Bronze is the composition of the alloy. Chemical composition of bronze

Many people know about bronze only that sculptures and monuments are cast from it. In fact, this metal is deprived of popular attention undeservedly. Indeed, not for nothing in the history of mankind was even the Bronze Age - a whole era, during which the alloy took a dominant position. This is one of the few materials used both in industry and in art. The qualities possessed by the alloy of copper with tin are simply indispensable in many branches of production. It is used in the manufacture of guns, in machine building, in the casting of church bells and so on. At the same time today there are a large number of metal brands, each of which has certain pre-modeled properties.

The use of bronze in the past

The first mention of the alloy of copper and tin is dated to the 4th millennium BC. It is this technological breakthrough, as historians believe, that allowed the civilization of Mesopotamia to occupy a leading position at that time. Archaeological excavations conducted in South Iran testify to the widespread use of bronze for the manufacture of arrowheads, daggers, spears, axes, swords. Among the finds there are even interior items, for example, furniture and mirrors, as well as pitchers, amphoras, vases and plates. For the minting of ancient coins and making jewelry, the same alloy was used.

Bronze in the Middle Ages is beginning to be actively used in Europe. It produces such massive objects as cannons and church domes. In a later period, with the development of machine building, so universal metal also did not go unnoticed. It was appreciated, for the most part, for antifriction and anticorrosive properties. At the same time, it should be noted that the material used before was somewhat different from that which today is bronze. The composition of the alloy contained a number of minor impurities, significantly worsening its quality.

The chemical composition of modern bronze

Today in material science bronze is called an alloy of two metals: copper and tin, which can be used in a variety of proportions. Zinc, phosphorus, magnesium, lead and silicon can be added to this metal to give the metal the specified qualities. The presence of random impurities with the help of modern technologies is practically reduced to zero.

In most cases, the ratio of copper to tin in proportions of 85 to 15 percent is acceptable. Reducing the proportion of the second component below this level raises a number of problems, the main one of which is segregation. This term metallurgists call the process of stratification of the alloy and its uneven congealing.

Influence of the color of the alloy on its quality

Knowledgeable people can learn a lot about the material, only by looking at the color that bronze possesses. The composition directly affects this parameter. It's not hard to guess, copper gives a red tinge to the alloy. Therefore, a decrease in its percentage ratio in favor of other components will mean a gradual transition of color to dimmer tones.

With the usual balance of constituents (85% copper), bronze casts yellowness. This kind of variety can be found most often. A white alloy is obtained after adjusting the ratio to a ratio of 50:50. But to make the bronze gray, you need to reduce the amount of copper to 35%.

As for changing the practical characteristics of the alloy when experimenting with its composition, the situation here is as follows. The malleability of the material will depend directly on the content of tin in it. The smaller, the more pliable bronze, but this statement is true only up to a certain limit. So, when the mark reaches 50%, the alloy again becomes soft.

Bronze in art

Strong and durable material, while having a sufficiently low melting point and good malleability, could not but interest creative people, in particular sculptors. Already in the 5th-4th centuries BC in Greece, the technology of making bronze statues was worked out to the smallest details, which is still relevant today. It consists in the fact that the statue of fire-resistant material is initially replaced with wax, which is directly destroyed during casting. To do this, the gypsum model must first be made, and then the mold for casting. The wax content when exposed to temperature simply melts, and its place is occupied by bronze, which cools and solidifies. After that, it remains only to process and bring to perfection.

Artillery metal

For the production of guns, and later of other military equipment, bronze was always used. The composition of the alloy, which is used for these purposes, usually contains 90% copper and only 10% tin. This is due to the fact that the material for the tools must be very strong and have an increased resistance to rupture. Such qualities are possessed by bronze brand BRAZhM10-3-1.5. In addition to the main components, it contains 1-2% manganese, which increases the antifriction and temperature characteristics.

Making church bells

Bell ringing should be melodic, and its sound should please the hearing at a great distance. Ironically, bronze has such musical talents. To improve the sound of the bell it is made of an alloy with an increased content of tin (from 20 to 22%). Sometimes it also adds a little silver. Bronze grades, which are used in the manufacture of bells and other percussion instruments, are absolutely unsuitable for practical application in other industries. This is due to the fact that such an alloy has a fine-grained structure and increased brittleness.

Phosphoric and aluminum bronze

For the first time an alloy consisting of 90% copper, 9% tin and 1% phosphorus was applied by Künzel in 1871. It was called phosphor bronze, and the material found its application mainly in engineering. Various parts of machines are cast from it, which are subject to increased friction. Phosphorus is necessary to increase the elasticity and increase the anti-corrosion properties. The main advantage of this metal is that it perfectly fills any grooves in the casting.

Aluminum bronze, whose composition is characterized by an increased content of copper (up to 95%), in appearance is very similar to gold. Besides beauty, it has a number of other undeniable advantages. For example, the addition of 5% aluminum allows the alloy to withstand a long time exposure to an aggressive medium, such as increased acidity.

As a material for the manufacture of various parts of machines, this metal almost universally replaced phosphor bronze in paper mills and in powder production due to a higher resistance to tearing.

Silicon and manganese bronze

Silicon is added to the alloy to increase the electrical conductivity. This is its quality used in the production of telephone wires. The reference composition of silicon bronze is as follows: 97.12% of copper, 1.14% of tin, 0.05% of silicon.

The most complex production process can boast an alloy containing manganese. The whole procedure goes through several stages. First, ferromangan is added to molten copper. Then, having sustained the given temperature regime, tin is added, and, if necessary, zinc. The English company Bronce Company manufactures several grades of manganese bronze, which has different viscosity and hardness. This alloy can be used in virtually all industries.