【作者】 宋佳；

【导师】 谢道华；

【作者基本信息】 天津大学 ， 微电子学与固体电子学， 2005， 硕士

【摘要】 本文选用复合钙钛矿结构Ba(Mg_1/3Ta_2/3)O₃型高端微波介质陶瓷为研究对象,用固相法合成工艺制备试样,采用XRD、SEM等分析手段,利用开式腔谐振法进行测试,对Ba(Mg_1/3Ta_2/3)O₃型高端微波陶瓷的晶体结构、物相结构和介电性能进行了深入的研究。系统研究了BMT系的晶体结构和介电性能。通过晶体学计算,标定出BMT主晶相存在的两种结构,1:2有序六方超晶格结构和无序立方结构。BMT的基本介电性能为ε=25.42, tgδ=0.64×10^-4,α_ε=-23.87×10^-6/℃,ρ_v=1.4×1014Ωcm,τf=1.93×10^-6/℃。两步煅烧法制备BMT克服了附加相Ba0.5TaO3对BMT烧结性能和介电性能的影响,使BMT的介电性能相对传统一步煅烧法有较明显的提高。其ε=25.05,tgδ=0.22×10^-4,αε=-20.01×10^-6/℃,ρv=7.2×1014Ωcm,τf=0.0075×10^-6/℃。研究了BMT-MC系的结构和介电性能,通过加入适量的MnCO3将BMT的烧结温度从1600℃左右降至1480℃以下,并在MnCO3的含量为0.5%时获得良好的介电性能:ε=25.58,tgδ=0.23×10^-4,αε=-17.58×10^-6/℃,ρv=1.0×1015Ωcm,τf=-1.21×10^-6/℃。为了有效降低BMT的烧结温度,在BMT中加入不同比例的BaWO4,使BMT致密化温度降至1380℃,并在BaWO4的含量为4%时获得良好的介电性能,ε=24.07,tgδ=0.4×10^-4,αε=-7.96×10^-6/℃,ρv=1.4×1015Ωcm,τf=-6.01×10^-6/℃。利用开式腔谐振法对Ba(Mg_1/3Ta_2/3)O₃型高端微波陶瓷材料的微波特性进行了测试,其结果如下: BMT系,ε=24.79, Qf=143000（10.10GHz）,τf=0.0075×10^-6/℃; BMT-MC系,ε=25.68,Qf=122040（10.17GHz）,τf=0.15×10^-6/℃; BMT-BW系,ε=23.00,Qf=124000（10.127GHz）,τf=-1.45×10^-6/℃。更多还原

【Abstract】 The high frequency microwave dielectric ceramics of complex perovskite structure Ba(Mg_1/3Ta_2/3)O₃ type were selected as the research objects, and the specimens were prepared by the mixed oxide method. The crystal structure and dielectric properties of Ba(Mg_1/3Ta_2/3)O₃ materials were investigated by using X-ray powder diffraction, scanning electron microscopy and the Hakki-Coleman opened resonator method. The crystal structure and dielectric properties of BMT materials were systematically investigated. The two structures of BMT main phase, that is 1:2 ordered hexagonal superlattice and disordered cubic structure reflections, were marked in XRD patterns by crystallography. A pure BMT ceramic with ε=25.42, tgδ=0.64 × 10^-4,αε=-23.87 × 10^-6/ ℃ , ρ v=1.4 × 1014 Ω cm,τf=1.93 × 10^-6/ ℃ was obtained. The process of two-step calcinations eliminates the effect on sintering ability made by satellite phase of Ba0.5TaO3. ε=25.05, tgδ=0.22×10^-4,αε=-20.01×10^-6/℃,ρv=7.2×1014Ωcm,τf=0.0075×10^-6/℃. The structure and dielectric properties of BMT-MC system were investigated. The sintering temperature of BMT was lowered from 1600℃ to 1480 ℃ for the first time by adding a small quantity of MnCO3, and got good dielectric properties at 0.5%: ε=25.58,tgδ=0.23×10^-4,αε=-17.58×10^-6/℃,ρv=1.0×1015Ωcm,τf=-1.21×10^-6/℃. By addition of BaWO4,the densification temperature of BMT ceramic is as low as 1380℃ contrasted with the normal sintering temperature, and got good dielectric properties at 4%:ε=24.07,tgδ=0.4 × 10^-4,αε=-7.96 × 10^-6/ ℃ , ρ v=1.4 × 1015 Ωcm,τf=-6.01×10^-6/℃. The microwave properties of Ba(Mg_1/3Ta_2/3)O₃ type ceramic materials were investigated by using the Hakki-Coleman opened resonator method. The results listed follow: BMT 系,ε=24.79, Qf=143000（10.10GHz）,τf=0.0075×10^-6/℃; BMT-MC 系,ε=25.68,Qf=122040（10.17GHz）,τf=0.15×10^-6/℃; BMT-BW 系,ε=23.00,Qf=124000（10.127GHz）,τf=-1.45×10^-6/℃。更多还原