The Characteristics Of The Vetrosa
Glass is made of silica and other chemical substances melted together (the main production of raw materials: soda ash, limestone, quartz). In the melting of the formation of a continuous network structure, the viscosity of the process gradually increased and hardened to cause the crystallization of silicate non-metallic materials.Vetrosa
The chemical composition of ordinary glass is Na2SiO3, CaSiO3, SiO2 or Na2O · CaO · 6SiO2, etc., the main component is silicate salt, is a kind of amorphous structure of amorphous solid. Widely used in buildings, used to light through the light, belong to the mixture. A colored glass having a color or a salt, and a tempered glass obtained by a physical or chemical method. Sometimes some transparent plastic (such as polymethylmethacrylate) is also known as plexiglass.
The molecular arrangement of the glass is irregular, and its molecules have statistically uniformity in space. In the ideal state, the physical and chemical properties (such as refractive index, hardness, elastic modulus, thermal expansion coefficient, thermal conductivity, electrical conductivity, etc.) of the homogeneous glass are the same in all directions.
Because the glass is a mixture, non-crystalline, so no fixed melting point. Glass from the solid into a liquid is a certain temperature range (ie softening temperature range) carried out, it is different from the crystalline material, there is no fixed melting point. Softening temperature range Tg ~ T1, Tg for the transition temperature, T1 for the liquidus temperature, the corresponding viscosity were 1013.4 dPa · s, 104 ~ 6dPa · s.Vetrosa
Glassy matter is generally obtained by the rapid cooling of the melt, from the molten state to the glass transition, the cooling process of rapid increase in viscosity, the mass is too late to do a regular arrangement to form crystals, did not release latent heat of crystallization, therefore, glass The substance contains a higher internal energy than the crystalline material, and its energy is between the molten state and the crystalline state, and belongs to the metastable state. From the mechanical point of view, the glass is an unstable high-energy state, such as the existence of low-energy state transition trend, that is, crystallization tendency, so the glass is a metastable solid material.Vetrosa