Hydrogen Permeation in 304 and 316 Steels: Transport Mechanisms in Oxide Layers*

Grant, David M.; Cummings, D.L.; Blackburn, D. A.

doi:10.1524/zpch.1989.164.part_2.1585

Cited by 4 publications

(3 citation statements)

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“…(2) Describing the initially dissolved hydrogen as a uniform concentration. (3) Using accurate, consistent values [1][2][3] to describe diffusion and recombination in stainless steel types 304 and 316. (4) Considering only one type of hydrogen trap, and ignoring trapping in components made from vacuum remelted stainless steel.…”

Section: Discussionmentioning

confidence: 99%

“…The most relevant studies for understanding vacuum chambers seem to be the measurements of AISI types 304 and 316 made by Grant, Cummings, and Blackburn. [1][2][3] Their results, which are discussed in Appendix A, are key parameters in the present model. The present model was devised to understand outgassing in a small vacuum chamber that was used to measure vapor pressures near 10 Pa. Hydrogen outgassing was a problem because the chamber (1) operated at temperatures up to 200 C, which greatly increased the outgassing rate, (2) had a large surfaceto-volume ratio, and (3) could not be pumped while it was being used to measure vapor pressure.…”

Section: Introductionmentioning

confidence: 99%

“…(2) The initially dissolved hydrogen was described as a uniform concentration. (3) Accurate, consistent values, obtained by Grant et al, [1][2][3] were used to describe diffusion and recombination in stainless steel types 304 and 316.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen traps in the outgassing model of a stainless steel vacuum chamber

Berg

2014

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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This article describes a model for hydrogen outgassing into a stainless steel vacuum chamber. It accounts for the geometry of the chamber components, the hydrogen dissolved in those components, and the processes of diffusion, recombination, and trapping. Strongly bound or "trapped" hydrogen, which occurs at heterogeneities such as dislocations and grain boundaries, can hold most of the dissolved hydrogen even though those locations comprise fewer than 0.1% of all lattice sites. Four simplifications allowed practical use of the model: (1) Each component was described as a one-dimensional object. (2) The hydrogen initially dissolved in each component was described as a uniform concentration. (3) Accurate, consistent values were used to describe diffusion and recombination in stainless steel types 304 and 316 [Grant et al., J. Nucl. Mater. 149, 180 (1987); 152, 139 (1988)]. (4) Only one type of hydrogen trap was considered, and trapping was ignored in components made from vacuum remelted stainless steel. The simple model was developed and validated by comparing it to outgassing measurements. Traps were required to describe the outgassing from a component made of drawn stainless steel 304. The initial hydrogen concentration in that component was comparable to concentrations found elsewhere by thermal desorption and almost 100 times larger than in the components made of vacuum remelted 316 stainless steel. The model's usefulness was illustrated by using it to predict the outgassing of a vacuum chamber made of type 304 stainless steel. [

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%