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実用材料における昇温脱離スペクトル

実用材料における昇温脱離スペクトル. Thermal desorption study of selected austenitic stainless steel: Bache, J.-P., J.Vacuum Science and Technology A21, 167(2003). 実用材料における昇温脱離スペクトル. Thermal desorption study of selected austenitic stainless steel: Bache, J.-P., J.Vacuum Science and Technology A21, 167(2003).

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実用材料における昇温脱離スペクトル

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  1. 実用材料における昇温脱離スペクトル Thermal desorption study of selected austenitic stainless steel: Bache, J.-P., J.Vacuum Science and Technology A21, 167(2003).

  2. 実用材料における昇温脱離スペクトル Thermal desorption study of selected austenitic stainless steel: Bache, J.-P., J.Vacuum Science and Technology A21, 167(2003). ARC:Melted in electric arc furnace MC(N) precipitates AOD:Arc-oxygen decarburation ESR:Electro slag remelting

  3. Precipitates MC: TiC/TiC M(CN): Nb(CN)/Ti(CN)/AlN M23C6: Cr16Fe5Mo2)C6;(FeCr)23C6;(Cr17Fe4-5)C6 M6C: (CrCoMoNi)6;(TiNi)6C;(Fe3Mo3)C Austenitic Stainless Steels, Microstructure and Mechanical Properties P.Marshall (Elsevier Applied Science, 1984),pp.32.

  4. 測定の課題 Surface desorption bulk outgassing Non-uniformity (poly crystalline, interfaces, precipitates Temperature uniformity is most important

  5. TDSスペクトル 316 Ti ARC+AOD 316LN ESR

  6. 全H2放出量 950℃　×2hheating Complete outgassing TDS after charging H2 No vented: 480℃ peak Air vented: 680 and 800℃　peaks

  7. Comments on TDS measurement • Surface composition change monitored by XPS • 110℃ : oxide and hydroxide of Cr and Fe + H2O • 270℃: reduction of iron oxide, decrease of H2O and C • 570℃: increase of Cr hydroxide, Segregation of Mn and Si • 870℃: complete reduction of oxide, metallic surface • Origin of desorption peak • 480℃ peak: diffusible interstitial H. Ed=0.52eV • 600-800℃: reduction of Fe or Cr oxide • Cracks in the thick oxide layer causes sharp peak above 600℃　in case of air bake process • 500-600℃　peak for 316 Ti: Hydrogen trapped at precipitates Hydrogen charging without air vent

  8. Electron Stimulated Desorption (ESD) Y.Ishikawa, Rev.Phys.Chem.Japan 16,83, 117 (1942). M.L.Knotek: Rep. Prog. Phys. 47,1499(1984). M.L.Knotek: Physics Today September, 24 (1984). R.D.Ramsier, T.T.Yates: Surface Science Report 12, 246(1991). Desorption induced by electron transition (DIET) 1:Springer series in chemical physics, 24,1(1983). Ta getter FE tube W surface filament tip doser e-gun Menzel, Gomer :J Chem Phys 41(1964)3311. Redhead:Can.J.Phys. 42(1964)886.

  9. 電離真空計の感度 • イオン化断面積 • 電子の飛距離 • イオン収集効率 電離真空計

  10. 電子励起脱離イオン Arakawa-Tuzi (C.Oshima)

  11. 電子衝撃脱離Electron stimulated desorption (ESD)Desorption induced by electronic transition(DIET)

  12. Menzel-Gomer-Redhead model (MGR) ★neutral M.L.Knotek:Rep.Prog.Phys. 47(1984)1499. ★Franck-Condon excitation to antibonding state Escape probability: v:velocity Sr:slope Escape time ～10-14s Excited state life time 全脱離断面積 For H/W(001), D/W(001) Franck-Condon Quantum mechanical formulation

  13. Threshold energy N2 Thershold energy: 5eV for N2 10eV for CO CO CO+ Knotek、Fig.8.

  14. Knotek-Feibelman model for ionic surfaces Maximal valency ionic compound K2O,CaO,ScO3,V2O5 Maximal valency: Cation is ionized to electron configuration of rare gas atom Ti 4 + in TiO2 O+ desorption Core-hole Sub-maximal valency Maximal valency 3 electrons of O2- released No O+ desorption

  15. Antoniewicz model for physisorbed molecules P.R.Antoniewicz, Phys.Rev. B21, 3811(1980). 正イオン ★positive ion formation ⇒ attraction by image force Surface electron density Repulsion by Pauli principle

  16. ESDIADElectron Stimulated Desorption Angular Distribution

  17. NH3, H2O/ Ni(111) Czyzewski, Maday, Yates; Phys.Rev.Lett. 32, 777(1974). NH3 O/Ni(111) H+ from NH3 H2O H2O+ O/Ni(111)

  18. Photo stimulated desorption in accelerators CERN 99-05, Dynamic outgassing, O.Groebner Total radiation power: [W] E: [GeV] I: [mA] r: [m] bending radius [Test chamber for SR induced outgassing] Photon flux per circumference [m-1] Total gas desorption Dynamic pressure rise

  19. D: beam dose [mAh] a=0.6～1 Straight line: constant S Data for OFHC copper [Beam cleaning]

  20. [Before degass process] [After degass process] ! High temperature degass is efficient For thermal outgassing. Not so efficiebt for photo induced outgassing.

  21. Beam induced gas desorption p:pressure in the beam line Particle balance

  22. Low energy photon induced desorption: PSD Ag plated D2 H2

  23. Electron induced desorption from cryogenic surfaces Bass, Sanche; Low Temperature Physics 29, 202 (2003). O- desorption Dissociative Electron Attachment (DEA)

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