lasivaiheen

Lasivaiheen is a term used in materials science to denote an amorphous, non-crystalline phase present in some solid materials. Unlike crystalline phases, lasivaihe lacks long-range atomic order, which leads to isotropic properties and a lack of distinct crystal planes. It can form by rapid cooling (quenched melts), vapor deposition, or chemical vitrification, and may occur as the major phase in purely amorphous solids or as a glassy matrix surrounding crystalline inclusions. The transition from liquid to glass is not marked by a sharp phase transition but by a kinetic glass transition; the material gradually becomes rigid as the temperature drops below the glass transition temperature Tg, becoming a glassy solid with significantly reduced atomic mobility.

In practical materials, lasivaiheen can be metallic, oxide-based, or polymeric. Metallic glasses exhibit high strength and hardness but often limited ductility; oxide glasses (such as silica) are common in windows and bottles and are chemically durable; glass-ceramics combine a glassy matrix with crystalline phases to tailor properties. In geology, natural glasses like obsidian are examples of lasivaihe materials formed when lava cools rapidly at the surface.

Characterization relies on techniques such as X-ray or neutron diffraction, which show broad halos rather than sharp peaks, and calorimetry, which detects Tg. The presence and amount of lasivaihen influence properties including hardness, brittleness, thermal stability, and corrosion resistance.