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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. Both of these are imprecise terms.
Today, depending on the dealer, "Pinchbeck" can mean original Pinchbeck or any gilt metal. [1] Pinchbeck fell out of use in the second half of the 19th century, being replaced by low-carat gold which had been legalised in 1854. [3] Pinchbeck is typically composed of copper and zinc in ratios of 89% copper to 11% zinc; or 93% copper to 7% zinc. [4]
Gunmetal ingot is a related alloy in which the zinc is replaced by 2% lead; this makes the alloy easier to cast but it has less strength. [2]Modified gunmetal contains lead in addition to the zinc; it is typically composed of 86% copper, 9.5% tin, 2.5% lead, and 2% zinc.
Examples include iron, nickel, lead and zinc. Copper is also considered a base metal because it oxidizes relatively easily, although it does not react with HCl. In mining and economics, the term base metals refers to industrial non-ferrous metals excluding precious metals. These include copper, lead, nickel and zinc. [3]
Raised jug, in gilding metal. Made in an English school metalwork class, 1970s–1980s. Gilding metal is a form of brass (an alloy of copper and zinc) with a much higher copper content than zinc content. Exact figures range from 95% copper and 5% zinc [1] to “8 parts copper to 1 of zinc” (11% zinc) in British Army Dress Regulations. [2]
Islamic Golden Age brass astrolabe Brass lectern with an eagle. Attributed to Aert van Tricht, Limburg (Netherlands), c. 1500.. Brass is an alloy of copper and zinc, in proportions which can be varied to achieve different colours and mechanical, electrical, acoustic and chemical properties, [1] but copper typically has the larger proportion, generally 2 ⁄ 3 copper and 1 ⁄ 3 zinc.
Alloys of 85–88% zinc, 4–10% copper, and 2–8% aluminium find limited use in certain types of machine bearings. Zinc has been the primary metal in American one cent coins (pennies) since 1982. [136] The zinc core is coated with a thin layer of copper to give the appearance of a copper coin.
Zinc is the fourth most common metal in use, trailing only iron, aluminium, and copper with an annual production of about 10 million tonnes. [78] Worldwide, 95% of the zinc is mined from sulfidic ore deposits, in which sphalerite (ZnS) is nearly always mixed with the sulfides of copper, lead and iron.