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1.
Dielectric and piezoelectric properties of 0.02Pb(Y2/3 W1/3 )O3 0.98Pb(Zr0.52Ti0.48)O3 ceramics doped with additives (Nb2 O5 , La2 O3 , MnO2 , and Fe2 O3 ) were investigated. The grain sizes of these ceramics decreased with increasing amounts of additives. For additions of MnO2 and Fe2 O3 , dielectric losses decreased, while for Nb2 O5 and La2 O3 , these values increased. The maximum values of the mechanical quality factor Qm were found to be 956 and 975 for additions of 0.9 wt% Fe2 O3 and 0.7 wt% MnO2 , respectively, but donor dopants (Nb2 O5 and La2 O3 ) did not change the values of Qm . On the other hand, the piezoelectric constant d33 and the electromechanical coupling factor kp decreased with additions of MnO2 and Fe2 O3 , but improved with additions of Nb2 O5 and La2 O3 . 相似文献
2.
Yang Gong-An Pu Yong-Ping Wang Jin-Fei Chen Xiao-Long Zhuang Yong-Yong 《Journal of the American Ceramic Society》2009,92(8):1891-1894
The influence of La2 O3 doped on the microstructure and dielectric properties, including the phase structure, temperature dependence of permittivity, and the hysteresis loop of BaTiO3 –Nb2 O5 –Fe2 O3 (BTNF) materials has been investigated in X-ray diffraction, SEM, and LCR analyzer, respectively. Experiments revealed that incorporation of proper content of La2 O3 basically soluted in the lattice of BaTiO3 and can control the grain-growth, reduce the dielectric loss of the BTNF materials. The development of microstructure promoted by the additives can result in the improvement of the dielectric constant. When the doping concentration of La2 O3 was 3.846 wt%, the relative dielectric constant of the sample sintered at 1280°C only for 2 h could reach 4308, and improve the dielectric-temperature characteristics markedly. As a result, a novel Y5P can be achieved in the BTNF ceramics, which is very promising for practical use in Y5P multilayer ceramic capacitors. 相似文献
3.
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
4.
Rajamma Rejini Mailadil Thomas Sebastian 《International Journal of Applied Ceramic Technology》2006,3(3):230-235
The La5 CrTi3 O15 and La4 MCrTi3 O15 (M=Pr, Nd, and Sm) microwave dielectric ceramics were prepared by the conventional solid-state ceramic route. The structure and microstructure of the ceramics were studied by X-ray diffraction and scanning electron microscopy methods. The dielectric properties of the ceramics were measured in the microwave frequency region using a network analyzer by the resonance method. The ceramics show a dielectric constant (ɛr ) in the range of 37 to 39.5, a quality factor ( Q u × f o ) 17,300 to 34,000 GHz, and a temperature coefficient of resonant frequency (τf ) in the range from −22 to −38 ppm/°C. 相似文献
5.
Phase relations at liquidus temperatures in the system La2 O3 -TiO2 were studied in air. The existence of two previously unreported compounds, La2 O3 . TiO2 and 2La2 O3 -TiO2 , is postulated on the basis of X-ray and microscopic examination of crystalline samples, and in the case of La2 O3 .-TiO2 , on a maximum in the liquidus curve at that composition. Quenched liquids of the primary-phase field of rutile were found to be semiconducting. This property was related to oxygen loss from both liquid and crystalline phases and is discussed in the light of weight loss experiments, microscopic examination of quenched samples, and information obtained from the literature. Dielectric constant and loss factor of the compounds La2 O3 -TiO2 , La2 O3 -2TiO2 , and 2La2 O3 -9TiO2 are reported at 1 Mc over the temperature range 25° to 500°C. 相似文献
6.
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
7.
Yong Hwan Park Ji Man Ryu Moo Young Shin Kyung Hyun Ko Dong Wan Kim Kug-Sun Hong 《Journal of the American Ceramic Society》2001,84(11):2542-2546
The effects of Nb2 O5 and ZnO addition on the dielectric properties, especially the quality factor, of (Zr0.8 Sn0.2 )TiO4 (ZST) ceramics were investigated in terms of the sintered density acquired by the zinc. For ZST ceramics with 2 mol% added ZnO, the relative density of the samples decreased with >0.5 mol% addition of Nb2 O5 . On the other hand, for samples with 6 mol% added ZnO, the relative density remained >97%, even when the amount of Nb2 O5 was increased to 2.0 mol%. When >0.5 mol% Nb2 O5 was added, both the quality factor and the dielectric constant exhibited similar trends with sintered density. The ZST ceramics with 6 mol% added ZnO, especially, still manifested a quality factor >40 000 and a dielectric constant of 37, even when the amount of Nb2 O5 was increased, values that are not explainable by the previously suggested electronic defect model. 相似文献
8.
Hyun-Jai Kim Sergey Kucheiko Seok-Jin Yoon Hyung-Jin Jung 《Journal of the American Ceramic Society》1997,80(5):1316-1318
Dielectric properties of the system (1 − x)(La1/2 Na1/2 )TiO3 – x Ca(Fe1/2 Nb1/2 )O3 , where 0.4 # x # 0.6, have been investigated at microwave frequencies. The temperature coefficient of resonant frequency (τf ), nearly 0 ppm/°C, was realized at x = 0.58. These ceramics had perovskite structure and showed relatively low dielectric losses. A new dielectric material applicable to microwave devices having Q · f of 12000–14000 GHz and a dielectric constant (εr ) of 59–60 has been obtained at 1300–1350°C for 5–15 h sintering. 相似文献
9.
Grain growth of ZnO during the liquid-phase sintering of binary ZnO–Bi2 O3 ceramics has been studied for Bi2 O3 contents from 3 to 12 wt% and sintering from 900° to 1400°C. The results are considered in combination with previously published studies of ZnO grain growth in the ZnO–Bi2 O3 system. For the Bi2 O3 contents of the present study, the rate of ZnO grain growth is found to decrease with increasing Bi2 O3 . Activation analysis, when combined with the results of similar analyses of the previous studies, reveals a change in the rate-controlling mechanism for ZnO grain growth. Following a low-Bi2 O3 -content region of nearly constant activation energy values of about 150 kJ/mol, further Bi2 O3 additions cause an increase of the activation energy to about 270 kJ/mol. consistent with accepted models of liquid-phase sintering, it is concluded that the rate-controlling mechanism of ZnO grain growth during liquid-phase sintering in the presence of Bi2 O3 changes from one of a phase-boundary reaction at low Bi2 O3 levels to one of diffusion through the liquid phase at about the 5 to 6 wt% Bi2 O3 level and above. 相似文献
10.
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
11.
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
12.
Hyo Tae Kim Myoung-Hwa Nam Jong-Hee Kim Sahn Nahm 《International Journal of Applied Ceramic Technology》2009,6(5):587-592
Dolomite-type borate ceramics consisting of CaZrB2 O6 were synthesized via a conventional solid-state reaction route; low-temperature sintering was explored using Bi2 O3 –CuO additives of 1–7 wt% for low-temperature co-fired ceramics applications. For several sintering temperatures, the microwave dielectric properties and chemical resistance of the ceramics were investigated. The CaZrB2 O6 ceramics with 3 wt% Bi2 O3 –CuO addition could be sintered below 925°C, and the microwave dielectric properties of the low-temperature samples were ɛr =10.55, Q × f =87,350 GHz, and τf =+2 ppm/°C. The chemical resistance test result showed that both CaZrB2 O6 - and Bi2 O3 –CuO-added CaZrB2 O6 ceramics were durable in basic solution but were degraded in acid solution. 相似文献
13.
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
14.
Near-field scanning microwave microscopy was applied to investigate the dielectric properties and microstructure in a polycrystalline LaAlO3 –TiO2 diffusion couple, which included three regions containing different phases and microstructures. Relatively low (La2 Ti4 Al18 O38 ), high (α-La2/3 TiO3 ), and intermediate (La4 Ti9 O24 ) dielectric constant phases were distinguished at the inter-diffusion interface in optical, backscattered electron scanning electron microscopy, and scanning microwave microscopy (SMM) images. The relative ranking of dielectric constants based on SMM examination was as follows: TiO2 >α-La2/3 TiO3 >La4 Ti9 O24 >LaAlO3 >La2 Ti4 Al18 O38 . La2/3 TiO3 and LaAlO3 will form solid solutions in the LaAlO3 -rich region. The reaction paths leading to phase development are discussed. 相似文献
15.
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
16.
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
17.
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
18.
Grain growth of ZnO during liquid-phase sintering of a ZnO-6 wt% Bi2 O3 ceramic was investigated for A12 O3 additions from 0.10 to 0.80 wt%. Sintering in air for 0.5 to 4 h at 900° to 1400°C was studied. The AI2 O3 reacted with the ZnO to form ZnAl2 O4 spinel, which reduced the rate of ZnO grain growth. The ZnO grain-growth exponent was determined to be 4 and the activation energy for ZnO grain growth was estimated to be 400 kJ/mol. These values were compared with the activation parameters for ZnO grain growth in other ceramic systems. It was confirmed that the reduced ZnO grain growth was a result of ZnAl2 O4 spinel particles pinning the ZnO grain boundaries and reducing their mobility, which explained the grain-growth exponent of 4. It was concluded that the 400 kJ/mol activation energy was related to the transport of the ZnAl2 O4 spinel particles, most probably controlled by the diffusion of O2- in the ZnAl2 O4 spinel structure. 相似文献
19.
Piezoelectric Properties of Pb(Mg1/3 Nb2/3 )O3 PbTiO3 -PbZrO3 Ceramics Modified with Certain Additives
HIROMU OUCHI MASAMITSU NISHIDA SHIGERU HAYAKAWA 《Journal of the American Ceramic Society》1966,49(11):577-582
Effects of additives on the piezoelectric properties of Pb(Mg1/3 Nb2/3 )O3 -PbTiO3 -PbZrO3 ceramics in a perovskite-type structure are described. The tetragonality of Pb(Mg1/3 Nb2/3 )0.375 -Ti0.375 Zr0.25 O3 ceramics increased with the addition of NiO, Cr2 O3 , or Fe2 O3 but decreased with the addition of MnO2 or CoO. The dielectric and piezoelectric properties of the base composition were improved markedly through selection of additives in proper amounts. Addition of NiO yielded a high dielectric constant and planar coupling coefficient for compositions at the morphotropic transition boundary. High mechanical Q -factors and low electrical dissipation factors were obtained by addition of MnO2 . Addition of both NiO and MnO2 produced a mechanical Q -factor of 2051 and a planar coupling coefficient of 0.553. The resonant frequency of Pb(Mg1/2 Nb2/3 )0.4375 Ti0.4375 zr0.125 O3 containing MnO2 had very low temperature and time dependence. The microstructure indicated that ceramics with a high mechanical Q -factor had a fine, uniform grain structure. Addition of Cr2 O3 retarded grain growth and addition of MnO2 , NiO, CoO, or Fe2 O3 promoted grain growth in the ternary system. 相似文献
20.
Eugene Chong Seongjin Hwang Wookyung Sung Hyungsun Kim Hyunho Shin 《International Journal of Applied Ceramic Technology》2009,6(2):295-301
This study examined the influence of the addition of ceramic fillers (up to 20 wt% of TiO2 , Al2 O3 , and ZnO, respectively) to a BaO–ZnO–B2 O3 –P2 O5 glass matrix on the dielectric and optical properties with the aim of using this material as the barrier ribs in plasma display panels. The modification of the dielectric constant by the fillers was related to the formation of secondary phases, the changes in the glass composition by the partial dissolution of the fillers, and the presence of pores. The reflectance of the composites ranged from 60% to 80% with the addition of 20 wt% filler. 相似文献