Glass is an amorphous inorganic nonmetallic material, which is generally made of various inorganic minerals (such as quartz sand, borax, boric acid, barite, barium carbonate, limestone, feldspar, soda ash, etc.). ) as the main raw material, and add a small amount of auxiliary raw materials. Its main components are silicon dioxide and other oxides. [ 1]? The chemical composition of ordinary glass is Na2SiO3 _ 3, CaSiO3 _ 3, SiO _ 2N2O Cao 6SiO _ 2, etc. The main component is silicate double salt, which is an amorphous solid with irregular structure. Widely used in buildings, used for wind and shading, belonging to a mixture. In addition, colored glass doped with oxides or salts of certain metals shows color, and tempered glass made by physical or chemical methods. Some transparent plastics are sometimes called plexiglass.
Generally speaking, glassy substances are obtained by rapid cooling of the melt. When the melt is transformed into glassy, the viscosity increases sharply during the cooling process, so that the particles can not be arranged regularly to form crystals, and the latent heat of crystallization can not be released. Therefore, glassy substances contain higher internal energy than crystalline substances, and their energy is between molten and crystalline substances, which belongs to metastable state. From the mechanical point of view, glass is an unstable high-energy state, such as the tendency of low-energy state transition, that is, the tendency of crystallization, so glass is a metastable solid material.
Timely glass, silicate glass, soda-lime glass, fluoride glass, high-temperature glass, high-pressure glass, ultraviolet-proof glass and explosion-proof glass. Usually refers to silicate glass, which is made of quartz sand, soda ash, feldspar and limestone through mixing, high-temperature melting, homogenization, processing and molding, and then annealing. Widely used in construction, daily use, art, medical care, chemistry, electronics, instrumentation, nuclear engineering and other fields.