Secondary ion mass spectrometry was used to measure diffusion profiles in monocrystalline specimens of nominally pure a-phase (with about 50ppm), or polycrystalline (1-2mm) samples of ultra-pure material (less than 1ppm) and Fe-doped material (50ppm). The results for ultra-pure material could be described by:
D (m2/s) = 2.6 x 10-5exp[-3.1(eV)/kT]
On the basis of the results (tables 177 and 178), it was concluded that intrinsic substitutional diffusion was normal, and that Fe was responsible for the enhanced substitutional diffusion which was observed in nominally pure Zr.
G.M.Hood, H.Zou, R.J.Schultz, J.A.Roy, J.A.Jackman: Journal of Nuclear Materials, 1992, 189[2], 226-30
Table 177
Diffusion of Hf in Monocrystals of Nominally Pure a-Zr
Direction | Temperature (K) | D (m2/s) |
|| | 1111.0 | 4.26 x 10-18 |
| 1111.0 | 3.76 x 10-18 |
|| | 1000.5 | 1.91 x 10-18 |
| 1000.5 | 1.26 x 10-18 |
|| | 873.0 | 2.31 x 10-20 |
| 873.0 | 1.41 x 10-20 |
|| | 799.5 | 3.6 x 10-23 |
| 799.5 | 4.5 x 10-23 |
Table 178
Diffusion of Hf in Polycrystalline Ultra-Pure or Fe-Doped -Zr
Sample | Temperature (K) | D (m2/s) |
ultra-pure | 1111.0 | 1.1 x 10-19 |
Fe-doped | 1110.9 | 1.1 x 10-17 |
ultra-pure | 1052.6 | 7.6 x 10-20 |
ultra-pure | 1000.0 | 8.2 x 10-21 |
ultra-pure | 934.2 | 5.3 x 10-22 |
Fe-doped | 933.4 | 1.1 x 10-18 |
ultra-pure | 873.0 | 2.5 x 10-23 |