【作者】 苏皓；

【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， 2007， 博士

【摘要】 论文从分析钛酸钡的晶体结构入手,运用XRD、SEM、EDS等现代微观分析手段,对钛酸钡基的高介X7R介质陶瓷材料、高介X8R介质陶瓷材料和中温烧结X8R介质陶瓷材料的制备进行了研究,讨论了介质陶瓷体系掺杂改性的作用效果和微观机理以及系统组分和工艺条件等对系统介电性能的影响。首先分析了Nb₂O₅、CoCO₃、MgO、CeO₂、Sm2O₃、MnCO₃、玻璃等添加剂以及工艺条件对X7R BaTiO₃陶瓷系统的介电性能具有各自的作用和影响,并研究了各种掺杂的微观机理,用实验验证了BaTiO₃陶瓷中的壳芯结构。最终获得符合X7R标准的优良高介陶瓷材料,参数如下:烧结温度1240℃,1kHz下ε≥5800,tanδ≤1.5%,-55～125℃范围内介电常数温度变化率-15%<Δε/ε<15%,绝缘电阻率:ρv≥1×10¹²Ω·cm。之后通过研究在钛酸钡系统中加入Nb₂O₅和MgO的作用和机理,获得符合X8R标准的介质陶瓷材料,并研究了Ba/Ti比对系统介电性能的影响。进一步对已经获得的X8R介质陶瓷系统掺杂改性,并首次应用PbTiO₃、PbO、Pb（Ti,Sn）O₃等添加剂改善系统的温度特性。将Pb(Ti_0.6,Sn_0.4)O₃掺杂到X7R BaTiO₃介质系统中获得了性能优良的高介X8R陶瓷材料。性能参数为:烧结温度1260℃,介电常数1kHz下ε≥3200,损耗因子tanδ≤1.8%,-55～170℃范围内-15%<Δε/ε<15%。在添加助熔剂Bi2O₃之后,系统实现了中温烧结。性能参数为:烧结温度1180℃,介电常数1kHz下ε≥2650,损耗因子tanδ≤1.1%, -55～190℃范围内-15%<Δε/ε<15%。论文还在在无铅环保材料的发展上作了初步探索,对（Na,Bi）TiO₃替代Pb(Ti_0.6,Sn_0.4)O₃掺杂的效果作了研究。性能参数为:介电常数ε≥2070,损耗因子tanδ≤2.7%。更多还原

【Abstract】 The dissertation started with the analysis of the crystal structure of BaTiO₃, then studied the preparation of high-K X7R, high-K X8R and intermediate temperature sintering high-K X8R dielectric ceramic system by modern methods such as XRD, SEM, EDS etc.. The article also discussed the effect and microscopic mechanism of modified dielectric ceramic system and the effect of system component and procedure to the dielectric properties of the system.The effects of the agents such as Nb₂O₅, CoCO₃, MgO, CeO₂, Sm2O₃, MnCO₃, glass and procedure conditions to the dielectric properties of X7R BaTiO₃ were studied first. The mechanism of the modification of the system by the agents was also analyzed, and the core-shell structure was proved by the experiments. A perfect high-K X7R ceramic system with the following parameters was gained: sintering temperature 1240℃,ε≥5800 under 1 kHz,tanδ≤1.5%,-15%<Δε/ε<15% in the region of -55～125℃,ρv≥1×1012Ω·cm.Then a X8R ceramic system was gained by the studies of the effect and mechanism of adding Nb₂O₅ and MgO to BaTiO₃ system. The effect of changing the ratio of Ba/Ti was also studied. The further researches focused on the doping of PbTiO₃, PbO, Pb（Ti,Sn）O₃ and gained a perfect high-K X8R ceramic system with the following parameters by adding Pb（Ti0.6,Sn0.4）O₃ to the high-K X7R ceramic system: sintering temperature 1260℃,ε≥3200 under 1kHz,tanδ≤1.8%, -15%<Δε/ε<15% in the region of -55～170℃.With the doping of Bi2O₃, the system was able to be sintered under intermediate temperature. The ceramic system with the following parameters was found: sintering temperature 1180℃,ε≥2650 under 1kHz,tanδ≤1.1%, -15%<Δε/ε<15% in the region of -55～190℃.The lead-free materials was also studied in the paper. The substitution of （Na,Bi）TiO₃ for Pb(Ti_0.6,Sn_0.4)O₃ was researched and gained a ceramic system with the following parameters:ε≥2070 under 1kHz,tanδ≤2.7%.更多还原