The diffusion of O was studied in liquid alloys which were used as precursors in the preparation of superconducting thin films via the liquid-gas solidification method. The diffusivities were measured by using a coulometric titration technique. It was found that the diffusivities were of the order of 0.0001 to 0.001cm2/s, and that the logarithm of the O diffusivity was inversely proportional to the logarithm of the O concentration (tables 14 and 15). It was suggested that an interstitial diffusion mechanism contributed to the rapid O migration, and that strong bonds between Ba and O enhanced the configurational structural order and accelerated O diffusion.

H.Chou, T.C.Chow, H.S.Chen: Journal of Applied Physics, 1995, 78[5], 3511-3

 

 

 

Table 14

Diffusivity of O in Liquid Cu3Ba2Ca2Ti at 900C

 

 

O(at%)

 

D(cm2/s)

 

 

2.01 x 10-3

 

2.864 x 10-4

1.76 x 10-3

3.124 x 10-4

1.54 x 10-3

3.278 x 10-4

1.15 x 10-3

3.741 x 10-4

 

 

 

 

Table 15

Diffusivity of O in Liquid Cu3Ba2Ca2Ti2Ag at 870C

 

 

O(at%)

 

D(cm2/s)

 

 

9.51 x 10-4

 

3.29 x 10-4

7.29 x 10-4

3.21 x 10-4

5.14 x 10-4

3.63 x 10-4

4.08 x 10-4

3.62 x 10-4

2.46 x 10-4

4.44 x 10-4

2.36 x 10-4

4.73 x 10-4

1.66 x 10-4

5.18 x 10-4

1.31 x 10-4

4.97 x 10-4

1.29 x 10-4

5.48 x 10-4

1.02 x 10-4

5.42 x 10-4

7.40 x 10-5

6.63 x 10-4

4.40 x 10-5

7.29 x 10-4