Properties of aluminum - the material at all times

Often the first names of something - a device, material or product - most accurately and clearly reflect their essence. And then comes the period of comprehension and comes a new name, scientific, in which an understandable "everyday" meaning goes into non-existence. Once aluminum was called alumina, i.e. "Clay of the earth," and clay, as is known, is the primary essence of the earth. Now so called aluminum oxide. And to replace the formerly known name "alumina" came a new name - "aluminum" - beautifully, mysteriously and scientifically. The legend of the first advent of aluminum has a sad end: the master who gave the emperor Tiberius an amazing bowl of hitherto unknown metal to save a gift in a single copy, just in case, cut off his head - he found someone to give. In those days, at the beginning of our era, questions of secrecy were solved radically, and gratitude for the mastery was also peculiar. Whatever it was, but only through fifteen centuries Paracelsus established that alumina (alum), used to fix paints in fabrics and skins, contains oxide of an unknown metal.

Pure metal was obtained only in 1825. The Danish scientist Oersted received as a side effect of his research "a piece of metal resembling tin," but he did not continue to work. Nevertheless, by the middle of the XIX century, aluminum - silver, light, easy-to-process metal - was valued more gold. Properties of aluminum were first appreciated by jewelers. He was fashion, and at an exhibition in Paris in 1855, aluminum products were displayed next to the diamonds of the French crown. As you know, demand leads to an increase in supply, so the production technology has received impetus to development. And by the middle of the twentieth century, aluminum had become a common material widely used in engineering, and the physical properties of aluminum had already been fairly well studied.

Technologies of industrial aluminum production

The basis for the production of aluminum is electrolysis, and the raw material is Al2O3, dissolved in the cryolite melt. For electrolysis, baths are used, the operating temperature of which is slightly less than 1000 ° C. Liquid aluminum is collected at the bottom of the bath - this is the cathode of the installation. Pour it into molds and get ingots or pigs - raw materials for further processing.

The properties of aluminum are changed in the right manner using alloying additives. At the same time, they achieve an increase in strength, hardness, heat resistance, etc. With a focus on specific applications. Alloying materials for various alloys - copper, manganese, zinc, magnesium, and (in small quantities) silicon, iron, nickel, etc. are added to the melt in the final manufacture of the desired type of finished product.

Basic physical properties of aluminum

Any material is characterized by a set of physico-chemical properties, which determines its subsequent use. The properties of aluminum - plasticity, low specific gravity, good heat and electrical conductivity - are known to all.

• The density of aluminum is 2.710 kg / m3
• Melting point - 660 ° C
• Boiling point - 2519 ° C
• Specific electrical resistance - 2,7 * 10-8 Ohm m / mm square.

From the point of view of the application in electrical engineering, the magnetic properties of aluminum, of which it belongs to the weakly magnetic substances of the paramagnet group, are of undoubted interest. This class of materials is characterized by the fact that its magnetic field coincides with it in the direction of the action of the external field, and, although very insignificantly, it increases.

Application of aluminum

The value of the material determines the demand for products from it. Aluminum is in demand primarily as a structural material. Ease of processing and corrosion resistance allow the use of aluminum products in construction, mechanical engineering, for the manufacture of thermal, food and other types of equipment. Aluminum is the main structural material of aviation. Aluminum alloys are increasingly used in shipbuilding - ship hulls, communications, deck superstructures, various ship equipment. Widely used in industry and household duralumin and silumin - non-corrosive alloys of aluminum with copper - up to 7% or silicon - up to 14%.

The electrical conductivity of aluminum is slightly inferior to copper, but aluminum is much lighter and cheaper than it is due to its wide application in electrical engineering. At the same time, the main properties of aluminum for such applications are low electrical resistance, weight and low cost. More and more often in electrical equipment, where exclusively copper conductors dominated exclusively, aluminum windings of transformers, inductors, reactors, "wires" of cables, etc. are used. The main power lines are also largely due to aluminum.

There is no doubt that this amazing metal has not yet revealed all its possibilities - it is to be done in the future.