入添加剂MnCO₃、ZnO和Bi₂O₃，分别研究了三种添加剂对体系介电性能的影响。结果表明：MnCO₃起到了助溶剂的作用，促进了陶瓷的致密化并有效地减少了体系中晶格缺陷，降低了体系的介电损耗；ZnO的添加有利于晶粒的长大和杂质离子在BaTiO₃晶格中的扩散，减小了非铁电相气孔，使系统的介电常数增大；Bi₂O₃在陶瓷烧结过程中形成液相，有效地降低了体系的烧结温度和介电损耗。另一方面，研究了制备工艺（球磨时间、保温时间、烧结温度）对体系介电性能的影响。结果表明：增长球磨时间可以使ε-T曲线的居里峰降低；保温时间的增长可以使低温段的介电常数大幅度增加；居里点T_c随着烧结温度的升高向高温方向移动。通过适当调节陶瓷的制备工艺，能够有效地改善系统的介电性能。当球磨时间为200min，烧结温度为1000℃，保温时间为4h时，系统有最佳的介电性能：在1kHZ下测试，室温介电常数ε≥2872.9，损耗tanδ≤1.3%，介电常数变化率|Δε/ε|≤15%，体绝缘电阻率ρv≥1.8×10¹³Ω·mm。更多还原

【Abstract】 Multilayer ceramic capacitor （MLCC） is one of electronic components，which isvery important in electronic information technology now. BaTiO₃-based X8R，whichis a kind of MLCC，is studied widely and its products has been used to electroniccommunications，automotive electronics，aerospace and other industries. But nowmost of X8R ceramic materials contain heavy metal lead，which is greatly harmful toour health and our environment. In this paper，the effect of additives and preparingtechnology on dielectric properties of lead-free BaTiO₃-based X8R was investigated.On one hand，three kinds of additives （ MnCO₃，ZnO，Bi₂O₃ ） were added inBaTiO₃ ceramics，their effects on dielectric properties of system were studied.MnCO₃，which played a role of cosolvent，promoted the densification of ceramics andeffectively reduced lattice defects of the system, so dielectric loss of system wasdecreased. ZnO was helpful to the growth of crystalline grain and the spread ofimpurity ions in BaTiO₃ lattice，reduced the non-ferroelectric phase pore，so thedielectric constant of system was increased. Bi₂O₃ can form liquid phase in thesintering process，so it can reduced effectively sintering temperature and dielectricloss of system.On the other hand，the effects of preparing technology （ milling time，soakingtime，sintering temperature ） on dielectric properties of system were studied. Theresults indicated that increase of milling time can make Curie peak ofε-T curvedecrease，the dielectric constant of lower temperature greatly increased as increase ofsoaking time，and Curie point T_c shifted to higher temperature direction as rise ofsintering temperature. Through the proper adjustment of preparation technology of theceramics，the dielectric properties of the system were improved effectively. Whenmilling time is 200 min, sintering temperature is 1000℃and soaking time is 4 h, thedielectric properties of system are the best，ε≥2872.9，tanδ≤1.3%，|Δε/ε|≤15%，ρv≥1.8×10¹³Ω·mm，which are tested in 1 KHz.更多还原