A new technique that was based upon surface coverage kinetic measurements was proposed for the determination of intergranular diffusion. This technique did not require the preparation of special samples, such as thin foils. It was limited to systems in which the solute segregated strongly at grain boundaries and free surfaces. By using this technique, intergranular S diffusion in Ni (table 22) was shown to be described by:

D (m2/s) = 2.7 x 10-9exp[-58700/RT]

at temperatures ranging from 723 to 1073K.

R.Le Gall, E.Quérard, G.Saindrenan, H.Mourton, D.Roptin: Scripta Materialia, 1996, 35[10], 1175-81

Table 22

Grain Boundary Diffusion of S in Ni