Interdiffusion (table 95) in the bulk of the alloy at 293 to 435K was observed by means of the movement of a thin (approximately 1nm thick) Au overlayer into the alloy during annealing. The measured activation energy of 0.74eV was attributed to the migration of mono- and di-vacancies which occurred predominantly in the grain boundaries. The lateral movement of an approximately 0.6nm-thick Au overlayer in a mechanically polished surface furnished data on surface diffusion at about 330K. It was found that the
diffusion coefficients exceeded 10-27m2/s and that the activation energies were 40 to 100kJ/mol for low-temperature diffusion in the bulk of most polycrystalline materials.
G.Hultquist: Journal of Materials Science, 1986, 21[9], 3253-8
Table 95
Interdiffusion in the Cu-Au System
Temperature (K) | Grain Size (mm) | D (m2/s) |
293 | 0.20 | 1.2 x 10-25 |
309 | 0.20 | 8.0 x 10-25 |
325 | 0.20 | 3.0 x 10-20 |
335 | 0.20 | 6.8 x 10-24 |
373 | 0.20 | 4.7 x 10-23 |
435 | 0.20 | 2.6 x 10-21 |
325 | 0.30 | 7.5 x 10-25 |
383 | 0.30 | 3.6 x 10-23 |
325 | 0.03 | 1.0 x 10-23 |
383 | 0.03 | 4.6 x 10-22 |