Self-diffusion coefficients (CHROMIUM ? NIOBIUM ?) 1

[maleck]

Hello folks, I am having problems to find de the self-diffusion coefficients of Cr and of Nb.

Does anyone have these numbers with reference ?

Thank you a lot for your time to answer me,
Maleck

 

[metengr]

If you need this data for free, the web site below is one of only a few that have lattice diffusion data for chromium and niobium;

http://thayer.dartmouth.edu/~defmech/chapter_5.htm#Molybdenum (Figs. 5.18 to 5.21)

 

[maleck]

Tnank you very much METENGR...very nice hearing from you! I have this book (Frost H. J., Ashby M. F., Deformation Mechanism Maps (Pergamon Press, Oxford, 1982) but they do not show the self-diffusion coefficient of chromium into chromium and that of niobium into niobium. This is what I am really looking for.

Anyway, I did not know this site and it can be very useful since it resumes many parts of the book. Having a electronic version saves a lot of space and it weights nothing

The other users can have the 18 chapters in their hard-drives browsing the pages :

http://thayer.dartmouth.edu/~defmech/chapter_1.htm

http://thayer.dartmouth.edu/~defmech/chapter_2.htm

(...)

http://thayer.dartmouth.edu/~defmech/chapter_18.htm

Anyway, if someone has the value of the self-difusion of chromium into chromium and that of niobium into niobium (with reference), it would be great !

Thank you again,
Maleck

 

[metengr]

Maleck;
The self diffusion parameters for Cr/Cr and Nb/Nb are as follows;

Element Tm Do Q
(K) (M^2S^-1) (Kj/mol)
x 10^4

Cr 2130 1280 441.9
Nb 2740 0.524 395.6

D = Do exp((-Q)/RT)

Note Do value is multiplied by X10^4 to obtain (cm^2s^-1)

Source; Physical Metallurgy Handbook, Sinha
pages 2.44 and 2.45

 

[maleck]

This was the best news I have received today Thanks a lot for your time in searching this data for me. You are great !

Cheers,
Maleck