Bronze

Bronze is a special kind of metal made by mixing mostly copper with a little tin. Sometimes, other metals or non-metals are added too. These extra ingredients make bronze stronger or easier to shape than copper alone.

A very important time in history, called the Bronze Age, started around 3500 BCE in parts of Europe and Asia. During this time, bronze was one of the strongest metals people knew how to make. Later, around 1300 BCE, people began using iron more, but bronze was still used a lot.

Because many beautiful old artworks were made from bronze or similar metals, museums and scholars today often use the term "copper alloy" to describe these items. This helps them talk about old artworks more clearly, even when they aren’t sure of the exact mixture of metals used.

Etymology

The word bronze started being used in English between 1730 and 1740. It came from the Middle French word bronze, which came from the Italian word bronzo. This Italian word described a special kind of metal used for making bells, called "bell metal" or brass.

The Italian word may have come from an old Byzantine Greek word, possibly linked to a place called Brindisi. Another idea is that it came from very old Persian words for brass and copper. This idea also influenced words in several other languages.

History

The discovery of bronze let people make metal objects that were stronger and lasted longer. Bronze was used for tools, weapons, armor, and beautiful building pieces that were tougher than older stone and copper items.

The oldest bronze object found is from around 4650 BCE, in a place called Pločnik in Serbia. It was made from a natural mix of tin and copper. Other early bronze items were found in Egypt, Iran, China, and Iraq. Some bronze had arsenic, which made it look silver and work more easily, but tin became the main ingredient mixed with copper because it was easier to control and made stronger bronze. Tin and copper ores are rarely found together, so people traded to get both materials. In Europe, tin from Cornwall in the United Kingdom was traded as far as Phoenicia in the eastern Mediterranean. Bronze objects were also a sign of wealth and status. As ironworking improved, iron became cheaper and stronger than bronze, leading to the Iron Age, but bronze is still used today for many things.

Composition

Bronze is made by mixing different metals together. Most modern bronze is about 88% copper and 12% tin. One type, called alpha bronze, has a little tin mixed with copper. It is used for making coins, springs, turbines, and blades.

In the past, people used many different mixtures for bronze, using whatever old pieces of metal they could find. For example, the metal of the 12th-century English Gloucester Candlestick had copper, zinc, tin, lead, nickel, iron, antimony, arsenic, and even some silver. During a time called the Bronze Age, people used two main types of bronze. One had about 10% tin for casting things like weapons. The other had about 6% tin for making sheets that could be hammered into shapes like helmets.

There are also many other bronze mixtures today, including aluminium bronze, phosphor bronze, manganese bronze, bell metal, arsenical bronze, speculum metal, bismuth bronze, and cymbal alloys.

Properties

Copper-based alloys melt at lower temperatures than steel or iron and are easier to make. They are a bit heavier than steel but not as heavy as other metals. Bronze carries heat and electricity better than most steels. These metals cost more than steel but less than some special alloys.

Bronze is flexible and not as likely to break as cast iron. Copper and its mixes are used in many ways because of their useful traits. For example, pure copper is great for electricity, some bronze with lead is good for moving parts, and bronze with tin makes beautiful bells. Certain bronze mixes can also resist rust from seawater.

Bronze melts around 950 °C (1,742 °F), but this changes with the mix of metals. Bronze usually isn’t magnetic, but some mixes with iron or nickel can be. Bronze forms a thin layer that protects it from rust, but if it gets a certain type of rust from copper chlorides, it can be badly damaged — this is called “bronze disease”.

Uses

Bronze was used for coins for a long time. It worked well for boat parts before stainless steel because it was tough and didn’t rust in salt water. Today, bronze is still used in ship propellers and parts under water.

Bronze won’t spark when hit against a hard surface, so it’s used for tools in places where sparks could be dangerous. It’s also used for special wood-cleaning pads for woodworking. A type called phosphor bronze is used for ship parts, musical instruments, and electrical connections.

Bronze parts are strong and used for things like bearings, clips, and electrical connectors. It also doesn’t stick easily to other metals, which made it useful for old cannons.

Architectural bronze

Main articles: Seagram Building and Roman Bronze Works

See also: General Bronze Corporation

The Seagram Building in New York City on Park Avenue is a famous building covered in bronze. It was the first building ever covered entirely in bronze.

Coins and medals

Bronze has been used to make coins. Many “copper” coins are actually bronze. Bronze has also been used for medals for many years. Today, bronze medals are given for third place in sports and other events.

Bronze is also used for special art pieces called plaquettes, usually rectangular with a raised scene. Bronze is linked to celebrating eighth wedding anniversaries.

Fountains and doors

The largest bronze fountain ever made was created by the Roman Bronze Works and General Bronze Corporation in 1952. These companies also made the big bronze doors for the United States Supreme Court Building in Washington, DC.

Lamps

Tiffany Glass Studios, famous for Louis C. Tiffany’s favrile glass or “Tiffany glass”, used bronze in making their Tiffany lamps.

Mechanical bearings and springs

Bronze is still used today for springs, bearings, and parts in cars and small motors. Phosphor bronze is especially good for precise bearings and springs. It’s also used for strings in guitar and piano. Bronze is good for bearings because of its low friction.

Mirrors

Before smooth glass mirrors were made, bronze was commonly used for mirrors all over the world. Bronze mirrors have been found from ancient Egypt and China, and later in Europe by the Etruscans.

Musical instruments

Bronze is the best metal for bells, made from a special mix called bell metal with about 23% tin. Most professional cymbals are made from bronze for their great sound. Different types of bronze are used, like B20 bronze with 20% tin, or B8 bronze with 8% tin.

Bronze is also used for the windings of strings in instruments like the double bass, piano, harpsichord, and guitar. Bronze is used for lower notes on pianos because it lasts longer. Bronze is used around the world for musical instruments like bells, singing bowls, gongs, and cymbals. Some saxophones are now made from phosphor bronze. Bell bronze is used for the tone rings of many professional banjos.

Sculptures

See also: Ormolu

Bronze is commonly used for sculptures because it fills every detail of a mould when it’s liquid and then shrinks a little as it cools. Bronze sculptures were very important in Ancient Greek art, though not many survive because they were often melted down.

In India, bronze sculptures from many periods have been found. Indian artists from the Chola empire in Tamil Nadu made detailed bronze statues of Hinduism gods using a special method. This tradition continues today. Other cultures, like the Greeks and Chinese, also made beautiful bronze art. Bronze is still a popular material for large statues.

Biblical references

The Bible talks about copper and its mixtures more than 125 times. In old translations, like the King James Version, these materials were called "brass." But scholars think the ancient Hebrews did not know how to make brass, which needs zinc. Instead, these references likely mean copper mixed with tin, known today as bronze. Bronze was used for many important items in the Tabernacle, such as altars and mirrors. It was also used for decorations in Solomon's Temple, made by a skilled craftsman named Hiram I. Bronze was used for armor in battles, including the famous fight between David and Goliath.