The technique of H introduction by mechanical abrasion was applied to the determination of H diffusivity, in high-purity Al and Al-1000ppm[at]Si dilute alloy, by coupling it with thermal evolution spectroscopy. The diffusion data for high-purity Al could be described by:

D (m2/s) = 3.0 x 10-6 exp[-30(kJ/mol)/RT]

The diffusivities were larger than those previously reported. It was suggested that the interstitial mechanism predominated for H diffusion in high-purity Al; even in the low temperature region. Similar measurements were performed on Al-1000ppm[at]Si dilute alloy. By means of the trapping-detrapping model, the binding energy of a H atom to a Si atom was estimated to be 16kJ/mol. This showed that Si atoms in Al served as weak trapping centers.

Measurement of Hydrogen Diffusivity in Aluminum and a Dilute Alloy by Thermal Evolution Spectroscopy. S.Hayashi: Japanese Journal of Applied Physics - 1, 1998, 37[3A], 930-7