5.0 - Hence as temperature increases, the number of point...

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Diffusion Diffusion is the material transport by atomic migration. Atoms move from an area of higher concentration to one of lower concentration. This is easy to imagine for gasses and liquids. It is harder to imagine in solids, but diffusion does occur in solids, just very slowly. For solids, diffusion requires the presence of point defects. Point Defects Point defects occur as a direct result of the thermal vibrations of atoms in the crystal structure.
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Unformatted text preview: Hence as temperature increases, the number of point defects increases exponentially according to the Maxwell-Boltzmann distribution. Hence, the concentration of point defects (i.e. the number of defects / total number of atomic sites in the crystal lattice) is given by: n defect = Ce (Edefect) /kT n sites where E defect is the activation energy required to form the point defect k is Boltzmanns constant T is absolute temperature...
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This note was uploaded on 08/10/2009 for the course ENGN 45 taught by Professor Wendy during the Spring '09 term at City College of San Francisco.

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