Electrical conductors, ceramic materials

The distinction between materials as electrical conductors and materials as insulators was made in the eighteenth century. Although historically the insulating properties of ceramics have often been one of their most... 

Inorganic polymers based on alternating main group element-nitrogen skeletons (e.g. I - IV) are of interest for their potential as elastomers, high-temperature oils, electrical conductors, biological molecule carriers, and precursors to ceramic materials (J - 6). 

Materials can be classified as conductors, semiconductors or insulators. Conductors typically have resistivity in the range 10 2-103 xQ cm, semiconductors approximately 106-10n iQ cm, and insulators about 1013-1018 (xQ cm. Table 1.5 compares the electrical resistivity of the elements and compounds at room temperature. Although the carbides and nitrides have somewhat higher resistivity than do the pure metals, they still have resistivity in the regime of metallic conductors. In comparison the ceramic materials have much higher values, and are typically insulators. 

The first use of ceramics in the electrical industry took advantage of their stability when exposed to extremes of weather and to their high electrical resistivity, a feature of many siliceous materials. The methods developed over several millennia for domestic pottery were refined for the production of the insulating bodies needed to carry and isolate electrical conductors in applications ranging from power lines to the cores bearing wire-wound resistors and electrical fire elements. 

Aluminum is the most abundant metal and the third most abundant element in the Earth s cmst, behind only oxygen and silicon. Its low weight and useful properties make aluminum and its alloys valuable materials for manufacturing and electrical applications. Inorganic compounds of aluminum are plentiful and used as absorbents, catalysts, ionic conductors, ceramics, and electrical materials. Organometalhc compounds of aluminum are also of great industrial importance and fundamental discoveries continue to be made regarding the variety of coordination numbers, structures, oxidation states, and reactivity exhibited by aluminum. ... 

Ceramic materials, after all, seemed more at home in a pottery class or factory. The stuff of bricks and drainpipes, of bathtubs, sinks, and toilet bowls, of cups and plates, these earthy compounds, especially clay, were useful but too ordinary and familiar to interest Ph.D.s tinkering about with differential scanning calorimetry instruments or scrutinizing the partial penetration of flux. Furthermore, the majority of ceramics are insulators, not conductors, and are so used on high-voltage electrical transmission lines. 

Superconductivity has been observed in all the classes of materials metals, ceramics, and polymers. Of all the elements in the periodic table only 27 are known to become superconducting under ordinary pressure. Niobium is the element with the highest T, 9.2 K, whereas for tungsten Tc is only 0.0154 K. An interesting fact is that metals having the highest o, e.g., Cu, Ag, and Au, are not superconducting even at extremely low temperatures, if at all. It is the metals that are the poorer electrical conductors that make... 

Some materials allow electricity to pass through them very easily and are electrical conductors. These include carbon and most of the metals, such as aluminium, copper, brass and silver. Other materials offer a high resistance to the flow of electricity and are bad electrical conductors, known as insulators - these include non-metallic materials such as plastics, rubber, mica, ceramics and glass. 

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