BaCu(B_2O_5)助烧对0.95MgTiO_3-0.05CaTiO_3微波介质陶瓷性能的影响

研究了BaCu(B2O5)的掺入对0.95MgTiO3-0.05CaTiO3微波介质陶瓷介电性能的影响。用XRD和SEM分析其相组成及微观形貌。结果表明:BaCu(B2O5)的加入能够使0.95MgTiO3-0.05CaTiO3陶瓷的烧结温度降至1100℃并有效抑制第二相MgTi2O5的形成。在1100℃烧结3h,加入3wt%BaCu(B2O5)的0.95MgTiO3-0.05CaTiO3陶瓷获得了较好的介电性能:εr=22.9,Q×f=25,000GHz(7GHz),τf=-3.3ppm/℃(7GHz)。     

低温B_2O_3掺杂对Ba_4Sm_(9.33)Ti_(18)O_(54)微波介质陶瓷性能的影响

为降低Ba_4Sm_(9.33)Ti_(18)O_(54)(BST)微波介质陶瓷的烧结温度,研究了B_2O_3掺杂对其烧结性能、物相组成、显微结构及介电性能的影响。结果表明:少量B2O3的引入未改变陶瓷的晶相组成,主晶相为Ba_(6-3x)Sm_(8+2x)Ti_(18)O_(54)固溶体,适量B_2O_3不仅能显著地降低BST陶瓷的烧结温度至1180℃,而且能提高其介电性能;随着B_2O_3添加量的继续增加,有烧绿石结构的Sm_2Ti_2O_7相出现并逐渐增多。当B_2O_3添加量为0.25 wt%,在1180℃温度烧结3 h时,BST陶瓷获得优异的微波介电性能:ε_r=76.58,Q·f=6794.24 GHz,τ_f=-7.06×10~(-6)/℃。     

Bi_2O_3-B_2O_3掺杂对BaAl_2Si_2O_8陶瓷结构及微波介电性能的影响

采用固相反应法制备BaAl_2Si_2O_8-x wt%Bi_2O_3-B_2O_3(x=0,1,2,3,4)陶瓷。探究了添加不同量的Bi_2O_3-B_2O_3(BiB)烧结助剂对BaAl_2Si_2O_8(BAS)陶瓷的烧结温度、结构及微波介电性能的影响。结果表明:添加1 wt%的BiB烧结助剂可促进BAS晶体结构由六方相全部转变为单斜相,并且BiB烧结助剂添加量在1～4 wt%范围内,均为单一单斜相。添加3 wt%的Bi B烧结助剂可使BAS陶瓷烧结密度增加到最大值,并能将烧结温度由1400℃降低至1250℃。在x=3,烧结温度为1250℃时,BAS陶瓷的介电常数和品质因数均达到最大值,并且谐振频率温度系数的绝对值也显著减小,其介电性能为:ε_r=6.2,Q·f=21 972 GHz,τ_f=-17.06×10~(-6)℃~(-1)。     

BaCu(B_2O_5)掺杂对0.4CaTiO_3-0.6(Li_(1/2)Nd_(1/2))TiO_3陶瓷烧结和介电性能的影响

研究了烧结助剂BaCu(B2O5)(BCB)对0.4CaTiO3-0.6(Li1/2Nd1/2)TiO3(CLNT)介质陶瓷的烧结特性、相组成、微观形貌及介电性能的影响。结果表明:添加少量的BCB能使CLNT陶瓷的烧结温度从1300℃降低至1050℃。随着BCB添加量的增加,介电常数下降,频率温度系数向负值偏移。添加4wt%BCB的CLNT陶瓷在1050℃烧结2h,获得了最佳的介电性能:εr=96.5,tanδ=0.017,τf=-13.6ppm/℃,满足高介多层片式微波元器件的设计要求。     

BaCu(B_2O_5)助烧剂对2.5ZnO-2.5Nb_2O_5-5TiO_2微波介质陶瓷介电性能的影响

研究了烧结助剂BaCu(B2O5)(BCB)对2.5ZnO-2.5Nb2O5-5TiO2(ZNT)陶瓷的微观结构、烧结特性及介电性能的影响。结果表明:当烧结温度高于900℃时,添加BCB的陶瓷片的致密度高于纯ZNT的致密度。介电常数(εr)随着BCB添加量的增加先增大后略有减小。由于液相的存在,品质因数和谐振频率的积(Qf)随着BCB添加量的增大而减小。谐振频率温度系数(τf)与纯ZNT陶瓷相比更接近零。添加质量分数为3%BCB的ZNT陶瓷在900℃烧结3h后得到良好的介电性能:εr=48,Qf=15258GHz,τf=41×10-6/℃(5GHz)。     

纳米Al_2O_3对CaTiO_3-(La,Nd)AlO_3陶瓷的烧结温度和介电特性的影响

为了降低Ca Ti O_3-(La,Nd)Al O_3(简称CT-LNA)陶瓷的烧结温度和提高其介电性能,研究纳米Al_2O_3对Ca Ti O_3-(La,Nd)Al O_3陶瓷的烧结温度和介电性能的影响。固相法制备粉料,采用XRD和SEM分析其晶相和显微结构,用网络分析测试样品的介电参数,结果表明,纳米Al_2O_3可促进陶瓷烧结,在1320~1400℃范围内可烧结成瓷,并具有较好的微波介电性能。当纳米Al_2O_3含量为50 wt%时,陶瓷在1340℃烧结可获得优良的微波介电性能:介电常数为42.6,Q×f值高达34,000GHz,频率温度系数为+4.8 ppm/℃。     

低温烧结Bi_2MoO_6-Bi_2Mo_2O_9陶瓷的微波介电性能

采用氧化物固相反应法制备x≤30%(质量分数)的不同xBi_2MoO_6-(1-x)Bi_2Mo_2O_9介质陶瓷材料,研究了Bi_2MoO_6掺入对Bi_2Mo_2O_9晶相结构、显微形貌和介电性能的影响。结果表明:烧结后陶瓷均为Bi_2MoO_6正交和Bi_2Mo_2O_9单斜两相混合,Bi_2MoO_6加入量对晶体结构和晶粒尺寸有明显影响;随着x的增大,xBi_2MoO_6-(1-x)Bi_2Mo_2O_9陶瓷的相对介电常数(ε_r)、品质因素(Qf)和谐振频率温度系数(τ_f)减小。0.3Bi_2MoO_6-0.7Bi_2Mo_2O_9在640℃空气下烧结2h,谐振频率7.72 GHz、ε_r=30.2、Qf=10 725 GHz、τ_f=1.6×10~(-6)/℃,具有优良的微波介电性能。     

CuO掺杂对ZnZrNb_2O_8微波介质陶瓷性能的影响

以分析纯的ZnO、ZrO_2、CuO及Nb_2O_5为原料,采用传统固相法制备了Zn_(1–x_Cu_xZrNb_2O_8(ZCZN,x=0.00–0.05)微波介质陶瓷,研究了不同CuO添加量对ZCZN陶瓷的烧结性能、显微结构、相组成以及微波介电性能的影响,利用X射线衍射仪、扫描电子显微镜和网络分析仪等对其微观结构、形貌以及微波介电性能进行表征。结果表明:CuO的添加能有效降低ZnZrNb_2O_8陶瓷的烧结温度,提高其品质因数和介电常数。当x=0.03时,陶瓷可在1 200℃烧结并获得最佳微波介电性能:介电常数ε_r=30.1,品质因数Q×f=53 037 GHz,频率温度系数τ_f=–57.21×10~(–6)/℃。     

CuO掺杂对ZnZrNb_2O_8微波介质陶瓷性能的影响EI北大核心CSCD

以分析纯的ZnO、ZrO_2、CuO及Nb_2O_5为原料,采用传统固相法制备了Zn_(1–x_Cu_xZrNb_2O_8(ZCZN,x=0.00–0.05)微波介质陶瓷,研究了不同CuO添加量对ZCZN陶瓷的烧结性能、显微结构、相组成以及微波介电性能的影响,利用X射线衍射仪、扫描电子显微镜和网络分析仪等对其微观结构、形貌以及微波介电性能进行表征。结果表明:CuO的添加能有效降低ZnZrNb_2O_8陶瓷的烧结温度,提高其品质因数和介电常数。当x=0.03时,陶瓷可在1 200℃烧结并获得最佳微波介电性能:介电常数ε_r=30.1,品质因数Q×f=53 037 GHz,频率温度系数τ_f=–57.21×10^(–6)/℃。     

非化学计量比铌酸锌微波介电陶瓷的低温烧结行为

采用固相烧结工艺制备低损耗、非化学计量比Zn_(1.01)Nb_2O_6微波介电陶瓷。研究了添加不同量的Li_2CO_3–B_2O_3–V_2O_5(LBV)对Zn_(1.01)Nb_2O_6陶瓷烧结温度、表面形貌以及微波介电性能的影响。结果表明:LBV作为助烧剂,在陶瓷烧结过程中产生了液相,当添加剂含量大于1.5%(质量分数)时,LBV与基体陶瓷发生了化学反应。液相的产生、副相LiZnNbO_4的形成以及V~(5+)的扩散共同改善了陶瓷的烧结行为,使烧结温度由1 175℃低至950℃。LBV加入到基体陶瓷后对微波介电性能影响较小。当LBV添加量为1.0%,并在950℃保温4 h后,Zn_(1.01)Nb_2O_6陶瓷微波介电性能最优:ε_r=20.6,Q×f=90 472 GHz,τ_f=–85.9×10–6℃~(–1)。     

添加Li_2O的CaO-B_2O_3-SiO_2系微晶玻璃的性能研究

以Li_2O为烧结助剂,采用DTA、XRD、SEM等分析手段研究了添加1.0～2.5 wt%Li_2O对CaO-B_2O_3-SiO_2(CBS)系微晶玻璃性能的影响.结果表明:Li_2O降低了CBS系微晶玻璃的玻璃转变温度和析晶温度.未添加Li_2O的试样在930 ℃烧结,而添加Li_2O的试样可以在820 ℃以下烧结,Li_2O显著降低了试样的烧结温度.当Li_2O添加量为1.0wt%时,试样可以在760～820 ℃范围内烧结,800 ℃烧结试样介电常数为5.71,介电损耗为0.0024(测试频率为10 MHz).     

BaO－TiO_2系中Ba_2Ti_9O_（20）相形成的研究

研究了ＢａＯ－ＴｉＯ_２系中Ｂａ_２Ｔｉ_９Ｏ_（２０）相的形成规律。结果表明：ＢａＯ－ＴｉＯ_２系中，不加任何添加剂可以合成Ｂａ_２Ｔｉ_９Ｏ_（２０）相；在ＢａＯ－ＴｉＯ_２系中Ｂａ：Ｔｉ＝２：９附近存在一个很窄的单相Ｂａ_２Ｔｉ_９Ｏ_（２０）区；烧结阶段Ｂａ_２Ｔｉ_９Ｏ_（２０）相的最终合成并不依赖于预烧阶段部分此相的形成；通氧烧结对Ｂａ_２Ｔｉ_９Ｏ_（２０）相的形成影响不大，但可以抑制钛的变价。实验还发现，Ｂａ_２Ｔｉ_９Ｏ_（２０）陶瓷化学计量比的偏离将导致微波下介电常数的下降。     

Synthesis of BaCu(B2O5) Ceramics and their Effect on the Sintering Temperature and Microwave Dielectric Properties of Ba(Zn1/3Nb2/3)O3 Ceramics

BaCu(B₂O₅) ceramics were synthesized and their microwave dielectric properties were investigated. BaCu(B₂O₅) phase was formed at 700°C and melted above 850°C. The BaCu(B₂O₅) ceramic sintered at 810°C had a dielectric constant (ɛ_r) of 7.4, a quality factor ( Q × f ) of 50 000 GHz and a temperature coefficient of resonance frequency (τ_f) of −32 ppm/°C. As the BaCu(B₂O₅) ceramic had a low melting temperature and good microwave dielectric properties, it can be used as a low-temperature sintering aid for microwave dielectric materials for low temperature co-fired ceramic application. When BaCu(B₂O₅) was added to the Ba(Zn_1/3Nb_2/3)O₃ (BZN) ceramic, BZN ceramics were well sintered even at 850°C. BaCu(B₂O₅) existed as a liquid phase during the sintering and assisted the densification of the BZN ceramic. Good microwave dielectric properties of Q × f =16 000 GHz, ɛ_r=35, and τ_f=22.1 ppm/°C were obtained for the BZN+6.0 mol% BaCu(B₂O₅) ceramic sintered at 875°C for 2 h.     

Microwave Dielectric Properties and Low-Temperature Sintering of Ba0.60Sr0.40TiO3 Ceramics

In the present work, the sintering behaviors and dielectric properties of Ba_0.60Sr_0.40TiO₃ (BST) ceramics with the addition of BaCu(B₂O₅) were investigated in detail. The results indicated that the addition reduced the sintering temperature of BST by about 500°C. It was suggested that a liquid phase BaCu(B₂O₅) assisted the densification of BST ceramics at lower temperatures. For a low-level BaCu(B₂O₅) addition (2.0 mol%), the BST sample sintered at 950°C for 5 h displayed good dielectric properties, with a moderate dielectric constant (ɛ=2553) and a low dielectric loss (tan δ=0.00305) at room temperature and at 10 kHz. The sample showed 45.9% tunability at 10 kHz under a dc electric field of 30 kV/cm. At the frequency of 0.984 GHz, BST-added 2.0 mol% BaCu(B₂O₅) possessed a dielectric constant of 2204 and a Q value of 146.7.     

B2O3掺杂对α-CaSiO3/Al2O3陶瓷低温烧结及微波介电性能的影响

通过传统固相法制备了α-CaSiO3/Al2O3-B2O3微波介质陶瓷,研究了不同B2 O3添加量对α-CaSiO3/Al2O3陶瓷烧结特性、相组成及微波介电性能的影响,通过XRD、SEM和网络分析仪对其相结构、微观形貌和微波介电性能进行了表征.结果表明:B2 O3的添加使陶瓷的烧结温度从1375℃降低到了1100℃,并使主晶相由α-CaSiO3相变为β-CaSiO3相;当B2 O3的添加量为3wt%时,在1100℃烧结2 h可获得最佳微波介电性能:εr=6.21,Q×f=30471 GHz,τf=-34.58 ppm/℃.     

低温烧结Mg_4Nb_2O_9微波介质陶瓷(英文)

分别研究了不同含量Li2CO3/V2O5共掺杂和部分Li取代Mg对Mg4Nb2O9基陶瓷烧结特性、显微结构和微波介电性能的影响.结果表明:Li2CO3/V2O5共掺杂或部分Li取代Mg,均能使Mg4Nb2O9基陶瓷的烧结温度从1 400℃降至950℃,但其烧结机理不同.Li2CO3/V2O5共掺杂Mg4Nb2O9(MNLV)样品中的低熔点液相,使MNLV陶瓷的致密化烧结温度降低.部分Li取代Mg显著降低了(Mg(4-x)Lix)(Nb1.92V0.08)O(9-δ)(MLNV)样品的致密化烧结温度.950℃烧结,相对于MNLV样品的品质因数(Q=13276)而言,MLNV样品的Q值(1 759)显著恶化,这是由于Li1+占据Mg2+晶格.使晶体中非谐振项损耗增加.     

H3BO3对Li2Zn3Ti4O12微波介质陶瓷低温烧结与微波介电性能的影响

采用传统固相反应法制备了添加H3BO3助烧剂的Li2Zn3Ti4O12 (LZT)陶瓷,分别通过XRD、SEM、排水法及网络分析仪等方法研究了不同H3BO3添加量对所得陶瓷的物相、微观形貌、烧结特性与微波介电性能的影响.结果表明在LZT陶瓷中添加3wt% H3BO3可有效降低烧结温度,在900 ℃/2 h烧结条件下可以获得高致密性及优异的微波介电性:ρ=4.15 g/cm3,εr=17.916,Q×f=61200 GHz,Tf=-52.87×10-6/℃.     

复合烧结助剂对Ca_(0.3)(Li_(0.5)Sm_(0.5))_(0.7)TiO_3微波介质陶瓷低温烧结与性能研究

研究了以Ca_(0.3)(Li_(0.5)Sm_(0.5))_(0.7)TiO_3(CLST-0.7)为基料,复合添加10 wt%CaO-B_2O_3-SiO_2(CBS)、4 wt%Li_2O-B_2O_3-SiO_2-CaO-Al_2O_3(LBSCA)和0～2 wt%CuO氧化物为烧结助剂的微波介质陶瓷的低温烧结行为及微波介电特性.结果表明:随着CuO添加量的增加,陶瓷体积密度、介电常数ε_r、无载品质因数与谐振频率乘积Qf值,都呈先增加后降低,频率温度系数τ_f呈降低的趋势.添加10 wt%CBS、4.0 wt% LBSCA和1.0 wt%CuO的CLST-0.7微波介质陶瓷,在900 ℃烧结5 h具有较佳的微波介电性能:ε_r ＝ 67.31,Qf ＝ 2197 GHz,τ_f＝40.28 ppm/℃.     

Microstructures and Microwave Dielectric Characteristics of Ca(Zn1/3Nb2/3)O3 Complex Perovskite Ceramics

Ca(Zn_1/3Nb_2/3)O₃ microwave dielectric ceramics were prepared using a solid-state reaction process, and their microwave dielectric properties were evaluated as functions of sintering and postdensification annealing conditions. The relationship between microwave dielectric properties and processing was interpreted through the variation of microstructures. The dielectric constant showed slight variation with sintering and annealing conditions, but the Q × f value increased at first and then decreased with increased sintering temperature, and annealing in oxygen indicated significant improvement in Q × f , especially for the specimens sintered at higher temperatures. The good microwave dielectric properties were obtained in the ceramics sintered at 1225°C in air for 3 h and annealed at 1100°C in oxygen for 8 h: ɛ= 34.1, Q × f = 15 890 GHz, τ_f=−48 ppm/°C.