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Ceramic Interface (ceramic + interface)
Selected AbstractsDetermination of the Thermal Resistance of the Polymer,Ceramic Interface of Alumina-Filled Polymer CompositesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2004Richard F. Hill To model the thermal conductivity of polymer composites that are filled with ceramic powders, the conductivity of each component as well as the interfacial resistance at each ceramic,polymer boundary must be known. An indirect method to determine this interfacial boundary resistance is proposed by preparing large-scale "macromodel" simulations of the polymer,ceramic interface. Macromodels, prepared by spin-coating a polymer layer onto sapphire wafers, were formed in a sapphire,polymer,sapphire sandwich type structure. The interfacial boundary thermal resistance was calculated from thermal resistance measurements made on the macromodels. [source] Microstructural and Mechanical Investigations on Porcelain-Fused-to-Metal in Multilayer SystemADVANCED ENGINEERING MATERIALS, Issue 4 2010Adele Carraḍ Results on porcelain-fused-to-metal (PFM) technique of ceramic films for biomedical applications on metal substrate are reported. The coating of metallic implants with bio-ceramic films (glassy and opaque ceramic) was proposed to be a solution for combining the mechanical properties of the metallic material with the bioactive character of the ceramic layer, leading to a better integration of the entire implant. The aim of this paper is to determine a stress field distribution by a non-destructive method as high-energy synchrotron X-ray diffraction in energy dispersive in the metal and glass ceramic bulk as well as at metal,opaque ceramic interface in PFM three layers sample. Tensile stresses were found in palladium substrate and compressive state in glass ceramic coating. Moreover thermal stresses induced by PFM coating at the interfaces were calculated by analytical mathematical model, confirming that the stresses induced, due to the selection of the materials, are low. Finally, the micro-structural and chemical characteristics of glassy and opaque bio-ceramic coatings on palladium alloy substrate were investigated and no inter-diffusion area between metal and ceramic could be detected as well as non-homogeneity in the interface ceramic. [source] Determination of the Thermal Resistance of the Polymer,Ceramic Interface of Alumina-Filled Polymer CompositesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2004Richard F. Hill To model the thermal conductivity of polymer composites that are filled with ceramic powders, the conductivity of each component as well as the interfacial resistance at each ceramic,polymer boundary must be known. An indirect method to determine this interfacial boundary resistance is proposed by preparing large-scale "macromodel" simulations of the polymer,ceramic interface. Macromodels, prepared by spin-coating a polymer layer onto sapphire wafers, were formed in a sapphire,polymer,sapphire sandwich type structure. The interfacial boundary thermal resistance was calculated from thermal resistance measurements made on the macromodels. [source] YSZ-Induced Crystallographic Reorientation of Ni Particles in Ni,YSZ CermetsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2007Miguel A. Laguna-Bercero Metal,ceramic interfaces in Ni,YSZ (YSZ, yttria-stabilized zirconia)-textured porous cermets prepared by reduction of NiO,YSZ directionally solidified eutectics have been studied by transmission electron microscopy and X-ray pole figure experiments. Before reduction of NiO, the interfacial plane isbut after reduction, the Ni phase does not maintain the same crystallographic orientation as the NiO parent phase. Ni undergoes an interface-induced crystallographic reorientation to form the lower energy (002)Ni,(002)YSZ interface. This process has been studied as a function of the reduction temperature, and it seems to be more effective at ,800°C. Metal,ceramic low-energy interfaces prevent Ni particle coarsening and impart long-term stability to the cermet. [source] Metal/Ceramic Interface Properties and Their Effects on SOFC DevelopmentFUEL CELLS, Issue 6 2009F. 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] Nanometer-Scale Mapping of Elastic Modules in Biogenic Composites: The Nacre of Mollusk ShellsADVANCED FUNCTIONAL MATERIALS, Issue 16 2010Haika Moshe-Drezner Abstract In this study, a newly developed nanoscale modulus mapping is applied in order to visualize the 2D-distribution of mechanical characteristics in the aragonitic nacre layer of Perna canaliculus (green mussel) shells. Modulus maps provide lateral resolution of about 10 nm. They allow the aragonitic mineral (CaCO3) tablets and the interfaces between them to be clearly resolved, which are filled by an organic substance (mainly beta-chitin). The experimental data are compared with finite element simulations that also take into account the tip radius of curvature and the thickness of organic layers, as measured by means of scanning electron microscopy with back-scattered electrons. Based on this comparison, the Young modulus of beta-chitin is extracted. The obtained number, E, = 40 GPa, is higher than previously evaluated. The collected maps reveal that the elastic modules in the nacre layer change gradually across the ceramic/organic interfaces within a spatial range four times wider than the thickness of the organic layers. This is possibly due to inhomogeneous distribution of organic macromolecules within ceramic tablets. According to the data, the concentration of macromolecules gradually increases when approaching the organic/ceramic interfaces. A behavior of this type is unique to biogenic materials and distinguishes them from synthetic composite materials. Finally, three possible mechanisms that attempt to explain why gradual changes of elastic modules significantly enhance the overall resistance to fracture of the nacre layer are briefly discussed. The experimental findings support the idea that individual ceramic tablets, comprising the nacre, are built of the compositionally and functionally graded ceramic material. This sheds additional light on the origin of the superior mechanical properties of biogenic composites. [source] | ||||||||||