The chronopotentiometric method was used to study the effect of temperature and alumina content upon the diffusion of Al and Na sub-ions, in the form of AlF and Na2F. The diffusivity decreased with increasing alumina content: slightly from 1 to 6%, and markedly above 6% (table 201).
M.M.Vetyukov, A.Z.Saber, Y.V.Borisoglebskii, L.V.Krylov: Izv. Vyssh. Uchebn. Zaved., Tsvetn. Metall., 1978, 4, 62-4
Table 201
Diffusivity of AlF and Na2F Ions in Na3AlF6-Al2O3 Melts
Al2O3 (wt%) | Temperature (C) | D (cm2/s) |
5 | 980 | 5.90 x 10-4 |
5 | 1000 | 6.30 x 10-4 |
5 | 1020 | 7.20 x 10-4 |
5 | 1040 | 9.40 x 10-4 |
5 | 1060 | 1.15 x 10-3 |
1 | 1060 | 1.20 x 10-3 |
2 | 1060 | 1.16 x 10-3 |
4 | 1060 | 1.18 x 10-3 |
6 | 1060 | 1.15 x 10-3 |
8 | 1060 | 1.00 x 10-3 |
9 | 1060 | 6.68 x 10-4 |
11 | 1060 | 2.51 x 10-4 |