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Bronze is any of a broad range of Copper Alloys , usually with Tin as the main additive, but sometimes with other Elements such as Phosphorus , Manganese , Aluminium , or Silicon . (See Table Below .) It is strong, tough and has myriad uses in industry. It was particularly significant in antiquity, giving its name to the Bronze Age . That name, in turn, is perhaps ultimately taken from the Persian word "birinj," meaning "copper". Online Etymological Dictionary http://www.etymonline.com/index.php?term=bronze HISTORY OF BRONZE pu vessel with interlaced Dragon design, Spring And Autumn Period ( 722 BC - 481 BC )]] Bronze was significant to any culture that encountered it. It was one of the most innovative alloys of mankind. Tools, weapons, armor, and various building materials like decorative tiles made of bronze were harder and more durable than their stone and copper (" Chalcolithic ") predecessors. In early use, the impurity Arsenic sometimes created a superior alloy; this is termed Arsenical Bronze . The earliest tin-alloy bronzes date to the late 4th Millennium BC in Susa (Iran) and some ancient sites in Luristan (Iran) and Mesopotamia (Iraq). While copper and tin can naturally co-occur, the two Ore s are rarely found together (although one ancient site in Thailand and one in Iran provide counterexamples). Serious bronze work has therefore always involved trade (and the compelling idea that there were really traders in such goods). In fact, archaeologists suspect that a serious disruption of the tin trade precipitated the transition to the Iron Age . In Europe, the major source for Tin was Great Britain , where significant deposits of ore could be found in Cornwall . Phoenician traders visited Great Britain to trade goods from the Mediterranean for tin. from 7th century Iran . Cast, chased, and inlaid bronze. New York Metropolitan Museum of Art.]] Bronze is stronger (harder)http://www.llnl.gov/tid/lof/documents/pdf/238547.pdf than became cheaper, and people figured out how to make Steel , which is stronger than bronze, holding a sharper edge longer.http://www.llnl.gov/tid/lof/documents/pdf/238547.pdf PROPERTIES With the exception of steel, bronze is superior to iron in nearly every application. Although bronze develops a Patina , it does not Oxidize beyond the surface. It is considerably less brittle than iron and has a lower casting temperature. Copper-based Alloys have lower Melting Point s than steel and are more readily produced from their constituent metals. They are generally about 10 percent heavier than steel, although alloys using Aluminium or Silicon may be slightly less dense. Bronzes are softer and weaker than steel, bronze Springs are less stiff (and so store less energy) for the same bulk. It resists Corrosion (especially Seawater Corrosion ) and Metal Fatigue better than steel and also conducts heat and electricity better than most steels. The cost of copper-base alloys is generally higher than that of steels but lower than that of Nickel -base alloys. Copper and its alloys have a huge variety of uses that reflect their versatile physical, mechanical, and chemical properties. Some common examples are the high Electrical Conductivity of pure copper, the excellent deep-drawing qualities of cartridge case brass, the low-friction properties of bearing bronze, the resonant qualities of bell bronze, and the resistance to corrosion by Sea Water of several bronze alloys. In the twentieth century, Silicon was introduced as the primary alloying element, creating an alloy with wide application in industry and the major form used in contemporary statuary. Aluminium is also used for the structural metal Aluminium Bronze . in the Bards' crypt in Wawel Cathedral , Cracow , Poland by sculptor Czesław Dźwigaj ]] Bronze is the most popular metal for top-quality Bell s and Cymbal s, and more recently, Saxophone s. It is also widely used for cast metal Sculpture (see Bronze Sculpture ). Common bronze alloys often have the unusual and very desirable property of expanding slightly just before they set, thus filling in the finest details of a Mould . Bronze parts are tough and typically used for Bearings , clips, electrical connectors and Springs . Bronze also has very little metal-on-metal Friction , which made it invaluable for the building of Cannon s where iron cannonballs would otherwise stick in the barrel. It is still widely used today for springs, bearings, bushings, automobile transmission pilot bearings, and similar fittings, and is particularly common in the bearings of small electric motors. Phosphor Bronze is particularly suited to precision-grade bearings and springs. Bronze is typically 88% Copper and 12% Tin .Knapp, Brian. (1996) Copper, Silver and Gold. Reed Library, Australia Alpha bronze consists of the alpha solid solution of tin in copper. Alpha bronze alloys of 4–5% tin are used to make Coin s, Springs , Turbine s and Blade s. Commercial bronze (otherwise known as Brass ) is 90% copper and 10% zinc, and contains no tin. It is stronger than copper and it has equivalent ductility. It is used for Screw s and Wire s. Another useful property of bronze is that it is non-sparking. That is, when struck against a hard surface, unlike steel, it will not generate sparks. This is used to advantage to make hammers, mallets, wrenches and other durable tools to be used in explosive atmospheres or in the presence of flammable vapours. CLASSIFICATION OF COPPER AND ITS ALLOYS SEE ALSO
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