共查询到20条相似文献,搜索用时 203 毫秒
1.
Sung Min Rhim Seokmin Hong Heungjin Bak Ok Kyung Kim 《Journal of the American Ceramic Society》2000,83(5):1145-1148
The effects of B2 O3 addition on the sintering behavior and the dielectric and ferroelectric properties of Ba0.7 Sr0.3 TiO3 (BST) ceramics were investigated. The dielectric and ferroelectric properties of a BST sample with 0.5 wt% B2 O3 sintered at <1150°C were as good as those of undoped BST sintered at 1350°C, and the dielectric loss was better. When >1.0 wt% B2 O3 was added to BST, the overdoped B2 O3 did not form a liquid phase or volatilize; it remained in the samples and formed a secondary phase that lowered the sintering behavior and the dielectric and ferroelectric properties of the BST. 相似文献
2.
Takahiro Takada Sea Fue Wang Shoko Yoshikawa Sei-Joo Jang Robert E. Newnham 《Journal of the American Ceramic Society》1994,77(7):1909-1916
The effect of glass addition on the properties of BaO–TiO2 -WO3 microwave dielectric material N-35, which has Q = 5900 and K = 35 at 7.2 GHz for samples sintered at 1360°C, was investigated. Several glasses including B2 O3 , SiO2 , 5ZnO–2B2 O3 , and nine other commercial glasses were selected for this study. Among these glasses, one with a 5 wt% addition of B2 O3 to N-35, when sintered at 1200°C, had the best dielectric properties: Q = 8300 and K = 34 at 8.5 GHz. Both Q and K increased with firing temperature as well as with density. The Q of N-35, when sintered with a ZnO–B2 O3 glass system, showed a sudden drop in the sintering temperature to about 1000°C. The results of XRD, thermal analysis, and scanning electron microscopy indicated that the chemical reaction between the dielectric ceramics and glass had a greater effect on Q than on the density. The effects of the glass content and the mixing process on the densification and microwave dielectric properties are also presented. Ball milling improved the densification and dielectric properties of the N-35 sintered with ZnO–B2 O3 . 相似文献
3.
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
4.
Masahide Okamoto Hironori Kodama Kazuo Shinozaki 《Journal of the American Ceramic Society》2008,91(4):1110-1114
The sintering of a composite of MgO–B2 O3 –Al2 O3 glass and Al2 O3 filler is terminated due to the crystallization of Al4 B2 O9 in the glass. The densification of a composite of MgO–B2 O3 –Al2 O3 glass and Al2 O3 filler using pressureless sintering was accomplished by lowering the sintering temperature of the composite. The sintering temperature was lowered by the addition of small amounts of alkali metal oxides to the MgO–B2 O3 –Al2 O3 glass system. The resultant composite has a four-point bending strength of 280 MPa, a coefficient of thermal expansion (RT—200°C) of 4.4 × 10−6 K−1 , a dielectric constant of 6.0 at 1 MHz, porosity of approximately 1%, and moisture resistance. 相似文献
5.
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
6.
A type of new low sintering temperature ceramic, Li2 TiO3 ceramic, has been found. Although it is difficult for the Li2 TiO3 compound to be sintered compactly at temperatures above 1000°C for the volatilization of Li2 O, dense Li2 TiO3 ceramics were obtained by conventional solid-state reaction method at the sintering temperature of 900°C with the addition of ZnO–B2 O3 frit. The sintering behavior and microwave dielectric properties of Li2 TiO3 ceramics with less ZnO–B2 O3 frit (≤3.0 wt%) doping were investigated. The addition of ZnO–B2 O3 frit can lower the sintering temperature of the Li2 TiO3 ceramics, but it does not apparently degrade the microwave dielectric properties of the Li2 TiO3 ceramics. Typically, the good microwave dielectric properties of ɛr =23.06, Q × f =32 275 GHz, τf = 35.79 ppm/°C were obtained for 2.5 wt% ZnO–B2 O3 frit-doped Li2 TiO3 ceramics sintered at 900°C for 2 h. The porosity was 0.08%. The Li2 TiO3 ceramic system may be a promising candidate for low-temperature cofired ceramics applications. 相似文献
7.
Haitao Jiang Jiwei Zhai Jingji Zhang Xi Yao 《Journal of the American Ceramic Society》2009,92(10):2319-2322
In the present work, the sintering behaviors and dielectric properties of Ba0.60 Sr0.40 TiO3 (BST) ceramics with the addition of BaCu(B2 O5 ) 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(B2 O5 ) assisted the densification of BST ceramics at lower temperatures. For a low-level BaCu(B2 O5 ) 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(B2 O5 ) possessed a dielectric constant of 2204 and a Q value of 146.7. 相似文献
8.
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
9.
Yanping Long Yilin Wang Wenjun Wu Dong Wang Yongxiang Li 《Journal of the American Ceramic Society》2009,92(11):2630-2633
The effect of B2 O3 –SiO2 liquid-phase additives on the sintering, microstructure, and microwave dielectric properties of LiNb0.63 Ti0.4625 O3 ceramics was investigated. It was found that the sintering temperature could be lowered easily, and the densification and dielectric properties of LiNb0.63 Ti0.4625 O3 ceramics could be greatly improved by adding a small amount of B2 O3 –SiO2 solution additives. No secondary phase was observed for the ceramics with B2 O3 –SiO2 additives. With the addition of 0.10 wt% B2 O3 –SiO2 , the ceramics sintered at 900°C showed favorable microwave dielectric properties with ɛr =71.7, Q × f =4950 GHz, and τf =−2.1 ppm/°C. The energy dispersive spectra analysis showed an excellent co-firing interfacial behavior between the LiNb0.63 Ti0.4625 O3 ceramic and the Ag electrode. It indicated that LiNb0.63 Ti0.4625 O3 ceramics with B2 O3 –SiO2 solution additives have a number of potential applications on passive integrated devices based on the low-temperature co-fired ceramics technology. 相似文献
10.
Qun Zeng Wei Li Jian-lin Shi Xian-lin Dong Jing-kun Guo 《Journal of the American Ceramic Society》2007,90(7):2262-2265
The effects of the addition of V2 O5 on the sintering behavior, microstructure, and microwave dielectric properties of 5Li2 O–1Nb2 O5 –5TiO2 (LNT) ceramics have been investigated. With low-level doping of V2 O5 (≤3 wt%), the microstructure of the LNT ceramic changed from a special two-level intergrowth structure into a two-phase composite structure with separate grains. And the sintering temperature of the LNT ceramics could be lowered to around 900°C by adding a small amount of V2 O5 without much degradation in microwave dielectric properties. Typically, better microwave dielectric properties of ɛr =41.7, Q × f =7820 GHz, and τ f =45 ppm/°C could be obtained for the 1 wt% V2 O5 -doped ceramics sintered at 900°C. 相似文献
11.
Sea-Fue Wang Chiang-Chuang Chung Chai-Hui Wang Jinn P. Chu 《Journal of the American Ceramic Society》2002,85(6):1619-1621
Preparation of dense and phase-pure Ba2 Ti9 O20 is generally difficult using solid-state reaction, since there are several thermodynamically stable compounds in the vicinity of the desired composition and a curvature of Ba2 Ti9 O20 equilibrium phase boundary in the BaO–TiO2 system at high temperatures. In this study, the effects of B2 O3 on the densification, microstructural evolution, and phase stability of Ba2 Ti9 O20 were investigated. It was found that the densification of Ba2 Ti9 O20 sintered with B2 O3 was promoted by the transient liquid phase formed at 840°C. At sintering temperatures higher than 1100°C, the solid-state sintering became dominant because of the evaporation of B2 O3 . With the addition of 5 wt% B2 O3 , the ceramic yielded a pure Ba2 Ti9 O20 phase at sintering temperatures as low as 900°C, without any solid solution additive such as SnO2 or ZrO2 . The facilities of B2 O3 addition to the stability of Ba2 Ti9 O20 are apparently due to the eutectic liquid phase which accelerates the migration of reactant species. 相似文献
12.
Jian-Xi Tong Qi-Long Zhang Hui Yang Jia-Li Zou 《Journal of the American Ceramic Society》2007,90(3):845-849
The effects of LiF and ZnO–B2 O3 –SiO2 (ZBS) glass combined additives on phase composition, microstructures, and microwave dielectric properties of Ca[(Li1/3 Nb2/3 )0.84 Ti0.16 ]O3−δ (CLNT) ceramics were investigated. The LiF and ZBS glass combined additives lowered the sintering temperature of CLNT ceramics effectively from 1150° to 880°C. The main diffraction peaks of all the specimens split due to the coexistence of the non-stoichiometric phase (A) and stoichiometric phase (B), which all possess CaTiO3 -type perovskite structures. The transformation from A into B became accelerated with the increase of LiF or ZBS content. ZBS glass restrained the volatilization of lithium salt, which greatly affected the microstructures and microwave dielectric properties. CLNT ceramics with 2 wt% LiF and 3 wt% ZBS sintered at 900°C for 2 h show excellent dielectric properties: ɛr =34.3, Q × f =17 400 GHz, and τf =−4.6 ppm/°C. It is compatible with Ag electrodes, which makes it a promising ceramic for low-temperature cofired ceramics technology application. 相似文献
13.
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
14.
Mi-Ri Joung Jin-Seong Kim Myung-Eun Song Jae-Hong Choi Jong-Woo Sun Sahn Nahm Jong-Hoo Paik Byung-Hyun Choi 《Journal of the American Ceramic Society》2009,92(9):2151-2154
Li2 CO3 was added to Mg2 V2 O7 ceramics in order to reduce the sintering temperature to below 900°C. At temperatures below 900°C, a liquid phase was formed during sintering, which assisted the densification of the specimens. The addition of Li2 CO3 changed the crystal structure of Mg2 V2 O7 ceramics from triclinic to monoclinic. The 6.0 mol% Li2 CO3 -added Mg2 V2 O7 ceramic was well sintered at 800°C with a high density and good microwave dielectric properties of ɛ r =8.2, Q × f =70 621 GHz, and τf =−35.2 ppm/°C. Silver did not react with the 6.0 mol% Li2 CO3 -added Mg2 V2 O7 ceramic at 800°C. Therefore, this ceramic is a good candidate material in low-temperature co-fired ceramic multilayer devices. 相似文献
15.
MgTiO3 -doped BaZr0.35 Ti0.65 O3 (BZT) composite ceramics have been prepared by the conventional solid-state route. The dielectric nonlinear characteristics and relaxor behavior of these composite ceramics have been investigated. The secondary-phase BaMg6 Ti6 O19 is formed among BZT composite ceramics with the increase of MgTiO3 . BZT composite ceramics show typical diffuse phase transition characteristic and ferroelectric relaxor behavior. The dielectric constant of BZT composite ceramics can be tailored from thousands to hundreds by manipulating the addition of MgTiO3 . The dielectric loss still keeps around 0.001 and the tunability is above 20% at a dc-applied electric field of 25 kV/cm. Suitable dielectric constant, low dielectric loss, and high tunability of this kind of composite ceramics can be useful for potential microwave tunable applications. 相似文献
16.
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
17.
The electrical properties of Sr0.5 Ba0.3 TiO3 in the presence of Nb2 O5 as a donor, 3Li2 O · 2SiO2 as a sintering agent, and Bi2 O3 as a dopant have been studied. When the compositions of the ceramics were 1 mol Sr0.7 Ba0.3 TiO3 + 0.5 mol% Nb2 O5 + 2 mol% 3Li2 O · 2SiO2 + 0.2 mol% Bi2 O3 , the ceramics were sintered at 1100°C and exhibited the following characteristics: apparent dielectric constant ɛ, 25000; loss factor tan δ, 2%; insulating resistivity ρj , 1010 Ω· cm; variation of dielectric constant with temperature Δɛ/ɛ (−25° to +85°C), +10%, −14%. ɛ and tan δ show only small changes with frequency. The study shows this ceramic can be used in multilayer technology. 相似文献
18.
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
19.
Beata Zalinska Mehdi Mirsaneh Ian M. Reaney 《Journal of the American Ceramic Society》2009,92(9):1981-1985
The effect of a bespoke glass sintering aid, 0.3Bi2 O3 –0.3Nb2 O5 –0.3B2 O3 –0.1SiO2 (BN1), developed from the base ceramic composition, BiNbO4 (BN), on the sinterability, microstructure, and microwave (MW) dielectric properties of BN ceramics has been investigated. Densities >97% theoretical could be achieved at 1020°C for samples with up to 15% BN1 additions. The resulting microstructure was composed of BN laths surrounded by a residual glass phase that contained small fibrous crystals. Some evidence of dissolution of BN crystals was observed. Optimum properties were exhibited for samples with 15 wt% of glass addition sintered for 4 h at 1020°C with a relative permittivity ɛr =38, a MW quality factor Q × f 0 =17 353 at 5.6 GHz, and a temperature coefficient of resonant frequency τf =−10 ppm/°C. The high Q × f 0 , ɛr , and low τf , coupled with a relatively low sintering temperature, suggest that the use of bespoke glass sintering aids of this type may have great potential for the fabrication of MW ceramics. 相似文献
20.
Jau-Ho Jean Chia-Ruey Chang Cheng-Dao Lei 《Journal of the American Ceramic Society》2004,87(7):1244-1249
Effects of Ag addition on sintering of a crystallizable CaO-B2 O3 -SiO2 glass have been investigated at 700°–900°C in different atmospheres. With Ag content increasing in the range of 1–10 vol%, the softening point, the densification, the onset crystallization temperature, and the total amount of crystalline phase formed of the crystallizable glass are reduced when fired in air. A bloating phenomenon is observed when the crystallizable CaO-B2 O3 -SiO2 glass doped with 1–10 vol% Ag is fired at 700°–900°C for 1–4 h. Fired in N2 or N2 + 1% H2 , however, the above phenomena disappear completely. It is thus believed that the diffusion of Ag into the crystallizable glass, which is caused by the oxidation of Ag in air, is the root cause for the above results observed. 相似文献