Bronze
Bronze is a metal alloy. Bronze is mostly copper, with some tin added (usually between 5% and 20% tin) to make it stronger. The most common alloy is just made of copper and tin. Some bronzes add other metals.
Other bronzes are:
- Aluminum bronze, which uses aluminum instead of tin.
- Leaded bronze
- Silicon bronze
- Phosphor bronze, which has both tin and phosphorus added to the copper.
Bronze should not be confused with brass which is a different alloy of copper and zinc.
History
Bronze was the first alloy that was used by humans. The first nation that used bronze was Egypt about 3500 years B.C. This gave the name for the Bronze Age.
Bronze is stronger than copper or tin alone. Bronze lasts longer than copper. Pure copper can be oxidized by air and also by water. When copper is oxidized by air or water, it turns green (the color of "copper oxide"), and falls apart.
When people learned how to make and work iron, the Bronze Age ended, and the Iron Age started. Iron can be made harder than bronze, but is susceptible to corrosion (see rust). Iron also wears away faster than bronze, when different pieces are moving against each other. Iron is very common, and easy to make. For this reason, iron costs less than bronze. This is the reason why iron is now used where bronze used to be used.
Current use
Bronze is still used to make many parts of machines. We use bronze when the part must last for a long time around water and air, or must not wear away. The main things that are made out of it are pump parts, bearings, bells, electrical components, gears, valves, and other things.
Bronze parts are usually cast in a foundry. After they are cast, bronze parts can also be worked in a lathe or milling machine, or drilled. Bronze is not normally worked with a hammer as iron is.
Pictures
Piece of bronze
Part of a bronze portrait of Marcus Aurelius
Bronze Media
Houmuwu ding (Chinese: 后母戊鼎; pinyin: Hòumǔwù dǐng), the heaviest Chinese ritual bronze ever found; 1300–1046 BC; National Museum of China (Beijing). This ding's name is based on the inscription in the bronze interior wall, which reads Hòumǔwù, meaning 'Queen Mother Wu'
Hoard of bronze socketed axes from the Bronze Age found in modern Germany. This was the most common tool of the period, and also seems to have been used as a store of value.
Roman bronze nails with magical signs and inscriptions, 3rd-4th century AD.
Bronze bell with a visible crystallite structure.
Bronze weight with an inscribed imperial order, Qin dynasty
Industrial products of the Bunting Brass and Bronze Company, 1912
The Seagram Building viewed from across Park Avenue at 52nd Street
Medal of the Emperor John VIII Palaiologos during his visit to Florence, by Pisanello (1438). The legend reads, in Greek: "John the Palaiologos, basileus and autokrator of the Romans".
Tiffany table lamp with bronze
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