Ceramic Compounds (ceramic + compound)

Distribution by Scientific Domains
Chemistry50%

Selected Abstracts

Thermodynamically Stable SiwCxNyOz Polymer-Like, Amorphous Ceramics Made from Organic Precursors

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2008
Riham M. Morcos
This communication reports new results on the enthalpy of formation of pseudo-amorphous ceramic compounds constituted from silicon, carbon, oxygen, and nitrogen (SiCNO), made from the polymer route. Again, like the SiCO materials, although with one exception, the enthalpy of formation from crystalline components (SiO2 cristobalite, ,-Si3N4, SiC, and excess C) is negative. Some of the alloyed oxygen,nitrogen compositions yield enthalpies that are much more negative (,100 kJ/g·atom) in comparison with compositions that contain mainly oxygen or nitrogen (,20 kJ/g·atom). The exception, having a N/O ratio near 2, has a positive value for the enthalpy. This may reflect the presence of nanoclusters of stoichiometric Si2N2O instead of the pseudo-amorphous nanodomain structure seen for the other samples. [source]

Friction and wear effects on a micro/nano-scale

LUBRICATION SCIENCE, Issue 1 2001
E. Santner
Abstract In this paper are described tribological effects which can be found in micro-tribological systems, and in those macro-systems which can be analysed by micro-methods, e.g., by atomic force microscopy (AFM) or related methods. Micro-tribology systems have friction contacts with loads in the micro/nano-newton range and/or dimensions in the micro/nanometre range. Experiments on the micro/nano-scale should be easier to explain by theoretical modelling due to their simpler system structure. An example is discussed of adhesion and friction measurements between AFM tips and clean, flat, solid surfaces in ultra-high vacuum, which shows some of the special aspects of micro/nano-tribology. Surprising friction characteristics on surfaces with an artificial micro-structure can be explained by skilled and careful topographical analysis of the friction path with an AFM. In micro-sensor contacts, ,single wear events' can be detected using AFM analysis of the contact region. For ceramic compounds, different friction levels for the components of the material can be found. The problems, difficulties, and dangers of misinterpretation are also discussed. [source]

Produktdesign , Möglichkeiten der Produktgestaltung

CHEMIE-INGENIEUR-TECHNIK (CIT), Issue 8 2004
W. Rähse Dr.-Ing.Article first published online: 29 JUL 200
Abstract Die Entwicklung leistungsstarker, auf den Anwendungsfall zugeschnittener Chemieprodukte erfolgt einerseits über gezielte Veränderungen am Molekül (Product Engineering) und andererseits über zugesetzte Hilfsstoffe, Formulierungen oder Mischungen (Product Design). Das Produktdesign umfasst zusätzlich die optimierte Produkthandhabung und Gestaltung. Es wird für Feststoffe an den Beispielen der Granulierung und des Coatings erläutert sowie konkret für die Qualitätseinstellung in der Papierindustrie und für die Gestaltung von Teigwaren diskutiert. Aus Schmelzen lassen sich über die Extrusionstechnologie beliebige Formen realisieren, z.,B. Folien, Stränge, Fasern, Hohl- bzw. Vollkörper (Flaschen, Rohre, Profile), oder über das Vertropfen/Versprühen entstehen Pulver, Granulate, Schuppen, Kügelchen und Pastillen. Für Flüssigkeiten erfolgt die Beschreibung der Einstellung gewünschter Produktleistungen am Beispiel der Niotenside, das Produktdesign am Beispiel der Milch und eines Öls. Die Kombination beider Produktdimensionen ist für die Lackindustrie dargestellt. Einige Gestaltungsmöglichkeiten von Suspensionen, Pasten und Lösungen werden an der Trocknung matrixverkapselter Enzyme, an der Zeolithherstellung sowie an der Verarbeitung keramischer Massen aufgezeigt. Product Design , Possibilities of Product Design The development of high-performance chemical products tailored to a concrete application is done either by making deliberate changes to a particular molecular structure (product engineering) or by adding auxiliary agents, formulations or mixtures (product design). Product design, besides the design proper, also includes the optimized application of the product. For solids it is exemplified by granulation and coating and discussed in concrete terms for the quality adjustment in the paper industry, and for the design of pasta products. Melts can take any desired shape when extruded, such as films, strands, fibers, hollow or solid bodies (bottles, tubes, sections) or they can be processed by dropping/spraying to produce powders, granulates, flakes, pearls or lozenges. The adjustment the desired properties for liquid products is described for the example of non-ionic surfactants and product design is shown for milk and for an oil. The combination of the two product dimensions is presented for the paint industry. Some design possibilities for suspensions, pastes and solutions are demonstrated by the drying of matrix-encapsulated enzymes, the production of zeolite and the processing of ceramic compounds. [source]

Metal/Ceramic Interface Properties and Their Effects on SOFC Development

FUEL CELLS, Issue 6 2009
F. Tietz
Abstract Development of solid oxide fuel cells (SOFCs) involves multidisciplinary research, which needs input from many directions. As an example, this contribution describes the influence of basic metallurgical experiments on the selection or the modification of specific materials used in SOFCs. Wettability studies, although typically regarded as model experiments, give clear indications of the combinations of materials, which show better compatibility and might be more successfully integrated in SOFC designs, especially when metal/ceramic interfaces are involved. Various material combinations, i.e. anode cermets, glass/steel and ceramic/silver/steel compounds, are discussed in more detail showing the impact of fundamental studies on the SOFC development actually applied. This work gives a short overview on the basic aspects of selected material combinations. [source]