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Ceramic Substrates (ceramic + substrate)
Selected AbstractsInfluence of a Ceramic Substrate on Aqueous Precipitation and Structural Evolution of Alumina Nano-Crystalline CoatingsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2007Marie Mahé Either boehmite (,-AlOOH) or gibbsite (,-Al(OH)3) nanocrystalline thin films (h,100 nm) can be precipitated from AlCl3 solution at fixed pH and temperature onto different substrates. It depends on the nature of the substrate (mica flakes, SiO2 flakes, or ,-Al2O3 flakes), on their crystallographic properties (crystalline or amorphous), and on some experimental parameters (agitation rate, addition rate). According to the surface charge of the substrates, different alumina species are involved in the precipitation process. When negative charges are present on the substrate, the [Al3O(OH)3(OH2)9]4+ polycation is promoted, leading to the formation of the (Al4) tetramer ([Al4O(OH)10(OH2)5]o) and then to the precipitation of bohemite. When positive charges are present, a ligand bridge containing complex ([Al3O(OH)3(O2H3)3(OH2)9]+) is likely favored, giving rise to hexagonal ring structures or amorphous solids that lead to the formation of gibbsite. Besides the surface effects, crystalline substrates can act as a template during precipitation of aluminum species as shown for the formation of gibbsite on muscovite. Finally, calcination at 850°C of boehmite samples leads to porous ,-Al2O3 layers, while calcination of gibbsite leads to ,-Al2O3 layers. [source] Conductive Polymer Coating on Nonconductive Ceramic Substrates for Use in the Electrophoretic Deposition ProcessJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2008Tetsuo Uchikoshi Uniform coating and line patterning of a conductive polypyrrole (Ppy) film on nonconductive ceramic materials were performed for use as substrates in the electrophoretic deposition (EPD) process. The Ppy was synthesized by chemical oxidation in the pyrrole solution. Direct shaping or line patterning of alumina or zirconia particles by EPD was carried out using the Ppy films as cathodes. [source] Development and Simulation of an Embedded Hydrogen Peroxide Catalyst Chamber in Low-Temperature Co-Fired CeramicsINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 5 2007Donald Plumlee Satellites in the range of 10,50 kg require small propulsion devices to perform station-keeping tasks in orbit. Low-temperature co-fired ceramic structures provide a unique platform to produce a reliable, low-cost micropropulsion system. The design uses microchannels embedded in the ceramic substrate to create a nozzle and embedded catalyst chamber. A hydrogen peroxide monopropellant is injected into a silver-coated catalyst chamber structure. The monopropellant decomposes into hot gas, which is expelled through the nozzle producing thrust. A thermal energy balance and a kinetic model is presented along with performance testing. [source] Lost Mold Rapid Infiltration Forming of Mesoscale Ceramics: Part 1, FabricationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2009Nicholas E. Antolino Free-standing mesoscale (340 ,m × 30 ,m × 20 ,m) bend bars with an aspect ratio over 15:1 and an edge resolution as fine as a single grain diameter (,400 nm) have been fabricated in large numbers on refractory ceramic substrates by combining a novel powder processing approach with photoresist molds and an innovative lost-mold thermal process. The colloid and interfacial chemistry of the nanoscale zirconia particulates has been modeled and used to prepare highly concentrated suspensions. Engineering solutions to challenges in mold fabrication and casting have yielded free-standing, crack-free parts. Molds are fabricated using high-aspect-ratio photoresist on ceramic substrates. Green parts are formed using a rapid infiltration method that exploits the shear thinning behavior of the highly concentrated ceramic suspension in combination with gelcasting. The mold is thermally decomposed and the parts are sintered in place on the ceramic substrate. Chemically aided attrition milling disperses and concentrates the as-received 3Y-TZP powder to produce a dense, fine-grained sintered microstructure. Initial three-point bend strength data are comparable to that of conventional zirconia; however, geometric irregularities (e.g., trapezoidal cross sections) are present in this first generation and are discussed with respect to the distribution of bend strength. [source] Preparation of Ceramic Well Plates for Combinatorial Methods Using the Morphogenic Effects of Droplet DryingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2006Yong Zhang When droplets of a ceramic suspension dry on a non-wetting substrate, powder migrates to the periphery and builds there a wall of powder. This intriguing phenomenon, which is a nuisance in some processes, can be used to make arrays of ceramic wells on a ceramic substrate. These wells can, after sintering, be used to hold ceramic samples made from powder by controlled mixing of ceramic inks or could be made from ceramics that act as heterogeneous catalysts and used to hold reactants. The well plates can even be made from electrically conducting ceramics so that electrical property measurements can be made with a ground electrode. [source] Microwave Bandgap in Multilayer Ceramic StructuresJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2006Bo Li A multilayer ceramic structure with a photonic bandgap (MC-PBG) was fabricated by a method of tape casting combined with screen printing. The MC-PBG structure is a two-dimensional array with either rectangular or hexagonal metal coils in a ceramic matrix. The metal coils are connected to the base metal layer in the ceramic substrate to form a monolithic body. The surface-wave dispersion properties of these MC-PBG structures were measured. A stop band, which is significantly influenced by the symmetrical characteristics of the inductor,capacitor (LC) arrays, was found in both the structures in the frequency range of 2.0,3.5 GHz. Because of their effective surface-wave suppression, MC-PBG structures can be used as high-performance antenna substrates to enhance the broadside gain of patch antenna devices. [source] Microstrip ring resonator bandpass filters using ceramic substrateMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2010Yuan-Bin Chen Abstract The miniaturization of ring bandpass filters by employing high-permittivity ceramic substrates (with respective dielectric constants of 9.7 and 23.5) are investigated. Microwave dielectric ceramics with high permittivity are commonly applied in several microwave communication components. With the advantages of compact size, high-permittivity ceramics can be used as the substrate for bandpass filters. Moreover, the fundamental characteristics of newly developed compact square-ring resonators have also been described and applied to the design of bandpass filters. In this paper, the designed square-ring resonators structures are simulated using an IE3D simulator. The responses of the fabricated bandpass filters using Al2O3 (,r = 9.7, tan , = 0.000036) and 0.875Mg0.95Zn0.05TiO3 -0.125Ca0.8Sm0.4/3TiO3 (,r = 23.5, tan , = 0.000021) ceramic substrates are designed at the center frequency of 2.4 GHz. This compact size, low loss bandpass filter should be useful in many wireless communication systems. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 218,220, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24847 [source] Nanosized Glass Frit as an Adhesion Promoter for Ink-Jet Printed Conductive Patterns on Glass Substrates Annealed at High Temperatures,ADVANCED FUNCTIONAL MATERIALS, Issue 19 2008Daehwan Jang Abstract Ink-jet printed metal nanoparticle films have been shown to anneal at high temperatures (above 500,°C) to highly conductive metal films on glass or ceramic substrates, but they suffer from cracking and inadequate substrate adhesion. Here, we report printable conductive materials, with added nanosized glass frit that can be annealed at 500,°C to form a crack-free dense microstructure that adheres well to glass substrates. This overcomes the previous challenges while still retaining the desired high film conductivity. Controlling the particle characteristics and dispersion behavior plays an important role in successfully incorporating the glass frit into the conductive inks. [source] Lost Mold Rapid Infiltration Forming of Mesoscale Ceramics: Part 1, FabricationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2009Nicholas E. Antolino Free-standing mesoscale (340 ,m × 30 ,m × 20 ,m) bend bars with an aspect ratio over 15:1 and an edge resolution as fine as a single grain diameter (,400 nm) have been fabricated in large numbers on refractory ceramic substrates by combining a novel powder processing approach with photoresist molds and an innovative lost-mold thermal process. The colloid and interfacial chemistry of the nanoscale zirconia particulates has been modeled and used to prepare highly concentrated suspensions. Engineering solutions to challenges in mold fabrication and casting have yielded free-standing, crack-free parts. Molds are fabricated using high-aspect-ratio photoresist on ceramic substrates. Green parts are formed using a rapid infiltration method that exploits the shear thinning behavior of the highly concentrated ceramic suspension in combination with gelcasting. The mold is thermally decomposed and the parts are sintered in place on the ceramic substrate. Chemically aided attrition milling disperses and concentrates the as-received 3Y-TZP powder to produce a dense, fine-grained sintered microstructure. Initial three-point bend strength data are comparable to that of conventional zirconia; however, geometric irregularities (e.g., trapezoidal cross sections) are present in this first generation and are discussed with respect to the distribution of bend strength. [source] Microstrip ring resonator bandpass filters using ceramic substrateMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2010Yuan-Bin Chen Abstract The miniaturization of ring bandpass filters by employing high-permittivity ceramic substrates (with respective dielectric constants of 9.7 and 23.5) are investigated. Microwave dielectric ceramics with high permittivity are commonly applied in several microwave communication components. With the advantages of compact size, high-permittivity ceramics can be used as the substrate for bandpass filters. Moreover, the fundamental characteristics of newly developed compact square-ring resonators have also been described and applied to the design of bandpass filters. In this paper, the designed square-ring resonators structures are simulated using an IE3D simulator. The responses of the fabricated bandpass filters using Al2O3 (,r = 9.7, tan , = 0.000036) and 0.875Mg0.95Zn0.05TiO3 -0.125Ca0.8Sm0.4/3TiO3 (,r = 23.5, tan , = 0.000021) ceramic substrates are designed at the center frequency of 2.4 GHz. This compact size, low loss bandpass filter should be useful in many wireless communication systems. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 218,220, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24847 [source] Design a new structure 2.4 GHz/5.2 GHz dual-band bandpass filters on the MgTa1.5Nb0.5O6 ceramicMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2009Cheng-Fu Yang Abstract In this article, a ,/2 U-shaped hairpin resonator was contained in a modified end-coupled microstrip line. The increase of the sizes of U-shaped hairpin resonator and modified end-coupled microstrip line had no influence on the lower operating frequency and would shift the upper operating frequency to lower values. After finding the best designed parameters, a miniature dual-band microstrip bandpass filter with three transmission zeros generated in the stop-bands was developed on the MgTa1.5Nb0.5O6 microwave dielectric ceramic substrates. The dual-band filter had the central frequencies of 2.45 and 5.2 GHz and was suitable for the applications in the modern WLAN communication. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1085,1087, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24264 [source] Structural, optical, and electrical characterizations of epitaxial lifted-off InGaAs/InAlAs metamorphic heterostructures bonded on AlN ceramic substratesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2008Y. Jeong Abstract We investigated epitaxial lift-off (ELO) of In0.57Ga0.43As/In0.56Al0.44As metamorphic high electron mobility heterostructures and their van der Waals bonding (VWB) on AlN ceramic substrates. Structural, optical, and electrical characterizations were carried out for samples obtained by ELO and VWB, in comparison with on-wafer counterparts before ELO. We confirmed a strain release after ELO and VWB from xray diffraction, and observed a consequent photoluminescence energy shift. The ELO samples exhibit very high electron mobilities owing to the high indium contents and successful ELO and VWB processes. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Fabrication of multilayer ceramic membranesASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009V.V. Zyryanov Abstract The development of multilayer mixed conducting oxide membranes on macroporous dead-end tubular composite glass/ceramic substrates is presented. Sol modification of glass/ceramic substrate enhances the performance of catalytic membrane reactor (CMR) with reduced thickness of ceramic layers. The shrinkage misfit between support and ceramic layers can be regulated by different processing steps including sol modification of substrate and preliminary annealing of ceramic powders. Nanopowders of compatible complex perovskites as membrane materials were obtained by mechanochemical synthesis. Porous and dense ceramic layers were supported onto the internal wall of substrate by slip casting of slurries comprised of the narrow fractions of agglomerated powders dispersed in organic media with addition of surfactants. For SrFeO3 -based dense perovskite ceramics, both dynamics of oxygen loss at high temperatures and mechanical properties were found to be affected by the presence of SrSO4 surface inclusions formed due to sulfur admixture in starting reactants. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. 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