Hydrogen Release Rate of SUS316 in Ar Gas Flow and Vacuum

To understand the mechanism of hydrogen release from materials used in vacuum technology, the release behavior of tritium from stainless steel SUS316 previously loaded with this gas was investigated isothermally at 423 K either under a stream of argon or under vacuum conditions. Depth profiles of the heated specimens were determined by chemical etching. The experimental release rate and the tritium depth profile in the solid could be simulated with a model based on bulk diffusion. The diffusion coefficients used to fit the depth profiles of specimens heated under vacuum at 423 K were non-discernible from those obtained with specimens heated under a stream of Ar at the same temperature.