The activity and diffusivity of O in the liquid high-temperature superconductor precursor alloy were measured by using a modified coulometric titration method at 913 to 957C. The standard Gibbs formation energies, and the diffusivity of O in the liquid under 1atm of 1at%O, were found to be described by:

G(kJ/mol) = -655.20 + 0.335T

and:

D(cm2/s) = 0.018 exp[-48100/RT]

In spite of a very strong bonding of O to the liquid alloy, the diffusivity of O was of the order of 0.0001cm2/s. The solubilities of O in the liquid alloy were of the order of 0.0145 and 0.017at% at 913 and 935C, respectively.

H.Chou, H.S.Chen, W.C.Fang, F.A.Thiel, M.K.Wu: Applied Physics Letters, 1992, 60[6], 760-2

 

Table 97

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 98

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