Electroceramics Research Papers - Academia.edu (original) (raw)

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- by
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- Materials Engineering, Materials Science, X Rays, Electroceramics

Embedded resistor circuits have been generated with the use of a Micropen system, Ag conductor paste (DuPont 6142D), a new experimental resistor ink from DuPont (E84005-140), and Low Temperature Co-fired Ceramic (LTCC) green tape (DuPont A951). Sample circuits were processed under varying peak temperature ranges (835°C–875°C) and peak soak times (10 min–720 min). Resistors were characterized by SEM, TEM, EDS, and high-temperature XRD. Results indicate that devitrification of resistor glass phase to Celcian, Hexacelcian, and a Zinc-silicate phase occurred in the firing ranges used (835–875°C) but kinetics of divitrification vary substantially over this temperature range. The resistor material appears structurally and chemically compatible with the LTCC. RuO2 grains do not significantly react with the devitrifying matrix material during processing. RuO2 grains coarsen significantly with extended time and temperature and the electrical properties appear to be strongly affected by the change in RuO2 grain size.

- by Mark Rodriguez
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- Materials Engineering, Kinetics, Electroceramics, Zinc
- by Beihai Ma
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- Materials Engineering, Electroceramics

Recent progress in the development of a ß-alumina gas sensor for automotive applications is reported. The sensing device consists of two solid electrolytes (namely a thin film of sodium sulfate deposited on ß-alumina by appropriate treatment in a gaseous atmosphere), with two electrodes having different catalytic properties, one made of platinum, the other of gold. The ß-alumina component was prepared

- by Laura Montanaro
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- Materials Engineering, Electroceramics, Thin Film, Screen printing
- by Shoufeng Yang and +1
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- Materials Engineering, Scanning Probe Microscopy, Electroceramics, Dielectric Properties
- by Laura Montanaro
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- Materials Engineering, Electroceramics, Viscosity, Screen printing
- by El Mostafa Bourim
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- Materials Engineering, Field emission, Electroceramics, Single Crystal

The frequency dependence of the elasto–piezo–dielectric constants of piezoelectric materials is usually neglected. By means of a new procedure of piezoelectric characterization based on the characterization in the overtones of resonant modes we can measure accurately the constants involved in the piezoelectric behaviour of the materials in a wide range of frequencies.
The characterization in the overtones of resonant modes is possible by using an automatic iterative method, described below, that takes account of the number of the overtone to obtain the appropriate solution of the equation system. The
proposed procedure has been checked for the radial resonances in materials that exhibit very different behaviour and very good agreement is obtained in all the overtones not overlapped with the thickness extensional mode of resonance.

- by Amador M González
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- Electroceramics, Piezoelectric Materials
- by Igor Lubomirsky and +1
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- Materials Engineering, Electroceramics, Phase transition, Mechanical Stress

Lithiated layered transitional metal oxide materials of the LiMO2 type and especially LiCoO2 presents interesting specific properties as high energy density, long cycle life and constant discharging properties in a wide range of working conditions as well as a good safety. These properties made these materials excellent candidates as active compounds for high capacity cathode materials for rechargeable lithium batteries. LiCoO2 is the most common lithium storage material for lithium rechargeable batteries, used widely to power portable electronic devices. Operation of lithium rechargeable batteries is dependent on reversible lithium insertion and extraction processes into and from the host materials of lithium storage. In this study, LiCoO2 thin films were prepared by the sol–gel spin coating technique using metal acetate and citric acid as starting materials. Citric acid acts as a chelating agent, which promotes the preliminary reaction between lithium and cobalt and suppresses the precipitation of acetates. The sol–gel method is well known as one of promising thin-film preparation methods, which has good advantages such as low fabrication cost, relatively easy stoichiometry control, high deposition rate and also known as a low-temperature synthesis method for various ceramics. In addition, the crystal phases involved in the thin film can also be controlled by changing the chemical compositions of the sol. The crystallinity, microstructure and electrochemical properties of final films are also studied by XRD, SEM, AFM and galvanostatic charge/discharge cycling test. Films heat-treated under appropriate conditions exhibit high capacity and good crystallinity so those films are considered to be candidates as cathodes for thin-film micro batteries.

- by Uwe Heisel and +1
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- Materials Engineering, Ultrasound, Low Frequency, Electroceramics
- by Woo Choi
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- Materials Engineering, Low Frequency, Energy Harvesting, Power Generation

Abstract An attempt was made to improve the conventional lamination process in the multilayered ceramic capacitors (MLCCs) fabrication by adapting a solvent treatment on the BaTiO 3 green sheets. During the lamination process, additional... more

- by Sangkyu Lee
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- Materials Engineering, Electroceramics, Dielectric Properties, Microstructures
- by J. Juuti
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- Materials Engineering, Electroceramics, Dielectric Constant, Piezoelectric Actuator

Low cost anode materials having a high electrochemical efficiency have been critical in the success of thin film batteries that are applicable in ubiquitous environments as a portable energy source. Nichrome thin films are ideally suited for use in hybrid assemblies but their applications include precision integrated circuits in fields of telecommunications, instrumentation, power supplies, military and medical equipment where low noise and good power dissipation are required. With such a wide spectrum of applications, it is important to understand the electric behavior of the Nichrome alloy thin films by their microstructure. In this work, nanocrystalline films of nickel chromium alloys were deposited on alumina substrate by radio frequency (RF) magnetron sputtering technology. High purity nickel and chromium sputtering target were used for the deposition. First, aluminum was deposited on ceramic substrate acts as a current collector and over that NiCr was deposited by RF sputtering method. Both the layers were analyzed for structural and electrical properties using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and cyclic voltammetry. The XRD peak confirms that deposited NiCr and Aluminum have tetragonal and cubic structures, respectively. The crystallite size was determined by full width at half maximum of XRD peaks. Structure, composition and the properties of the film are the major focus of this paper. Composition ratio between nickel and chrome obtained by EDS is 1:1. Particle size and microstructure of the film have been studied by SEM and AFM. Electrochemical properties of the films were analyzed. Reaction mechanism for the insertion and excretion is reported. After Lithium insertion and extraction the effect on the surface and structure of the thin film has been studied. The composition of equilibrium phases of NiCr as useful as attracting anode for the thin film battery. Nichrome on aluminum thin films as an anode has been attracted because it provides practical advantages including low cost production and competitive electrical performance.

- by Jay Patil
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- Materials Engineering, Electroceramics
- by jerry lin
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- Materials Engineering, Electroceramics, Grain Growth, Dielectric Properties
- by Kimberly Cook-chennault and +1
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- Materials Engineering, Composite Materials and Structures, Composite Materials, Electroceramics
- by Mohsen Shahini
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- Materials Engineering, Modal Analysis, Finite Element, Electroceramics
- by Ludwig J Gauckler
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- Materials Engineering, Solar Cell, Thin Films, Electroceramics
- by Jens M Hovem
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- Materials Engineering, Underwater Acoustics, Ultrasound, Electromagnetic Waves
- by Neil White
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- Materials Engineering, Elastic waves, Electroceramics, Screen printing
- by Daniel Guyomar and +1
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- Electrical Engineering, Materials Engineering, Mechanical Engineering, Renewable Energy
- by Kunal Karan
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- Materials Engineering, Performance, Scanning Electron Microscopy, Density
- by Ludwig J Gauckler
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- Materials Engineering, Kinetics, Modeling, Impedance Spectroscopy
- by Matias Acosta
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- Materials Engineering, Electroceramics

Tin dioxide is a widely used sensitive material for gas sensors. Many research and development groups in academia and industry are contributing to the increase of (basic) knowledge/(applied) know-how. However, from a systematic point of view the knowledge gaining process seems not to be coherent. One reason is the lack of a general applicable model which combines the basic principles with measurable sensor parameters. The approach in the presented work is to provide a frame model that deals with all contributions involved in conduction within a real world sensor. For doing so, one starts with identifying the different building blocks of a sensor. Afterwards their main inputs are analyzed in combination with the gas reaction involved in sensing. At the end, the contributions are summarized together with their interactions. The work presented here is one step towards a general applicable model for real world gas sensors.

- by Piotr Jasinski
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- Materials Engineering, Electroceramics, Lattice Parameter, Structural Properties
- by jose varela
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- Engineering, Materials Engineering, Mechanical Engineering, Materials Science
- by Hans-Peter Buchkremer
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- Materials Engineering, Electroceramics, Microstructures, Power Density
- by Kenji Uchino
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- Materials Engineering, Electroceramics, Piezoelectric Actuator
- by K. Astafiev
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- Materials Engineering, Electroceramics, Thin Film, Dielectric Loss
- by Marielle Eyraud
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- Materials Engineering, Atomic Force Microscopy, Copper, Electroceramics
- by Scott Swartz
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- Materials Engineering, Electroceramics, BARIUM TITANATE, Grain Growth

- by Changki Mo
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- Materials Engineering, Finite Element, Energy Harvesting, Finite Element Analysis

Highly c-axis-oriented zinc oxide (ZnO) thin films were deposited on Au electrodes by reactive radio frequency (RF) magnetron sputtering and their sputtering pressure on thin film bulk acoustic-wave resonator (FBAR) characteristics are presented. The evolution of the preferred orientation and the surface morphologies of the deposited ZnO films are investigated using X-ray diffraction, scanning electron microscopy, and atomic force microscopy measurement techniques. The result obtained in this study show that the ZnO films prepared using a lower sputtering pressure of 2 × 10−3 Torr have a strong c-axis orientation, promote smoother surface and higher resonance frequency. The experimental results demonstrate that the fabricated two-port FBAR using the optimum process parameters yields an effective electromechanical coupling constant ( $ k^{2}_{{{\text{eff}}}} $ ) of 2.8%, series quality factor (Q s) of 436, and a parallel quality factor (Q p) of 600.

- by Po-Hsun Sung
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- Materials Engineering, Electroceramics
- by Sukanda Jiansirisomboon
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- Materials Engineering, Electroceramics, Grain size, Frequency Dependence
- by 영준 신
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- Materials Engineering, Electroceramics, Thin Film, Radio Frequency

Ferroelectric ceramics, SrBi2Nb2O9 (SBN), Sr0.8Cu0.2Bi2Nb2O9 (SCBN) and Sr0.8K0.1Na0.1Bi2Nb2O9 (SKNBN) were prepared by a solid state reaction process. X-ray diffraction analysis shows that the alkali and Cu almost diffuse into the SBN lattice to form a solid solution during sintering and some slight secondary phases was detected. The effect of alkali and Cu on dielectric properties of the SBN ceramics was discussed. The dielectric loss factor of (K,Na) doped SBN ceramics degraded considerably to 0.01 and their frequency and temperature stabilities were enhanced. The dielectric constant was enhanced by approximately 60% and the Curie temperature (Tc) was also improved for Cu doped SrBi2Nb2O9 ceramics.

- by laijun liu
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- Materials Engineering, Electroceramics
- by Matias Acosta
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- Materials Engineering, Electroceramics

Page 1. Tactile tissue characterisation by piezoelectric systems Ralf Stroop & David Oliva Uribe & Melisa Orta Martinez & Michael Brökelmann & Tobias Hemsel & Jörg Wallaschek Received: 1 December... more

- by Tobias Hemsel and +2
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- Materials Engineering, Electroceramics, Pressure Sensor, High Sensitivity

This paper presents synthesis of calcium cobaltites of the nominal composition of Ca3Co4O9 prepared by the solid state reaction. The reaction between CaCO3 and Co3O4 was investigated at 700–900 °C during 20 h and at 800 °C during 2–30 h. Mass changes, phase composition and Co+3, Co+4 content were examined. Stability of the calcined specimens was tested by DTA/TG. It was found that two phases: Ca3Co4O9 and Ca3Co2O6 were present as a result of calcinations above 800 °C. On the other hand, the temperature of 750 °C was too low for calcium cobaltites to be synthesized. Mono-phase material with Ca3Co4O9 phase was obtained after calcinations at 800 °C but non-stoichiometry of the compound and its relation to the calcinations time were found. Once synthesized, the compound was stable up to 900 °C.

- by Karolina Kozłowska
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- Materials Engineering, Electroceramics, Low Temperature, Solid State Reaction

Application of ultrasonic waves has been considerably progressed during the last decade and piezoelectric ceramics have had a common use as the driving source of such waves. However, there is not enough documented information on design and technology of manufacturing a high power ultrasonic transducer. In this paper, an attempt has been made to analyze the stress produced along the oscillating PZT employed ultrasonic head by applying the principles of acoustic wave propagation. Then, based on such analysis, general principles of PZT transducer design, excited by a DC-biased alternating electrical source, has been derived and finally a typical such transducer has been designed, manufactured and tested. By employing finite element modal analysis, the resonance frequency of the transducer was determined and compared with the experimental results. It was concluded that, the constitutive piezoelectric equations referred to in most sources and books are not valid for analyzing the acoustical dynamic stress in ultrasonic transducers. Instead, the analysis should be done with considering the dynamic behavior (elastic, damping and Inertia factors) of the problem.

- by Amir Abdullah
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- Materials Engineering, Modal Analysis, Finite Element, Electroceramics
- by Katherine Kirk
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- Materials Engineering, Ultrasonic, Electroceramics
- by Ali Hussain
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- Materials Engineering, Electroceramics