Dependence of the outgassing rate of a “vacuum fired” 316LN stainless steel chamber on bake-out temperature

Jousten, Karl

doi:10.1016/s0042-207x(98)00002-5

Cited by 33 publications

(21 citation statements)

References 14 publications

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“…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. This behavior has also been reported in literature 13,37 where it is believed that 250 °C provides sufficient thermal energy to liberate hydrogen atoms from strongly bound defect states. Once liberated, these hydrogen atoms serve to repopulate the reservoir of mobile hydrogen in the chamber walls, resulting in higher outgassing.…”

Section: A Bare Stainless Steelsupporting

confidence: 82%

“…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 Steelsupporting

confidence: 56%

“…For stainless steel systems with no leaks and where no process gas is introduced, the gas load is primarily from hydrogen outgassing from the steel 5 . There are numerous reports of successful reduction of the outgassing rate via moderate [6][7][8][9][10][11][12] and high temperature [11][12][13][14][15][16][17][18] heat treatments which serve to reduce hydrogen outgassing. There are also numerous reports of coatings such as titanium nitride (TiN) [19][20][21][22][23][24] , boron nitride 24,25 , silicon 26,27 , or silicon oxide 28 that may reduce the outgassing rate by acting as diffusion barriers.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: A Bare Stainless Steelsupporting

confidence: 82%

Section: A Bare Stainless Steelsupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

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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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“…To exploit the benefits of removing hydrogen dissolved in the bulk materials, 24 we annealed the steels at 850 C for 12 h. The outgassing rate for the low-carbon steel D3752 decreased by $66% after heat treatment at 850 C for 12 h in vacuum (Table II, sample 1). No meaningful reduction was measured even after a second consecutive heat treatment.…”

Section: 7-10mentioning

confidence: 99%

Thermal outgassing rates of low-carbon steels

Park¹,

Ha²,

Cho

2015

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

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Outgassing rates of three low-carbon steels were measured using rate-of-rise and throughput methods. Outgassing rates of water vapor during pump-down were higher than those of stainless steels, probably due to the nature of native surface oxide layer. However, hydrogen outgassing rates without a high temperature pretreatment were as low as (1–4) × 10−10 Pa m3 s−1 m−2, which is much lower than that of untreated stainless steels. No dramatic reduction was observed in H2 outgassing after vacuum annealing at 850 °C for 12 h, suggesting that the low-carbon steels had been fully degassed during the steelmaking processes. This may be due to the use of the Ruhrstahl-Hausen vacuum process during steel refining instead of an older process, such as argon-oxygen decarburization. The extremely low H2 outgassing rate from low-carbon steels makes them applicable for use in ultrahigh vacuum or even extreme high vacuum applications, particularly where magnetic field shielding is needed.

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“…There is a considerable body of work attempting to describe the hydrogen outgassing behaviour of SS during and after thermal treatment. For description of the outgassing rate basically two common models such as the diffusion limited model (DLM) and recombination limited model (RLM) have been discussed [2][3][4][5][6][7][8][9][10]. On the assumption made by Calder and Lewin [2], the outgassing rate of hydrogen from stainless steel should be limited only by the bulk diffusion rate in the fcc lattice.…”

Section: Introductionmentioning

confidence: 99%