Diffusion coefficient

[mporcu]

hi
i require the diffusion coefficient of carbon in tungsten and tantalum.
Who can help me?

 

[kenvlach]

Not much data, unless there’s something recent not in the handbooks.
From Tracer diffusion data for metals, alloys, and simple oxides, John Askill, New York, (1970), reprinted in CRC Handbook of Chemistry and Physics, etc.

Measurements for C¹⁴ isotope. Ta & W each polycrystalline.

D = D_o e^-Q/RT

C in Ta: D_o = 0.012 cm²/sec, Q = 40.3 kcal/mol, Temp. range 1450-2200^oC.

C in W: D_o = 0.00891 cm²/sec, Q = 53.5 kcal/mol, Temp. range 1200-1600^oC.

Hope this helps,
Ken

 

[elguero]

I would check Chemical Abstracts. There should be a collection available at a nearby college or university library.