Here are some quick questions: | ||||||

The answers
are sometimes (and possibly only indirectly) contained in the links. |
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3.1.1 Diffusion and Point Defects |
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Give examples of products / processes / technologies that depend in a major way on point defect diffusion. | ||||||

Write down and discuss Fick's 1st law | ||||||

Write down and discuss Fick's 2nd law | ||||||

How do Ficks Laws connect to atomic diffusion?
Give the two important equations dermining the diffusion
coefficient i) by atomic
jumping, and ii) via the diffusion
length D.L |
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What is the
geometry
factor concerning jumping point defects in lattices? Can
you give numbers for some common lattices?g |
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3.2 Diffusion mechanisms |
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Describe at least 2 possibilites for the
diffusion of a substitutional and interstial impurity atom, respectively. |
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Which diffusion mechanisms are the most important ones? | ||||||

For a substitutional impurity atom that diffuses
via a vacancy mechanism, the diffusion coefficient will be
proprotional to ....?D |
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How do atoms diffuse in amorphous materials - e.g. glasses and polymers? | ||||||

What is self diffusion? The self-diffusion
coefficient is given by....?D_{self } |
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Any given atom in a given crystal will sooner or later leave its original place because of self diffusion. How long - roughly - does it take at high temperatures for all atoms to have changed positions? How about the atoms in your brain? | ||||||

3.1.1 Diffusion and Point Defects

© H. Föll (Defects - Script)