Hydrogen in Vacuum Systems: An Overview

Redhead, P. A.

doi:10.1063/1.1597372

Cited by 36 publications

(24 citation statements)

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“…Three types of baking schemes are commonly employed to degas hydrogen from stainless steel: Vacuum firing, in which the entire vacuum chamber is placed in a vacuum furnace operating at >950°C and pressures below 10 −3 Pa; 2,5–9 medium heat treatment vacuum bake, in which the vacuum chamber is evacuated and heated to 400–500°C, typically with the outside of the chamber in air at atmospheric pressure; 10–13 and a medium heat treatment air-bake, in which the vacuum chamber is baked entirely in air at atmospheric pressure at a temperature of 400°C or greater. 6,7,13,14 Hydrogen diffuses through stainless steel as atomic H, 15,16 and the diffusion coefficient for hydrogen in stainless steel depends exponentially on temperature; 17 increasing the temperature greatly decreases the time it takes for the hydrogen to migrate from the stainless steel bulk to the surface, where it recombines to form H 2 and desorbs from the surface. 18 The time it takes to remove most of the hydrogen from the stainless steel bulk depends on the temperature and material thickness.…”

Section: Introductionmentioning

confidence: 99%

Investigations of medium-temperature heat treatments to achieve low outgassing rates in stainless steel ultrahigh vacuum chambers

Sefa

Fedchak

Scherschligt

2017

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

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The authors investigated the outgassing rates and fluxes of vacuum chambers constructed from common 304L stainless steel vacuum components and subjected to heat treatments. Our goal was to obtain H2 outgassing flux on the order of 10−11 Pa l s−1cm−2 or better from standard stainless steel vacuum components readily available from a variety of manufacturers. The authors found that a medium-temperature bake in the range of 400 to 450°C, performed with the interior of the chamber under vacuum, was sufficient to produce the desired outgassing flux. The authors also found that identical vacuum components baked in air at the same temperature for the same amount of time did not produce the same low outgassing flux. In that case, the H2 outgassing flux was lower than that of a stainless-steel chamber with no heat treatment, but was still approximately 1 order of magnitude higher than that of the medium-temperature vacuum-bake. Additionally, the authors took the chamber that was subjected to the medium-temperature vacuum heat treatment and performed a 24-h air bake at 430°C. This additional heat treatment lowered the outgassing rate by nearly a factor of two, which strongly suggests that the air-bake created an oxide layer which reduced the hydrogen recombination rate on the surface. [http://dx.doi.org/10.1116/1.4983211]

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Section: Introductionmentioning

confidence: 99%

Investigations of medium-temperature heat treatments to achieve low outgassing rates in stainless steel ultrahigh vacuum chambers

Sefa

Fedchak

Scherschligt

2017

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

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“…The one with highest energy is assigned to H-O bond in H 2 O. It was reported that at low pressure condition, hydrogen gas can be considered as a residual element, and the dissociated H atom might interact with other species to form H 2 O or C x H y [19].…”

Section: Resultsmentioning

confidence: 99%

Effect of surface treatment on adhesion strength between magnetron sputtered copper thin films and alumina substrate

Lim

Lee

Rhee

et al. 2015

Applied Surface Science

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“…Volume 4, Issue 4, April -2017, e-ISSN: 2348-4470, print-ISSN: 2348 Hydrogen is predominant residual gas at metal vacuum systems at very low pressure and the reduction in the hydrogen outgassing rate is most challenging problem in achieving vacuum of desired level [2]. Hydrogen outgassing can be well understood by ways of its outgassing.…”

Section: International Journal Of Advance Engineering and Research Dementioning

confidence: 99%

Review on Different Methods for Reducing Outgassing Rate From Vacuum Materials

2017

IJAERD

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Hydrogen in Vacuum Systems: An Overview

Cited by 36 publications

References 0 publications

Investigations of medium-temperature heat treatments to achieve low outgassing rates in stainless steel ultrahigh vacuum chambers

Investigations of medium-temperature heat treatments to achieve low outgassing rates in stainless steel ultrahigh vacuum chambers

Effect of surface treatment on adhesion strength between magnetron sputtered copper thin films and alumina substrate

Review on Different Methods for Reducing Outgassing Rate From Vacuum Materials

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