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Traductions

• anglais

  Date : 1990

  Définition

  An amorphous inorganic usu. transparent or translucent substance consisting typically of a mixture of silicates or ((...)) borates or phosphates and sometimes metallic oxides or other coloring agents ((...)).
  A semisynthetic, amorphous material classed as a ceramic.

  Notes :

  It is vitreous liquid which is not fluid except at high temperatures; it cools from the molten state without forming the crystal structure characteristic of solids, even though it is mechanically rigid. Glass does not have a specific melting point, but softens gradually on heating. Glass occurs in nature in limited amounts as the volcanic glass, obsidian.
  Glass is typically hard and brittle, and has a conchoidal fracture.
  When a specific kind of glass is indicated, such descriptive terms as flint glass, barium glass, and window glass should be used following the basic definitions, but the qualifying term is to be used as understood by trade custom.
  Objects made of glass are loosely and popularly referred to as glass; such as glass for a tumbler, a barometer, a window, a magnifier, or a mirror.
  The basic constituents of glass are silica, soda, lithium, etc., are often added. These are heated to melting in a lehr, or furnace, from which the melt is withdrawn by ladles and poured onto tables (for flat products) or removed in small amounts and formed into specific shapes by manipulation. Superior grades (plate glass) are annealed ((...)). The simplest glass is sodium silicate, or water glass.

  Terme :

  1. glass