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Download as PDF; Printable version; ... Spectral lines of copper: Other properties; ... and gold are in group 11 of the periodic table; ...
Sometime around 1913, several copper samples from 14 important refiners and wire manufacturers were analyzed by the U.S. Bureau of Standards. The average resistance of the samples was determined to be 0.15292 Ω for copper wires with a mass of 1 gram of uniform cross section and 1 meter in length at 20 °C. In the United States this is usually ...
Copper occurs in its native form in Chile, China, Mexico, Russia and the USA. Various natural ores of copper are: copper pyrites (CuFeS 2), cuprite or ruby copper (Cu 2 O), copper glance (Cu 2 S), malachite (Cu(OH) 2 CuCO 3), and azurite (Cu(OH) 2 2CuCO 3). Copper pyrite is the principal ore, and yields nearly 76% of the world production of copper.
Copper alloys are metal alloys that have copper as their principal component. They have high resistance against corrosion . Of the large number of different types, the best known traditional types are bronze , where tin is a significant addition, and brass , using zinc instead.
Copper's higher tensile strength (200–250 N/mm 2 annealed) compared to aluminium (100 N/mm 2 for typical conductor alloys [16]) is another reason why copper is used extensively in the building industry. Copper's high strength resists stretching, neck-down, creep, nicks and breaks, and thereby also prevents failures and service interruptions. [17]
On the other hand, copper is a material with small ρ and large σ — because even a small electric field pulls a lot of current through it. This expression simplifies to the formula given above under "ideal case" when the resistivity is constant in the material and the geometry has a uniform cross-section.
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The method of producing OFHC copper ensures an extra high grade of metal with a copper content of 99.99%. With so small a content of extraneous elements, the inherent properties of elemental copper are brought forth to a high degree. In practice the oxygen content is typically 0.001 to 0.003% with a total maximum impurity level of 0.03%.