The diffusion of Co was measured, by using radio-tracer techniques, at temperatures ranging from 449 to 859K (tables 270 and 271). It was found that the diffusivity in the grain boundaries was 8 orders of magnitude higher than the self-diffusivity in α-Zr. It was proposed that Co diffused interstitially in the grain boundaries, and this suggestion was supported by the small activation volume which was measured for Co grain boundary diffusion.

K.Vieregge, C.Herzig: Journal of Nuclear Materials, 1990, 175, 29-41

 

Table 271

Grain Boundary Diffusivity of Co in α-Zr

 

Temperature (K)

D (m3/s)

859

5.9 x 10-16

773

4.5 x 10-18

726

8.3 x 10-19

686

2.0 x 10-19

666

3.2 x 10-19

641

1.3 x 10-20

610

2.7 x 10-20

579

2.3 x 10-21

516

6.3 x 10-23

473

1.5 x 10-23

449

6.5 x 10-24