Physical And Chemical Properties Of The Metal Aluminum

Aluminum is a silver-white light metal. It's malleable. Commodities are often made into columns, rods, sheets, foils, powders, ribbons and filaments. In the humid air can form a layer of oxide film to prevent metal corrosion. Aluminum powder treated with acid is heated in the air and burns violently, emitting a blinding white flame. Soluble in dilute sulfuric acid, dilute nitric acid, hydrochloric acid, sodium hydroxide and potassium hydroxide solution, insoluble in water, but can react slowly with hot water to produce aluminum hydroxide, relative density 2.70, elastic modulus 70Gpa, Poisson's ratio 0.33. Melting point 660℃. Boiling point 2327℃. It is widely used for its light weight, good electrical and thermal conductivity, high reflectivity and oxidation resistance. The aluminum used for daily use is usually called "steel essence" or "steel seed". The thermal expansion coefficient of Al at (room temperature) 25℃ is 0.0000236mm/℃ or 23.6ppm*k-1.

Aluminum is an active metal. In dry air, a dense oxide film of about 50 angstroms (1 angstroms =0.1 nm) is formed immediately on the surface of aluminum, so that aluminum will not be further oxidized and can withstand water. But aluminum powder, when mixed with air, burns easily; Molten aluminum a metal that can correspond violently with water; Aluminum is amphoteric and soluble in strong bases as well as dilute acids.