The use of a substance depends to a large extent on the nature of the substance. Because aluminum has a variety of excellent properties, aluminum has a very wide range of uses. Aluminum and aluminum alloys are currently one of the most economical and suitable materials that are widely used. Since 1956, the world's aluminum output has surpassed the copper output and has always ranked first in non-ferrous metals. The current production and consumption of aluminum (calculated in ton) is second only to steel, becoming the second largest metal used by mankind; and aluminum resources are very abundant. According to preliminary calculations, aluminum reserves account for more than 8% of the earth's crust. .
Aluminum's light weight and corrosion resistance are two outstanding features of its performance.
The density of aluminum is very small, only 2.7 g/cm. Although it is relatively soft, it can be made into various aluminum alloys, such as hard aluminum, super-hard aluminum, rust-proof aluminum, cast aluminum, etc. These aluminum alloys are widely used in manufacturing industries such as airplanes, automobiles, trains, and ships. In addition, space rockets, space shuttles, and satellites also use large amounts of aluminum and its aluminum alloys. For example, a supersonic aircraft is composed of approximately 70% aluminum and its aluminum alloys. Aluminum is also used in large quantities in ship construction, and the amount of aluminum used in a large passenger ship often reaches several thousand tons.
The conductivity of aluminum is second only to silver, copper and gold. Although its conductivity is only 2/3 of copper, its density is only 1/3 of copper. Therefore, the quality of aluminum wire is only copper for the same amount of electricity. Half of the line. The oxide film on the surface of aluminum not only has the ability to resist corrosion, but also has a certain degree of insulation, so aluminum has a wide range of uses in the electrical manufacturing industry, wire and cable industry, and radio industry.
Aluminum is a good conductor of heat, and its thermal conductivity is three times greater than that of iron. Aluminum can be used to manufacture various heat exchangers, heat dissipation materials and cooking utensils in the industry. Aluminum has good ductility (its ductility is second only to gold and silver), and can be made into aluminum foil thinner than 0.01 mm at 100 ℃ to 150 ℃. These aluminum foils are widely used for packaging cigarettes, candy, etc., and can also be made into aluminum wire, aluminum strips, and rolled various aluminum products. Because of the dense oxide protective film on the surface of aluminum, it is not easy to be corroded. It is often used to make chemical reactors, medical equipment, refrigeration equipment, petroleum refining equipment, oil and natural gas pipelines, etc. Aluminum powder has a silver-white luster (generally the color of metal in powder form is mostly black). It is commonly used as paint, commonly known as silver powder and silver paint, to protect iron products from corrosion and be beautiful.
Aluminum can emit a lot of heat and dazzling light when burned in oxygen. It is often used to make explosive mixtures, such as ammonium-aluminum explosives (mixed with ammonium nitrate, charcoal powder, aluminum powder, soot and other combustible organic matter) , Combustion mixture (such as bombs and shells made of thermite can be used to attack hard-to-fire targets or tanks, artillery, etc.) and lighting mixtures (such as 68% barium nitrate, 28% aluminum powder, 4% shellac). Thermite is often used to smelt refractory metals and weld steel rails. Aluminum is also used as a deoxidizer in the steelmaking process. Aluminum powder, graphite, titanium dioxide (or oxides of other high melting point metals) are uniformly mixed in a certain ratio, then coated on the metal and calcined at high temperature to make high temperature resistant cermet. It has important applications in rocket and missile technology. . The reflection performance of the plate to light is also very good. The reflection of ultraviolet rays is stronger than that of silver. The purer the aluminum, the better its reflection ability. Therefore, it is often used to manufacture high-quality mirrors, such as solar cooker mirrors. Aluminum has sound-absorbing properties and good acoustics, so aluminum is also used in the ceilings of broadcast rooms and modern large-scale buildings. Low temperature resistance. When the temperature is low, aluminum will increase its strength without brittleness. Therefore, it is ideal for low-temperature equipment materials, such as cold storage, freezer, Antarctic snowmobiles, and hydrogen oxide production equipment.
