Solidification and Crystallization
In order to understand the crystalline state and its difference from the amorphous state, it is important to consider the process of Solidification.
Solidification is the transformation of material from liquid to the solid state on cooling.
When the liquid solidifies, the energy of each atom is reduced. This energy is given out as latent heat during the solidification process, which for a pure mental occurs at a fixed temperature Ts as shown figure
During solidification, the disordered structure of the liquid(constituents of material in liquid state have more velocity, more collisions and hence have random position) transforms to the orderly arrangement depending upon the time of solidification. Crystal growth techniques.
The crystal growth technique is classified into six categories namely
i. Melt growth
ii. Low temperature solution growth
iii. High temperature solution growth
iv. Hydrothermal growth
v. Gel growth
vi. Epitaxial growth
Melt growth is the process of crystallization by fusion and re solidification of the starting materials
The growth from melt is further sub-grouped into various techniques. The mani techniques are
a) Czochralski technique
b) Bridgmen Technique
c) Verneuil method
d) Zone melting technique
The major practical factors is to be considered during growth crystals from melt are
2) Chemical resistivity
3) Melting point
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