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Bronze is the traditional name for a broad range of alloys of copper, usually with zinc and tin but not limited to those metals. First used during the Bronze Age, to which it gave its name, bronze made tools, weapons and armor that were either harder or more durable than their stone and copper predecessors. During the Bronze Age, arsenic was often included in the bronze (mostly as an impurity), which made the alloy harder still.Bronze was also stronger than iron, another common metal of the era, and quality steels were not available until thousands of years later. Nevertheless the Bronze Age gave way to the Iron Age as the shipping of tin around the Mediterranean Ocean ended during the major population migrations around 1200 - 1100 BCE, which dramatically limited supplies and raised prices. Bronze was still used to a considerable extent during the Iron Age, but for many purposes the weaker iron was sufficiently strong to serve in its place. As an example, Roman officers were equipped with bronze swords while foot soldiers had to make do with iron blades.
Copper-based alloys have lower melting points than steels and are more readily produced from their constituent metals. They are comparable to steel in density, most copper alloys being only about 10 percent heavier, although ones with a lot of aluminium or siliconSilicon is the chemical element in the periodic table that has the symbol Si and atomic number 14. A tetravalent metalloid, silicon is less reactive than its chemical analog carbon. It is the second most abundant element in the Earth's crust, making up 25 may be slightly less dense than steel. Bronzes are softer and weaker than steel, and more elasticThere are separate articles about elasticity in economics, and about British rubber bands. In solid mechanics, the adjective elastic characterises both collisions between, and deformations of, physical objects. A collision is perfectly elastic if the tota, though bronze springsA spring is a flexible elastic object used to store mechanical energy. Springs are commonly made out of steel or brass. Types of spring The most common types of spring are: the helical or coil spring (made by winding a wire around a cylinder) this is a ty are less stiff (lower energy) for the same bulk. Bronzes resist corrosionCorrosion is the destructive reaction of a metal with another material, e. oxygen, or in an extreme pH environment (either acidic or basic). The corrosion product is a mix of oxide and salts of the original metal. Corrosion is the primary means by which m (especially seawater corrosion ) and metal fatigue better than steel. Bronzes also conduct heat and electricity better than most steels. The cost of copper-base alloys is generally higher than that of steels but lower than nickelThis article is about the element nickel. See also nickel (U. coin) and nickel (Canadian coin). Nickel is a metallic chemical element in the periodic table that has the symbol Ni and atomic number 28. Notable characteristics Nickel is silvery white metal-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 conductivityElectrical conductivity is a measure of how well a material accommodates the transport of electric charge. Its SI derived unit is the siemens per metre ( A2 s3 m-3 kg-1) (named after Werner von Siemens). It is the ratio of the current density to the elect 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 waterSea water is water from a sea or ocean. On average, sea water in the world's oceans has a salinity of ~3. This means that for every 1 liter (1000mL) of sea water there are 35 grams of salts (mostly, but not entirely, sodium chloride) dissolved in it. by several bronze alloys.
Starting in the twentieth century silicon was introduced as the primary alloying element with copper. Silicon bronze is used in a wide variety of industrial applications, and largely represents the bronze used in the production of contemporary statuary.
Bronze is the most popular metal for top quality bells and cymbals, and also 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 mold.
Bronze also has very little metal-on-metal friction, which made it invaluable for the building of cannons where iron cannonballs would otherwise stick in the barrel. Bronze is still widely used today for bearings, bushings and similar roles, and is particularily common as the bearing on small electric motors.
