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1.
Synthesis of BaCu(B2 O5 ) Ceramics and their Effect on the Sintering Temperature and Microwave Dielectric Properties of Ba(Zn1/3 Nb2/3 )O3 Ceramics 总被引:1,自引:0,他引:1
Min-Han Kim Jong-Bong Lim Jae-Chul Kim Sahn Nahm Jong-Hoo Paik Jong-Hee Kim Kyeong-Soon Park 《Journal of the American Ceramic Society》2006,89(10):3124-3128
BaCu(B2 O5 ) ceramics were synthesized and their microwave dielectric properties were investigated. BaCu(B2 O5 ) phase was formed at 700°C and melted above 850°C. The BaCu(B2 O5 ) ceramic sintered at 810°C had a dielectric constant (ɛr ) of 7.4, a quality factor ( Q × f ) of 50 000 GHz and a temperature coefficient of resonance frequency (τf ) of −32 ppm/°C. As the BaCu(B2 O5 ) 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(B2 O5 ) was added to the Ba(Zn1/3 Nb2/3 )O3 (BZN) ceramic, BZN ceramics were well sintered even at 850°C. BaCu(B2 O5 ) 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, ɛr =35, and τf =22.1 ppm/°C were obtained for the BZN+6.0 mol% BaCu(B2 O5 ) ceramic sintered at 875°C for 2 h. 相似文献
2.
A narrow region of Zn-vacancy-containing cubic perovskites was formed in the (1− x )Ba3 (ZnNb2 )O9 −( x )Ba3 W2 O9 system up to 2 mol% substitution ( x =0.02). The introduction of cation vacancies enhanced the stability of the 1:2 B-site ordered form of the structure, Ba(Zn1− x □ x )1/3 (Nb1− x W x )2/3 O3 , which underwent an order–disorder transition at 1410°C, ∼35° higher than pure Ba(Zn1/3 Nb2/3 )O3 . The Zn vacancies also accelerated the kinetics of the ordering reaction, and samples with x =0.006 comprised large ordered domains with a high lattice distortion ( c/a =1.226) after a 12 h anneal at 1300°C. The tungstate-containing solid solutions can be sintered to a high density at 1390°C, and the resultant ordered ceramics exhibit some of the highest microwave dielectric Q factors ( Q × f =1 18 000 at 8 GHz) reported for a niobate-based perovskite. 相似文献
3.
X. M. Chen D. Liu R. Z. Hou X. Hu X. Q. Liu 《Journal of the American Ceramic Society》2004,87(12):2208-2212
Ca(Zn1/3 Nb2/3 )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, τf =−48 ppm/°C. 相似文献
4.
The effect of different muffling environments on the structure and dielectric losses of Ba(Zn1/3 Nb2/3 )O3 (BZN) microwave ceramics was investigated. The microwave dielectric losses of stoichiometric BZN pellets heated in ZnO-rich environments were severely degraded (e.g. Q × f ∼15 000 in ZnO powder) compared with samples muffled in their own powder ( Q × f ∼80 000). Structure analyses and gravimetric measurements confirmed that the ceramics muffled in ZnO powder or vapor absorb excess ZnO to form non-stoichiometric solid solutions with reduced cation order and Q . By using starting compositions in the (1− x )BZN−( x )BaNb4/5 O3 binary ( x =0.04), the stoichiometry can be tailored to ensure that after the uptake of ZnO, the ceramics remain well ordered and are located in a high Q region of the system. For example, ZnO-vapor-protected (0.96)BZN−(0.04)BaNb4/5 O3 reached a very high Q × f (∼1 05 000) after sintering at 1400°C for 5 h. 相似文献
5.
Kazuaki Endo Kenji Fujimoto Kyohei Murakawa 《Journal of the American Ceramic Society》1987,70(9):215-C
The dielectric properties of the Ba (Co1/3 Nb2/3 )O3 –Ba(Zn1/3 Nb2/3 )O3 system were determined. Ba (Co1/3 Nb2/3 )O3 –Ba(Zn1/3 Nb2/3 )O3 has a complex perovskite structure, a high dielectric constant, a low dielectric loss, and a low temperature coefficient of the resonant frequency. A solid-solution ceramic with 0.7Ba (Co1/3 Nb2/3 )O3 ·0.3 Ba(Zn1/3 Nb2/3 )O3 has a dielectric constant of K=33.5, Q=11000 at 6.5 GHz, and a temperature coefficient of the resonant frequency of τf =0 ppm/°C. The temperature coefficient of resonant frequency can be varied by changing the composition. The Q values of the ceramics can be increased by annealing in a nitrogen atmosphere. These ceramics can be used for resonant elements and stabilized oscillators. 相似文献
6.
A possibility to produce microwave (MW) dielectric materials by liquid-phase sintering of fine particles was investigated. Zn3 Nb2 O8 powders with a grain size 50–300 nm were obtained by the thermal decomposition of freeze-dried Zn–Nb hydroxides or frozen oxalate solutions. The crystallization of Zn3 Nb2 O8 from amorphous decomposition products was often accompanied by the simultaneous formation of ZnNb2 O6 . Maximum sintering activity was observed for single-phase crystalline Zn3 Nb2 O8 powders obtained at the lowest temperature. The sintering of as-obtained powders with CuO–V2 O5 sintering aids results in producing MW dielectric ceramics with a density 93%–97% of the theoretical, and a Q × f product up to 36 000 GHz at sintering temperature ( T s )≥680°C. The high level of MW dielectric properties of ceramics was ensured by intensive grain growth during the densification and the thermal processing of ceramics. 相似文献
7.
Dong-Wan Kim Jeong-Ryeol Kim Sung-Hun Yoon Kug Sun Hong Chang Kyung Kim 《Journal of the American Ceramic Society》2002,85(11):2759-2762
The effect of B2 O3 on the sintering temperature and microwave dielectric properties of Ba5 Nb4 O15 has been investigated using X-ray powder diffraction, scanning electron microscopy, and a network analyzer. Interactions between Ba5 Nb4 O15 and B2 O3 led to formation of second phases, BaNb2 O6 and BaB2 O4 . The addition of B2 O3 to Ba5 Nb4 O15 resulted in lowering the sintering temperature from 1400° to 925°C. Low-fired Ba5 Nb4 O15 could be interpreted by measuring changes in the quality factor ( Q × f ), the relative dielectric constant (ɛr ), and the temperature coefficient of resonant frequency (τf ) as a function of B2 O3 additions. More importantly, the formation of BaNb2 O6 provided temperature compensation. The microwave dielectric properties of low-fired Ba5 Nb4 O15 had good dielectric properties: Q × f = 18700 GHz, ɛr = 39, and τf = 0 ppm/°C. 相似文献
8.
Jin-Seong Kim Ngoc-Huan Nguyen Myung-Eun Song Jong-Bong Lim Dong-Soo Paik Sahn Nahm Jong-Hoo Paik Byung-Hyun Choi Soon-Jae Yu 《International Journal of Applied Ceramic Technology》2009,6(5):581-586
Bi2 O3 was added to a nominal composition of Zn1.8 SiO3.8 (ZS) ceramics to decrease their sintering temperature. When the Bi2 O3 content was <8.0 mol%, a porous microstructure with Bi4 (SiO4 )3 and SiO2 second phases was developed in the specimen sintered at 885°C. However, when the Bi2 O3 content exceeded 8.0 mol%, a liquid phase, which formed during sintering at temperatures below 900°C, assisted the densification of the ZS ceramics. Good microwave dielectric properties of Q × f =12,600 GHz, ɛr =7.6, and τf =−22 ppm/°C were obtained from the specimen with 8.0 mol% Bi2 O3 sintered at 885°C for 2 h. 相似文献
9.
A Zn2 Te3 O8 ceramic was investigated as a promising dielectric material for low-temperature co-fired ceramics (LTCC) applications. The Zn2 Te3 O8 ceramic was synthesized using the solid-state reaction method by sintering in the temperature range 540°–600°C. The structure and microstructure of the compounds were investigated using X-ray diffraction (XRD) and scanning electron microscopy methods. The dielectric properties of the ceramics were studied in the frequency range 4–6 GHz. The Zn2 Te3 O8 ceramic has a dielectric constant (ɛr ) of 16.2, a quality factor ( Q u × f ) of 66 000 at 4.97 GHz, and a temperature coefficient of resonant frequency (τf ) of −60 ppm/°C, respectively. Addition of 4 wt% TiO2 improved the τf to −8.7 ppm/°C with an ɛr of 19.3 and a Q u × f of 27 000 at 5.14 GHz when sintered at 650°C. The chemical reactivity of the Zn2 Te3 O8 ceramic with Ag and Al metal electrodes was also investigated. 相似文献
10.
Ching-Fang Tseng Cheng-Liang Huang Wen-Ruei Yang Cheng-Hsing Hsu 《Journal of the American Ceramic Society》2006,89(4):1465-1470
The microwave dielectric properties and the microstructures of Nd(Zn1/2 Ti1/2 )O3 (NZT) ceramics prepared by the conventional solid-state route have been studied. The prepared NZT exhibited a mixture of Zn and Ti showing 1:1 order in the B-site. The dielectric constant values (ɛr ) saturated at 29.1–31.6. The quality factor ( Q × f ) values of 56 700–170 000 (at 8.5 GHz) can be obtained when the sintering temperatures are in the range of 1300°–1420°C. The temperature coefficient of resonant frequency τf was not sensitive to the sintering temperature. The ɛ r value of 31.6, the Q × f value of 170 000 (at 8.5 GHz), and the τf value of −42 ppm/°C were obtained for NZT ceramics sintering at 1330°C for 4 h. For applications of high selective microwave ceramic resonators, filters, and antennas, NZT is proposed as a suitable material candidate. 相似文献
11.
Jian Jiang Bian Yun Fei Dong Guo Xiang Song 《Journal of the American Ceramic Society》2008,91(4):1182-1187
The sintering behavior, ordering state, and microwave dielectric properties of Ba1− x La2 x /3 (Zn0.3 Co0.7 )1/3 Nb2/3 O3 Ceramics (0≤ x ≤0.06) were investigated in this paper. The X-ray diffraction (XRD) results show that all samples exhibit a single perovskite phase except for the sample with x ≥0.03. The sinterability is slightly improved by La doping. The long range order (LRO) degree on B-site is greatly increased with the increase of x value up to x =0.015 and then slightly decreased with the further increase of x due to the increasing amount of second phases. The dielectric constant at microwave frequency decreases slightly with the increase of x when x <0.015 and increases slightly with further increasing x for the samples sintered at 1375°C/10 h. The Q × f value increases with x up to x =0.015 and then decreases with further increase of x , which is consistent with the variation trend of LRO degree. The τf value decreases slightly with the increase of x up to 0.006, then increases greatly with the further increase of x . An optimized dielectric properties of ɛ r =34, Q × f =63 159, GHz and τf =5.21 ppm/°C were obtained for the x =0.01 sample sintered at 1425°C/10 h. 相似文献
12.
Jin-Seong Kim Ngoc-Huan Nguyen Jong-Bong Lim Dong-Soo Paik Sahn Nahm Jong-Hoo Paik Jong-Hee Kim Hwack-Joo Lee 《Journal of the American Ceramic Society》2008,91(2):671-674
B2 O3 was added to nominal composition Zn1.8 SiO3.8 (ZS) ceramics to decrease their sintering temperature for application to low-temperature cofired ceramic (LTCC) devices. B2 O3 reacted with SiO2 to form a liquid phase containing SiO2 and B2 O3 . The composition and melting temperature of the liquid phase depended on the sintering temperature and the B2 O3 content. The specimen containing 20.0 mol% of B2 O3 sintered at 900°C exhibited high microwave dielectric properties of Q × f =53 000 GHz, ɛ r =5.7, and τf =−16 ppm/°C, confirming the promising potential of the B2 O3 -added ZS ceramics as candidate materials for the LTCC devices. 相似文献
13.
The effect of the addition of V2 O5 on the structure, sintering and dielectric properties of M -phase (Li1+ x − y Nb1− x −3 y Ti x +4 y )O3 ceramics has been investigated. Homogeneous substitution of V5+ for Nb5+ was obtained in LiNb0.6(1− x ) V0.6 x Ti0.5 O3 for x ≤ 0.02. The addition of V2 O5 led to a large reduction in the sintering temperature and samples with x = 0.02 could be fully densified at 900°C. The substitution of vanadia had a relatively minor adverse effect on the microwave dielectric properties of the M -phase system and the x = 0.02 ceramics had [alt epsilon]r = 66, Q × f = 3800 at 5.6 GHz, and τf = 11 ppm/°C. Preliminary investigations suggest that silver metallization does not diffuse into the V2 O5 -doped M -phase ceramics at 900°C, making these materials potential candidates for low-temperature cofired ceramic (LTCC) applications. 相似文献
14.
Qun Zeng Wei Li Jian-lin Shi Xian-lin Dong Jing-kun Guo 《Journal of the American Ceramic Society》2008,91(2):644-647
A group of new y M-phase/(1− y ) Li2+ x Ti1−4 x Nb3 x O3 composite ceramics with adjustable permittivities for low-temperature co-fired ceramic applications was initially investigated in the study. The 0.5 M-phase/0.5 Li2+ x Ti1−4 x Nb3 x O3 ( x =0.01, 0.02, 0.04, 0.06, 0.081) composite ceramics were first investigated to find the appropriate "Li2 TiO3 ss" composition ( x value). The best dielectric properties of ɛr =40.1, Q × f values up to 9318 GHz, τf =25 ppm/°C, were obtained for the ceramics composites at x =0.02. Based on the good dielectric properties, the suitable "Li2 TiO3 ss" composition with x =0.02 was mixed with the Li1.0 Nb0.6 Ti0.5 O3 powder as the ratio of y "M-phase"/(1− y ) "Li2 TiO3 ss" ( y =0.2, 0.4, 0.5, 0.6, 0.8). By adjusting the y values, the group of composite ceramics could exhibit largely are adjustable permittivities varying from ∼20 to ∼60, while Q × f and τf values relatively good. Nevertheless, in this study, because there are interactions between the M-phase and Li2 TiO3 ss during sintering process, their microwave dielectric properties could not be predicted precisely by the empirical model. 相似文献
15.
Hanxing Liu Hongtao Yu Zhongqing Tian Zhenghua Meng Zhaohui Wu Shixi Ouyang 《Journal of the American Ceramic Society》2005,88(2):453-455
The microwave dielectric properties of the (1− x )CaTiO3 – x Ca(Zn1/3 Nb2/3 )O3 ceramic system have been investigated. The ceramic samples sintered at 1300°–1450°C for 4 h in air exhibit orthorhombic pervoskite and form a complete solid solution for different x value. When the x value increased from 0.2 to 0.8, the permittivity ɛr decreased from 115 to 42, the unloaded quality factor Q × f increased from 5030 to 13 030 GHz, and the temperature coefficient τf decreased from 336 to −28 ppm/°C. When x =0.7, the best combination of dielectric properties, a near zero temperature coefficient of resonant frequency of τf ∼−6 ppm/°C, Q × f ∼10 860 GHz and ɛr ∼51 is obtained. 相似文献
16.
Sergey Kucheiko Dong-Hun Yeo Ji-Won Choi Seok-Jin Yoon Hyun-Jai Kim 《Journal of the American Ceramic Society》2002,85(5):1327-1329
The microwave dielectric properties of CaTi1− x (Al1/2 Nb1/2 ) x O3 solid solutions (0.3 ≤ x ≤ 0.7) have been investigated. The sintered samples had perovskite structures similar to CaTiO3 . The substitution of Ti4+ by Al3+ /Nb5+ improved the quality factor Q of the sintered specimens. A small addition of Li3 NbO4 (about 1 wt%) was found to be very effective for lowering sintering temperature of ceramics from 1450–1500° to 1300°C. The composition with x = 0.5 sintered at 1300°C for 5 h revealed excellent dielectric properties, namely, a dielectric constant (ɛr ) of 48, a Q × f value of 32 100 GHz, and a temperature coefficient of the resonant frequency (τf ) of −2 ppm/K. Li3 NbO4 as a sintering additive had no harmful influence on τf of ceramics. 相似文献
17.
Ca(Mg1/3 Nb2/3 )O3 and Ba(Zn1/3 Nb2/3 )O3 ceramic cylinders with the same diameter were bonded by adhesive with low dielectric loss to yield the layered dielectric resonators, and the microwave dielectric characteristics were evaluated with TE01δ mode. With increasing the Ba(Zn1/3 Nb2/3 )O3 thickness fraction, the resonant frequency ( f 0 ) decreased, while the effective dielectric constant (ɛ r ,eff ) and temperature coefficient of resonant frequency (τ f ) increased. Good microwave dielectric characteristics were attained for the samples with the Ba(Zn1/3 Nb2/3 )O3 thickness fraction of 0.5: ɛ r ,eff =34.33, Q × f =57 930 GHz and τ f =2.6 ppm/°C. Finite-element method was used to predict the microwave dielectric characteristics of the layered resonators and good agreements were attained between the experimental results and predicted ones. Also, both experiment and finite-element analysis indicated that the effects of the adhesive on f 0 , ɛ r ,eff , and τ f were slight, while that on Q × f value was significant. 相似文献
18.
Hui Zhang Liang Fang Heping Su Qian Yu Bolin Wu 《Journal of the American Ceramic Society》2009,92(1):238-240
Single-phase polycrystalline microwave dielectric ceramics Ba6 Ti1− x Sn x Nb4 O18 , with x changing from 0 to 1, were synthesized by the solid-state reaction method. All the solid solutions fitted well with A6 B5 O18 cation-deficient hexagonal perovskite structure. The substitution of Sn for Ti effectively enhanced the quality factor and controlled τf . With increasing Sn content, the dielectric constant decreased from ∼47 to ∼32, and the Q × f value increased significantly from 11 530 to 28 496 GHz, with τf varying from 64 to 0 ppm/°C. A zero τf was realized when Sn was fully replaced by Ti with the composition Ba6 SnNb4 O18 . 相似文献
19.
Qun Zeng Wei Li Jian-lin Shi Jing-kun Guo 《Journal of the American Ceramic Society》2006,89(10):3305-3307
The effects of V2 O5 addition on the sintering behavior, microstructure, and the microwave dielectric properties of 5Li2 O–0.583Nb2 O5 –3.248TiO2 (LNT) ceramics have been investigated. With addition of low-level doping of V2 O5 (≤2 wt%), the sintering temperature of the LNT ceramics could be lowered down to around 920°C due to the liquid phase effect. A secondary phase was observed at the level of 2 wt% V2 O5 addition. The addition of V2 O5 does not induce much degradation in the microwave dielectric properties but lowers the τf value to near zero. Typically, the excellent microwave dielectric properties of ɛr =21.5, Q × f =32 938 GHz, and τf =6.1 ppm/°C could be obtained for the 1 wt% V2 O5 -doped sample sintered at 920°C, which is promising for application of the multilayer microwave devices using Ag as an internal electrode. 相似文献
20.
Byung-Kook Kim†‡§ Hiro-o Hamaguchi‡¶ In-Tae Kim†† Kug Sun Hong† 《Journal of the American Ceramic Society》1995,78(11):3117-3120
The 1:2 ordering in Ba(Ni1/3 Nb2/3 )O ceramics sintered at 1350-1500°C has been investigated by using XRD and Raman spectroscopy. Both of the techniques show that the degree of the 1:2 ordering decreases as the sintering temperature increases. However, XRD discerns the 1:2 ordering only for the samples sintered at 1350-1400°C, whereas Raman spectroscopy discerns the 1:2 ordering for all the samples. Similar results have been obtained for Ba(Zn1/3 Nb2/3 )O3 ceramics, where only the temperature range is slightly different. It is demonstrated that Raman spectroscopy can be a useful tool for probing of the 1:2 ordering in the A(B'II 1/3 B"V 2/3 )O3 -type complex perovskite compounds. 相似文献