Functionalized ceramic

The removal of pores and internal cracks is also of value where functional ceramics are concerned. Dielectrics such as are used in capacitors in enormous quantities, alumina in particular, have long been made with special attention to removing any pores because these considerably lower the breakdown field and therefore the potential difference that the capacitors can withstand. 

Improved characterization of the morphological/microstructural properties of porous solids, and the associated transport properties of fluids imbibed into these materials, is crucial to the development of new porous materials, such as ceramics. Of particular interest is the fabrication of so-called functionalized ceramics, which contain a pore structure tailored to a specific biomedical or industrial application (e.g., molecular filters, catalysts, gas storage cells, drug delivery devices, tissue scaffolds) [1-3]. Functionalization of ceramics can involve the use of graded or layered pore microstructure, morphology or chemical composition. 

Fabrication processing of these materials is highly complex, particularly for materials created to have interfaces in morphology or a microstructure [4—5], for example in co-fired multi-layer ceramics. In addition, there is both a scientific and a practical interest in studying the influence of a particular pore microstructure on the motional behavior of fluids imbibed into these materials [6-9]. This is due to the fact that the actual use of functionalized ceramics in industrial and biomedical applications often involves the movement of one or more fluids through the material. Research in this area is therefore bi-directional one must characterize both how the spatial microstructure (e.g., pore size, surface chemistry, surface area, connectivity) of the material evolves during processing, and how this microstructure affects the motional properties (e.g., molecular diffusion, adsorption coefficients, thermodynamic constants) of fluids contained within it. 

The inherent sensitivity of NMR signals to the fluid-substrate interactions via a large number of mechanisms provides a direct connection between the NMR measurables, the pore structure and the motional characteristics of the imbibed fluid. While the large number of potential NMR variables makes the experimental design and analysis complex, it also provides the potential for a measurement method capable of measuring and spatially resolving the parameters of interest to functionalized ceramics. 

Full evaluation of functionalized ceramics requires the ability to characterize the spatial variations in structure and morphology. Using NMRI, it is possible to map the underlying structure on a spatial scale of hundreds of microns. 

Institute of Structural and Functional Ceramics, University of Leoben, A8700 Leoben, Austria. Department of Chemistry, University of New Mexico, Albuquerque, NM 87131. 

What new developments the future holds nobody knows for certain. In electronics people will try to miniaturise electric equipment even further. Non-functional, ceramic packaging will be converted into functional components. For this new ceramic materials are necessary, as are ways to process them. High-temperature superconductors will lead to magnetic levitation craft, cheap electricity and improved MRI (magnetic resonance imaging). 

Ferroelectric ceramics and single crystals have found wide applications in many electronic, acoustoptic and piezoelectric devices [1,2], Perovskites represent one of the most important classes of inorganic powders that are of great interest in functional ceramics used for electronic components among them BaTiOj is a typical and most frequently used representative. 

Functional ceramic thin films have been used in a variety of electronic devices. In particular, Si02 thin films are widely used for device passivation and protection of magnetic and optical disks. The synthesis of Si02 thin films can be conveifiently... 

Piezoceramics are currently no longer manufactured from BaTi03, but from lead titanate zirconate, Pb(Ti,Zr)03, which aLso crystallizes in a perovskite lattice. Ceramic capacitors to a value of 4.1 10 DM were produced in 1995, ca. 50% of the turnover for functional ceramics, in which the three region USA, Japan and Europe have equal shares. 

Forsgren, J. (2010) Functional ceramics in biomedical applications. On the use of ceramics for controlled drug release and targeted cell stimulation. PhD dissertation. Uppsala University, Sweden, Acta University Upsaleiensis, Uppsala, ISBN 978-91-554-7930-5. 

From Metal-Organic Precursors to Functional Ceramics and Related Nanoscale Materials... 

Functional Ceramics Chemical Composition, Function and Form... 

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