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1.
《Ceramics International》2021,47(19):27545-27552
B2O3 and CuO were codoped into 6Nd[(Zn0.7Co0.3)0.5Ti0.5]O3–4(Na0.5Nd0.5)TiO3 (abbreviated as 6NZCT–4NNT) ceramics as sintering aids. The influences of the sintering aids on the sintering characteristics, microstructure and microwave dielectric properties of the 6NZCT–4NNT ceramics were systematically investigated as a function of the proportion of B2O3 and CuO. Codoping could greatly reduce the sintering temperature from 1410 °C to 1150 °C, indicating that B2O3/CuO are good sintering aids for 6NZCT–4NNT ceramics. The B2O3/CuO sintering aids had no significant impact on the phase purity of the investigated ceramics, even though a solid solution was formed due to Cu2+ ion substitution. However, they had evident influences on the surface morphology and grain size. The average grain size was enlarged with increasing amounts of CuO in the B2O3/CuO sintering aids. Remarkable deterioration of the microwave dielectric properties for 6NZCT-4NNT ceramics was not observed when codoping an appropriate amount of B2O3 and CuO. The 6NZCT–4NNT ceramics codoped with 2.0 mol% B2O3 and 2.0 mol% CuO sintered at 1150 °C for 3 h exhibited a homogeneous microstructure and promising microwave dielectric properties: an appropriate dielectric constant (εr = 49.37), a high quality factor (QF = 47,295 GHz), and a near-zero temperature coefficient of resonant frequency (TCF = +0.9 ppm/°C). 相似文献
2.
Nam Binh Do Hyun Deok Jang Inki Hong Hyoung Su Han Duc Thang Le Weon Pil Tai Jae Shin Lee 《Ceramics International》2012
Effect of excess CuO additive on the sintering behavior and piezoelectric properties of Bi0.5(Na82K0.18)0.5TiO3 ceramics was investigated. The addition of small amount of excess CuO as low as 1 mol% was quite effective to lower the sintering temperature (Ts) of BNKT ceramics down to 975 °C while their piezoelectric properties were degraded by Cu doping. However, the electric field-induced strain was markedly enhanced by further addition of Nb2O5 with CuO without elevating Ts. The normalized strain Smax/Emax of 427 pm/V was obtained with a specimen sintered with 0.02 mol CuO and 0.03 mol Nb2O5 in excess. 相似文献
3.
Junxia Wang Genshui Wang Hengchang Nie Xuefeng Chen Fei Cao Xianlin Dong Yan Gu Hongliang He 《Journal of the American Ceramic Society》2013,96(8):2370-2373
The low‐temperature sintering and electric properties of Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 (PZTN 95/5) ferroelectric ceramics with CuO addition was investigated. The CuO addition significantly promoted the densification and reduced the sintering temperature of PZTN 95/5 ceramics by more than 200°C. The 0.2 wt% CuO‐added sample sintered at 1150°C exhibited the optimum relative density of 96.7% and excellent electric properties with values of Pr = 37.80 μC/cm2, TC = 223°C, εr = 329, and tan δ = 0.016, which were superior to that of PZTN 95/5 ceramics sintered at 1350°C. 相似文献
4.
Excellent piezoelectric properties of PNN-PHT ceramics sintered at low temperature with CuO addition
Yushun Xia Zhimin Li Yangxi Yan Mo Zhao Maolin Zhang Dongyan Zhang 《International Journal of Applied Ceramic Technology》2020,17(2):707-712
Multilayer components with excellent piezoelectric performance have been developed for fulfilling the requirement of new-generation electromechanical devices and systems. Multilayering of the piezoelectric ceramic requires good sinterability preferentially at lower temperature. In this study, copper (II) oxide (CuO) was utilized as the sintering additive to increase the sinterability of 0.49Pb(Ni1/3Nb2/3)O3–0.51Pb(Hf0.3Ti0.7)O3 (PNN-PHT) ceramics at low temperature, and simultaneously enhance the piezoelectric and dielectric properties of the ceramics. The results demonstrated that the addition of CuO influenced the sintering behavior, grain growth, and piezoelectric properties of the PNN-PHT ceramics. A ternary high performance piezoelectric PNN-PHT ceramic sintered at 1050°C with 0.5 mol% CuO exhibited excellent properties as follows: d33 = 912 pC N−1 and εr = 6665. 相似文献
5.
Effects of CuO Addition on Electrical Properties of 0.6BiFeO3–0.4(Bi0.5K0.5)TiO3 Lead‐Free Piezoelectric Ceramics
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0.6BiFeO3–0.4(Bi0.5K0.5)TiO3 (0.6BF–0.4BKT) ceramic samples with 0.0–4.0 mol% CuO were prepared by the solid‐state reaction. The CuO addition aided the densification of the samples and slightly increased the lattice constant. The relaxor‐like defuse dielectric peak of 0.6BF–0.4BKT became sharper with increasing the CuO content. Polarization–electric field curve of the undoped 0.6BF–0.4BKT was a pinched loop in the as‐sintered state, while that was a square hysteresis with a large remanent polarization of 48 μC/cm2 after the thermal quenching, demonstrating a strong domain wall pinning due to defect dipoles. We found that the CuO addition up to 2.0 mol% facilitates the polarization switching in the as‐sintered samples to increase the remanent polarization and the piezoelectric d33 coefficient. The results of the structural and electrical investigations suggested that the copper ion acts as a donor in 0.6BF–0.4BKT by compensating the potassium vacancy created by the evaporation of K2O during the calcination and sintering processes. 相似文献
6.
Dae‐Hyeon Kim Mi‐Ri Joung In‐Tae Seo Joon Hur Jong‐Hyun Kim Bo‐Yun Kim Hwack‐Joo Lee Sahn Nahm 《Journal of the American Ceramic Society》2014,97(12):3897-3903
Dielectric and piezoelectric properties of CuO‐added KNbO3 (KN) ceramics were investigated. The CuO reacted with the Nb2O5, formed a CuO–Nb2O5‐related liquid phase during the sintering, and assisted the densification of the KN ceramics at low temperatures. Moreover, some of the Cu2+ ions replaced the Nb5+ ions in the matrix and behaved as a hardener. The dielectric and piezoelectric properties of the KN ceramics were considerably influenced by the relative density. The 1.0 mol% CuO‐added KN ceramic sintered at 960°C for 1.0 h, which showed a maximum relative density, exhibited a high phase angle of 86.9°, Pr of 14.8 μC/cm2, and Ec of 1.8 kV/mm. This specimen also exhibited good dielectric and piezoelectric properties: εT33/εo of 364, d33 of 122 pC/N, kp of 0.29, and Qm of 611. 相似文献
7.
Large recoverable energy storage density and low sintering temperature in potassium‐sodium niobate‐based ceramics for multilayer pulsed power capacitors
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Bingyue Qu Hongliang Du Zetian Yang Qinghui Liu 《Journal of the American Ceramic Society》2017,100(4):1517-1526
Multilayer pulsed power ceramic capacitors require that dielectric ceramics possess not only large recoverable energy storage density (Wrec) but also low sintering temperature (<950°C) for using the inexpensive metals as the electrodes. However, lead‐free bulk ceramics usually show low Wrec (<2 J/cm3) and high sintering temperature (>1150°C), limiting their applications in multilayer pulsed power ceramic capacitors. In this work, large Wrec (~4.02 J/cm3 at 400 kV/cm) and low sintering temperature (940°C) are simultaneously achieved in 0.9(K0.5Na0.5)NbO3–0.1Bi(Mg2/3Nb1/3)O3–1.0 mol% CuO ceramics prepared using transition liquid phase sintering. Wrec of 4.02 J/cm3 is 2‐3 times as large as the reported value of other (Bi0.5Na0.5)TiO3 and BaTiO3‐based lead‐free bulk ceramics. The results reveal that 0.9(K0.5Na0.5)NbO3–0.1Bi(Mg2/3Nb1/3)O3–1.0 mol% CuO ceramics are promising candidates for fabricating multilayer pulsed power ceramic capacitors. 相似文献
8.
Li Wang Chaoliang Mao Genshui Wang Gang Du Ruihong Liang Xianlin Dong 《Journal of the American Ceramic Society》2013,96(1):24-27
Low‐temperature sintering of 0.25PMN–0.40PT–0.35PZ ceramics was investigated using CuO as a sintering aid. Effect of CuO on the sinterability, microstructure, and electric properties of 0.25PMN–0.40PT–0.35PZ system was systematically studied. The CuO addition significantly reduced the sintering temperature of 0.25PMN–0.40PT–0.35PZ from 1260°C to 950°C. SEM results indicated that a dense microstructure without any second phase was obtained when the amount of CuO was 0.25 wt%, which gave rise to high values of d33 = 532 pC/N and kp = 58.4%. A large field‐induced longitudinal strain ~2.28% (at 30 kV/cm) can also be obtained for 0.25 wt% CuO‐added specimens, which shows a great promise for multilayer actuator applications. 相似文献
9.
《Ceramics International》2016,42(3):4274-4284
Bi0.5(Na0.65K0.35)0.5TiO3 (BNKT) and Mn-modified Bi0.5(Na0.65K0.35)0.5(MnxTi1−x)O3 (BNKMT-103x), (x=0.0–0.5%) ferroelectric ceramics were synthesized by solid-state reaction method. Optimization of calcination temperature in Mn-doped ceramics was carried out for the removal of secondary phases observed in XRD analysis. BNKMT ceramics sintered at 1090 °C showed enhanced dielectric, piezoelectric and ferroelectric properties in comparison to pure BNKT. The average grain size was found to increase from 0.35 μm in BNKT to 0.52 μm in Bi0.5(Na0.65K0.35)0.5(Mn0.0025Ti0.9975)O3 (BNKMT-2.5) ceramics. The dielectric permittivity maximum temperature (Tm) was increased to a maximum of 345 °C with Mn-modification. AC conductivity analysis was performed as a function of temperature and frequency to investigate the conduction behavior and determine activation energies. Significant high value of piezoelectric charge coefficient (d33=176 pC/N) was achieved in BNKMT 2.5 ceramics. Improved temperature stability of ferroelectric behavior was observed in the temperature dependent P–E hysteresis loops as a result of Mn-incorporation. The fatigue free nature along with enhanced dielectric and ferroelectric properties make BNKMT-2.5 ceramic a promising candidate for replacing lead based ceramics in device applications. 相似文献
10.
Effect of Ga2O3 on Sintering and Phase Stability of Sc2O3‐Doped Tetragonal Zirconia Prepared via Aqueous Solution Route
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Masanori Hirano Hideo Kojima Hideaki Minami 《Journal of the American Ceramic Society》2015,98(1):44-49
The effects of the presence of Ga2O3 on low‐temperature sintering and the phase stability of 4, 5, and 6 mol% Sc2O3‐doped tetragonal zirconia ceramics (4ScSZ, 5ScSZ, and 6ScSZ, respectively) were investigated. A series of zirconia sintered bodies with compositions (ZrO2)0.99?x(Sc2O3)x(Ga2O3)0.01, x = 0.04, 0.05, and 0.06 was fabricated by sintering at 1000°C to 1500°C for 1 h using fine powders that were prepared via the combination of homogeneous precipitation method and hydrolysis technique using monoclinic zirconia sols synthesized through the forced hydrolysis of an aqueous solution of zirconium oxychloride at 100°C for 168 h. The presence of 1 mol% Ga2O3 was effective in reducing sintering temperature necessary to fabricate dense bodies and enabled to obtain dense sintered bodies via sintering at 1100°C for 1 h. The phase stability, that is, low‐temperature degradation behavior of the resultant zirconia ceramics was determined under hydrothermal condition. The zirconia ceramics codoped with 1 mol% Ga2O3 and 6 mol% Sc2O3 (1Ga6ScZ) fabricated via sintering at 1300°C for 1 h showed high phase stability without the appearance of monoclinic zirconia phase, that is the tetragonal‐to‐monoclinic phase transformation was not observed in the 1Ga6ScZ after treatment under hydrothermal condition at 150°C for 30 h. 相似文献
11.
Yang Wan Ying Li Qiang Li Wei Zhou Qiaoji Zheng Xiaochun Wu Chenggang Xu Benpeng Zhu Dunmin Lin 《Journal of the American Ceramic Society》2014,97(6):1809-1818
0.725BiFe1?xScxO3–0.275BaTiO3 + y mol% MnO2 multiferroic ceramics were fabricated by a conventional ceramic technique and the effects of Sc doping and sintering temperature on microstructure, multiferroic, and piezoelectric properties of the ceramics were studied. The ceramics can be well sintered at the wide low sintering temperature range 930°C–990°C and possess a pure perovskite structure. The ceramics with x/y = 0.01–0.02/1.0 sintered at 960°C possess high resistivity (~2 × 109 Ω·cm), strong ferroelectricity (Pr = 19.1–20.4 μm/cm2), good piezoelectric properties (d33 = 127–128 pC/N, kp = 36.6%–36.9%), and very high Curie temperature (618°C–636°C). The increase in sintering temperature improves the densification, electric insulation, ferroelectric, and piezoelectric properties of the ceramics. A small amount of Sc doping (x ≤ 0.04) and the increase in the sintering temperature significantly enhance the ferromagnetic properties of the ceramics. Improved ferromagnetism with remnant magnetization Mr of 0.059 and 0.10 emu/g and coercive field Hc of 2.51 and 2.76 kOe are obtained in the ceramics with x/y = 0.04/1.0 (sintered at 960°C) and 0.02/1.0 (sintered at 1050°C), respectively. Because of the high TC (636°C), the ceramic with x/y = 0.02/1.0 shows good temperature stability of piezoelectric properties. Our results also show that the addition of MnO2 is essential to obtain the ceramics with good electrical properties and electric insulation. 相似文献
12.
Cheng-Fan Lee Cheng-Feng Wu Jau-Ho Jean 《Journal of the American Ceramic Society》2019,102(1):158-166
Effects of CuO on constrained sintering of a polycrystalline TiO2 ceramics have been investigated. The densification temperature of TiO2 is reduced from 1100-1200°C for pure TiO2 to 900°C with the presence of 0.5-3 mol% CuO under free sintering. For the samples with 1 mol% CuO, the constrained densification is slowed down, but a high sintered density of >95% at 950°C, which is close to that sintered freely, is still obtained. The above results are caused by the formation of CuO-rich film at the grain boundaries, which reduces grain-boundary energy and enhances grain-boundary migration kinetics of TiO2. To confirm the above findings, molecular dynamics simulation, at which the ratio of grain boundary energy of TiO2 between with and without CuO agrees well with that obtained experimentally, is conducted. 相似文献
13.
Low‐temperature sintering of β‐spodumene ceramics with low coefficient of thermal expansion (CTE) was attained using Li2O–GeO2 sintering additive. Single‐phase β‐spodumene ceramics could be synthesized by heat treatment at 1000°C using highly pure and fine amorphous silica, α‐alumina, and lithium carbonate powders mixture via the solid‐state reaction route. The mixture was calcined at 950°C, finely pulverized, compacted, and finally sintered with or without the sintering additive at 800°C–1400°C for 2 h. The relative density reached 98% for the sample sintered with 3 mass% Li2O–GeO2 additive at 1000°C. Its Young's modulus was 167 GPa and flexural strength was 115 MPa. Its CTE (from R.T. to 800°C) was 0.7 × 10?6 K?1 and dielectric constant was 6.8 with loss tangent of 0.9% at 5 MHz. These properties were excellent or comparative compared with those previously reported for the samples sintered at around 1300°C–1400°C via melt‐quenching routes. As a result, β‐spodumene ceramics with single phase and sufficient properties were obtained at about 300°C lower sintering temperature by adding Li2O–GeO2 sintering additive via the conventional solid‐state reaction route. These results suggest that β‐spodumene ceramics sintered with Li2O–GeO2 sintering additive has a potential use as LTCC for multichip modules. 相似文献
14.
Structure,Microwave Dielectric Properties,and Low‐Temperature Sintering of Acceptor/Donor Codoped Li2Ti1−x(Al0.5Nb0.5)xO3 Ceramics
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The structure, microwave dielectric properties, and low‐temperature sintering behavior of acceptor/donor codoped Li2TiO3 ceramics [Li2Ti1?x(Al0.5Nb0.5)xO3, x = 0–0.3] were investigated systematically. The x‐ray diffraction confirmed that a single‐phase solid solution remained within 0 < x ≤ 0.2 and secondary phases started to appear as x > 0.2, accompanied by an order–disorder phase transition in the whole range. Scanning electron microscopy observation indicated that the complex substitution of Al3+ and Nb5+ produced a significant effect on the microstructural morphology. Both microcrack healing and grain growth contributed to the obviously enhanced Q×f values. By comparison, the decrease of εr and τf values was ascribed to the ionic polarizability and the cell volume, respectively. Excellent microwave dielectric properties of εr ~ 21.2, Q×f ~ 181 800 GHz and τf ~ 12.8 ppm/°C were achieved in the x = 0.15 sample when sintered at 1150°C. After 1.5 mol% BaCu(B2O5) additive was introduced, it could be well sintered at 950°C and exhibited good microwave dielectric properties of εr ~ 20.4, Q×f ~ 53 290 GHz and τf ~ 3.6 ppm/°C as well. The cofiring test of the low‐sintering sample with Ag powder proved its good chemical stability during high temperature, which enables it to be a promising middle‐permittivity candidate material for the applications of low‐temperature cofired ceramics. 相似文献
15.
Li He Di Zhou Haibo Yang Yujuan Niu Feng Xiang Hong Wang 《Journal of the American Ceramic Society》2014,97(8):2552-2556
The coexistence of Li2MoO4 (LMO) and Ni0.5Zn0.5Fe2O4 (NZO) has been proven and their low‐temperature‐sintered magneto‐dielectric composites (1?x)LMO–xNZO (volume fraction factor x = 0.1, 0.3, 0.5, 0.7) were prepared by the conventional solid‐state reaction method and were sintered below 700°C. It is found that the optimal sample (x = 0.5) has good and relatively stable magneto‐dielectric performance in the frequency range from 10 MHz to 1 GHz with permittivity between 7.14 and 6.84, dielectric loss tangent between 0.09 and 0.02, and permeability between 5.23 and 3.30, magnetic loss tangent between 0.06 and 0.65, respectively. Furthermore, the verified chemical compatibility with silver indicates that the LMO–NZO ceramics are potential for low‐temperature cofired ceramic application and their multifunctional magneto‐dielectric properties also make them for potential applications in electronic devices. 相似文献
16.
Dunmin Lin Qiaoji Zheng Ying Li Yang Wan Qiang Li Wei Zhou 《Journal of the European Ceramic Society》2013,33(15-16):3023-3036
The effects of composition, sintering temperature and dwell time on the microstructure and electrical properties of (0.75 ? x)BiFeO3–0.25BaTiO3–xBi0.5K0.5TiO3 + 1 mol% MnO2 ceramics were studied. The ceramics sintered at 1000 °C for 2 h possess a pure perovskite structure and a morphotropic phase boundary of rhombohedral and pseudocubic phases is formed at x = 0.025. The addition of Bi0.5K0.5TiO3 retards the grain growth and induces two dielectric anomalies at high temperatures (T1 ~ 450–550 °C and T2 ~ 700 °C, respectively). After the addition of 2.5 mol% Bi0.5K0.5TiO3, the ferroelectric and piezoelectric properties of the ceramics are improved and very high Curie temperature of 708 °C is obtained. Sintering temperature has an important influence on the microstructure and electrical properties of the ceramics. Critical sintering temperature is 970 °C. For the ceramic with x = 0.025 sintered at/above 970 °C, large grains, good densification, high resistivity and enhanced electrical properties are obtained. The weak dependences of microstructure and electrical properties on dwell time are observed for the ceramic with x = 0.025. 相似文献
17.
Hai Tao Jiang Ji Wei Zhai Jing Ji Zhang Xi Yao 《International Journal of Applied Ceramic Technology》2013,10(5):873-878
The sintering behaviors and dielectric properties of Ba0.6Sr0.4TiO3 ceramics were investigated as a function of B2O3 and CuO content. The addition of both B2O3 and CuO reduced the sintering temperature of Ba0.6Sr0.4TiO3 about 500°C. It was suggested that a liquid phase BaCu(B2O5) was formed and assisted the densification of Ba0.6Sr0.4TiO3 ceramics. Ba0.6Sr0.4TiO3 ceramics co‐doped with 3.0 mol% B2O3, and 2.0 mol% CuO, sintered at 950°C for 5 h, had a dense microstructure and showed good microwave dielectric properties of a moderate dielectric constant (ε = 1048), low dielectric loss (0.0090) and high tunability (42.2%) at dc electric field of 30 kV/cm. 相似文献
18.
Xue-Kai Lan Jie Li Zheng-Yu Zou Meng-Qi Xie Gui-Fen Fan Wen-Zhong Lu Wen Lei 《Journal of the American Ceramic Society》2019,102(10):5952-5957
Low-permittivity ZnAl2-x(Zn0.5Ti0.5)xO4 ceramics were synthesized via conventional solid-state reaction method. A pure ZnAl2O4 solid-state solution with an Fd-3m space group was achieved at x ≤ 0.1. Results showed that partial substitution of [Zn0.5Ti0.5]3+ for Al3+ effectively lowered the sintering temperature of the ZnAl2O4 ceramics and remarkably increased the quality factor (Q × f) values. Optimum microwave dielectric properties (εr = 9.1, Q × f = 115,800 GHz and τf = −78 ppm/°C) were obtained in the sample with x = 0.1 sintered at 1400°C in oxygen atmosphere for 10 h. The temperature used for the sample was approximately 250°C lower than the sintering temperature of conventional ZnAl2O4 ceramics. 相似文献
19.
Qi Xu Zhe Song Wenlin Tang Hua Hao Lin Zhang Millicent Appiah Minghe Cao Zhonghua Yao Zichen He Hanxing Liu 《Journal of the American Ceramic Society》2015,98(10):3119-3126
The microstructure, phase structure, ferroelectric, and dielectric properties of (1?x)Bi0.5Na0.5TiO3‐xNaNbO3 [(1?x)BNT‐xNN] ceramics conventionally sintered in the temperature range of 1080°C–1120°C were investigated as a candidate for capacitor dielectrics with wide temperature stability. Perovskite phase with no secondary impurity was observed by XRD measurement. With increasing NN content, (1?x)BNT‐xNN was found to gradually transform from ferroelectric (x = 0–0.05) to relaxor (x = 0.10–0.20) and then to paraelectric state (x = 0.25–0.35) at room temperature, indicated by P–I–E loops analysis, associated with greatly enhanced dielectric temperature stability. For the samples with x = 0.25–0.35, the temperature coefficient of capacitance (TCC) was found <11% in an ultra‐wide temperature range of ?60°C–400°C with moderate dielectric constant and low dielectric loss, promising for temperature stable capacitor applications. 相似文献
20.
Yu Hong Jeon Eric A. Patterson David P. Cann Peter Mardilovich William Stickel Brady J. Gibbons 《Journal of the American Ceramic Society》2013,96(7):2172-2178
Bulk ceramic 72.5 mol%(Bi0.5Na0.5)TiO3–22.5 mol%(Bi0.5K0.5)TiO3–5 mol%Bi(Mg0.5Ti0.5)O3 (BNT–BKT–BMgT) has previously been reported to show a large high‐field piezoelectric coefficient (d33* = 570 pm/V). In this work, the same composition was synthesized in thin film embodiments on platinized silicon substrates via chemical solution deposition. Overdoping of volatile cations in the precursor solutions was necessary to achieve phase‐pure perovskite. An annealing temperature of 700°C resulted in good ferroelectric properties (Pmax = 52 μC/cm2 and Pr = 12 μC/cm2). Quantitative compositional analysis of films annealed at 650°C and 700°C indicated that near ideal atomic ratios were achieved. Compositional fluctuations observed through the film thickness were in good agreement with the existence of voids formed between successive spin‐cast layers, as observed with electron microscopy. Bipolar and unipolar strain measurements were performed via double laser beam interferometry and a high effective piezoelectric coefficient (d33,f) of approximately 75 pm/V was obtained. 相似文献