Trapping Effect In Hydrogen Retention In Metals

Abstract

For the case of hydrogen interaction with a metal, modified equation for the timedependent change of trapped hydrogen has been derived. The present equation is essentially the same with previous models but slightly different in details, namely

• it is more general because covers all of previous models which are the particular cases of the present equation,

• it takes into account the difference in the structure of bcc and fcc metals,

• it does not include unknown parameters as in previous models such as attempt frequency (Wilson-Longhurst’s model) and trap radius (Myers-Doyle and Franzen’s models), but only well-known lattice parameter and diffusion coefficient from the literature.

Comparison of the present model with Longhurst’s and Franzen’s models for hydrogen retention in tungsten shows that the present and Longhurst’s approaches differ by factor of six and Franzen’s approach results in about two orders of magnitude higher retention.