Impurity diffusion characteristics were determined for relaxed amorphous alloy samples at temperatures ranging from 573 to 694K. It was observed that there was no systematic dependence of the diffusivity upon the 2 different methods of surface preparation (table 73); thus proving the non-existence of crystalline particles in the surface layers of relaxed amorphous ribbons. The data could be described by the expression:

D(m2/s) = 1.1 x 10-6exp[-1.80(eV)/kT]

No difference between Fe impurity diffusion and Co diffusion could be detected in the relaxed amorphous alloy. This suggested that Fe and Co diffused via the same mechanism.

J.Pavlovský, J.Cermák: Scripta Metallurgica et Materialia, 1994, 30[10], 1317-20

Table 72

Diffusivity of 95Nb in Co2Nb

 

Temperature (K)

Method

D (m2/s)

1569

sputtering

2.24 x 10-16

1519

sputtering

9.45 x 10-17

1469

sputtering

3.51 x 10-17

1469

grinding

4.01 x 10-17

1419

sputtering

1.46 x 10-17

1369

sputtering

5.51 x 10-18

1369

grinding

9.42 x 10-18

1320

sputtering

2.10 x 10-18

1270

sputtering

9.19 x 10-19

1220

sputtering

2.97 x 10-19

1180

sputtering

1.28 x 10-19

1143

sputtering

4.56 x 10-20