The H desorption properties of the pure Al and of the Al alloy were investigated by means of thermal desorption spectroscopy. In the case of the H thermal desorption spectrum, 2 peaks in the temperature were observed which were thought to correspond to desorption that was due to second-order surface reactions and diffusion. The activation energy for desorption, due to surface reaction, was equal to 38kJ/mol in the case of AA1050. In the case of AA1001, the activation energy and diffusion constant of H were calculated, by using a simple diffusion model, to be 50kJ/mol and 0.0005 to 0.0035cm2/s, respectively. The H which was desorbed from the Al alloy was estimated to be 0.159cm3 per 100g of Al. This was twice the equivalent value for AA1050.
Y.Hirohata, S.Fujimoto, T.Hino, T.Yamashina: Journal of Vacuum Science and Technology A, 1993, 11[5], 2637-41
Table 39
Triple Product at 553K for Zn Diffusion through Tilt Grain Boundaries in Al
Tilt Axis: <111>
Tilt Angle (º) | Pressure (MPa) | sδD (m3/s) |
38 | 0.1 | 1.85 x 10-20 |
38 | 0.4 | 1.9 x 10-20 |
38 | 600 | 9.4 x 10-21 |
38 | 1200 | 5.5 x 10-21 |
39 | 0.1 | 2.35 x 10-20 |
39 | 0.4 | 3.3 x 10-20 |
39 | 300 | 1.3 x 10-20 |
39 | 600 | 1.3 x 10-20 |
39 | 900 | 1.1 x 10-20 |
39 | 1200 | 1.1 x 10-20 |
43 | 0.1 | 2.15 x 10-20 |
43 | 0.4 | 3.41 x 10-20 |
43 | 300 | 1.7 x 10-20 |
43 | 600 | 1.8 x 10-20 |
43 | 900 | 1.8 x 10-20 |
43 | 1200 | 8.6 x 10-21 |