Applications of Ceramic Superconductors

The range of applications of superconducting materials is potentially enormous, and includes specialized uses as thin layers and single crystals, apart from bulk ceramic materials. Some market projections are listed in Table 9.6, from which it is clear that LTS, at least for the immediate future, will command a market share far exceeding that of HTS. 

Many relevant properties and already commercially available applications of ceramic superconductors are listed in Tables 9.7 and 9.8 it is important to note that LTS operate at low temperatures, close to 4K (liquid helium), while HTS operate from the temperature of liquid helium to 77 K (liquid nitrogen). Although limited details of these materials are described in the following sections, the electronic applications which often employ thin films or type 1 superconducting metals have been partly omitted. 

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Schoonman, J., High-temperature applications of ceramic superconductors, in Supergeleiding, Stuivinga, M. and van Woerkens, E.C.C., Eds., SCME, Delft, 1990 (in Dutch). 

Electrical and Electronic Applications. Silver neodecanoate [62804-19-7] has been used in the preparation of a capacitor-end termination composition (110), lead and stannous neodecanoate have been used in circuit-board fabrication (111), and stannous neodecanoate has been used to form patterned semiconductive tin oxide films (112). The silver salt has also been used in the preparation of ceramic superconductors (113). Neodecanoate salts of barium, copper, yttrium, and europium have been used to prepare superconducting films and patterned thin-fHm superconductors. To prepare these materials, the metal salts are deposited on a substrate, then decomposed by heat to give the thin film (114—116) or by a focused beam (electron, ion, or laser) to give the patterned thin film (117,118). The resulting films exhibit superconductivity above Hquid nitrogen temperatures. 

In this chapter, we ll look at both metals and solid-state materials. We ll examine the natural sources of the metallic elements, the methods used to obtain metals from their ores, and the models used to describe the bonding in metals. We ll also look at the structure, bonding, properties, and applications of semiconductors, superconductors, ceramics, and composites. 

The processing of ceramic superconductors is a highly challenging enterprise which has, in fact, limited their large-scale industrial applications to date. In... 

A unique application of the solid oxygen electrolytes is in dre preparation of mixed oxides from metal vapour deposits. For example, the ceramic superconductors described below, have been prepared from mixtures of the metal vapours in the appropriate proporhons which are deposited on the surface of a solid electrolyte. Oxygen is pumped tluough the electrolyte by the application of a polarizing potential across the electrolyte to provide the oxidant for the metallic layer which is formed. 

XPS has been used in almost every area in which the properties of surfaces are important. The most prominent areas can be deduced from conferences on surface analysis, especially from ECASIA, which is held every two years. These areas are adhesion, biomaterials, catalysis, ceramics and glasses, corrosion, environmental problems, magnetic materials, metals, micro- and optoelectronics, nanomaterials, polymers and composite materials, superconductors, thin films and coatings, and tribology and wear. The contributions to these conferences are also representative of actual surface-analytical problems and studies [2.33 a,b]. A few examples from the areas mentioned above are given below more comprehensive discussions of the applications of XPS are given elsewhere [1.1,1.3-1.9, 2.34—2.39]. 

Adams, P. B. 1992. Predicting corrosion. In Clark, D. E. Zoitos, B. K. (eds) Corrosion of Glass, Ceramics and Ceramic Superconductors Principles, Testing, Characterization and Applications. Noyes, Park Ridge, USA, 29-50. 

Several serious problems must be surmounted before applications of high-temperature superconductors can become a reality. Presently known ceramic superconductors are brittle powders with high melting points, so they are not easily fabricated into the wires and coils needed for electrical equipment. Also, the currents that these materials are able to carry at 77 K are still too low for practical applications. Thus, applications are likely in the future but are not right around the corner. 

A crucial concern in the application of superconducting ceramics is to devise ways to fabricate the new materials in desired shapes such as wires. This will be quite a challenge because these superconductors are ceramics and have the brittleness and fragility typical of ceramic materials. 

Ceramics have many applications depending on the components. The following sections describe preparation of ceramic materials ranging from graphite (sporting equipment) to superconductors and control rods for nuclear reactors. 

The Synthesis and Fabrication of Ceramics for Special Application 261 17.3.10. Preparation of Superconductive Ceramics 17.3.10.1. Low Temperature Superconductors... 

High-temperature ceramic superconductors, which would fall into the category of advanced ceramics, are not presently a major market area. They constitute less than 1% of the advanced ceramics market. Significant growth has been predicted because of their increased use in microwave filters and resonators, with particular application in the area of cell phones. 

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