共查询到20条相似文献,搜索用时 31 毫秒
1.
Wenli Zhang Richard E. Eitel 《International Journal of Applied Ceramic Technology》2013,10(2):354-364
Materials and processing conditions have been developed allowing co‐firing of fluxed PZT‐SKN materials with commercial low temperature co‐fired ceramic (LTCC) tapes. Previously, Pb(Zr0.53, Ti0.47)O3–Sr(K0.25, Nb0.75)O3 (PZT‐SKN) ceramics fluxed with 1 wt% LiBiO2 and 1 wt% CuO addition were shown to sinter to high density at 900°C for 1 h, with a large d33 piezoelectric coefficient of ~415 pm/V. Currently, the master sintering curve (MSC) approach has been used to study the densification behaviors of fluxed PZT‐SKN and LTCC tapes. Different sintering mechanisms for fluxed PZT‐SKN ceramics and LTCC materials are confirmed by analyzing the apparent activation energy (Qa). Using knowledge gained from MSC results, an optimized sintering profile was developed. Multilayer PZT‐SKN/HL2000 (HeraLock? Tape, Heraeus) stacks co‐fired at 900°C for 0.5 h maintain large piezoelectric coefficient (high field d33 > 340 pm/V). EDS analysis reveal limited interdiffusion of Pb from PZT‐SKN layers in LTCC and the appearance of Al, Ca, and Si in the PZT‐SKN near the PZT‐SKN/LTCC interface. Further, elemental interdiffusion was not detected at the center of piezoelectric layer in PZT‐SKN/LTCC multilayer ceramics and no subsequent reduction in piezoelectric coefficient d33 was observed. Finally, a piezoelectric microbalance with mass sensitivity of 150 kHz/mg was fabricated using the materials and methods developed. 相似文献
2.
Thomas Schulz Timmy Reimann Arne Bochmann Andre Vogel Beate Capraro Björn Mieller Steffen Teichert Jörg Töpfer 《Journal of the European Ceramic Society》2018,38(4):1600-1607
The sintering behavior and the thermoelectric performance of Ca3Co4O9 multilayer laminates were studied, and a multilayer thermoelectric generator was fabricated. Compacts and multilayer samples with anisotropic microstructure and residual porosity were obtained after conventional sintering at 920 °C, whereas dense and isotropic multilayer samples were prepared by firing at 1200 °C and reoxidation at 900 °C. A hot-pressed sample has a dense and anisotropic microstructure. Samples sintered at 920 °C exhibit low electrical conductivity due to the low density, whereas the Seebeck coefficient is not sensitive to preparation conditions. However, thermal conductivity of multilayers is very low, and, hence acceptable ZT values are obtained. A transversal multilayer thermoelectric generator (TMLTEG) was fabricated by stacking layers of Ca3Co4O9 green tapes, AgPd conductor printing, and co-firing at 920 °C. The TMLTEG has a power output of 3 mW at ΔT = 200 K in the temperature interval of 25 °C to 300 °C. 相似文献
3.
Influence of Cold Low Pressure Lamination Parameters on the Joining of Low Temperature Co‐Fired Ceramics Green Tapes and Sintered Alumina Substrates
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Michael Hambuch Christoph Hutzler Frieder Gora Frieder Wittmann Karin Beart Andreas Roosen 《International Journal of Applied Ceramic Technology》2016,13(3):532-539
In this study, laminates consisting of sintered alumina substrates and green Low Temperature Co‐fired Ceramics (LTCC) tapes have been produced via Cold Low Pressure Lamination which is based on adhesive tapes for joining of layers at room temperature and pressures <5 MPa. The influences of lamination parameters such as temperature, pressure, and time on the quality of the green and sintered multilayer stack have been determined. If the bottom LTCC layer of an alumina–LTCC–LTCC laminate is metallized by screen printing defects such as crack formation can occur due to stress formation caused by constrained sintering. By adapting the lamination parameters, these stresses can be avoided. Another defect observed is cavities which form along the printed circuit lines. This type of defect is caused by the shrinkage of the circuit line width during firing; by reducing the height of the conductor line during screen printing, the cavity size can be reduced. In addition, different screen‐printed metallization layouts have been tested to determine the influence of line and spaces on the quality of sintered laminates. 相似文献
4.
Fabrication of a transversal multilayer thermoelectric generator with substituted calcium manganite
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Timmy Reimann Arne Bochmann Andy Vogel Beate Capraro Steffen Teichert Jörg Töpfer 《Journal of the American Ceramic Society》2017,100(12):5700-5708
The sintering behavior and thermoelectric performance of Ca0.99Gd0.01Mn0.99W0.01O3 was studied, and a multilayer thermoelectric generator was fabricated. The addition of CuO as sintering additive was found to be effective for the reduction in the sintering temperature from 1300°C to about 1000°C‐1050°C. Dense samples were obtained after firing at 1050°C, whereas some porosity remained after firing at 1000°C. Samples sintered at reduced temperature exhibit lower electrical conductivity, whereas the Seebeck coefficient S = ?150 μV/K at 100°C is not affected by lowering the sintering temperature. The figure of merit is ZT = 0.12 at 700°C for samples sintered at 1300°C; ZT = 0.08 and 0.03 were obtained for multilayer laminates sintered at 1050°C and 1000°C, respectively. A transversal multilayer thermoelectric generator (TMLTEG) was built by stacking layers of substituted CaMnO3 green tapes, and printing AgPd conductor stripes onto the thermoelectric layers at an angle of 30° relative to the direction of the heat flow. The multilayer stack was co‐fired at 1000°C. The TMLTEG has a power output of 2.5 mW at ?T= 200 K in the temperature interval of 25°C‐300°C. A meander‐like generator with larger power output comprising six TMTEGs is also presented. 相似文献
5.
Björn Brandt Hamid Naghib‐zadeh Torsten Rabe 《Journal of the American Ceramic Society》2013,96(3):726-730
Co‐firing of low temperature co‐fired ceramics (LTCC) and functional ceramics like ferrites is a promising approach to increase the level of integration in future microsystems, and to create new applications for LTCC technology. Besides the development of compatible material combinations, the configuration of the sintering process is an important issue for successful co‐firing. A method is presented to derive the linear shrinkage mismatch of a material combination based on density data calculated from the master sintering curves (MSCs) of the individual materials. The influence of the firing profile on the constraint in the combined multilayer can be anticipated using this method. To investigate and improve the co‐firing of ferrite and dielectric tape, the shrinkage mismatch with respect to heating rate was studied. A significant reduction of shrinkage mismatch was found for increased heating rates. The calculated results are verified by lateral shrinkage measurements on combined laminates. 相似文献
6.
Timmy Reimann Beate Capraro Heike Bartsch Jörg Töpfer 《International Journal of Applied Ceramic Technology》2021,18(1):129-137
We studied the sintering behavior and magnetic properties of Ni0.60-yCuyZn0.42Fe1.98O3.99 ferrites. The shrinkage is shifted toward lower temperature with increasing Cu content y. The addition of Bi2O3 sintering aid induces enhanced shrinkage at T < 900°C and dense ceramics are obtained after sintering at 900°C. Such ferrites exhibit a permeability of µ = 135-250 depending on the composition, sintering temperature and concentration of sintering additive. Ferrites with y = 0.20 show a high Curie temperature of Tc = 307°C. Multilayer inductors were fabricated and cofired at 900°C using ferrite tapes without and with 0.75 wt% Bi2O3. The compatibility of ferrite tapes with different metal pastes (Ag, AgPd, and Au) was evaluated. Ferrite tapes were also integrated between layers of low-k dielectric CT708 tapes and successfully cofired at 900°C. Preliminary tests indicate that the multilayer inductors can be operated up to temperatures of 250°C. This demonstrates that high-Tc Ni-Cu-Zn ferrites are promising magnetic materials for inductive components for high operating temperatures. 相似文献
7.
Hsing‐I Hsiang Li‐Then Mei Chi‐Shiung Hsi Wei‐Cheng Wu Jer‐Hao Wu Fu‐Su Yen 《International Journal of Applied Ceramic Technology》2013,10(1):160-167
The Bi2O3–B2O3–ZnO–SiO2 (BB35SZ) glass effects on the sintering behavior and magnetic properties of Bi–Zn co‐doped Co2Y ferrites were investigated in developing low‐temperature‐fired ferrites. The results indicate that BB35SZ glass can be used as a sintering aid to reduce the densification temperature of Co2Y ferrites from 1300°C to 900°C. The 2(Ba0.9Bi0.1O)·2(Zn0.4Co0.4Cu0.2O)·6(Fe1.97Zn0.03O3) ferrite with 4 wt% BB35SZ glass can be densified below 900°C, exhibiting an initial permeability of 3.4 and quality factor of 55. This process provides a promising candidate for multilayer chip magnetic devices for microwave applications. 相似文献
8.
Arne. Bochmann Timmy. Reimann Thomas. Schulz Steffen. Teichert Jörg. Töpfer 《Journal of the European Ceramic Society》2019,39(9):2923-2929
Sintering of Ca2.7Bi0.3Co4O9 pellets and multilayer laminates at 920 °C results in a ceramic microstructure with low density with a pronounced anisotropy. The electrical conductivity of multilayers is 56 S/cm at 400 K (perpendicular to pressing direction). The Seebeck coefficient is positive, and the power factor increases from 60 μW/(K²m) at 400 K to 200 μW/(K²m) at 900 K. The thermal conductivity (parallel to pressing direction) is 0.65 W/(mK). Transverse multilayer thermoelectric generators (TMLTEG) were fabricated by stacking layers of Ca2.7Bi0.3Co4O9 green tapes, screen-printing of AgPd stripes at various tilt angle φ relative to the heat flux direction (20°, 45°, and 65°), and co-firing at 920 °C. For φ = 65° the power output is 8 mW at ΔT = 200 K with room temperature at the cold side. FEM modelling as well as analytical calculations agree well with measurements, and the optimum tilt angle is found to be φ = 58°. 相似文献
9.
Dense proton‐conducting BaZr0.1Ce0.7Y0.2O3 – δ (BZCY) electrolyte membranes were successfully fabricated on NiO–BZCY anode substrates at a low temperature of 1,150 °C via a combined co‐press and co‐firing process. To fabricate full cells, the LaSr3Co1.5Fe1.5O10 – δ–BZCY composite cathode layer was fixed to the electrolyte membrane by two means of one‐step co‐firing and two‐step co‐firing, respectively. The SEM results revealed that the cathode layer bonded more closely to the electrolyte membrane via the one‐step co‐firing process. Correspondingly, determined from the electrochemical impedance spectroscopy measured under open current conditions, the electrode polarisation and Ohmic resistances of the one‐step co‐fired cell were dramatically lower than the other one for its excellent interface adhesion. With humidified hydrogen (2% H2O) as the fuel and static air as the oxidant, the maximum power density of the one‐step co‐fired single cell achieved 328 mW cm–2 at 700 °C, showing a much better performance than that of the two‐step co‐fired single cell, which was 264 mW cm–2 at 700 °C. 相似文献
10.
Development of a lead‐free copper co‐fired BNT‐based piezoceramic sintered at low temperature
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Compatibility of Bi‐based piezoelectric ceramic and copper electrodes is demonstrated by co‐firing 0.88Bi1/2Na1/2TiO3–0.08Bi1/2K1/2TiO3–0.04BaTiO3 (BNKBT88) with copper. A combination of Bi2O3, CuO, ZnO, Li2CO3, and B2O3 are used as additives to reduce firing temperature to 900°C with minimal effect on the electromechanical properties compared to sintering at 1150°C without additives. Co‐firing with copper electrodes requires controlled oxygen sintering at low temperature. The atmosphere is controlled using carbon dioxide and hydrogen gas to maintain an oxygen partial pressure of 6.1 × 10?8 atm, which is necessary for the coexistence of Cu metal and Bi2O3. The thermodynamic activity of bismuth oxide in BNKBT88 is calculated to be 0.38. BNKBT88 ceramics were successfully co‐fired with internal as well as surface Cu metal electrodes. The copper co‐fired ceramics were successfully polarized and the dielectric and piezoelectric properties are evaluated. 相似文献
11.
Timmy Reimann Jörg Töpfer Stefan Barth Heike Bartsch Jens Müller 《International Journal of Applied Ceramic Technology》2013,10(3):428-434
Negative temperature coefficient (NTC) thermistor thick films were fabricated by screen printing on alumina substrates and firing at 900°C. Spinel‐type NiMn2O4 exhibits limited stability in air between 730 and 970°C only and interacts with the Bi2O3 additive. The Zn–Co‐substituted spinel Zn0.75Ni0.5Co0.5Mn1.25O4 with 3 wt% additive shows complete densification at 900°C; no interaction between spinel and additive was observed. Alternatively, a Cu–Zn–Co‐substituted Cu0.37Zn0.52Ni0.44Co0.44Mn1.23O4 spinel with excellent sintering characteristics even without sintering additive was investigated. The thermistor films display a sheet resistance of about 300 kΩ/□ and B = 3300 K. The firing behavior, microstructure formation, and electrical properties of NTC thick films are reported. 相似文献
12.
Steve X Dai 《Journal of the American Ceramic Society》2013,96(8):2499-2505
Low‐temperature cofired ceramic (LTCC) is a multilayer 3D packaging, interconnection, and integration technology. For LTCC modules targeting radio and microwave frequency (RF and MW) applications, a low or near 0 ppm/°C temperature coefficient of resonant frequency (τf) ensures temperature stability of embedded resonator and filter functions. The base dielectrics of most commercial LTCC systems have a τf in the range ?50 to ?80 ppm/°C. This study explored a method to achieve a zero τf on stripline (SL) resonators by locally cofiring, in a multilayer LTCC structure, compensating dielectrics (CD) with an opposite τf to that of the host dielectric. The formulation, synthesis, dielectric properties, and microstructure of SrTiO3 (STO)‐based low‐fire τf CD are presented. Chemical interactions and physical compatibility between the compensating and the host LTCC dielectrics are investigated for cofireability. The dependence of τf compensation on the wt% of STO, the printed thickness, and the location of the CD in multilayer LTCC are discussed. The most effective τf compensation is achieved by integrating CD next to the resonator lines, and can be explained by the concentration of electromagnetic energy via total internal reflection of electromagnetic waves inside the CD layer. 相似文献
13.
Formation of BaFe12−xNbxO19 and its high electromagnetic wave absorption properties in millimeter wave frequency range
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Chuyang Liu Yujie Chen Yangyu Yue Yu Tang Zongrong Wang Ning Ma Piyi Du 《Journal of the American Ceramic Society》2017,100(9):3999-4010
BaFe12?xNbxO19 (BFNO, x=0‐0.6) powders with Nb5+ substituting for Fe3+ were prepared by sol‐gel method. The formation process and electromagnetic (EM) wave absorption properties of the BFNO are investigated in detail. With Nb5+ content increasing from x=0 to x=0.6, the formation temperature of barium ferrite phase without heat time increases from ~700°C to ~900°C, while the appearance temperature of typical plate grains decreases from ~1300°C to ~1100°C, and the crystallization ability decreases at 600°C‐900°C, while the grain size increases gradually at 1100°C‐1300°C. Increasing sintering temperature and time promote the formation of barium ferrite phase and grain growth in all the samples. The ε′ and ε″ of the sample with x=0.6 sintered at 1300°C for 3 hours reach highest of ~7.9 and ~0.95 over 26.5‐40 GHz. Multiresonance peaks in permeability decrease from 40+ GHz to ~30 GHz with x rising from 0 to 0.6. Ultimately, small RLmin of ~?42 dB, thin dm of ~0.76 mm, and broad bandwidth of >12 GHz can be exhibited simultaneously around millimeter wave atmospheric window of 35 GHz. 相似文献
14.
Tape casting system for ULTCCs to fabricate multilayer and multimaterial 3D electronic packages with embedded electrodes
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Mei‐Yu Chen Timo Vahera Chi‐Shiung Hsi Maciej Sobocinski Merja Teirikangas Jani Peräntie Jari Juuti Heli Jantunen 《Journal of the American Ceramic Society》2017,100(4):1257-1260
A 3D multilayer structure built by two ultra‐low temperature co‐fired ceramic (ULTCC) compositions with silver embedded electrodes are co‐fired at a temperature of 450°C. The 3D multilayer module is prepared by laminating the ULTCC green tapes with a new binder system, which organics can be completely burned out at temperature of 250°C before the sintering of the ULTCC 3D modulus. High‐density microstructures are achieved for the sintered module. In this study, the ULTCC feasible binder system is introduced. Also, ULTCC multilayers and multimaterial structures with surface and embedded silver electrodes are fabricated. This research opens up a new horizon for fabrication of electroceramic devices with embedded electrodes in multimaterial devices. 相似文献
15.
Kostja Makarovič Raul Bermejo Irina Kraleva Andreja Benčan Marko Hrovat Janez Holc Barbara Malič Marija Kosec 《International Journal of Applied Ceramic Technology》2013,10(3):449-457
For the fabrication of complex, micro‐electromechanical systems (MEMS) devices based on low‐temperature co‐fired ceramic (LTCC), higher firing temperatures and longer times than those proposed by the LTCC producer are needed. These changes to the thermal budget may influence the material properties and consequently its functional properties. The effect of the firing conditions on the LTCC DuPont 951 and thus on the phase composition, that is, the alumina/anorthite ratio and porosity, on the mechanical properties is presented. The samples fired at low temperatures (800°C) had a high porosity (7%), which significantly contributed to the low elastic modulus (100 GPa) and the low mechanical strength of the LTCC (140 MPa). The samples fired at 850°C, which had only 1% of porosity, resulted in an elastic modulus of 122 GPa and a flexural strength of 224 MPa. A further increase in the temperature contributed to a slight decrease in the elastic modulus, while no significant difference in the flexural strength could be observed. The enhancement of the flexural strength with an increasing firing temperature was mainly related to a decrease in the porosity and to a lesser extent to the different ratio of the alumina/anorthite phases. The effect of firing time on the phase composition at selected temperatures (i.e., 100 h at 700 and 800°C) is also discussed. 相似文献
16.
Novel glass–free low temperature firing microwave dielectric ceramics Li2CeO3 with high Q prepared through a conventional solid‐state reaction method had been investigated. All the specimens in this paper have sintering temperature lower than 750°C. XRD studies revealed single cubic phase. The microwave dielectric properties were correlated with the sintering conditions. At 720°C/4 h, Li2CeO3 ceramics possessed the excellent microwave dielectric properties of εr = 15.8, Q × f = 143 700 (GHz), and τf = ?123 ppm/°C. Li2CeO3 ceramics could be excellent candidates for glass‐free low‐temperature co‐fired ceramics substrates. 相似文献
17.
Jie Zhang Zhenxing Yue Yu Luo Xiaohua Zhang Longtu Li 《Journal of the American Ceramic Society》2016,99(4):1122-1124
A novel low‐temperature sintering microwave dielectric based on forsterite (Mg2SiO4) ceramics was synthesized through the solid‐state reaction method. The effects of LiF additions on the sinterability, phase composition, microstructure, and microwave dielectric properties of Mg2SiO4 were investigated. It demonstrated that LiF could significantly broaden the processing window (~300°C) for Mg2SiO4, and more importantly the sintering temperature could be lowered below 900°C, maintaining excellent microwave dielectric properties simultaneously. The 2 wt% LiF‐doped samples could be well‐sintered at 800°C and possessed a εr ~ 6.81, a high Q×f ~ 167 000 GHz, and a τf ~ ?47.9 ppm/°C, having a very good potential for LTCC integration applications. 相似文献
18.
Sintering behavior and biocompatibility of a low temperature co‐fired ceramic for microfluidic biosensors
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A low temperature co‐fired ceramic (LTCC) has been formulated and evaluated for in‐vitro microfluidic sensors and cell culture applications. Using a 75/25 vol% glass to alumina ratio, high density was achieved for sintering temperatures <900°C. No toxicity was observed in the leachate medium obtained by soaking LTCC in cell medium for 5 days. The human umbilical vein endothelial cells (HUVECs) also attached on the fibronectin‐coated LTCC after 14 hours and proliferated after 74 hours. On the basis of these results, the current LTCC formulation is a viable candidate for the continued development of LTCC‐based microfluidic biosensors. 相似文献
19.
Hexagonal structure magnetoplumbite ferrites have revealed a higher dispersion frequency than that of nickel ferrites because of the magnetoplumbite's magnetic anisotropy. The magnetoplumbite ferrite densification temperature always exceeds 1000 °C and the initial low temperature firing permeability of magnetoplumbite ferrites with added glass is too low (μi = 2–4). Therefore, it is desirable to develop a material that has a higher permeability at above 300 MHz and can be densified at temperatures below 900 °C. The Bi2O3–B2O3–ZnO–SiO2 (BBSZ) glass addition effects on the densification and magnetic properties of Co2Y–NiCuZn ferrite composites with various Co2Y/NiCuZn ferrite ratios were investigated. The densification of Co2Y–NiCuZn ferrite composites was enhanced by the addition of glass at low sintering temperatures (<900 °C) due to the liquid phase sintering. Co2Y–NiCuZn ferrite composites with 4 wt% BBSZ glass sintered at 900 °C show a relative density above 90%, a high-initial-permeability of 5–6, a quality factor of above 30 in the 200–300 MHz frequency and a resonance frequency above 1 GHz, which can be used in high frequency multilayer chip inductors. 相似文献
20.
Shuichi Funahashi Hanzheng Guo Jing Guo Amanda L. Baker Ke Wang Kosuke Shiratsuyu Clive A. Randall 《Journal of the American Ceramic Society》2017,100(8):3488-3496
Cold‐sintered ZnO and Ca3Co4O9 polycrystalline materials were shown to have thermoelectric properties comparable to those of conventionally sintered ceramics. Extending these processing conditions into a cold sintering co‐fired ceramic (CSCC) technology, we integrated n‐type and p‐type thermoelectric oxides and a separating insulating layer to demonstrate functional multilayer thermoelectric generator devices. A co‐fired structure with an insulating 8 mol% yttria‐stabilized zirconia (8YSZ) layer enabled multilayer thermoelectric generators (TEG) to be fabricated with a 5 n‐p junction device (20 layers). A transmission electron microscopy analysis of the interfaces between the various materials under the co‐firing cold sintering showed some interdiffusion of chemical constitutes in a 2.0 μm interface region between the respective ceramic phases. The co‐firing of multilayer ceramic and polymer structures were also shown to be possible using insulation layers of polytetrafluoroethylene (PTFE) thermoplastic layers. This demonstrated the feasibility of a single‐step process for new structures with both ceramics and polymers, opening up new directions for many new device designs. 相似文献