The effects of different doping amounts of BaCu(B2 O5 )(BCB)on the sintering behavior,dielectric properties and compatibility with Ag of 2.5ZnO-2.5Nb2 O5-5TiO2 (ZNT)ceramics were investigated.The sintering temperature of ZNT ceramics was effectively lowered from 1 100 ℃ to 900 ℃ with BCB addition.3.0wt% BCB doped ZNT ceramic specimens sintered at 900 ℃ for 3 h exhibit optimum dielectric properties with values ofεr=48, Qf=15 258 GHz,τf=41×10-6/℃.Furthermore,no second crystalline phase and no silver migration were detec-ted in the BCB-doped ZNT ceramic specimen co-fired with Ag,which indicates that 3.0wt% BCB doped ZNT ceramics could be a suitable candidate for LTCC applications.

The effects of BaCu(B2O5) (BCB) and ZnO co-doping on the sintering properties and dielectric properties of 0.95MgTiO3-0.05CaTiO3(95MCT) microwave dielectric ceramics were investigated. The crystal phase structure and micromorphology of the 95MCT ceramics were studied by XRD and SEM. The results show that the sintering temperature of the 95MCT ceramic can be reduced from 1 400 ℃ to 1 050 ℃ and it can be co-fired with Cu. Formation of second phase MgTi2O5 can be effectively restrained through the addition of ZnO. After sintering at 1 050 ℃ for 3 h, the 95MCT ceramic co-doped with 3.00% BaCu (B2O5) and 1.00% ZnO (mass fraction) shows good dielectric properties of er= 20.5,Q·f = 21 133 and τf = – 10.1×10–6/ ℃ at 7 GHz.

CaO-BaO-Li2O-Sm2O3-TiO2(CBLST) ceramics were prepared by conventional solid-state reaction method. Effect of BaCu(B2O5)(BCB) and Li2O-B2O3-SiO2(LBS) complex additive on the sintering behaviors, microstructure, phase composition and dielectric properties of the CBLST ceramics were investigated. The results show that the CBLST ceramics possess two phases of orthorhombic perovskite and BST phase when adding with w(BCB)=6.0% and w(LBS)=0.5%～5.0% additive. The sintering temperature of the CBLST ceramics is reduced from 1 325 ℃ to 1 050 ℃ and the excellent dielectric properties of er=81.9, tanδ=0.006 2, τf =–3.75×10–6 ℃ are obtained with w(BCB)=6.0% and w(LBS)=0.5% doped CBLST ceramics sintered at 1 050 ℃ for 2 h. The dielectric loss of w(BCB)=6.0% and w(LBS)=0.5% doped CBLST ceramics is lower obviously than that of pure CBLST ceramics (tanδ=0.016).

The effects of the compound sintering aids of ZnO-B_2O_3-SiO_2(ZBS) glass and LiF addition amounts on the phase structures,sinterability and dielectric properties of CLLNT ceramics are investigated.After adding combination of ZnO-B_2O_3-SiO_2 glass and LiF,the sintering temperature of the CLLNT ceramics has been efficiently lowered from 1400℃to 1000℃.When the addition amount of ZBS glass is 4wt%and the addition amount of LiF is lower than 3wt%,the second phases are not found and the major phase of CLLNT ceramics is still orthorhombic perovskite.When the addition amount of ZBS glass is 4wt%and the addition amount of LiF is 1wt%,CLLNT ceramics have excellent properties when sintered at 1000℃for 3h,dielectric constante_r = 97,Q×f= 1286GHz,T_(CF) = 43×10~(-6)/℃(4GHz).

The Effects of BaCu(B2O5 )on the dielectric properties of 0.95MgTiO3-0.05CaTiO3 microwave dielectric ceramics were investigated.The crystalline structure and micromorphology were studied by XRD and SEM,respectively.The sintering temperature of BaCu(B2O5 )-doped 0.95MgTiO3 -0.05CaTiO3 ceramics can be lowed to 1100℃and effectively inhibited the formation of second phase MgTi2O5 .The microwave dielectric Properties of 0.95MgTiO3-0.05CaTiO3Ceramics with 3wt%BaCu(B2O5)additions sintered at 1100 for 3h showed ε r of 22.9,Q×f of 25,000(7 GHz),τ f of-3.3 ppm/℃.

The effects of the sintering aids of ZnO-B2O3(ZB)glass addition amounts on the sinterability, phase structures, and dielectric properties of CLLNT ceramics were investigated. The results indicated that the sintering temperature of the CLLNT ceramics was efficiently lowered by 400℃ . When the addition amount of ZB glass was 1 ～ 5wt.% the second phases were not found and the major phase of CLLNT ceramics was still orthorhombic perovskite. When the addition amount of ZB glass was 4wt.% , CLLNT ceramics has excellent properties which were sintered on 1000 for 3h; Dielectric constantεr=97,tgθ=0.029,TCF= 13ppm/℃(1MHz).

Effects of BaCu(B2O5)on the dielectric properties of 14CaO-4BaO-8Li2O-12Sm2O3-63TiO2 microwave dielectric ceramics were investigated.The crystalline structure and micromorphology were studied by XRD and SEM,respectively.The sintering temperature of the specimens could be reduced from 1325 ℃ to 1100 ℃ and perovskite phase and BST phase were formed after sintering at 1100 ℃ for 2 h.The specimens with 6wt% BaCu(B2O5)sintered at 1100 ℃ for 2 h showed Kr of 87.76,tanδ of 0.018,TCF of-4.27 ppm/℃(1 MHz).

The effects of BaCu(B2O5) (BCB) addition on the microstructure and microwave dielectric properties of 2.5ZnO-2.5Nb2O5-5TiO2 (ZNT) ceramics were investigated. The bulk density of the specimens is higher than that of pure ZNT specimens when the sintering temperature is above 900°C. The dielectric constant εr increases initially and then decreases slightly with the increase of BCB content. The product of quality factor and resonance frequency of Qf value degrades with the addition of BCB because of the presence of the liquid phase in the sintering. The temperature coefficient of the resonance frequency τf is effectively lowered compared with the pure ZNT specimens. The 3% in mass BCB-added ZNT ceramics sintered at 900°C for 3 h have good dielectric properties of εr=48, Qf = 15 258 GHz, and τf = 41 × 10-6/°C at 5 GHz.

研究烧结助剂ZB玻璃对CLLNT陶瓷的烧结特性、相结构、微波介电性能的影响.结果表明,添加适量的ZB玻璃可把CLLNT陶瓷的烧结温度降低400℃,并且获得较高的介电常数.ZB玻璃添加量为1～5wt%时不影响该陶瓷体系的主晶相,依然是斜方钙钛矿相.掺杂4wt.%ZB玻璃的CLLNT陶瓷在1000℃烧结3h,可获得较好的介电性能:介电常数ε=97,tg θ=0.029,TCF=-13ppm/℃(1MHz).