Nucleation
 Crystallization is the transformation of material from a liquid stage to solid state crystals. Crystallization occurs in two stages: 1) nucleus formation and 2) crystal growth.
For metals and other crystalline materials, atomic motion in a liquid state is almost completely disordered. As the energy of the liquid system decreases, the movement of the atoms decreases and the atoms start to arrange in a lattice. Materials expect to solidify when the liquid phase is cooling below its freezing temperature (or melting temperature), since the energy related to the crystalline structure of the solid is less then the energy of the liquid. When the temperature of a liquid metal decreases significantly below its freezing point, stable solidified nuclei appear spontaneously at different points in the liquid. The new nuclei are now acting as centers for additional crystallization. As cooling process continues, more atoms are freezing. These atoms may stick to the existing nuclei or they can form new nuclei.
Recommended Websites
Solidification - The crystallization of a large amount of matter from a single point of nucleation results in a single crystal…
http://www.ndt-ed.org/EducationResources/CommunityCollege/Materials/Structure/solidification.htm Dendritic Solidification - A liquid when cooled solidifies. Once nucleation has occurred…
http://www.msm.cam.ac.uk/phase-trans/dendrites.html DENDRITES http://www.youtube.com/watch?v=ph1R9JjTY-Y Nucleation Theory - Phase fluctuations are random atomic events resulting from atomic vibrations that are driven by thermal energy… http://www.geology.um.maine.edu/geodynamics/microdynamics/ellemodules/nucleation/theory.html Lessons for Cryonics from Metallurgy and Ceramics - Mixtures of some metals, such as copper (Cu) and nickel (Ni), are completely soluble in each other in solid state for all concentrations of both metals... http://www.benbest.com/cryonics/lessons.html Heat Treating
Polymorphism - Dr. Dana Ashkenazi Homepage
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Crystal growth KDP Crystal Growth
Solid State Structure
Atoms can be gathered together through different processes, including condensation, chemical reaction, pressurization, electrodeposition, and melting... STM Image Gallery - The artist, shortly after discovering a way to move atoms with the STM, decided to give something back to the corporation (IBM) which gave him the job... http://www.almaden.ibm.com/vis/stm/atomo.html Recrystallization of copper vitriol http://www.youtube.com/watch?v=erjXD1iUXKo  |
