By measuring out-diffusion from samples which had previously been loaded with H, the H diffusion coefficients in binary alloys were determined. They were found for the α-phase of each alloy, for temperatures of between 25 and 300C, and could be described by:

log[D] = -3.723 - 0.002Co - (1452 + 29Co)/4.575T(K)

when the contents of the alloying elements were expressed in mol%. The additions decreased the H diffusion coefficient. The diffusion-retarding effect of the alloying element increased with decreasing temperature. The overall temperature expression for diffusion of H in Fe:

log[D] = -3.67 - 1438/4.575T

was obtained by extrapolating the above equation to 0% alloying element concentration. This result agreed quite well with the most likely value for the lattice diffusion of H; as extrapolated from measurements made at high temperatures.

H.J.Koenig, K.W.Lange: Archiv für Eisenhüttenwesen, 1975, 46[10], 669-75

 

Table 53

Self-Diffusion of 59Fe in Equiatomic Fe-Co

 

Temperature (K)

D(m2/s)

1238

8.84 x 10-15

1236

7.21 x 10-15

1206

4.14 x 10-15

1185

1.79 x 10-15

1164

1.01 x 10-15

1145

6.82 x 10-16

1129

3.34 x 10-16

1104

1.70 x 10-16

1091

1.44 x 10-16

1060

4.50 x 10-17

1015

1.00 x 10-17

993

3.08 x 10-18

981

1.01 x 10-18

954

2.40 x 10-19

923

2.94 x 10-20

877

2.08 x 10-21