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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.
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
3.
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
4.
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
5.
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
6.
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
7.
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
8.
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
9.
Low-Temperature Fabrication of Cordierite Ceramics from Kaolinite and Magnesium Hydroxide Mixtures with Boron Oxide Additions 总被引:3,自引:0,他引:3
Katsuhiro Sumi Yuichi Kobayashi Etsuro Kato 《Journal of the American Ceramic Society》1999,82(3):783-785
Thermal reactions of mixtures of ultrafine particles of magnesium hydroxide (Mg(OH)2 ) and kaolinite in a composition of MgO:Al2 O3 :2SiO2 were investigated to obtain dense cordierite ceramics at temperatures <1000°C. While heating the mixture of kaolinite and Mg(OH)2 with the equivalent of 2 mass% of boron oxide (B2 O3 ) (in the form of magnesium borate, 2MgOB2 O3 ), an amorphous phase formed at a temperature of ∼850°C after thermal decomposition. Firing the mixture at a temperature of 900°C yielded dense ceramics with an apparent porosity of almost zero. The addition of B2 O3 promoted the densification at 850°-900°C and accelerated the crystallization of alpha-cordierite. The specimen with 3 mass% of B2 O3 that was fired at a temperature of 950°C showed a linear thermal expansion coefficient of ∼3 × 10−6 K−1 , a bending strength of >200 MPa, and a relative dielectric constant of 5.5 at 1 MHz. These cordierite ceramics may be used as substrate materials for semiconductor interconnection applications. 相似文献
10.
Donhang Liu Yi Liu Shui-Q. Huang Xi Yao 《Journal of the American Ceramic Society》1993,76(8):2129-2132
Phase structures and dielectric properties of the compounds with formulas BixZn2/3 Nb4/3 O4+3x/2 (group M), Bix Zn8/3-x Nb4/3 O6+x/2 (group V), and Bix Zn2-2x/3 Nb2-x/3 O7 (group W) have been investigated. Initial results indicate that a cubic pyrochlore structure is the predominant phase of these compound. Most of the measured ceramic specimens exhibit dielectric properties suitable as temperatures-stable and temperature-compensating dielectrics in the capacitor industry. The values of the dielectric constant K are 80-160, while those of the temperature coefficient are–500 to + 160 ppm/°C. The composition limits of the single pyrochlore phase are determined mainly by Bi2 O3 additives. 相似文献
11.
Reactions and Microstructure Development in Mullite Fibers 总被引:3,自引:0,他引:3
Elizabeth A. Richards Chris J. Goodbrake Harold G. Sowman 《Journal of the American Ceramic Society》1991,74(10):2404-2409
Microstructural and compositional changes during heat treatment of sol–gel-derived mullite fibers with additions of 2 wt% B2 O3 , 2 wt% P2 O5 , 2 wt% Cr2 O3 , and (1 wt% P2 O5 + 1 wt% Cr2 O3 ) were compared with those of undoped mullite fibers. For all compositions the sequence of phase development was the crystallization of a spinel phase (†-Al2 O3 or Al–Si spinel) from amorphous material, followed by the formation of mullite at higher temperatures. Differential thermal analysis showed that additions of B2 O3 and P2 O5 increased the temperature of spinel formation and that B2 O3 significantly decreased the temperature of mullite formation. After 1 h at 1200°C, the size of mullite grains in fibers that contained B2 O3 was less than 1000 Å the grains in fibers of other compositions were 6000 to 12000 Å. After 60 h at 1400°C, fibers modified with B2 O3 had a grain size less than 2000 to 3000 Å the grains in fibers of other compositions were 6000 to 12000 Å. B2 O3 was the most volatile additive. 相似文献
12.
Hee-Kyun Shin Hyunho Shin Seo-Yong Cho Kug Sun Hong 《Journal of the American Ceramic Society》2005,88(9):2461-2465
Effects on phase evolution caused by the addition of a new sintering agent, lithium borosilicate, Li2 O·B2 O3 ·SiO2 (LBS) glass to 0.9MgTiO3 –0.1CaTiO3 ceramic and resultant dielectric properties were investigated. The added LBS glass, a liquid phase sintering agent, significantly lowered the densification temperature from 1300° to about 950°C, while yielding decomposition of MgTiO3 into MgTi2 O5 and Mg2 TiO4 . At the same time, the by-products of the decomposition reaction, MgO and TiO2 , were dissolved into the glass network. Such phase evolution partly compensated the influence of deleterious glass addition so that the specimen demonstrated fairly good apparent dielectric properties. 相似文献
13.
A New Microwave Dielectric Ceramic for LTCC Applications 总被引:4,自引:0,他引:4
Qun Zeng Wei Li Jian-lin Shi Jing-kun Guo Ming-wen Zuo Wen-jun Wu 《Journal of the American Ceramic Society》2006,89(5):1733-1735
A new low-sintering temperature microwave dielectric ceramic, the Li2 TiO3 solid solution, was found and investigated in the Li2 O–Nb2 O5 –TiO2 system. The compound with the composition of Li2.081 Ti0.676 Nb0.243 O3 crystallizes as a monoclinic structure. This new microwave dielectric ceramic shows a relatively low permittivity (∼20), high Q × f values up to 50 000 (7.8 GHz), and near-zero temperature coefficients (13 ppm/°C), which were obtained via sintering at 1100°C. The addition of ≤2 wt% B2 O3 was very effective in lowering the sintering temperature ( T s ), and dense ceramics could be obtained at T s ≤900°C. The addition of B2 O3 does not induce apparent degradation in the microwave properties but lowers the τf value to near zero. It is obvious that the ceramics could be promising candidates for multilayer low-temperature co-fired ceramics applications. 相似文献
14.
Mi-Ri Joung Jin-Seong Kim Myung-Eun Song Sahn Nahm Jong-Hoo Paik Byung-Hyun Choi 《Journal of the American Ceramic Society》2009,92(7):1621-1624
The formation process and microwave dielectric properties of the Mg2 V2 O7 ceramics were investigated. The MgV2 O6 phase that was formed at around 450°C interacted with remnant MgO above 590°C to form a homogeneous monoclinic Mg2 V2 O7 phase. Finally, this monoclinic Mg2 V2 O7 phase was changed to a triclinic Mg2 V2 O7 phase for the specimen fired at 800°C. Sintering at 950°C for more than 5 h produced high-density triclinic Mg2 V2 O7 ceramics. In particular, the Mg2 V2 O7 ceramics sintered at 950°C for 10 h exhibited the good microwave dielectric properties of ɛr =10.5, Q × f =58 275 GHz, and τf =−26.9 ppm/°C. 相似文献
15.
Nine compositions containing 40 to 68% B2 O3 were used to study the high-lithia portion of the system Li2 O-B2 O3 by quenching and differential thermal analysis methods. The compounds 3Li2 O 2B2 O3 and 3Li2 O B2 O3 melted incongruently at 700°± 6°C, and 715°± 15°C., respectively. The compound 2Li2 O B2 O3 is assumed to dissociate slightly below 650°± 15° C., although the data could also be interpreted as in-congruent melting. Below 600°± 6°C. it does dissociate to the 3:2 and 3:1 compounds. In this narrow temperature interval the 2:1 compound had an inversion at 618°± 6°C. Both forms of the 2:1 compound could be quenched to room temperature. X-ray diffraction data for the compounds are tabulated, and the complete phase diagram for the system Li2 O-B2 O3 is presented. 相似文献
16.
Sung Min Rhim Heungjin Bak Seokmin Hong Ok Kyung Kim 《Journal of the American Ceramic Society》2000,83(12):3009-3013
The effects of heating rate on the sintering behavior and the dielectric properties of Ba0.7 Sr0.3 TiO3 ceramics prepared by boron-containing liquid-phase sintering were investigated. When 0.5 wt% B2 O3 was added to Ba0.7 Sr0.3 TiO3 , sintering was achieved at ∼1150°C, and the overdoped B2 O3 did not form an adequate amount of liquid phase or volatilize; it remained in the samples and formed a secondary phase. A transition broadening was observed as the heating rate increased. As the heating rate increased, the Curie temperature increased and the maximum dielectric constant ( k max ) at the Curie temperature decreased. This result is attributable to a decrease in the diffuseness parameter (δ) and the tetragonality ( c / a ). 相似文献
17.
Tentative phase relations in the binary system BnOa-A12 O3 are presented as a prerequisite to the understanding of the system Li2 O-B2 O3 -Al2 O3 . Two binary compounds, 2A12 O3 .B2 O3 and 9A12 O3 .-2B2 O3 , melted incongruently at 1030° f 7°C and about 144°C, respectively. Two ternary compounds were isolated, 2Li2 O.A12 O3 .B2 O3 and 2Li2 O. 2AI2 O3 . 3B2 03 . The 2:1:1 compound gave a melting reaction by differential thermal analysis at 870°± 20° C, but the exact nature of the melting behavior was not determined. The 2:2:-3 compound melted at 790°± 20° C to Liz O.-5Al2 O3 and liquid. X-ray diffraction data for the compounds are presented and compatibility triangles are shown. 相似文献
18.
Yong Jun Seo Dong Joo Shin Yong Soo Cho 《Journal of the American Ceramic Society》2006,89(7):2352-2355
A new potential low-temperature co-fired ceramics (LTCC) system based on a simple lanthanum borate (La2 O3 –B2 O3 ) glass was investigated with regard to phase development and microwave dielectric properties as functions of alumina filler content less than 50 wt% and firing temperature up to 1050°C. Unexpected crystalline phases, such as La(BO2 )3 , LaAl2.03 (B4 O10 )O0.54 , LaBO3 , and Al20 B4 O36 , developed during the firing process are likely responsible for substantial resultant changes in physical and microwave dielectric properties. As a specific example, a high-quality factor of 785 at 15.8 GHz obtained for a composition containing 30 wt% alumina supports the hypothesis that the phase-dielectric property relation exists in this LTCC system. On a practical basis, two phases of LaAl2.03 (B4 O10 )O0.54 and LaBO3 must be important in determining the final dielectric performance by manipulating the ratios of glass and filler and by selecting a desirable temperature. 相似文献
19.
A new crystalline variety of B2 O3 has been prepared at pressures above 22,000 atmospheres and above 400°C. The properties are listed. These moderate pressures also are sufficient to catalyze the crystallization of the more common hexagonal form from B2 O3 glass. Pressures, however, of up to 50,000 atmospheres will not convert GeO2 quartz to GeO2 rutile at room temperature. From the infrared absorption patterns of appropriate phases it can be shown that in coesite the tetrahedral coordination of Si4+ (or Be2+ in the model BeF2 -coesite phase) must be unchanged. In the new form of B2 O3 , however, the coordination number must be substantially different from that in the common hexagonal B2 O3 . 相似文献
20.
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