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Crystallization is the process by which solids form, where the atoms or molecules are highly organized into a structure known as a crystal. Some ways by which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas.
The process is repeated, decreasing temperature and precipitating more crystals. The process is then stopped at a desired temperature, and the growth is removed from the furnace. Practically, the flux method is done by placing the growth into a programmable furnace: [citation needed]
The process can be carried out in a horizontal or vertical orientation, and usually involves a rotating crucible/ampoule to stir the melt. [1] The Bridgman method is a popular way of producing certain semiconductor crystals such as gallium arsenide, for which the Czochralski method is more difficult. The process can reliably produce single ...
In chemistry, fractional crystallization is a stage-wise separation technique that relies on the liquid–solid phase change. This technique fractionates via differences in crystallization temperature and enables the purification of multi-component mixtures, as long as none of the constituents can act as solvents to the others.
Nevertheless, secondary crystallization can proceed even below T g, in the time scale of months and years. This process affects mechanical properties of the polymers and decreases their volume because of a more compact packing of aligned polymer chains. [4] [7] The chains interact via various types of the van der Waals forces. The interaction ...
The Czochralski method, also Czochralski technique or Czochralski process, is a method of crystal growth used to obtain single crystals of semiconductors (e.g. silicon, germanium and gallium arsenide), metals (e.g. palladium, platinum, silver, gold), salts and synthetic gemstones.
In this technique, crystallization takes place without a temperature gradient between the growth and dissolution zones. The supersaturation is achieved by a gradual reduction in temperature of the solution in the autoclave. The disadvantage of this technique is the difficulty in controlling the growth process and introducing seed crystals. For ...
A powder X-ray diffractometer in motion. X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract in specific directions.