ADSORPTION OF HYDROGEN BY A THIN FILM OF TITANIUM
ARO INC ARNOLD AFS TN
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Past experience has shown that the capture coefficient of a Ti surface for H2 is strongly dependent upon the surface temperature and the conditions under which the film is formed. This report presents the results of an investigation which determined the importance of some of the variables. It was found that the capture coefficient increased as the Ti surface temperature was decreased from 273 to 77 K. Moreover, the capture coefficient could be further increased by lowering the temperature of the substrate upon which the Ti film was deposited from 273 to 77 K. Also, the capture coefficient was found to be independent of film thickness and chamber pressure but increased when the deposition was carried out in an inert He atmosphere. For the range of conditions investigated, the sticking fraction was found to vary from 0.01 to 0. 5. The experimental data suggest that surface diffusion is an important part of the mechanism by which Ti captures H2. Calculations using a theoretical model which incorporates diffusion agreed well with experimental results.
- Metallurgy and Metallography