中高介电微波陶瓷的低温制备与性能调控研究
发布时间：2018-08-31 12:28
【摘要】：近年来,随着无线通讯技术的快速发展,对以微波介质陶瓷为基础的微波器件提出了小型化、高品质化、低成本化的新要求。低温共烧技术和高介电常数(εr)微波介质陶瓷是实现通讯设备片式化和微型化的有效方法。目前,低烧和低温共烧(LTCC)介质材料多集中于低介微波陶瓷体系,而高介微波陶瓷体系常常存在烧结温度高,谐振频率温度系数(ηf)大,品质因数(Q)较低的缺点。因此,寻找具有低烧结温度(≤1100℃)和综合性能优异(εr≥20,Q×f≥5000GHz,ηf≈±10 ppm/℃)的新型微波介质材料成为当务之急。本文采用复合材料的工艺原理制备新型中、高介电常数微波介质陶瓷,采用XRD、SEM、EDS和网络分析仪,系统研究了几种微波介质陶瓷的烧结特性、晶体结构、显微组织和介电性能,得到如下结果:1.(1-x)Li3Nb O4-x Ca0.8Sr0.2Ti O3(x=0.1-0.4)体系:XRD和EDS结果表明,在0.1≤x≤0.4成分范围内,所有样品均由钙钛矿结构的钛酸锶和Li3Nb O4两相共存构成。随着x值增大,εr从18.6增到31.2;Q×f值从86962GHz降至9472GHz;ηf从-30 ppm/?C增加到+119ppm/?C。实测结果与理论计算值及变化规律相一致。当x=0.2时,在1075℃下烧结的陶瓷的介电性能最优:εr=21.4,Q×f=49,276GHz,ηf=+5.15 ppm/℃。2.(1-x)Bi VO4-x Li0.5Re0.5WO4(Re=La,Nd,Sm)(x=0.05-0.11)体系:XRD结果表明,该体系在替代范围内均形成了单斜晶系Bi VO4结构固溶体,且晶胞体积随着x的增加呈近似线性增加。SEM结果表明,该体系的最佳烧结温度均为750℃。(1-x)Bi VO4-x Li0.5La0.5WO4在x=0.09时,介电性能最理想:εr=76.65,Q×f=6789.4GHz,ηf=+7.3ppm/℃;(1-x)Bi VO4-x Li0.5Nd0.5WO4在x=0.08时,介电性能最优:εr=71.8,Q×f=7481.7GHz,ηf=0.8ppm/℃;(1-x)Bi VO4-x Li0.5Sm0.5WO4在x=0.07时,介电性能最好:εr=74.7,Q×f=9054GHz和ηf=-1.6ppm/℃。该系陶瓷材料有望用于微波天线和LTCC领域。3.(1-x)Ca0.8Sr0.2Ti O3-x Li0.5Sm0.5Ti O3(CST-LST)体系:XRD结果表明,所有样品均为正交晶系钙钛矿结构。当x=0.8,1250℃烧结的陶瓷介电性能最好。添加5wt%BCB可使CST-LST陶瓷的烧结温度从1250℃降至950℃,微波介电性能优异:εr=66.7,Q×f=3222 GHz,ηf=-21.3ppm/℃。添加适量的Ti O2能有效地调节ηf和提高εr。950℃/4h时CST-LST+5wt%BCB+1.5wt%Ti O2样品的微波介电性能为:εr=71.6,Q×f=3441GHz,ηf=-10.8ppm/℃。该陶瓷与Ag电极共烧相容性好,有望应用于LTCC领域。
[Abstract]:In recent years, with the rapid development of wireless communication technology, microwave devices based on microwave dielectric ceramics have put forward the new requirements of miniaturization, high quality and low cost. Low temperature co-firing and high dielectric constant (蔚 r) microwave dielectric ceramics are effective methods to realize chip and miniaturization of communication equipment. At present, low and low temperature co-fired (LTCC) dielectric materials are mostly concentrated in low dielectric microwave ceramic systems. However, high dielectric microwave ceramic systems often have the disadvantages of high sintering temperature, large temperature coefficient of resonance frequency (畏 f) and low quality factor (Q). Therefore, it is urgent to find new microwave dielectric materials with low sintering temperature (鈮，
本文编号：2214988
[Abstract]:In recent years, with the rapid development of wireless communication technology, microwave devices based on microwave dielectric ceramics have put forward the new requirements of miniaturization, high quality and low cost. Low temperature co-firing and high dielectric constant (蔚 r) microwave dielectric ceramics are effective methods to realize chip and miniaturization of communication equipment. At present, low and low temperature co-fired (LTCC) dielectric materials are mostly concentrated in low dielectric microwave ceramic systems. However, high dielectric microwave ceramic systems often have the disadvantages of high sintering temperature, large temperature coefficient of resonance frequency (畏 f) and low quality factor (Q). Therefore, it is urgent to find new microwave dielectric materials with low sintering temperature (鈮，
本文编号：2214988
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