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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.
Gold, silver and bronze or copper were the principal coinage metals of the ancient world, the medieval period and into the late modern period when the diversity of coinage metals increased. Coins are often made from more than one metal, either using alloys, coatings (cladding/plating) or bimetallic configurations. While coins are primarily made ...
Bell bronze is a two-phase alloy, meaning some of the tin is not dissolved in the copper grains but exists between them. This makes the metal harder and more brittle than a single-phase alloy, and also affects the way the metal responds to hardening by hammering and lathing, and greatly restricts the use of mechanised techniques of manufacture.
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.
Arsenical bronze is an alloy in which arsenic, as opposed to or in addition to tin or other constituent metals, is combined with copper to make bronze. The use of arsenic with copper, either as the secondary constituent or with another component such as tin, results in a stronger final product and better casting behavior. [1]
Bronze with the ideal percentage of tin was therefore expensive and the proportion of tin was often reduced to save cost. The discovery and exploitation of the Bolivian tin belt in the 19th century made tin far cheaper, although forecasts for future supplies are less positive.
One gym owner even told the Washington Post that Nedoroscik has increased boys' interest in gymnastics. Nedoroscik also took home the bronze in the individual pommel horse event. No other male ...
Old Japanese weapons and other military paraphernalia, c. 1892–95 A Gilbertese shark-toothed weapon (late 19th century). Major innovations in the history of weapons have included the adoption of different materials – from stone and wood to different metals, and modern synthetic materials such as plastics – and the developments of different weapon styles either to fit the terrain or to ...