Self-diffusion in nanocrystalline samples was studied by investigating the rotating-frame nuclear magnetic relaxation time of 63Cu at temperatures ranging from 283 to 425K. At temperatures above 350K, an atomic motion induced relaxation was observed. The activation enthalpy for diffusion was estimated to be equal to 0.69eV. This value was some 30% smaller than the value for grain-boundary diffusion in Cu bi-crystals.

W.Dickenscheid, R.Birringer, H.Gleiter, O.Kanert, B.Michel, B.Günther: Solid State Communications, 1991, 79[8], 683-6

 

Table 41

Grain-Boundary Diffusion in Cu

 

Purity

Temperature (K)

δD (m3/s)

5N8

1066

1.08 x 10-19

5N8

1050

1.15 x 10-19

5N

973

3.10 x 10-20

5N8

968

4.49 x 10-20

5N

923

1.97 x 10-20

5N

877

1.08 x 10-20

5N8

872

1.78 x 10-20

5N8

825

1.08 x 10-20

5N8

817

9.70 x 10-21

5N

784

2.57 x 10-21

5N8

777

5.60 x 10-21

5N8

740

2.67 x 10-21

5N8

720

2.16 x 10-21