Dependence of outgassing rate on surface oxide layer thickness in type 304 stainless steel before and after surface oxidation in air

Odaka, Kenji; Ueda, Shinjiro

doi:10.1016/0042-207x(96)00048-6

Cited by 23 publications

(14 citation statements)

References 3 publications

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“…17 The oxide layers are mostly iron oxide, compared to chromium oxide which dominates the surfaces of unbaked steel. 19 Some have observed that oxide layers can act as diffusion barrier to hydrogen 2,18–20 and, consequently, can lower the hydrogen outgassing rate. On the other hand, the oxide layers produced by baking have been also observed to change the surface reaction rate, 16 and may also reduce the number of desorption sites.…”

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 use of oxides as a transport barrier is realized in most vacuum systems, due to the formation of native oxides on the surface of the construction materials. Deliberate oxidation has also been used to reduce the out-gassing rate of stainless steel, improving the vacuum performance by orders of magnitude [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

The influence of amorphous Al2O3 coating on hydrogen uptake of materials

Wang

Pálsson

Raanaei

et al. 2008

Journal of Alloys and Compounds

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“…The reduction in outgassing rate due to the 150 °C bake is larger than would be expected due to hydrogen depletion through diffusion during the low temperature bake. Similar behavior seen elsewhere 13,35,36 is postulated to be a result of an oxide-layer diffusion barrier that forms after venting, evacuation and baking. The outgassing rate following the 250 °C bake increased to 2.79(±0.05)×10 -13 Torr L s -1 cm -2 , higher than the rate following either the 400 °C or the 150 °C bake.…”

Section: A Bare Stainless Steelmentioning

confidence: 64%

Effect of heat treatments and coatings on the outgassing rate of stainless steel chambers

Mamun¹,

Elmustafa²,

Stutzman

et al. 2013

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

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The outgassing rates of three nominally identical 304L stainless steel vacuum chambers were measured to determine the effect of chamber coatings and heat treatments. One chamber was coated with titanium nitride (TiN) and one with amorphous silicon (a-Si) immediately following fabrication. The last chamber was first tested without any coating, and then coated with a-Si following a series of heat treatments. The outgassing rate of each chamber was measured at room temperatures between 15 and 30 °C following bakes at temperatures between 90 and 400 °C. Measurements for bare steel showed a significant reduction in the outgassing rate by nearly a factor of 20 after a 400 °C heat treatment-12 Torr L s -1 cm -2 prior to heat treatment, reduced to 1.7×10 -13 Torr L s -1 cm -2 following heat treatment). The chambers that were coated with a-Si showed minimal change in outgassing rates with heat treatment, though an outgassing rate reduced by heat treatments prior to a-Si coating was successfully preserved throughout a series of bakes.The TiN coated chamber exhibited remarkably low outgassing rates, up to four orders of magnitude lower than the uncoated stainless steel, but the uncertainty in these rates is 2 large due to the sensitivity limitations of the spinning rotor gauge accumulation measurement and the possibility of a small pump speed due to inhomogeneity in the TiN coating. The outgassing results are discussed in terms of diffusion-limited versus recombination-limited processes.3

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Dependence of outgassing rate on surface oxide layer thickness in type 304 stainless steel before and after surface oxidation in air

Cited by 23 publications

References 3 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

The influence of amorphous Al2O3 coating on hydrogen uptake of materials

Effect of heat treatments and coatings on the outgassing rate of stainless steel chambers

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