【作者】 张斌；

【导师】 李月明；

【作者基本信息】 景德镇陶瓷学院 ， 材料学， 2009， 硕士

【摘要】 低温烧结微波介质陶瓷材料的研究近年来受移动通信事业的推动,发展非常迅速,为了满足微波元器件小型化、集成化的需要,迫切需要开发低温烧结的高介电常数微波介质材料。本研究选用具有高介电常数的CaO-Li₂O-Sm₂O₃-TiO₂体系为基体材料,选用低熔点氧化物和玻璃料为烧结助剂,研究烧结助剂对该微波介质陶瓷体系烧结特性、晶相组成、显微结构及微波介电性能的影响,探讨烧结助剂对促进陶瓷低温烧结的内在机理。选用复合钙硼硅氧化物CaO-B₂O₃-SiO₂（CBS）、低熔点玻璃Li₂O-B₂O₃-SiO₂-CaO-Al₂O₃（LBSCA）以及氧化物CuO为烧结助剂,对（1-x）CaTiO₃-x(Li_1/2Sm_1/2)TiO₃（简称CLST-x）体系微波介质陶瓷的低温烧结性能进行研究。研究结果表明:添加上述烧结助剂的各组分陶瓷的晶相均为斜方钙钛矿结构。单独添加5-20 wt%CBS复合氧化物,通过CBS熔融产生液相促进陶瓷低温烧结,可将Ca_0.3(Li_1/2Sm_1/2)_0.7TiO₃（CLST-0.7）与Ca_0.2(Li_1/2Sm_1/2)_0.8TiO₃（CLST-0.8）烧结温度降低300-350℃,其中添加10wt%CBS的CLST-0.7陶瓷（CLST-0.7-10wt%CBS）与CLST-0.8陶瓷（CLST-0.8-10wt%CBS）可在1000℃保温5h烧结,此时,CLST-0.7-10wt%CBS陶瓷具有的微波介电性能:ε_r=80.21,Qf=2128GHz,τ_f=35.88ppm/℃,同时,CLST-0.8-10wt%CBS陶瓷具有的微波介电性能:ε_r=73.11,Qf=2048GHz,τ_f=-9.64 ppm/℃。上述组成的陶瓷已具有良好的微波介电性能,但其烧结温度达1000℃,无法实现与银等金属的低温共烧,因此,在上述基础上继续添加2-6wt%LBSCA玻璃料,通过LBSCA玻璃液相来进一步促进烧结,可将CLST-0.7-10wt%CBS陶瓷与CLST-0.8-10wt%CBS陶瓷烧结温度再降低50-100℃,其中添加4wt%LBSCA的CLST-0.7-10wt%CBS陶瓷（CLST-0.7-10wt%CBS-4wt%LBSCA）与CLST-0.8-10wt%CBS陶瓷（CLST-0.8-10wt%CBS-4wt%LBSCA）可在950℃保温5h烧结,此时,CLST-0.7-10wt%CBS-4wt%LBSCA陶瓷的微波介电性能:ε_r=71.84,Qf=1967GHz,τ_f=41.7 ppm/℃,同时,CLST-0.8-10wt%CBS-4wt%LBSCA陶瓷的微波介电性能:ε_r=61.81,Qf=1707GHz,τ_f=-8.3ppm/℃。虽然通过添加LBSCA玻璃料可以降低烧结温度至950℃,但该烧结温度仍然偏高,为此,继续添加复合烧结助剂来进一步降低烧结温度,选择CuO可以做为较好的烧结助剂。在CLST-0.7-10wt%CBS-4wt%LBSCA与CLST-0.8-10wt%CBS-4wt%LBSCA的基础上添加0.5-2wt%CuO氧化物,由于CuO能与CLST形成固溶体活化晶格,促进陶瓷的低温烧结,可将陶瓷烧结温度再降低50-80℃,其中添加1wt%CuO的CLST-0.7-10wt%CBS-4wt%LBSCA陶瓷（CLST-0.7-10wt%CBS-4wt%LBSCA-1wt%CuO）与CLST-0.8-10wt%CBS-4wt%LBSCA陶瓷（CLST-0.8-10wt%CBS-4wt%LBSCA-1wt%CuO）在900℃保温5h烧结时,CLST-0.7-10wt%CBS-4wt%LBSCA-1wt%CuO陶瓷具有良好的微波介电性能:ε_r=67.77,Qf=2197GHz,τ_f=40.28 ppm/℃,同时,CLST-0.8-10wt%CBS-4wt%LBSCA-1wt%CuO陶瓷具有良好的微波介电性能:ε_r=58.36,Qf=2011 GHz,τ_f=3.44ppm/℃。该组成可用于多层片式微波频率器件的低温烧结微波介质材料。更多还原

【Abstract】 With the quick development of mobile telecommunication industry, lowtemperature co-firing ceramics are developed very quickly. In order to fulfill the need ofLTCC design, not only the low-temperature sintering materials but also high dielectricconstant materials should be developed. CaO-Li₂O-Sm₂O₃-TiO₂ system material withhigh dielectric constant was selected as bulk material in this research. The effects ofdifferent sintering aids on sintering characteristics, phase compositions, microstructuresand microwave dielectric properties of ceramics were studied. The low-temperaturesintering properties and mechanisms of the microwave dielectric ceramics were alsoresearched by using low melting point glass and oxide as sintering additives.The microwave dielectric properties of （1-x）CaTiO₃-x(Li_1/2Sm_1/2)TiO₃ ceramics（abbreviated CLST-x） were studied systematically. The CaO-B₂O₃-SiO₂（CBS）Li₂O-B₂O₃-SiO₂-CaO-Al₂O₃ （LBSCA） and CuO were selected as sintering additives. Theresults indicated that the major phase of additives-doped Ca_0.3(Li_1/2Sm_1/2)_0.7TiO₃（CLST-0.7） ceramics was orthorhombic perovskite by XRD analysis. The sinteringtemperature of CLST-0.7 and CLST-0.8 ceramics were decreased 300 350°C by using5-20 wt% CBS as liquid-sintering additives, which could promote low-temperaturesintering. The sample of Ca_0.3(Li_1/2Sm_1/2)_0.7TiO₃ with 10.0 wt% CBS（CLST-0.7-10wt%CBS） sintered at 1000℃for 5 h had good microwave dielectricproperties:ε_r= 80.21, Qf= 2128GRz,τ_f= 35.88 ppm/℃. At the same time, the sampleof Ca_0.2(Li_1/2Sm_1/2)_0.8TiO₃ with 10.0 wt% CBS （CLST-0.8- 10wt%CBS） sintered at1000℃for 5 h also had good microwave dielectric properties:ε_r= 73.11, Qf= 2048GHz,τ_f= -9.64 ppm/℃. Although both of the ceramics showed excellent dielectricproperties, the sintering temperature of 1000℃was too high. The ceramics and silvercould not realize co-firing. So LBSCA glass was selected as other liquid-sinteringadditives. Doping LBSCA glass could further promote low-temperature sintering. Thesintering temperature of CLST-0.7- 10wt%CBS and CLST-0.8- 10wt%CBS ceramicswere decreased 50- 100℃again by continued doping 2-6 wt% LBSCA, and thesample of CLST-0.7-10wt%CBS with 4.0 wt%LBSCA（CLST-0.7-10wt%CBS-4wt%LBSCA） sintered at 950℃for 5 h had bettermicrowave dielectric properties:ε_r= 71.84, Qf= 1967GHz,τ_f= 41.7 ppm/℃. at the sametime, The sample of CLST-0.8-10wt%CBS with 4.0 wt%LBSCA（CLST-0.8-10wt%CBS-4wt%LBSCA） sintered at 950℃for 5 h also had bettermicrowave dielectric properties:ε_r- 61.81, Qf = 1707 GHz,τ_f= -8.3 ppm/℃.Accordingly, although LBSCA could be lower sintering temperature, the sintering temperature of 950℃was still too high. In order to further lower sintering temperature,using doping multiple sintering additives method, the CuO was selected as bettersintering additives, the sintering temperature of CLST-0.7-10wt%CBS- 4wt%LBSCAand CLST-0.8-10wt%CBS- 4wt%LBSCA ceramics are decreased 50-80℃again bydoping 0.5-2.0 wt% CuO. The formation of solid solution by doping CuO can makecrystal lattice active to decrease the sintering temperature. The sample ofCLST-0.7-10wt%CBS-4wt%LBSCA with 1.0 wt% CuO（CLST-0.7-10wt%CBS-4wt%LBSCA-1wt%CuO） sintered at 900℃for 5 h had excellent dielectricproperties:ε_r= 67.77, Qf= 2197 GHz,τ_f= 40.28 ppm/℃. At the same time, the sample ofCLST-0.8-10wt%CBS-4wt%LBSCA with 1.0 wt% CuO（CLST-0.8- 10wt%CBS-4wt%LBSCA-1wt%CuO） sintered at 900℃for 5 h also had excellent dielectricproperties:ε_r= 58.36, Qf= 2011 GHz,τ_f= 3.44 ppm/℃. This composition would be usedas low-temprature sintering and multi-layer microwave dielectric frequency componentsmaterial.更多还原