Thermodesorption of hydrogen from a tantalum foil

The effect of preliminarily treating the surface of a Ta foil in hydrogen a nd CO on the temperature dependence of the rate of hydrogen desorption in t he range 573-783 K was studied. It was experimentally found that the larges t amount of H-2 was desorbed at the highest rate and highest desorption rat e constant at 753 K. The activation energy of desorption was determined. Th e desorption process involves the transfer of hydrogen dissolved in the sub surface bulk H-sub to the surface: H-sub --> H-s. The presence of Hsub caus ed a decrease in the H-s-Ta bond energy.