Hydrogenation characteristics of air-exposed magnesium films

A study of the hydrogenation characteristics of 30-mum thick air-exposed magnesium film has been made using a volumetric method. Magnesium films were prepared by vacuum evaporation. Morphological and structural properties were studied by scanning electron microscopy, X-ray diffraction and Auger profile. It was shown that magnesium films absorb hydrogen at 623 K under 10 bar of hydrogen pressure and desorb it at the same temperature under a residual hydrogen pressure of 0.21 bar. The first absorption follows a nucleation and growth process. Furthermore, macroscopic and microscopic observations made at different stages of the absorption-desorption process are presented. (C) 2002 Elsevier Science B.V. All rights reserved.