The behavior of Fe and Ni in monocrystalline material was investigated at temperatures ranging from 651 to 870K, and from 613 to 949K, respectively (tables 40 and 41). Ion-beam sputtering and secondary-ion mass spectrometry were used to measure the concentration versus depth profiles. It was found that the diffusion of Fe and Ni could be described by:

Fe:     D (m2/s) = 1.0 x 10-5exp[-2.04(eV)/kT]

Ni:     D (m2/s) = 6.2 x 10-5exp[-2.32(eV)/kT]

It was noted that these results were consistent with previously reported high-temperature tracer data. By combining the latter data with the present low-temperature results, a curvature of the Arrhenius plot was revealed. This curvature was attributed to the contribution that was made by di-vacancies at high temperatures. The variation of the diffusivities of Fe and Ni as a function of temperature could be explained by using a modified electrostatic model for impurity diffusion and by assuming effective values for the charge difference between host atoms and impurities.

A.Almazouzi, M.P.Macht, V.Naundorf, G.Neumann: Physical Review B, 1996, 54[2], 857-63

 

 

 

Table 40

Diffusivity of Ni in Cu

 

Temperature (K)

D (m2/s)

613

4.67 x 10-24

622

8.32 x 10-24

637

2.10 x 10-23

659

1.38 x 10-22

685.5

4.00 x 10-22

698

1.02 x 10-21

705

1.87 x 10-21

732.5

4.28 x 10-21

735

7.15 x 10-21

750

1.68 x 10-20

766.5

3.75 x 10-20

782.5

9.86 x 10-20

801

1.44 x 10-19

849

9.25 x 10-19

872

3.05 x 10-18

921.5

1.08 x 10-17

949

2.22 x 10-17

 

 

 

Table 41

Diffusivity of Fe in Cu

 

Temperature (K)

D (m2/s)

651

1.96 x 10-21

663

3.35 x 10-21

680

4.59 x 10-21

691

1.98 x 10-20

704

2.34 x 10-20

719

5.93 x 10-20

741

1.15 x 10-19

756

2.80 x 10-19

787

9.53 x 10-19

801

1.40 x 10-18

830

4.14 x 10-18

843

7.38 x 10-18

850

8.81 x 10-18

870

1.55 x 10-17