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Lead-free Sr0.6Ca0.4TiO3 ceramic was prepared by solid-state reaction route. X-ray diffraction technique showed the phase purity and identified the orthorhombic perovskite structure. Scanning Electronic Microscopy observation evidenced homogeneous morphology and dense microstructure. Electrical conduction and dielectric relaxation mechanisms at high temperature have been studied by complex impedance measurement techniques over a wide range of frequencies and temperatures, from 100 Hz to 1 MHz and from 573 K to 783 K. Fitting of impedance measurements allowed us to study grains and grain boundaries electrical characteristics and their contribution to the conduction and dielectric relaxation processes in the ceramic. Electrical conduction in grains is due to oxygen vacancy jumps for temperatures below 733 K and to polarons above 763 K. Electrical DC conductivity in grains and grain boundaries is mainly due to oxygen vacancies. Impedance measurements and relaxation time distribution function calculations show non-Debye-type relaxation effects for both grains and grain boundaries. [ABSTRACT FROM AUTHOR]

A polycrystalline ceramic oxide, BaFe2MnO6 was produced through a regular solid-state route. The phase creation in the synthesized substance was investigated through X-ray diffraction (XRD) technique. The present material has found with made up of a single phase orthorhombic structure. The electrical properties of the compound were recorded through an LCR meter for a broader range of frequencies and temperatures. This perovskite oxide material possesses a large relative permittivity (ɛr = 1139) and low dielectric loss (tanδ = 0.421) at the ambient atmospheric condition, while the curie temperature arise beyond 450 °C. The resultant dielectric properties of this material assure its promising candidature for feasible applications in smart electronic devices such as dielectric material in ceramic capacitors. [ABSTRACT FROM AUTHOR]

In this report, a complex barium titanate ceramic oxide of the form BaBi1.6Fe0.4TiO6 was prepared by the solid-state casting process. More Bi3+ percentage was selected to boost the dielectric and ferroelectric effects, while lowering the Fe3+ content could minimize the leakage current and consequently, the dielectric loss (tanδ). The X-ray diffraction (XRD) data suggests an establishment of monoclinic distortion (P21/c) of smaller mean crystallite size (∼40 nm) using the Debye-Scherrer formula. The compound exhibits dielectric values, such as ɛr ∼ 771, and relatively low loss, tanδ ∼ 0.017 at the ambient experimental conditions. Thus, the material can be incorporated into different electronic devices where higher dielectric constant and lower losses are essential, for example, multi-layered ceramic capacitors, transmission lines, and gate dielectrics. The AC-conductivity essence of the compound follows Jonscher's power law as well as Arrhenius relation. The PE hysteresis loop was traced at different conditions with a function of the incident electric field in the ambient atmospheric conditions. The outcome of this study revealed that the material has remanent polarization hence suggesting a ferroelectric effect with less hysteresis loss; therefore, it could be useful in memory storage devices. [ABSTRACT FROM AUTHOR]

The well-known lead-based complex-double perovskite [A(BIBII)O3] material is lead iron niobate, or Pb(Fe1/2Nb1/2)O3. The effect of the liquid phase of borosilicate glass SiO2-B2O3 (BS) on the sinterability and dielectric behaviors of PFN is comprehensively explored in the current study. The PFN-BS-glass powder was synthesized by sol-gel. XRD is used to validate the crystalline structure of PFN as it is synthesized, PFN-BS-glass, and the amorphous nature of BS-glass. The SEM was used to analyses microstructure. PFN and PFN-BS green pellets were sintered under various sintering circumstances. The shape, compactness, dielectric properties, and magnetic behavior of PFN are discovered to be significantly influenced by the liquid phase sintering by BS-glass in PFN for the application high electrical resistivity material having low dissipation and low sintering temperature in multilayer ceramic capacitor. [ABSTRACT FROM AUTHOR]

In general, NaNbO3 (NN) ceramics are considered to be one of the most promising lead-free perovskites (AFE) materials with low cost, low density, and nontoxic advantages. However, the energy storage capability of this material is often greatly hindered by the hysteresis exhibited during the transition from the antiferroelectric to the ferroelectric phase. In this study, lead-free dielectric (1−x)NaNbO3−xBi(Li1/3Sn2/3)O3, x = 0.0 − 0.08, ceramics were synthesized by solid-state reaction method. The XRD data show a structural change from orthorhombic to pseudo-cubic at x = 0.06 composition. With increasing Bi(Li1/3Sn2/3)O3 content, changes in dielectric properties demonstrated that the AFE P phase was successively replaced by the relaxor AFE R phase, resulting in a thin P–E loop characteristic which leads to the improvement of the energy storage density and efficiency of the ceramic capacitors. The optimum recoverable energy storage density (Wrec = 0.56 J/cm3) and efficiency (η = 74%) were obtained at x = 0.06 under an electric field of 120 kV/cm. The optimum composition also exhibited temperature stability in the range of 25 °C–100 °C. In addition, an increase in Bi(Li1/3Sn2/3)O3 content can lead to a decrease in leakage current density. This research shows that BLS modified NN ceramics are promising dielectric material candidates for energy storage applications. [ABSTRACT FROM AUTHOR]

Multilayer ceramic capacitors (MLCCs) for electric vehicles require their room temperature capacitance to change ≤ ±15% at −55°C to 200°C. The dielectric constant (ε) of BaTiO3, a dielectric material widely used in MLCCs, drops at >125°C making its application to electric vehicles difficult. Here, we propose KCa2Nb3O10 (KCNO)-layered perovskite as a strong candidate for electric vehicle MLCCs as its ε does not change abruptly with temperature. The effect of sintering temperature on the temperature coefficient of capacitance (TCC) of KCNO is studied. The KCNO powder calcined at 900–1200°C is sintered at 1200°C–1300°C. Microstructure and temperature-dependent ε are determined by the sintering temperature, while the sintered density is related to the difference between the calcining and sintering temperatures. Only the room temperature ε of the samples sintered at 1300°C (except the one calcined at 900°C) varies ≤ ±15% at 25°C–200°C (ε ~250 at room temperature). The sample calcined at 1100°C and sintered at 1300°C has highly elongated grains and the highest activation energy. These factors are responsible for the TCC of the 1300°C sintered KCNO being ≤ ±15% at 25–200°C. [ABSTRACT FROM AUTHOR]

This article presents a new Spk-based sample-size tightening sampling system by variables inspection for lot determination when the quality characteristic has bilateral specification limits. The proposed system has a flexible switching mechanism between normal and tightened inspection, which is adaptively employed for the occurrence of quality deterioration in submitted lots. The performances of discriminatory power, economy and sensitivity to quality shift of the proposed method are demonstrated by comparing the operating characteristic (OC) curve, average sample number (ASN) and average run length (ARL), respectively, with the existing sampling plans. Furthermore, for practical application, the solved plan parameters under certain quality conditions are tabulated for quick reference, and an example taken from the Multi-layer Ceramic Capacitor (MLCC) industry is studied for illustration. [ABSTRACT FROM AUTHOR]

High-temperature stability and reliability are in high demand for ultra-thin multilayer ceramic capacitors (MLCCs), which are ubiquitous in electronic industries. Here, two doping matrices of BaTiO3 (BT) and Ba0.97Ca0.03TiO3 (BCT) are chosen to prepare ultra-thin MLCCs, whose effects on the microstructure, nonlinear dielectric properties, temperature stability, and reliability of the capacitors were investigated. Compared with BT-based MLCCs, BCT-based MLCCs possess better core-shell structures, thus, leading to a higher Schottky barrier for inhibiting carrier migration and improving aging performance. For the 1.5 μm-thickness capacitors using the BCT doping matrix rather than BT, the temperature coefficient of capacitance reaches the X7R standard, and the breakdown field increases from 148 to 172 V/μm. Moreover, the ability to resist insulation resistance degradation has been significantly improved. This work demonstrates the great potential of using BCT as the doping matrix to prepare ultra-thin MLCCs with excellent temperature stability and reliability. [ABSTRACT FROM AUTHOR]

In this study, solid-state BaTiO3 was successfully synthesized after the disintegration of the starting materials (BaCO3 and TiO2) under various conditions. By analyzing the microstructure, tetragonality, crystallinity, and particle size distribution of the synthesized powder, the factors that affected the properties of the BaTiO3 solid-state synthetic powder were successfully identified. Furthermore, the changes in the dielectric constants (temperature characteristic coefficients) of the sintered specimens were investigated using each powder, according to the dielectric characteristics, high-temperature resistance, and temperature, to identify the direct and indirect relationships between the disintegration conditions, synthetic powders, and sintered specimens. Finally, optimal conditions for the uniform solid-state synthesis of BaTiO3 powder for multilayer ceramic capacitor production were derived. [ABSTRACT FROM AUTHOR]

Recent electric vehicle multilayer ceramic capacitors (MLCCs) adopt submicron-sized solid-state synthesized BaTiO3 for dielectric layers for high reliability. Unlike BaTiO3 nanoparticles synthesized by the hydrothermal method, particle size distribution control becomes demanding with the solid-state synthesis. Here, BaTiO3 with 260 and 390 nm average particle sizes were synthesized using a solid-state method, and the dielectric properties of the samples sintered at 1100, 1150, and 1200°C were studied in terms of particle size distributions. Notably, BaTiO3 samples sintered with 260 nm particles with smaller grain sizes and lower tetragonality exhibited higher dielectric properties than those prepared with 390 nm particles. The reasons behind the high dielectric performance were found in the lower skewness of the 260 nm particles, which produced a higher density of the sintered sample. For electric vehicle MLCC BaTiO3, engineering their skewness is as important as controlling their grain size or tetragonality for high dielectric performance. [ABSTRACT FROM AUTHOR]

This paper discusses the approach to formulate mathematical model (MM) for synthesis of any ceramic and to decide reliability of density measurement. In the research of basic science, the majority of operations are still executed manually which needs to be focused and develop a mathematical relation which simulate the real input and output data directly. The advantages and limitations of the developed mathematical models are identified and the models are classified in terms of range of application and goals. In this study, a generalized experimental data based model developed to simulate the contemporary techniques for the purpose of study, compression, inducing generalized approach for the mathematical model of ceramic synthesis. The findings indicate that the topic understudy is of great importance, as no such approach of experimental data based mathematical simulation is adopted for the formulation of synthesis of ceramics so far. Thus the results of this experimental research would be useful to industry for manufacturing of multilayer capacitors. [ABSTRACT FROM AUTHOR]

A novel compact low-temperature-cofired ceramic (LTCC) bandpass filter with sharp rejection and wide stopband is presented in this paper. Semi-lumped resonant cells composed of multilayer ceramic capacitors and via-hole inductors are utilized with source–load coupling, thus two transmission zeros (TZs) can be generated near both sides of the passband, resulting in a high skirt selectivity and wide harmonic suppression. A LTCC bandpass filter works from 2.1 to 2.3 GHz has been designed and fabricated in a four-layer substrate to verify the proposed topology. With an extremely compact size of 2.0 mm × 1.25 mm × 0.9 mm, the design is highly integrated and suitable for miniaturized modern wireless communication applications. [ABSTRACT FROM AUTHOR]

A compact, flat coupling, and broadband directional coupler are presented for high-power applications in the frequency band of 100 ∼ 1000 MHz. The coupler is mainly composed of two compact semi-flexible coaxial cables with the length of the λ0/4 (λ0 is the free-space wavelength at the frequency of 850 MHz), four chip ceramic capacitors, and two air wound inductors that can tune the coupling coefficient. The phase inverter of the coupler is well designed and experimentally validated. The directional coupler exhibits high performance in the whole operation frequency band with low insertion loss (less than 0.3 dB), high directivity (more than 18 dB), and high power (up to 300 W). The amplitude imbalance of the coupling coefficient is less than 0.3 dB. The measured results exhibit good consistency with the theoretical analysis. And the proposed design method can be readily extended to other low-cost, high-power, and broadband directional couplers. [ABSTRACT FROM AUTHOR]

Electroslag surfacing was performed in a \empty 180 mm current-conducting mould on 110G13L steel billets using shavings and electrodes from the same steel grade as a remelted material. It has been established that for any type of surfacing material, the structure of the deposited metal is austenitic. It is shown that the use of electroslag facing with chips allows to obtain a lower penetration of the base metal in comparison with electrode surfacing. The most dangerous area for the appearance of microcracks is the zone of fusion of the base and deposited metals, the width of which depends on the technology of surfacing and, accordingly, the power of thermal action on the base metal. [ABSTRACT FROM AUTHOR]

Lead-free 0.9(0.92Bi0.5Na0.5TiO3–0.08BaTiO3)–0.1(NaNb(1-x)TaxO3) ceramics (abbreviated as BNBT − NN1-xTx), x = 0, 0.25, 0.50, 0.75 and 1.00, were prepared by conventional solid-state mixed oxide route. The effects of Ta substitution on the crystal structure, morphology, dielectric, ferroelectric as well as energy-storage properties were systematically investigated. X-ray diffraction revealed a single-phase perovskite structure for x ≤ 0.75 with coexisting rhombohedral and tetragonal phases. With increasing Ta substitution, a weakening of tetragonal distortion was observed. The SEM micrographs of all samples displayed dense microstructure with an average grain size of 0.70–0.99 µm. Good temperature stability of dielectric properties was maintained in the whole range of Ta substitution. The composition with x = 0.25 showed an optimum energy-storage density of 0.37 J/cm3 and the energy-storage efficiency of 75.1% at 50 kV/cm, thus indicating the promising application of BNBT–NN1-xTx ceramics as energy-storage capacitors. [ABSTRACT FROM AUTHOR]

A novel lead-free Ba(1-x)(La,Na)xTiO3 (BLNT), (0 ≤ x ≤ 0.08) ferroelectric ceramic with enhanced energy storage density was fabricated by the conventional solid-state method. With an increase in La3+/Na+ content, the energy storage density, efficiency and power density were increased. The samples with (x = 0.08) show recoverable energy storage of (1.07 J/cm3), 3 times higher than that of pure BaTiO3 ceramics, energy storage efficiency of (87.6%) and power density of 0.314 MW/cm3, 17 times greater than that of pure BaTiO3 ceramics. Comparison with other lead-free ferroelectric ceramics confirmed the superiority potential of (BLNT-0.08) ceramics for the design of ceramics capacitors for energy storage applications. The effect of La3+/Na+ contents on the optical properties of BaTiO3 ceramics was studied via UV spectroscopy. The results revealed that the introduction of structure disorder by means of A-site vacancies leading to the creation of shallow defects resulting in narrowing the bandgap energy. This work may provide a simple and powerful method to develop inexpensive energy storage and photovoltaic devices based on ferroelectric ceramics. [ABSTRACT FROM AUTHOR]

We investigated the characteristics of thermally evaporated fullerene (C60)/Ag/C60 (CAC) multilayer films for use in semi-transparent perovskite solar cells (PSCs) and thin-film heaters (TFHs). The top and bottom C60 layers and Ag interlayer were prepared using multi-source thermal evaporation, and the thickness of the Ag interlayer was investigated in detail for its effects on the resistivity, optical transmittance, and mechanical properties of the CAC electrodes. We used a figure-of-merit analysis to obtain a CAC electrode with a smooth surface morphology that exhibited a sheet resistance of 5.63 Ohm/square and an optical transmittance of 66.13% at a 550 nm wavelength. We conducted mechanical deformation tests to confirm that the thermally evaporated multilayer CAC electrode has a high durability, even after 10,000 times of inner and outer bending, rolling, and twisting due to the flexibility of the amorphous C60 and Ag interlayer. We evaluated the feasibility of using CAC electrodes for semi-transparent PSCs and TFHs. The semi-transparent PSC with 1.08 cm2 active area prepared with a transparent multilayer CAC cathode showed a power conversion efficiency (PCE) of 5.1%. Furthermore, flexible TFHs (2.5 × 2.5 cm2) fabricated on a thermally evaporated CAC electrode show a high saturation temperature of 116.6 C, even at a low input voltage of 4.5 V, due to a very low sheet resistance. Based on the performance of the PSCs and TFHs, we conclude that the thermally evaporated multilayer CAC electrode is promising for use as a transparent conductive electrode (TCE) for semi-transparent PSCs and TFHs, with characteristics comparable to sputtered TCEs. [ABSTRACT FROM AUTHOR]

Metal-insulator-metal (MIM) capacitor with high-k insulator such as BST enhances specific capacitance. The effects of barium mole fraction (x) of BaxSr1 –xTiO3 ceramic-based MIM capacitor on specific capacitance and leakage current density are reported in this article. BaxSr1 –xTiO3 nanopowder for various x are synthesized using solid-state reaction method and the performance parameters of Ag/BaxSr1 –xTiO3/Ag MIM capacitors are evaluated. The mean crystallite sizes are in 20 to 60 nm range. Ba0.7Sr0.3 TiO3 ceramics show higher relative permittivity owing to its higher mean crystallite size. The insulator with higher crystallite size at dominant orientation shows enhanced leakage performance. Ba0.1 Sr0.9 TiO3 ceramic capacitor shows optimum performance altogether. [ABSTRACT FROM AUTHOR]

Various glass compositions were prepared in a glassy system [25BaCO3-(10-x) ZrO2-20TiO2-45SiO2-xCrO3] (x = 0, 2, 4, and 6) using melt-quenching technique. XRD patterns of glass and glass ceramics showed amorphous and crystalline nature. Density of glass and glass ceramics decreased from 3.4553 to 3.4381 g/cm3 and 3.7485 to 3.1977 g/cm3 with increasing concentration of CrO3. DTA of the glasses revealed a shift in base line which suggests a change in specific heat and attributed to the glass transition temperature, Tg. FTIR and Raman spectroscopic analysis indicated that an increasing doping of CrO3 changes structural network by increasing number of nonbridging oxygens (NBO) within glassy matrix. These results revealed that bands toward low frequency side endorsed to the vibration of Ba2+ metal cation, bending vibration of Si-O-Si and bonding formation of ZrO2. Concentration of CrO3, changed the microsture significantly and hence, a denser, fully developed mixed morphology was noticed with spherical grains of ZrO2, irregular shape of bazirite (BaZr0.97Ti0.03Si3O9) phase and TiO2 grains. Glass ceramic sample BZTS6C971 CrO3 (x = 6) retains high value of dielectric constant, ~4555 due to space charge polarization. Hence, these glass ceramics might be useful for diverse applications such as in optical devices, electronic circuits, and multilayer ceramic capacitors. [ABSTRACT FROM AUTHOR]

The imbalance between energy density and power density largely limits lithium-ion hybrid capacitor (Li-HEC) advance for various applications. In this work, we report on the construction of a binder-free and porous electrode, which is self-standing T-Nb2O5/graphene hybrid aerogels, as Li-intercalating pseudocapacitive electrodes of Li-HECs. The aerogels, with ultrafine T-Nb2O5 nanorods (10 ~ 40 nm) uniformly growing on the surface of graphene, feature short lithium-ion transport length, large specific surface area, 3D porous structure and good conductivity, and thus demonstrate both reversible specific capacity (~190 mAh/g at 1 C) and good rate capability (~90 mAh/g at 20 C). Most importantly, Li-HEC devices using activated graphene foam as binder-free cathode can achieve excellent energy densities (53 and 19.7 Wh/kg at power of 355 and 2009 W/kg, respectively) and remarkable cycling performance (capacitance retention of 89% after 3000 cycles), benefitting from good matching between cathode and anode as well as their fascinating microstructures. [ABSTRACT FROM AUTHOR]

Ba0.985Bi0.01Mn0.067Ti0.933O3 (BBMT) ceramic samples were prepared using solid phase and precipitation methods. The influence of preparation method on phase composition, microstructure, and dielectric properties of BBMT ceramic samples was studied. Results show that grain size of ceramic sample prepared by solid-phase method (BBMT-1) was not uniform and was larger than 1 µm. The dielectric peak at the Curie temperature was sharp and the tangent loss was large (0.067). Fine-grained ceramics (BBMT-2) with uniform grain size (∼300 nm) were prepared by precipitation, and these ceramics exhibited broadened, flattened permittivity peaks. At room temperature, BBMT-2 ceramic samples have high dielectric constant of 1280 and low dielectric loss of 0.028, and samples exhibit good stability at temperatures ranging from −60 to 110 °C. These materials have potential applications in multilayer ceramic capacitors (MLCCs). [ABSTRACT FROM AUTHOR]

The fast progress of technology has made a product's life cycle shorter and shorter. Transferring experience gained from pilot runs to mass production rapidly has thus become an important issue for enterprises. Neural networks are one of the learning models widely applied to implement this task. However, neural networks generally require a great amount of training data to establish the learning model, which is difficult to collect in the early stages of a manufacturing system. Therefore, in this paper, for cases when the collected data is insufficient, a procedure proposed by Li et al. (Li, D.C., Wu, C.S., Tsai, T.I. and Lin, Y.S. Using mega-trend-diffusion and artificial samples in small data set learning for early flexible manufacturing system scheduling knowledge. Comput. & Oper. Res., 2009, 34, 966-982), called mega-trend-diffusion, is applied to make the forecast more precise. This paper takes the multi-layer ceramic capacitor as an object of study, and applies the procedure to the pilot runs of production to create a robust model of the process to shorten the lead-time for mass production. The results reveal that it is possible to rapidly develop a model of production with limited data from pilot runs. [ABSTRACT FROM AUTHOR]

Motivated by a bottleneck operation in an MLCC (multi-layer ceramic capacitor) production line, we study the scheduling problem of parallel batch processing machines in which a number of jobs can be processed simultaneously in a machine as a batch. Volumes of the jobs are different from each other and each job belongs to the family in which all jobs have the same processing time. In this situation, we analyse three kinds of problems whose performance measures are makespan, total completion time, and total weighted completion time, respectively. Since these problems are known to be NP-hard, we propose a number of heuristics and design genetic algorithms for the problems. Through some computational experiments, we evaluate the performances of the heuristic algorithms proposed, including the genetic algorithms for each of three problems. [ABSTRACT FROM AUTHOR]

0.6PMN-0.4PZN solid solution ceramic was synthesized employing two stage columbite route using sintering temperature range 1000–1170 °C for calcination temperature 800 °C and 850 °C, respectively. XRD and SEM characterization revealed single perovskite phase formation in ceramic between 1050 °C to 1100 °C. The highest density upto 94% was achieved for the composition under study. The excellent dielectric properties were obtained at lower sintering temperature 1000–1100 °C. Ceramics sintered between 1000 °C–1100 °C exhibit εmax≈14000 and 24000 at 1 kHz with Tc = 51–48 °C which is near room temperature. A good correlation was obtained between dielectric properties with structure, microstructure and density. The TCC values within the limit of Z5U capacitor specification reflect ceramics of composition 0.6PMN-0.4PZN is a potential candidate for MLC. [ABSTRACT FROM AUTHOR]

Lead free Ba0.7Ca0.3O3 (BCT) ceramic has been synthesized by sol-gel method. Properties of ceramics are studied at sintering temperatures of 850 °C and 1050 °C. Structural Confirmation done using X-ray diffraction (XRD), diffractions patterns confirm the perovskite kind of structure without any impurity phase even at sintering of 850 °C. Surface morphology is studied using Scanning Electron Micrograph (SEM). Reduction in porosity and improvement in density detected at annealing temperature of 1050 °C. Improvement has been observed in dielectric constant and reduction in dielectric losses. Further ferroelectric property and leakage current density are studied under dielectric and electric study. [ABSTRACT FROM AUTHOR]

This work is devoted to the development of an experimental technique based on Brillouin spectroscopy for the study of aqueous suspensions of multilayer vesicles of phospholipids at different temperatures using the example of DPPC phospholipid (1,2-dipalmitoyl-sn-glycero-3-phosphocholine). The temperature dependence of the Brillouin line position is studied. A comparison of the behavior of Brillouin lines of polycrystalline ice, dry vesicles, and vesicles suspension reveals the contribution of phospholipid layers to the Brillouin spectrum. Analysis of the data makes it possible to estimate the value of sound velocity of the vesicles membranes and its temperature dependence. [AQ1] [AQ2] [ABSTRACT FROM AUTHOR]

Multilayer piezo stack based on Na0,5Bi4,5Ti4O15 was produced by tape casting slurry technology. X-ray diffraction, dielectric permittivity, piezoelectric and pyroelectric studies have been performed on the specimens. It was established that specimens have a textured structure due to the orientation of basal planes (001) plate-like grains parallel to the direction of film casting. The Curie point (Tc = 645 °C) of the obtained stacks have been determined from the temperature-frequency dependences of the dielectric permittivity and loss tangent, it is established that they have a relatively high effective piezoelectric constant (d33*= 180 pC/N) for NBT based ceramic system. In concluding it has been analyzed the prospect of the specimens in high temperature applications. [ABSTRACT FROM AUTHOR]

A grand challenge with regard to multilayer ceramic capacitor (MLCC) technology is to simultaneously increase permittivity, material break-down strength and resistivity, while reducing material dissipation loss, and temperature sensitivity of permittivity, using reasonably environmentally friendly constituents. Dipole-like substituted barium titanate (BaTiO3), Ba[(M1/20Ta1/20)Ti9/10]O3 where M is a trivalent ion, Sc3+, Cr3+, Mn3+, or Fe3+, and more complicated electric-field interaction materials, Ba[(M1/30Ta2/30)Ti9/10]O3 where M is a divalent ion, Mn2+, Ni2+, or Cu2+, are investigated as potential candidate materials for MLCC technology. Measured temperature dependent, 273 K to 1173 K, electrical conductivity of Ba[(M1/20Ta1/20) Ti9/10]O3 and Ba[(M1/30Ta2/30)Ti9/10]O3 are reported. The dipole-like substituted materials, Ba[(M1/20Ta1/20)Ti9/10]O3, possess activation energies ranging from 2.02 to 2.40 eV and are nearly independent of the M3+ ion utilized. More complicated electric-field interaction materials, Ba[(M1/30Ta2/30)Ti9/10]O3 possess activation energies ranging from 2.50 to 2.61 eV and are nearly independent of the M2+ ion utilized. The results suggest that the introduction of stronger dipole-like electric fields increase the activation energy of the matrix compared to BaTiO3. Hence, dipole-like substituted materials, Ba[(M1/20Ta1/20)Ti9/10] O3, and more complicated electric-field interaction materials, Ba[(M1/30Ta2/30) Ti9/10] O3, which can be used to significantly and controllable tailor the activation energy of BaTiO3 based materials, remain of interest for MLLC technology. [ABSTRACT FROM AUTHOR]

Ba0.70Ca0.30TiO3-(BCT),Ba(Zr0.2Ti0.8)O3-(BZT) ceramics were fabricated by conventional mixed oxide route to develop inorganic dielectric materials suitable for use as an insulator with high dielectric constant and low energy loss for capacitor applications. The structural phase transition, ferroelectric, dielectric and energy storage properties of BCT, BZT ceramic capacitors were investigated. Room temperature X-ray diffraction (XRD) patterns revealed prominent peaks corresponding to tetragonal perovskite crystal structure for both BCT, BZT solid solutions. Slim ferroelectric hysteresis (P-E) loops were observed for BCT, BZT solid solutions. Temperature dependent dielectric property measurements of BCT, BZT solid solutions have shown a high dielectric constant and low dielectric loss. Room temperature (300K) breakdown field strength and energy densities were obtained from the integral area of P-E loops. For the BCT ceramics, the largest recoverable energy (unreleased energy) density is 1.41 J/cm3with dielectric breakdown strength as high as 150 kV/cm. For the BZT ceramics, the largest recoverable energy (unreleased energy) density is 0.71 J/cm3with dielectric breakdown strength as high as 150 kV/cm. Bulk BCT, BZT ceramics have shown interesting energy densities; these might be the strong candidate materials for capacitor applications. [ABSTRACT FROM AUTHOR]

This paper presents the results of investigations of the ceramic samples of perovskite type solid solution (Pb1-xLax)(Zr1-yTiy)O3(PLZT—with x = 0.02, 0.03, 0.06 and 0.10, y = 0.9). Ceramic samples have been obtained from oxides using classical ceramic technology. The main aim of this paper is to compare the energy storage densities calculated from the P-E loops (at frequency of 1Hz) obtained as a result of integrating the area enclosed by E-P curve for tree types of ceramics—ferroelectric (PLZT with x = 0.02), slim-loop antiferroelectric (PLZT with x = 0.6, 0.10) and normal antiferroelectric with double loops (PLZT with x = 0.03). [ABSTRACT FROM AUTHOR]

In nondestructive testing Structural Health Monitoring (SHM) has become very attractive because it allows for permanent and online damage detection and characterization of structural components. SHM systems using transmission and receiving of ultrasonic waves are mainly based on piezoceramic transducers made of piezoceramic-polymer-composites. We introduce a new generation of SHM transducers which are fully based on inorganic materials showing a distinguished improve of temperature and chemical stability. Using ceramic multilayer technology piezoceramic discs are integrated into a package of low temperature cofired ceramic sheets enabling for the production of compact ultrasonic transducers with integrated electronic circuits and signal processing units. [ABSTRACT FROM AUTHOR]

The paper presents synthesis, sintering procedure, microstructure and dielectric properties of a new high permittivity perovskite material relative to Cu2Ta4O12, with the composition Bi2/3CuTa4O12. Impedance spectroscopic studies carried out at frequencies 10 Hz–2 MHz and in a temperature range –55 to 740°C revealed two dielectric responses. The high-frequency and low-temperature response was attributed to grains, and the low-frequency and high-temperature one - to grain boundaries. The high dielectric permittivity was suggested to be related to spontaneous formation of internal barrier layers at the grain boundaries of the semiconducting grains. [ABSTRACT FROM AUTHOR]

In this work, several compositions of BaTiO3 (or BT) ceramics were prepared by BT route according to the general formula Ba(Ti1-5xNb4xVx)O3. The effect of different concentrations of Nb5+ was studied by X-ray diffraction, scanning electron microscopy (SEM), Raman spectroscopy, and electrical measurements. X-ray diffraction showed all compositions to be single phase, and SEM showed that the grain size increased with Nb5+ content. Electrical measurements revealed the samples were electrically inhomogeneous. [ABSTRACT FROM AUTHOR]

The stability and electrical properties of Ni/BaTiO3(BT)/Ni capacitors were investigated for the preparation of MLCCs by the deposition method. The Ni and BT films were deposited by r.f. magnetron sputtering. The electrical resistivities of Ni films before and after annealing were 2.3 and 5.2 × 10-4 Ω-cm, respectively. The Ni electrode was completely oxidized at 650°C in an O2 atmosphere, but very stable in an Ar+H2 atmosphere and in a vacuum. The interdiffusion depth between the nickel and BT layer at 650∼800°C was 90∼100 nm. The capacitor annealed at 650°C showed a dielectric constant of 258 and a dissipation factor of 3.1% at 1 kHz. The leakage current of Ni/BT/Ni capacitors increased with the increase of the annealing temperature. The leakage current density of the capacitors annealed at 650 and 700°C was about 4.5 × 10-6 and 7 × 10-4 A/cm2 at 100 kV/cm, respectively. The Ni/BT/Ni capacitor prepared by the deposition method offers an attractive alternative for application in MLCCs with high volumetric efficiency. [ABSTRACT FROM AUTHOR]

Novel electronic devices require higher performance and miniaturization. Due to the increased demands for the high density of passive components in the mobile system, integration of passive components in the inner layers of multi-layer substrates has been actively investigated. In this paper, we studied on SrTiO3-epoxy composites thick films for embedded capacitor applications. SrTiO3-epoxy composites were employed to explore its feasibilities of embedded capacitors applications. We have investigated the frequency dependent dielectric permittivity and the temperature dependent dielectric permittivity of SrTiO3-epoxy composite thick film metal-insulator-metal (MIM) capacitors. As the amount of epoxy resin was increased, the dielectric permittivity of composites was decreased. In temperature dependent dielectric permittivity characteristics, however, the dielectric permittivity was increased with the elevated temperature. We will show and discuss the leakage current density (j) - electric field (E) characteristics of SrTiO3-epoxy composite thick films. [ABSTRACT FROM AUTHOR]

Barium titanate is used as material for many important and widely used ceramic components and devices such as high permittivity ceramic capacitors, piezoelectric ceramic transducers and thermisters with positive temperature coefficient of resistivity (PTCR) [1, 2, 3, 4]. Samples of compositions BaTi1 - xWxO3; x = 0.0, 0.15 were prepared by solid-state reaction technique using high purity oxides/carbonates. The samples were calcined at 1150°C for 2 hrs and sintered at 1200°C and 1300°C for 2 hrs. XRD diffroctgrams show that a single phase layered perovskite structure is formed in the samples. Lattice parameters and tetragonal strain (c/a) are observed to decrease in the substituted sample. Dielectric constant and dielectric loss have been measured as a function of temperature and frequency. The variations of dielectric constant (εr) with temperature at various frequencies show that the compounds undergo a diffuse type ferro—paraelectric phase transition. Curie temperature is observed to decrease from 120°C to 85°C in the tungsten substituted sample. The temperature dependence of dc conductivity of the compound have also been investigated. [ABSTRACT FROM AUTHOR]

To fulfill the demand on the miniaturization of ceramic capacitor, the approach of adding ferromagnetic particles (nickel) into ferroelectric (barium titanate) is adopted in the present study. Both bulk and multilayered (ML) specimens are prepared. For the bulk specimens, the dielectric constant reaches a value above 100, 000 as Ni content approaches its percolation threshold. The composites also offer superb ferromagnetic properties. For ML specimens with six 20-μm-dielectric layers, the capacitance can reach 120 nF. [ABSTRACT FROM AUTHOR]

To optimize the capacitance and reliability of MLCC is an important development trend of high cap. Technology. A new slurry milling process to stabilize MLCC capacitance and upgrade its quality & Reliability is developed during this investigation. The coarser powders are got well control by the milling process improvement. The optimum distribution of slurry is obtained and applied for high cap MLCC productions. According to the experimental results, the diffusion path of grain boundary is extended within the inner electrodes. The quality and reliability of high capacitance of MLCC productions are upgraded by the new milling process development. [ABSTRACT FROM AUTHOR]

BaTiO3 films were deposited by the direct vapor deposition (DVD) technique to prepare thin dielectric layers for multilayer ceramic chip capacitors (MLCCs). The BaTiO3 films were successfully prepared by co-evaporation of the BaTiO3 ceramic and Ti metal source. The films deposited at room temperature and 600°C were amorphous and crystalline phases, respectively. The intensity of (110) and (111) peaks increased as Ba/Ti ratios were close to stoichiometric composition. BaTiO3 films deposited with e-beam power of 700 W showed the deposition rate of 33 nm/min. The dielectric constant and dissipation factor of BaTiO3 films measured at 1 kHz were 150 ∼ 180 and 2 ∼ 5%, respectively. The capacitance decreased with increasing the temperature and varied only between 787pF and 752pF in the temperature range 15∼ 125°C. [ABSTRACT FROM AUTHOR]

This study conducted performance simulations for ceramic recuperators and performed thermal stress analysis to provide reliable guidance for heat recuperator designers. A numerical simulation was conducted utilizing STAR-CD to predict thermal and pressure flow fields inside two 50 W ceramic compact heat exchangers, one made of SiC and the other made of MAS. The predicted temperature and pressure profiles from performance simulations were then used to compute thermal stress analysis of the ceramic plate recuperators. Thus, three issues were discussed - the impact of fluid pressure and the thermal expansion on the ceramic recuperators, the effects of the constraint condition of the model boundary on the ceramic plates, and the different effects of the two different ceramic recuperator cores could made to the outer metal shells. [ABSTRACT FROM AUTHOR]

BaTiO3 films were deposited by the direct vapor deposition (DVD) technique to prepare thin dielectric layers for multilayer ceramic chip capacitors (MLCCs). The BaTiO3 films were successfully prepared by co-evaporation of the BaTiO3 ceramic and Ti metal source. The films deposited at room temperature and 600°C were amorphous and crystalline phases, respectively. The intensity of (110) and (111) peaks increased as Ba/Ti ratios were close to stoichiometric composition. BaTiO3 films deposited with e-beam power of 700 W showed the deposition rate of 33 nm/min. The dielectric constant and dissipation factor of BaTiO3 films measured at 1 kHz were 150∼ 180 and 2∼ 5%, respectively. The capacitance decreased with increasing the temperature and varied only between 787pF and 752pF in the temperature range 15∼ 125°C. [ABSTRACT FROM AUTHOR]

Expected lifetime and reliability of multiplayer ceramic actuators were considered. 5 × 5 × 5 mm3 sized multilayer ceramic actuators with 60 ceramic sheet layers embedded internal electrodes were selected in this experimental analysis. Specially selected rectified AC bias was applied to the multilayer ceramic actuators to remove heating during charging and discharging process. 16 sets of multilayer ceramic actuators were tested for statistical analysis. Weibull function method was employed to calculate mean time to failure. Arrhenius model and power law model were considered to simulate experimental data. From the experimental data and theoretical consideration, equation of expected lifetime was estimated. [ABSTRACT FROM AUTHOR]

The solid solutions of La modified xPb(Mg1/3Nb2/3)-(1-x)Pb(Zr0.55Ti0.45)O3 ceramic system are synthesized by columbite precursor method and characterized for phase formation, microstructure, dielectric and relaxor studies. Powder X-ray diffraction patterns indicate pseudocubic phase of compositions on PMN-PZT system phase diagram. La doping in PMN-PZT system inhibited grain growth while increasing grain size with PMN concentration. Density of the ceramics is increased to 1.5 mole% La doped PMN-PZT compositions and decreased with the increment of PMN concentration. εRT and Tanδ are increased to 1.5 mole% La doped PMN-PZT compositions while εTc and Tc are decreased with La modification in PMN-PZT system. Pure and La modified 0.8PMN-0.2PZT compositions have shown the most promising relaxor behavior applicable to multilayer capacitor (MLC) applications. [ABSTRACT FROM AUTHOR]

Tunable ferroelectric ceramic capacitors have shown great promise in reducing the size, weight, and power (SWAP) of traditional varactor-based devices. Ferroelectric devices fabricated from Barium Strontium Titanate (BST) have been demonstrated in the laboratory and are just now becoming available for commercial narrowband applications. This paper presents some of the tradeoffs in designing a small form factor (SFF), easily manufacturable, broadband tunable filter utilizing high volume, low-cost BST devices. Development status for filters that cover the 225 MHz to 2.7 GHz frequency range with superior narrowband performance, low in-band insertion loss, and high out-of-band rejection that is directly applicable to the stringent requirements of Joint Tactical Radio System (JTRS) Cluster 5 Software Defined Radio (SDR) is also presented. These Manufacturing Readiness Level (MRL) 4 filters currently provide a 50% reduction in size over traditional approaches, and future short-term plans promise further reductions in unit production cost (UPC) and SWAP. [ABSTRACT FROM AUTHOR]

We have explored the switching in ferroelectric capacitors of PZT over the range in lateral area, from A > 100 to 0.19 μ m 2 , and over several orders of magnitude in ramp rate of applied field. We found that the LYD model fits PZT capacitors of size 166 μ m 2 , and implies an activation field α of 622 ± 20 kV/cm. However, nano-cell capacitors of areas 0.32 and 0.19 μ m 2 conform with the PK theory, in which nucleation and domain movement are both important. Fringing field effects due to mesa-structured capacitors gives the excess capacitance satisfies an empirical correction formula of Δ C / C = L -0.36 , particularly as the aspect ratio increases. [ABSTRACT FROM AUTHOR]

Internal stresses are calculated in multilayer capacitors due to applied electric fields via axial displacement compatibility relationships. Closed-form solutions are used to depict approximate levels of stresses in the active and margin regions of multilayer ceramic capacitors (MLCs) due to applied DC voltages. Normal strains and shear strains are superimposed in order to calculate the approximate internal electromechanical stresses. Principal stresses are determined in the margin region and active regions. Corrections are made for lateral restraint and shearing strains. [ABSTRACT FROM AUTHOR]

Multilayer ceramic capacitors (MLCCs) are widely used in consumer electronics. The compact design of the MLCC in high-speed printed circuit board assembly makes it the major form of capacitor design. Yield improvement is the most challenging part of MLCC manufacturing in view of its processing complexity, particularly in the paste screen-printing process. Industrial reports have shown that the yield loss for fine-pitch MLCCs could be as high as 40% and screen-printing quality problems could represent about 80% of yield loss. Thus, paste screen-printing quality is critical if an MLCC firm is to gain a competitive edge. This paper reports on the use of the Taguchi method to improve screen-printing quality for fine-pitch MLCCs. Empirical results demonstrate a significant improvement in printing quality and point to a successful application of this process. [ABSTRACT FROM AUTHOR]

The article focuses on SPARK Award projects funded by the Materials KTN's powders sector. A die filling and tooling design concepts were developed by Magnet Applications Ltd. and Powder Pressing Tools Ltd. Multilayer Ceramic Capacitors were manufactured by Syfer Technology Ltd. for the automotive, medial and defence sectors. A study for Bodycote Metallurgical Coatings Ltd. found that thermal spraying techniques are key to the development of low cost manufacturing solutions.