1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Diffusion coefficient.

  1. Feb 29, 2008 #1
    [SOLVED] Diffusion coefficient.

    Hi everybody

    I have a Nitrogen atom sitting at the octahedral site in fcc iron. I have calculated the minimum energy path (diffusion path) when moving the Nitrogen atom to the neighboring octahedral site.

    My question is:
    How can i calculate the diffusion coefficient? (only considering the diffusion in that one direction)
     
  2. jcsd
  3. Feb 29, 2008 #2

    Mapes

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Hi tkjacobsen, welcome to PF. The standard way is to estimate [itex]D[/itex] for interstitial diffusion is

    [tex]D=\frac{r^2 \nu}{6} \exp\left(\frac{-G_m}{kT}\right)[/tex]

    where [itex]r[/itex] is the distance between sites, [itex]\nu[/itex] is the attempt frequency (the characteristic vibration frequency in the crystal), and [itex]G_m[/itex] is the energy barrier involved in jumping from one interstitial site to another.

    Edit: Sorry, I really should have given a reference. Try Allen and Balluffi's Kinetics of Materials, Porter and Easterling's Phase Transformations in Metals and Alloys, or any good kinetics book.
     
    Last edited: Feb 29, 2008
  4. Feb 29, 2008 #3
    Thanks alot, this was exactly what I was looking for.

    Best Regards
    T.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Diffusion coefficient.
  1. Diffusion path (Replies: 1)

  2. Diffusion length (Replies: 1)

Loading...