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Carbides, Borides, Nitrides

Several carbon-containing superconductors are listed in Table 4.2-29. Superconductivity in the fullerenes can be achieved by alkali metal intercalation, resulting in [Pg.745]

The superconducting transition temperatures of boron and selected borides are listed in Table 4.2-30. Boron itself, which is an isolator at ambient pressure, was recently found to become superconducting under high pressure [2.129]. The boron atoms in transition metal borides can form chains, nets, and three-dimensional networks. In this respect the borides differ markedly from other interstitial compounds such as carbides [Pg.745]

Therefore, high currents can flow across the grain boundaries of bulk polycrystalline MgB2. This is due to the relatively large coherence length of this superconductor (Table 4.2-31). On the other hand, this large coherence length is responsible for the relatively low values of the upper critical field Hc2 observed, [Pg.746]

Werkstoffe (VEB Deutscher Verlag fur Grundstoffind-ustrie, Leipzig 1982) (in German) [Pg.749]

Larbalastier Superconductor Materials Science. 2.14 In Metallurgy, Fabrication, Applications, ed. by [Pg.749]

Superconducting transition temperature Lattic parameters Theoretical density Resistivity near Residual resistance ratio Coherence lengths [Pg.746]

Anisotropy parameter Lower critical fields Irreversibility fields [Pg.746]


Along with compound semiconductor nanoparticles, nanoparticles of many other materials, including metals, metal oxides, carbides, borides, nitrides, silicon, and other elemental... [Pg.1049]

One of the simplest calorimetric methods is combustion bomb calorimetry . In essence this involves the direct reaction of a sample material and a gas, such as O or F, within a sealed container and the measurement of the heat which is produced by the reaction. As the heat involved can be very large, and the rate of reaction very fast, the reaction may be explosive, hence the term combustion bomb . The calorimeter must be calibrated so that heat absorbed by the calorimeter is well characterised and the heat necessary to initiate reaction taken into account. The technique has no constraints concerning adiabatic or isothermal conditions hut is severely limited if the amount of reactants are small and/or the heat evolved is small. It is also not particularly suitable for intermetallic compounds where combustion is not part of the process during its formation. Its main use is in materials thermochemistry where it has been used in the determination of enthalpies of formation of carbides, borides, nitrides, etc. [Pg.82]

Another way of production is the coating of c-BN by electro-less plating with Ni-P, Ni-B, Ni-Fe-P, Ni-Cr-P, Ni-Cu-P, or Ni-W-P alloys, and mixing these powders with >1% of various carbides, borides, nitrides, silicides, and/or oxides. These powders are compacted and pre-sintered at 700-900 °C. Finally, hot-isostatic pressing at 1000-1400 °C and 1000-2000 bar is performed to reduce porosity [264]. [Pg.36]

The plasma-spraying technology has been best evaluated and most widely utilized for oxide materials but may also serve for application of high - temperature metals, carbides, borides, nitrides, silicides, etc. Of the non-metallic materials employed in plasma spraying at present, leading position has been gained by AI2O3 possibly modified by further oxides. [Pg.422]

The use of chemical vapor deposition (CVD) and physical vapor deposition (PVD) for forming coatings of carbides, boride, nitrides, and oxides has increased. The CVD method has been developed the furthest for the deposition of TiC, titanium nitride (TiN), chromium carbide (CrC), WC, and aluminum trioxide (AI2O3) (Simon and Thoma 1985). [Pg.529]

The history of ceramics is as old as civilization, and our use of ceramics is a measure of the technological progress of a civilization. Ceramics have important effects on human history and human civilization. Earlier transitional ceramics, several thousand years ago, were made by clay minerals such as kaolinite. Modem ceramics are classified as advanced and fine ceramics. Both include three distinct material categories oxides such as alumina and zirconia, nonoxides such as carbide, boride, nitride, and silicide, as well as composite materials such as particulate reinforced and fiber reinforced combinations of oxides and nonoxides. These advanced ceramics, made by modem chemical compounds, can be used in the fields of mechanics, metallurgy, chemistry, medicine, optical, thermal, magnetic, electrical and electronics industries, because of the suitable chemical and physical properties. In particular, photoelectron and microelectronics devices, which are the basis of the modern information era, are fabricated by diferent kinds of optical and electronic ceramics. In other words, optical and electronic ceramics are the base materials of the modern information era. [Pg.237]

There are three categories of ceramics oxides (e.g., alumina, zirconia), nonoxides (carbides, borides, nitrides, silicides), and composites of oxides/non-oxides. The two common approaches to synthesize ceramics include a low-temperature sol-gel route vide supra), and a high-temperature multi-step process involving ... [Pg.139]

Engineering ceramics can be classified into three—oxides, nonoxides, and composites. Examples for oxides are alumina and zirconia. Carbides, borides, nitrides, and silicides come under nonoxides. Particulate-reinforced oxides and nonoxides are examples for composites. Oxide ceramics are characterized by oxidation resistance, chemical inertness, electrical insulation. [Pg.39]

The author considered it best not to include in the reference book the properties of certain little-studied compounds rarely used in practice. Thus, in the presentation of the information on carbides, borides, nitrides, and other classes of metal-like compounds, no data are given on the refractory compounds of metals of the platinum group for the sulfides, data are given only for the class of sulfides of the rare-earth metals and actinides, in most of which the properties of refractory compounds in the wide sense are most clearly expressed, the proportion of ionic bond, in particular, being small. It was, however, found e qpedient to consider also the properties of oxysulfides of the rare-earth metals and actinides, which are very similar to the properties of sulfides and are obtained simply by replacement of two atoms of sulfur in a sesquisulfide by two atoms of oxygen. This is one of the few exceptions where the tables of the reference book give the properties of ternary and not binary compounds. [Pg.6]


See other pages where Carbides, Borides, Nitrides is mentioned: [Pg.208]    [Pg.1050]    [Pg.407]    [Pg.208]    [Pg.152]    [Pg.152]    [Pg.179]    [Pg.173]    [Pg.73]    [Pg.71]    [Pg.575]    [Pg.213]    [Pg.695]    [Pg.744]    [Pg.695]    [Pg.744]   


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