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Temperature Applications (temperature + application)
Kinds of Temperature Applications Selected AbstractsOutstanding Ceramic Matrix Composites for High Temperature ApplicationsADVANCED ENGINEERING MATERIALS, Issue 3 2005L. Vandenbulcke Accurate deposition of boron and silicon carbides and nitrides permits to improve the oxidation resistance of self-healing matrices of multilayered composites. The uniformity and the microstructure of each layer and of their interfaces induce the final properties of these composites. Their mechanical behaviour in conditions very close to the applications in the energy, space and aeronautic domains, allows to demonstrate the breakthrough enabled by this new composite generation. [source] Microstructure and Properties of an HfB2 -SiC Composite for Ultra High Temperature Applications,ADVANCED ENGINEERING MATERIALS, Issue 5 2004F. Monteverde An ultra-high-temperature ceramic (UHTC) based on HfB2 was produced. The microstructure consisted of fine and regular diboride grains (2 ,m average size), with SiC particulate distributed intergranularly, not rarely in clustered formation, and low levels of secondary phases were identified. The resulting thermo-mechanical properties proved interesting results for microhardness and fracture toughness. The microstructural alteration experienced within the explored temperature range renders the material unsuitable for service in extreme conditions of temperature and pressure. [source] Novel Composites Constituted from Hafnia and a Polymer-Derived Ceramic as an Interface: Phase for Severe Ultrahigh Temperature ApplicationsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2007Sudhir Brahmandam HfO2,SiCN (polymer-derived silicon carbonitride) composites were prepared by two methods. In one case, equal volume fractions of HfO2 and pyrolyzed powders of SiCN were co-sintered, to create a particulate composite. The second type, called interface composites, were prepared by coating HfO2 particles with a thin film of the polymer precursor, followed by sintering so that densification and pyrolysis of the precursor occurred simultaneously; this process results in a ,5-nm-thick grain boundary film constituted from Hf, O, and Si. The fracture properties and environmental degradation (in a humid environment at a velocity of 17.6,35.0 cm/s at 1300°C) of these two composites were measured. They were compared with the properties of a reference material made by sintering HfO2 powders without any additives, under similar conditions (1450°C for 2 h in air). The interface composite yielded the highest sintered density (0.90), exhibited negligible grain growth, and possessed the highest fracture strength (110 MPa). The strength remained immune to hydrothermal oxidation for several hundred hours. In contrast, the particulate composite suffered severe degradation in strength after hydrothermal exposure. The interface composites, with their highly refractory grain boundaries, represent a new class of ceramics for structural applications in harsh environments and at ultrahigh temperatures. [source] Protective Systems for High Temperature Applications: From Theory to Industrial ImplementationMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 5 2008Michael Schütze [source] Effect of mating surface on the high temperature wear of 253 MA alloyMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 4 2004M. Roy Abstract The wear behaviour of metallic material is influenced by the friction force, which in turn, is governed by the hardness and oxidation kinetics of the mating surface. In view of this, present investigation is undertaken to find the influence of mating surface on the high temperature wear of 253 MA alloy. This alloy is developed for high temperature application. In this work 253 MA alloy is made to slide against two different types of counter face material, namely 100Cr6 steel and PM 1000 alloy, at five different temperatures. 100Cr6 steel gets soften with increase of temperature whereas PM 1000 alloy retains its strength even at high temperature. The friction coefficient and the thickness loss of 253 MA alloy is measured and compared against both variety of mating surfaces as function of temperatures. The morphology of the worn surfaces and the transverse section of the worn surfaces are examined under scanning electron microscope (SEM) to identify the material removal mechanisms. The results showed that the friction coefficient of test material against PM 1000 alloy is around 40% higher than the friction coefficient against 100Cr6 steel. The transverse section of the worn surface showed presence of a transfer layer, mechanically mixed layer and composite layer, which govern the wear behaviour particularly at elevated temperature. The chemical characteristics of these layers are dependent on the test temperature and the counter face material. [source] On the Design of High-Efficiency Thermoelectric Clathrates through a Systematic Cross-Substitution of Framework ElementsADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Xun Shi Abstract Type I clathrates have recently been identified as prospective thermoelectric materials for power generation purposes due to their very low lattice thermal conductivity values. The maximum thermoelectric figure of merit of almost all type I clathrates is, however, less than 1 and occurs at, or above, 1000,K, making them unfavorable especially for intermediate temperature applications. In this report, the Zintl,Klemm rule is demonstrated to be valid for Ni, Cu, and Zn transition metal substitution in the framework of type I clathrates and offers many degrees of freedom for material modification, design, and optimization. The cross-substitution of framework elements introduces ionized impurities and lattice defects into these materials, which optimize the scattering of charge carriers by the substitution-induced ionized impurities and the scattering of heat-carrying lattice phonons by point defects, respectively, leading to an enhanced power factor, reduced lattice thermal conductivity, and therefore improved thermoelectric figure of merit. Most importantly, the bandgap of these materials can be tuned between 0.1 and 0.5,eV by adjusting the cross-substitution ratio of framework elements, making it possible to design clathrates with excellent thermoelectric properties between 500 and 1000,K. [source] Linear all-fiber temperature sensor based on macro-bent erbium doped fiberLASER PHYSICS LETTERS, Issue 10 2010P. Hajireza Abstract A new all fiber temperature sensor is proposed and demonstrated based on a pair of 1 meter erbium-doped fiber (EDF), which are respectively macro-bent and straight. The sensor has a linear normalized loss (dB) response to temperature at 6.5 mm bending radius and 1580 nm input wavelength. The main advantage of this sensor is high temperature resolution (less than 1 °C) and sensitivity (0.03 dB/°C) due to combination of temperature dependence of EDF and bending loss. The proposed silica based sensor, has the potential for wide range and high temperature applications in harsh environments. (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Investigation of top gate electrode options for high-k gate dielectric MOS capacitorsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2008D. C. Moschou Abstract Capacitors with a high-k HfO2 film as gate dielectric were fabricated, using three different variations for the top gate electrode. This way it was possible to acquire important information on which kind of gate material should be used in combination with HfO2 as a gate insulator for optimum performance of possible low temperature applications, such as high-k TFTs. The variations of gate electrode were e-gun evaporated Al, sputtered W and CVD polysilicon followed by ion implantation and annealing. The capacitors were then characterized with capacitance-voltage measurements and current-voltage measurements. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Impression creep of PMR-15 resin at elevated temperaturesPOLYMER ENGINEERING & SCIENCE, Issue 1 2010Rong Chen The polyimides formed from the polymerization of monomeric-reactants (PMR) approach have been increasingly used as matrix materials in fiber-reinforced composites on aerospace and space structures for high temperature applications. The performance of PMR-based structures depends on the mechanical durability of PMR resins at elevated temperatures, including creep and stress relaxation. In this work, the creep behavior of PMR-15 resin was studied using the impression technique in the temperature range of 563,613 K and the punching stress range of 76,381 MPa. It was found that there existed a steady state creep for the creep tests performed at temperatures of 563 K and higher, from which a constant impression velocity was calculated. The steady state impression velocity increased with temperature and punching stress with the stress exponent in the range of 1.5,2.2. The average of the apparent activation energy of the PMR-15 was calculated as 122.7 ± 6.1 kJ/mol. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source] Fuel Cells, Advanced Reactors and Smart Catalysis: The Exploitation of Ceramic Ion-Conducting MembranesCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 8 2003I.S. Metcalfe Abstract Membrane reactors are of great interest in the chemical industries because they offer the possibility of improved yields, improved selectivities and more compact plant. However, a significant barrier to their uptake is the unavailability of membrane systems having the required performance at an acceptable cost. In this paper we will explore the use of one class of membrane that has the potential to deliver high performance at reasonable cost. Ion-conducting ceramic membranes can be used in a wide range of high temperature applications including fuel cells, advanced reactors and even smart catalytic systems. [source] | |||||||||||||