Information about bronze

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Assorted ancient Bronze castings found as part of a cache, probably intended for recycling.

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 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".^[1]

History of Bronze

Chinese 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 ores 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.

Ewer from 7th century Iran. Cast, chased, and inlaid bronze. New York Metropolitan Museum of Art.

Bronze is stronger (harder)^[2] than wrought iron, but the Bronze Age gave way to the Iron Age. That may have been because the shipping of tin around the Mediterranean (or from Great Britain) became more limited during the major population migrations around 1200 – 1100 BC, which dramatically limited supplies and raised prices.^[3] Bronze was still used during the Iron Age, but for many purposes the weaker wrought iron was found to be sufficiently strong. As ironworking improved, iron became cheaper, and people figured out how to make steel, which is stronger than bronze, holding a sharper edge longer.^[4]

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 points 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 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.

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.

Fragment of the grave of Cyprian Kamil Norwid in the Bards' crypt in Wawel Cathedral, Cracow, Poland by sculptor Czesław Dźwigaj

Bronze is the most popular metal for top-quality bells and cymbals, and more recently, saxophones. 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 cannons 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.^[5] 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.

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

Classification of Copper and Its Alloys - Wrought / Extruded^[6]
Family	Principal alloying element	UNS numbers
Copper alloys, Brass	Zinc (Zn)	C1xxxx–C4xxxx,C66400–C69800
Phosphor bronzes	Tin (Sn)	C5xxxx
Aluminium bronzes	Aluminium (Al)	C60600–C64200
Silicon bronzes	Silicon (Si)	C64700–C66100
Copper nickel, Nickel silvers	Nickel (Ni)	C7xxxx

References

1. ^ Online Etymological Dictionary [1]
2. ^ [2]
3. ^ [3]
4. ^ [4]
5. ^ Knapp, Brian. (1996) Copper, Silver and Gold. Reed Library, Australia
6. ^ Machinery's Handbook, Industrial Press Inc, New York, ISBN 0-8311-2492-X, Edition 24, page 501

External links

Copper alloys are alloys with Copper as their principial component. They have high resistance to corrosion.

Due to its high electric conductivity, pure electrolytic copper is used mostly for making of electrical cables.
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TIN may refer to:

Tax identification number
Triangulated irregular network, a data structure used in a geographic information systems

History

Susa (Biblical Hebrew:
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Mesopotamia was a cradle of civilization geographically located between the Tigris and Euphrates rivers, largely corresponding to modern-day Iraq. Sumer in southern Mesopotamia is commonly regarded as the world's earliest civilization.
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ore is a volume of rock containing components or minerals in a mode of occurrence that renders it valuable for mining. An ore must contain materials that are

valuable
in concentrations that can be profitably mined, transported, milled, and processed.

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Anthem
Phleng Chat
Royal anthem
Phleng Sansoen Phra Barami

Capital
(and largest city) Bangkok ^[1]

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Anthem
Sorūd-e Mellī-e Īrān ²

Capital
(and largest city) Tehran

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Iron Age was the stage in the development of any people in which tools and weapons whose main ingredient was iron were prominent. The adoption of this material coincided with other changes in some past societies often including differing agricultural practices, religious beliefs
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TIN may refer to:

Tax identification number
Triangulated irregular network, a data structure used in a geographic information systems

Overview

The 12th century BC is the period from 1200 to 1101 BC.

Events

1197 BC — The beginning of first period (1197 BC — 982 BC) by Sau Yung's concept of the I Ching and history.
1194 BC — The beginning of the legendary Trojan War.

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The eleventh century BC comprises all years from 1100 BC to 1001 BC .

Events

1089 BC — Melanthus, legendary King of Athens, dies after a reign of 37 years and is succeeded by his son Codrus.

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3, 4, 6
(amphoteric oxide)
Electronegativity 1.83 (Pauling scale)
Ionization energies
(more) 1st: 762.5 kJmol⁻¹
2nd: 1561.9 kJmol⁻¹
3rd: 2957 kJmol⁻¹

Atomic radius 140 pm
Atomic radius (calc.
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Steel is an alloy consisting mostly of iron, with a carbon content between 0.02% and 1.7 or 2.04% by weight (C:1000–10,8.67Fe), depending on grade. Carbon is the most cost-effective alloying material for iron, but various other alloying elements are used such as manganese and
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Patina is a chemical compound formed on the surface of metal. Patinas form on metal from exposure to the elements. They are often deliberately added by artists and metalworkers. Patinas may be used to 'antique' objects, as a part of the design or decoration of art and furniture.
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Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed.

This can be either a simple redox process such as the oxidation of carbon to yield carbon dioxide, or the
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Bronze

History of Bronze

Properties

Classification of copper and its alloys

See also

References

External links

See also

History

See also

Overview

Events

Events