US3833430A - Treatment of stainless steel and similar alloys to reduce hydrogen outgassing - Google Patents

Treatment of stainless steel and similar alloys to reduce hydrogen outgassing Download PDF

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Publication number
US3833430A
US3833430A US00318139A US31813972A US3833430A US 3833430 A US3833430 A US 3833430A US 00318139 A US00318139 A US 00318139A US 31813972 A US31813972 A US 31813972A US 3833430 A US3833430 A US 3833430A
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Prior art keywords
hydrogen
layer
stainless steel
vacuum
oxide
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US00318139A
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English (en)
Inventor
E Hill
J Walls
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Varian Medical Systems Inc
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Varian Associates Inc
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Priority to US00318139A priority Critical patent/US3833430A/en
Priority to FR7345757A priority patent/FR2211347B3/fr
Priority to DE2364638A priority patent/DE2364638A1/de
Priority to JP49004463A priority patent/JPS4997737A/ja
Application granted granted Critical
Publication of US3833430A publication Critical patent/US3833430A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
    • B01J3/006—Processes utilising sub-atmospheric pressure; Apparatus therefor
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • C23C28/042—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/32—Hydrogen storage

Definitions

  • a reduced layer having a low heat of adsorption for water is formed on the exposed surface of the oxide and nitride mixture layer.
  • This reduced layer is made sufficiently thin to preclude outgassing of significant amounts of hydrogen into the vacuum system.
  • a vacuum envelope is formed which outgasses only from a thin layer of reduced oxide.
  • the rate of permeation of hydrogen through stainless steels at 371C is in the order of X cc(STP)mm/hr/cm /atm- It is known with respect to'stainless steels, from which a major share of the components of a vacuum system are typically made, that an oxide layer on the surface of such a stainless steel component serves to decrease the rate of hydrogen permeation through the surface by a factor of 10 as compared to an untreated surface. However, such oxide layers are generally nonadherent or only poorly adherent to stainless steel surfaces.
  • a vacuum system component made of stainless steel or of a similar alloy is shown by reference number 1 in the drawing.
  • the component could, for example, be part of an ultrahigh vacuum pumping system designed to attain pressures lower than l0' torr, i.e., pressures lower than would be attainable where significant outgassing of hydrogen from the system components can occur.
  • the component might instead be part of a hydrogen detection system used in conjunction with a sodium-cooled nuclear reactor.
  • the sodium leak detection system of such a reactor could be designed to degreen oxide has not heretofore been used as a hydrogen diffusion barrier in high-vacuum technology because of the extremely high heat of adsorption of water on the green oxide, about 30,000 calories per mole.
  • This invention provides a readily adherent coating which serves as a barrier to the outgassing of hydrogen from stainless steel and similar alloys.
  • the coating can be applied by well-known techniques to components of vacuum systems known to the present art.
  • present technology can be used'in applications requiring reliable routine operation at pressures as low as 10*torr.
  • a stainless steel component to be treated according to this invention is first treated by a chemical process which fonns an adherent layer comprising anoxide, or more typically a mixture of oxides and nitrides, on the surface thereof.
  • the oxide and nitride mixture layer provides a barrier to the outgassing of hydrogen by diffusion as atomic hydrogen through the metal lattice of the component.
  • the oxide and nitride mixture layer is then treated by a chemical process which forms a thin reduced metal-like layer on the surface exposed to the tect the presence of hydrogen gas generated by the chemical interaction of leaking sodium with materials disposed in the immediate vicinity of the sodium circulation system.
  • Such a hydrogen detection system would not function effectively if the components of the system were allowed to outgas hydrogen to a significant extent, because theoutgassed hydrogen could mask and render undiscemible any hydrogen generated as a result of a sodium leak.
  • Oxide coatings are known to be effective in reducing the rate of hydrogen diffusion out of stainless steels and similar alloys. Oxide coatings made by direct oxidation with air or oxygen, however, are generally nonadherent or only poorly adherent to stainless steels and similar alloys, and furthermore, tend to form porous rather than smooth coating surfaces. A porous surface is unsuitable as a high-vacuum envelope because the hydrogen can diffuse through it almost as rapidly as through unoxidized stainless steels. Furthermore, a porous surface has a high heat of adsorbtion for water. In addition, such oxides are often unstable at high temperatures. However, a particular substance that does adhere well to stainless steels and similar alloys and that is stable at high temperatures, is known to brazing practice as green oxide or chrome oxide. It seemed advantageous, therefore, to examine the properties with respect to hydrogen diffusion of the so-called green oxide.”
  • Green oxide or chrome oxide adheres readily to stainless steels and similar alloys, and is used as a coating on brazing jigs to prevent brazing alloys from sticking to the jig surfaces.
  • the green oxide coating is formed on a stainless steel componentby exposing the component to an atmosphere of dissociated ammonia saturated with water vapor so that the atmosphere has a dew point in the range from 10C to 19C, and heating the component in this atmosphere for approximately 20 minutes at a temperature in the range from 1,000C to 1,100C.
  • green oxide is a complex mixture of nitrides and oxides including the following compounds: Fe N, CrN, Ni N, NiO, and Cr O Compounds of manganese and silicon were also found as minor or trace constituents.
  • the precise proportions of the nitrides and oxides vary with the relative proportions of the constituents of the stainless steel, and probably also with such factors as temperature and exposure time to the dissociated ammonia atmosphere. It was found that by coating a stainless steel surface with the complex mixture of nitrides and oxidesthat comprises the green oxide, the rate of diffusion of hydrogen from the stainless steel at 400C can be reduced to 25 percent of the rate of hydrogen diffusion for untreated stainless steel at the same temperature.
  • Green oxide adheres readily to stainless steel, as shown by reference number 2 in the drawing, but unfortunately, has a high surface adsorbtion capacity to water.
  • the heat of adsorbtion of green oxide for polar molecules such as water is especially high, being on the order of 30,000 calories per mole. This characteristic renders green oxide particularly unsuitable as the exposed surface of a vacuum envelope. Water vapor is ever-present in the ambient atmosphere, and water molecules adsorbed onto the green oxidecoating would establish such a high partial pressure of water vapor in the vacuum systemv that an unacceptably high base-line pressure for the system would result.
  • the low hydrogen permeation rate of green oxide estimated-to be less than 5 lOcc(STP)mm/hr/cm- /atm' is a desirable property for high-vacuum sysan atmosphere of anhydrous hydrogen.
  • Such treatment will chemically reduce the exposed surface of the green oxide coating to a metal-like layer which has a relatively low heat of adsorbtion with respect to water molecules, i.e., approximately 20,000 calories per .mole.
  • the result is a sandwich structure in which a hydrogen diffusion barrier in the form of a layer 2-composed of a mixture of oxides and other compounds is sandwiched between the underlying vacuum system component 1 on the one side and a thin reduced layer shown by reference number 3 on the other side. Analysis shows that the thin reduced layer exposed to the vacuum has substantially the same metal composition as the underlying vacuum system component.
  • a base-line hydrogen pressure of '8 l0 torr-is obtainable at room temperature using exgen pressure at room temperature was only 2 10 torr;
  • oxidation and reduction conditions described herein for sandwiching the hydrogen barrier layer between the underlying vacuum system component and the thin vacuum envelope surface may vary according to the type of stainless steel or other alloy used, the structural strength required of the component to be treated and design requirements of a given vacuum system. Such variations canbe made without departing from the scope of the present invention. It is anticipated that the technique of this invention for reducing the outgassing of hydrogen can be practiced with any metal that forms protective oxides or nitrides, particularly high chromium alloys, so that the scope of this invention is limited only by the following claims.
  • An article having a surface thereof intended for exposure to a vacuum in a vacuum system comprising'a stainless steel substrate, a first layer coating a portion of said substrate, said first layer comprising an oxidized form of said stainless steel substrate and having a rate of permeation for hydrogen which is substantially less than the rate of permeation of hydrogen through said substrate, and a second layer coating said first layer, said second layer comprising a reduced form of said first layer and having a lower heat of adsorption for water than said first layer, the surface of said second layer being the surface intended for exposure to said vacuum.
  • said second layer comprises substantially the same material as said substrate and is substantially thinner than said substrate.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
  • Pressure Vessels And Lids Thereof (AREA)
  • Physical Vapour Deposition (AREA)
US00318139A 1972-12-26 1972-12-26 Treatment of stainless steel and similar alloys to reduce hydrogen outgassing Expired - Lifetime US3833430A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US00318139A US3833430A (en) 1972-12-26 1972-12-26 Treatment of stainless steel and similar alloys to reduce hydrogen outgassing
FR7345757A FR2211347B3 (xx) 1972-12-26 1973-12-20
DE2364638A DE2364638A1 (de) 1972-12-26 1973-12-24 Bauteil fuer eine vakuumanlage und verfahren zur herstellung dieses bauteils
JP49004463A JPS4997737A (xx) 1972-12-26 1973-12-26

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00318139A US3833430A (en) 1972-12-26 1972-12-26 Treatment of stainless steel and similar alloys to reduce hydrogen outgassing

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US43655774A Division 1974-01-25 1974-01-25

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US (1) US3833430A (xx)
JP (1) JPS4997737A (xx)
DE (1) DE2364638A1 (xx)
FR (1) FR2211347B3 (xx)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4284687A (en) * 1978-11-29 1981-08-18 Fried Krupp Gesellschaft Mit Beschrankter Haftung Compound body
US5789086A (en) * 1990-03-05 1998-08-04 Ohmi; Tadahiro Stainless steel surface having passivation film
EP1486586A1 (en) * 2003-06-10 2004-12-15 Vaclab Inc. Material for a vacuum device vacuum device and vacuum apparatus thereof
US20050189525A1 (en) * 2004-02-27 2005-09-01 Thomas Kuckelkorn Radiation-selective absorber coating with an adherent oxide layer and method of making same
WO2008072046A1 (en) * 2006-12-13 2008-06-19 Toyota Jidosha Kabushiki Kaisha Pressure container
US20110108441A1 (en) * 2008-07-09 2011-05-12 Toyota Jidosha Kabushiki Kaisha Gas tank and manufacturing method of gas tank

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5832229B2 (ja) * 1978-09-22 1983-07-12 日本真空技術株式会社 金属窒化物を被覆した真空容器及び真空機器用部品

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2703298A (en) * 1949-10-14 1955-03-01 Robertshaw Fulton Controls Co Process for annealing stainless steel
US3691055A (en) * 1968-09-27 1972-09-12 Kawasaki Steel Co Method of coating steel sheet surfaces
US3700505A (en) * 1971-01-11 1972-10-24 Jerome J Kanter Coating ferrous base metal articles
US3741735A (en) * 1964-01-08 1973-06-26 Atomic Energy Commission Coating molybdenum with pure gold

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2703298A (en) * 1949-10-14 1955-03-01 Robertshaw Fulton Controls Co Process for annealing stainless steel
US3741735A (en) * 1964-01-08 1973-06-26 Atomic Energy Commission Coating molybdenum with pure gold
US3691055A (en) * 1968-09-27 1972-09-12 Kawasaki Steel Co Method of coating steel sheet surfaces
US3700505A (en) * 1971-01-11 1972-10-24 Jerome J Kanter Coating ferrous base metal articles

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4284687A (en) * 1978-11-29 1981-08-18 Fried Krupp Gesellschaft Mit Beschrankter Haftung Compound body
US5789086A (en) * 1990-03-05 1998-08-04 Ohmi; Tadahiro Stainless steel surface having passivation film
EP1486586A1 (en) * 2003-06-10 2004-12-15 Vaclab Inc. Material for a vacuum device vacuum device and vacuum apparatus thereof
US20040253448A1 (en) * 2003-06-10 2004-12-16 Vaclab, Inc. Material for vacuum device, vacuum device, vacuum apparatus, manufacturing method of material for vacuum device, processing method of vacuum device, and processing method of vacuum apparatus
US7297419B2 (en) 2003-06-10 2007-11-20 Vaclab Inc. Material for vacuum device, vacuum device, vacuum apparatus, manufacturing method of material for vacuum device, processing method of vacuum device, and processing method of vacuum apparatus
US20050189525A1 (en) * 2004-02-27 2005-09-01 Thomas Kuckelkorn Radiation-selective absorber coating with an adherent oxide layer and method of making same
ES2289854A1 (es) * 2004-02-27 2008-02-01 Schott Ag Aparato de absorcion con un revestimiento absorbente selectivo para radiaciones y procedimiento para su produccion.
US7793653B2 (en) 2004-02-27 2010-09-14 Schott Ag Radiation-selective absorber coating with an adherent oxide layer and method of making same
US20100025411A1 (en) * 2006-12-13 2010-02-04 Toyota Jidosha Kabushiki Kaisha Pressure container
WO2008072046A1 (en) * 2006-12-13 2008-06-19 Toyota Jidosha Kabushiki Kaisha Pressure container
US8087537B2 (en) 2006-12-13 2012-01-03 Toyota Jidosha Kabushiki Kaisha Pressure container
US20110108441A1 (en) * 2008-07-09 2011-05-12 Toyota Jidosha Kabushiki Kaisha Gas tank and manufacturing method of gas tank
EP2325543A1 (en) * 2008-07-09 2011-05-25 Toyota Jidosha Kabushiki Kaisha Gas tank and process for producing gas tank
EP2325543A4 (en) * 2008-07-09 2011-08-10 Toyota Motor Co Ltd GAS CONTAINER AND METHOD FOR PRODUCING THE GAS CONTAINER
US20110209817A1 (en) * 2008-07-09 2011-09-01 Toyota Jidosha Kabushiki Kaisha Gas tank and manufacturing method of gas tank
US8172108B2 (en) 2008-07-09 2012-05-08 Toyota Jidosha Kabushiki Kaisha Gas tank and manufacturing method of gas tank
US9140408B2 (en) 2008-07-09 2015-09-22 Toyota Jidosha Kabushiki Kaisha Gas tank and manufacturing method of gas tank

Also Published As

Publication number Publication date
FR2211347A1 (xx) 1974-07-19
JPS4997737A (xx) 1974-09-17
FR2211347B3 (xx) 1976-04-16
DE2364638A1 (de) 1974-06-27

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