Cation tracer diffusion coefficients were measured in pure samples in the intrinsic ionic conductivity range of 876 to 970C. The best-fit defect parameters which had been deduced during a previous conductivity study had yielded a free vacancy contribution which was described by:
D (cm2/s) = 4.25 exp[-2.21(eV)/kT]
Combining these data with the present diffusion results (table 204) indicated a vacancy-pair contribution of:
D (cm2/s) = 1.15 x 108 exp[-4.04(eV)/kT]
G.P.Pantanelli, D.H.Whitmore: Journal of the Physics and Chemistry of Solids, 1974, 35[3], 445-53
Table 204
Diffusivity of 22Na in 4N8-Purity NaF Single Crystals
Temperature (C) | D (cm2/s) |
970.0 | 9.32 x 10-9 |
966.0 | 7.40 x 10-9 |
962.5 | 7.36 x 10-9 |
958.0 | 6.71 x 10-9 |
952.0 | 5.03 x 10-9 |
947.0 | 4.34 x 10-9 |
937.0 | 4.20 x 10-9 |
931.0 | 3.60 x 10-9 |
919.0 | 2.59 x 10-9 |
901.0 | 1.80 x 10-9 |
894.0 | 1.26 x 10-9 |
876.0 | 9.90 x 10-10 |