Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive, but sometimes with other elements such as phosphorus, manganese, aluminium, or silicon. It was particularly significant in antiquity, giving its name to the Bronze Age. "Bronze" derives from the Italian: bronzo and, in turn, is perhaps ultimately taken from the Persian word "berenj," meaning "brass.

Bronze can be superior to iron in many applications. It is considerably less brittle than iron. Bronze only oxidizes superficially; once the surface oxidizes, the thin oxide layer protects the underlying metal from further corrosion. Copper-based alloys have lower melting points than steel or iron, and are more readily produced from their constituent metals. They are generally about 10 percent heavier than steel, although alloys using aluminum or silicon may be slightly less dense. Bronzes are softer and weaker than steel, e.g. bronze springs are less stiff (and so store less energy) for the same bulk. Bronze 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 such as stainless steel.
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.

Uses

Ewer from 7th century Iran. Cast, chased, and inlaid bronze. New York Metropolitan Museum of Art.
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. Aluminum is also used for the structural metal aluminum bronze.
It is also widely used for cast bronze sculpture. Many common bronze alloys 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 where iron cannonballs would otherwise stick in the barrel.[citation needed] 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. It is also used in guitar and piano strings.
Bronze is typically 88% copper and 12% tin. Alpha bronze consists of the alpha solid solution of tin in copper. Alpha bronze alloys of 4–5% tin are used to make coins, springs, turbines and blades.
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 screws and wires.
Unlike steel, bronze struck against a hard surface will not generate sparks, so it (along with beryllium copper) is used to make hammers, mallets, wrenches and other durable tools to be used in explosive atmospheres or in the presence of flammable vapours.