EP0509971B1 - A process for the sorption of residual gas and especially nitrogen gas by means of a non-evaporated barium getter - Google Patents

A process for the sorption of residual gas and especially nitrogen gas by means of a non-evaporated barium getter Download PDF

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Publication number
EP0509971B1
EP0509971B1 EP92830186A EP92830186A EP0509971B1 EP 0509971 B1 EP0509971 B1 EP 0509971B1 EP 92830186 A EP92830186 A EP 92830186A EP 92830186 A EP92830186 A EP 92830186A EP 0509971 B1 EP0509971 B1 EP 0509971B1
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EP
European Patent Office
Prior art keywords
alloy
sorption
group
vessel
gas
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EP92830186A
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German (de)
English (en)
French (fr)
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EP0509971A1 (en
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Claudio Boffito
Antonio Schiabel
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SAES Getters SpA
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SAES Getters SpA
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J7/00—Details not provided for in the preceding groups and common to two or more basic types of discharge tubes or lamps
    • H01J7/14—Means for obtaining or maintaining the desired pressure within the vessel
    • H01J7/18—Means for absorbing or adsorbing gas, e.g. by gettering
    • H01J7/183—Composition or manufacture of getters
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C24/00—Alloys based on an alkali or an alkaline earth metal

Definitions

  • the barium-aluminium (about 50% Ba) alloy is mixed with, preferably, 15% by weight of powdered tin to produce getters.
  • Said getters are heated by means of high frequency electrical induction to about 600°C for one minute during the exhaust process.
  • BaSn 2 may be produced, or liberated barium is produced, from the barium-aluminium alloy by reaction of aluminium and tin.
  • a mixed getter material of barium-aluminium alloy and tin which is stable at a normal temperature is activated and absorb gases at a normal temperature. Nevertheless there is a heating process involved which requires temperatures of several hundreds of degrees centigrade. Furthermore an uncontrolled chemical reaction is taking place.
  • Lithium organic resins have been proposed for the sorption of gas impurities from impure gas streams, but they are used for the purification of nitrogen gas and not for its sorption, see US-A-4,603,148 and US-A-4,604,270.
  • non-evaporated getters can be introduced into the device in a pre-activated form, that is when they have already been heated to a high temperature of about 600°C, they have already been subjected to many manufacturing processes such as grinding to fixed particle size, mixing with other materials, compaction or forming into pellets.
  • a further object of the present invention to provide a process for the sorption of unwanted gas in a vessel which does not require temperatures of greater than 150°C.
  • Yet a further object of the present invention is to provide a process for the sorption of nitrogen gas in a vessel made of organic plastic or which contains organic plastic.
  • the process of the present invention provides for the sorption of residual gas in a vessel by means of a non-evaporated barium getter. It comprises the steps of reducing an alloy of Ba 1-x A x Li 4-y B y , preferably to a particle size of less than 5mm, under vacuum or an inert gas atmosphere and then placing the reduced alloy in the vessel. Upon exposing the reduced alloy to the residual gas in the vessel at a temperature of less than 150°C the gas is sorbed.
  • the metal A is a metal chosen from the group consisting of elements of Group IIa of the periodic table of elements, excluding barium.
  • the metal B is chosen from the group consisting of elements of Group IIIa of the periodic table of elements and magnesium.
  • the alloys of the present invention do not have to be activated, that is they are already capable of sorbing gases at room temperature and furthermore they do not have to be evaporated to produce a film of active material, such as barium before they sorb gas. Nevertheless they can be activated by heating to a temperature of not greater than 150°C. This could be between 50°C and 150°C for at least 10 minutes and then reducing the temperature to less than 50°C.
  • the alloys can be described by the general formula Ba 1-x A x Li 4-y B y , where A is a metal chosen from the group consisting of elements of Group IIa of the periodic table of elements, excluding barium. The numbering of the Groups of elements is that adopted by The American Chemical Society.
  • A can be calcium, magnesium and strontium but is preferably calcium as calcium is only slightly less reactive than barium. Magnesium and strontium are less preferred for their lower reactivity.
  • the value of x may be as low as zero such that there is no metal of Group IIa present (except the barium). On the other hand it may be as high as 0.8. Above about 0.8 the alloy begins to lose its ability to react at room temperature with the residual gas at a sufficiently high sorption speed.
  • the element B is any metal chosen from the group consisting of elements Group IIIa of the periodic table of elements and magnesium. All members of Group IIIa can be adopted, for instance boron, but aluminium is preferred as it is readily available, it has a relatively high melting point and is extremely cheap, while gallium is liquid near ambient temperatures. Indium has a low melting point and is more expensive then aluminium. Tl is highly toxic. Furthermore 0 ⁇ y ⁇ 3.5.
  • These compounds can be easily comminuted or reduced to a particulate form without any difficulty. For instance they can be reduced to a particle size of less than 5 mm in diameter, and preferably less than 1 mm, by known techniques under a vacuum or inert atmosphere and then transferred to the vessel containing the unwanted gas which is desired to be removed. This is accomplished by placing the reduced alloy in the vessel and exposing the reduced alloy to the residual gas at room temperature.
  • the reduced alloy can be transferred to the vessel immediately but preferably takes place by means of an intermediate vessel in which the alloy is stored under vacuum or an inert atmosphere until it is required.
  • FIG. 1 is a drawing showing in a schematic form an apparatus 100 for measuring the sorptive properties of Ba 1-x A x Li 4-y B y alloys useful in the present invention.
  • a vacuum pumping system 102 is connected by means of a first valve 104 to a dosing volume 106.
  • dosing volume 106 Connected with dosing volume 106 there is a series of second valves 110, 110', 110'' for the inlet of test gases from a series of test gas reservoirs 112, 112', 112'', containing N2, artificial air, and CO respectively, and a pressure measuring gauge 114.
  • To dosing volume 106 is also connected, by third valve 116, a test chamber 118 containing the sample 120 under test.
  • valves 110, 110', 110'' and 116 are closed and 104 is opened and the vacuum pump system 102 pumped the system down to 10 ⁇ 6 mbar.
  • the dosing volume 106 was a volume of 0.71 litre.
  • Valve 116 was opened and again the system was pumped down to 10 ⁇ 6 mbar while the sample was held at about 100°C for 20 minutes which simulates a process to which the getter may be subject.
  • Valves 104 and 116 were then closed and test gas was admitted to dosing volume 106, from gas reservoir 112, (112', 112'') by opening valve 110 (110', 110'') for a short while.
  • the pressure was noted on pressure gauge 114, and was arranged to be such that the pressure was about 0.4-1.0 mbar after opening valve 116 to introduce a dose of test gas to the sample 120.
  • This example was designed to show how to manufacture an alloy useful in the process of the present invention.
  • the alloy corresponds to the intermetallic compound BaLi4.
  • This example was designed to show the use of an alloy in the process of the present invention.
  • a barium-lithium alloy as prepare in Example 2 above was placed in a glove-box under a protective atmosphere of argon at slightly greater than 1 atmosphere pressure.
  • the alloy was ground using a mortar and pestle to a particle size of less than 1mm and a sample of 2.7 g was sealed in a glass vessel of volume 0.17 litre.
  • the sample in the glass vessel was then attached as test chamber 118 to the test apparatus of Example 1.
  • the procedure of Example 1 was followed and a first dose of gas, in this case nitrogen (from reservoir 112 by means of valve 110), was introduced to the sample.
  • the pressure in the vessel was measured by means of pressure gauge 114 as a function of time.
  • the curve obtained is reported on Fig. 2 as curve 1.
  • the sorption was so rapid that the pressure drop was almost instantaneous.
  • a second dose of nitrogen was introduced and the pressure in the vessel as measured by the pressure gauge 114 was reported as curve 2 on Fig. 2.
  • the gas was replaced by artificial air, that is a mixture of 80% v/v N2 + 20% v/v O2 (from reservoir 112' by means of valve 110') and the pressure in the vessel was recorded as curve 3 on Fig. 3. This was repeated to give curve 4.
  • the gas was replaced by CO (from reservoir 112'' by means of valve 110'') and the pressure in the vessel was recorded as curve 5 for which the sorption was so rapid that the pressure drop was almost instantaneous. Artificial air was again introduced to give curve 6.
  • the sample was then cooled to 0°C and on introducing a sample of N2 gas curve 7 was recorded.
  • the sample was then cooled to about -8°C to -9°C with a bath of alcohol + iced water and on introducing a dose of nitrogen curve 8 was recorded.
  • Fig. 6 shows the gas sorption speed derived from the curves of Figs. 2-5, by differentiation, as a function of gas sorbed.
  • This example was designed to show how to manufacture another alloy, by partial replacement of barium by calcium, useful in the process of the present invention.
  • the crucible was placed in an induction furnace and heated under an argon atmosphere of 400 mbar with medium frequency induction heating until the mixture was thoroughly melted and homogeneous thus forming a fusion.
  • the fusion was then poured into a cold iron mould and allowed to cool to room temperature while still under the protective atmosphere of argon.
  • the weight of alloy after fusion was 138 g.
  • the alloy corresponds to the composition Ba 0.75 Ca 0.25 Li4.
  • This example was designed to show the use of the alloy produced as in Example 4 in the process of the present invention.
  • a barium-calcium-lithium alloy as prepared in Example 4 above was placed in a glove box under a protective atmosphere of argon at slightly greater than 1 atmosphere pressure.
  • the alloy was ground to a particle size of less than 1 mm with a pestle and a mortar and a sample of 2.0 g was sealed in a glass vessel of volume 0.32 litre.
  • the sorption properties were measured as in Example 3 for N2 at 25°C and are reported as curves 1-14 in Figs. 7-9.
  • Fig. 10 shows the nitrogen sorption speed derived from the curves of Figs. 7-9, by differentiation, as a function of nitrogen sorbed.
  • This example was designed to show how to manufacture another alloy, by replacement of more barium by calcium, useful in the process of the present invention.
  • the alloy corresponds to a composition Ba 0.5 Ca 0.5 Li4.
  • This example was designed to show- the use of the alloy produced as in Example 6 in the process of the present invention.
  • a barium-calcium lithium alloy as prepared in Example 6 above was placed in a glove box under a protective atmosphere of argon at slightly greater than 1 atmosphere pressure.
  • the alloy was ground to a particle size of less than 1 mm with a pestle and mortar and a sample of 2.47 g was sealed in a glass vessel of volume 0.15 litre.
  • the sorption properties were measured for nitrogen at 25°C as in Example 3, and are reported as curves 1-28 in Figs. 11-15.
  • Fig. 16 shows the gas sorption speed derived from the curves of Figs. 11-15 as a function of quantity of gas sorbed.
  • the crucible was placed in an induction furnace and heated under an argon atmosphere of 400 mbar with medium frequency induction heating until the mixture was thoroughly melted and homogeneous thus producing a fusion.
  • the fusion was then poured into a cold iron mold and allowed to cool to room temperature while still under the protective atmosphere of argon.
  • the weight of alloy after fusion was 78.3 g.
  • the alloy corresponds to the composition BaLi3Al.
  • This example was designed to show the use of the alloy produced as in Example 8 in the process of the present invention.
  • a barium-lithium-aluminium alloy as prepared in Example 8 above was placed in a glove box under a protective atmosphere of argon at slightly greater than 1 atmosphere pressure.
  • the alloy was ground to a particle size of less than 1 mm with a pestle and a mortar and a sample of 2.4 g was sealed in a glass vessel of volume 0.32 litre.
  • the sorption properties were measured as in Example 3 for N2 at 25°C and are reported as curves 1-7 in Figs. 17-18.
  • Fig. 19 shows the gas sorption speed derived from the curves of Figs. 17-18, by differentiation, as a function of gas sorbed.
  • This example was designed to show the N2 sorption properties of a prior art alloy.
  • a low temperature activatable non-evaporated of 70% Zr - 24.6% V - 5.4% Fe (nominal weight composition) of weight 100 mg was activated by heating to 450°C for 10 minutes under vacuum at better than 10 ⁇ 3 mbar and then caused to sorb N2 at 25°C at a pressure of about 10 ⁇ 5 mbar in an apparatus described in the ASTM F798-82 Standard Practice for Determining Gettering Rate, Sorption Capacity, and Gas Content of Nonevaporable Getters in the Molecular Flow Region.
  • the gettering rate (sometimes called sorption speed) was plotted against the quantity sorbed, for the equivalent 2g getter, to give curve A on Fig. 20.
  • This example was designed to show the N2 sorption properties of an alloy according to the present invention.
  • a barium-lithium alloy as prepared in Example 2 above was prepared and 2g, having a particle size of less than 1mm, was placed in the same ASTM apparatus used for Example 10. After being held at a temperature of 100°C for 15-20 minutes, which simulates a process to which the getter may be subjected the getter was cooled to 25°C and its curve of nitrogen sorption was plotted as curve C on Fig. 20. After the getter had sorbed a quantity of gas the flow was interrupted. On continuing, the curve C' was obtained, and successively with curves C'' and C'''.
  • Example 11 was repeated except that the getter was activated at a temperature of 130°C for 3 hours followed by 100°C for 16 hours and the getter was held at 80°C while sorbing nitrogen.
  • Figs. 6, 10, 16 and 19 show a remarkable ability for the large quantities of N2 and other gases sorbed.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Gas Separation By Absorption (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
EP92830186A 1991-04-16 1992-04-16 A process for the sorption of residual gas and especially nitrogen gas by means of a non-evaporated barium getter Expired - Lifetime EP0509971B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
ITMI911038 1991-04-16
ITMI911038A IT1246786B (it) 1991-04-16 1991-04-16 Processo per l'assorbimento di gas residui, in particolare azoto, mediante una lega getter a base di bario non evaporato.
CN92109723.9A CN1036703C (zh) 1991-04-16 1992-08-24 吸收残余气体的方法

Publications (2)

Publication Number Publication Date
EP0509971A1 EP0509971A1 (en) 1992-10-21
EP0509971B1 true EP0509971B1 (en) 1995-09-27

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EP92830186A Expired - Lifetime EP0509971B1 (en) 1991-04-16 1992-04-16 A process for the sorption of residual gas and especially nitrogen gas by means of a non-evaporated barium getter

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EP (1) EP0509971B1 (it)
JP (1) JP2627703B2 (it)
CN (1) CN1036703C (it)
DE (1) DE69205050T2 (it)
IT (1) IT1246786B (it)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITMI20012273A1 (it) * 2001-10-29 2003-04-29 Getters Spa Leghe e dispositivi getter per l'evaporazione del calcio
WO2006075680A1 (ja) * 2005-01-14 2006-07-20 Matsushita Electric Industrial Co., Ltd. 気体吸着性物質、気体吸着合金および気体吸着材
JP4889947B2 (ja) * 2005-01-14 2012-03-07 パナソニック株式会社 気体吸着合金
JP5061289B2 (ja) * 2005-03-25 2012-10-31 パナソニック株式会社 気体吸着性物質および気体吸着材
ITMI20051500A1 (it) * 2005-07-29 2007-01-30 Getters Spa Sistemi getter comprendenti una fase attiva inserita in un materiale poroso distribuito in un mezzo disperdente permeabile
EP1791151A1 (en) * 2005-11-29 2007-05-30 Nanoshell Materials Research & Development GmbH Metallic gas sorbents on the basis of lithium alloys
CN101890328A (zh) * 2010-08-06 2010-11-24 朱雷 一种非蒸散型吸气剂及其应用
WO2012111267A1 (ja) 2011-02-14 2012-08-23 パナソニック株式会社 気体吸着デバイス及びそれを備えた真空断熱材
CN102258975A (zh) * 2011-05-03 2011-11-30 济南桑乐真空管有限公司 一种全玻璃太阳能真空集热管高效蒸散型合金吸气剂
DE102012110083B4 (de) 2012-10-23 2014-12-11 Gabriele Uslenghi Verfahren zur Herstellung von Vakuumisolierglas
US10421059B2 (en) 2014-10-24 2019-09-24 Samsung Electronics Co., Ltd. Gas-adsorbing material and vacuum insulation material including the same

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB387724A (en) * 1931-07-04 1933-02-06 Osborg Hans Improvements in scavengers or improvers for use in the treatment of molten metals and alloys
US2706554A (en) * 1952-05-12 1955-04-19 King Lab Inc Getter assembly
US3193508A (en) * 1962-07-13 1965-07-06 Union Carbide Corp Silicon-containing barium-aluminum getter material
IT1206459B (it) * 1984-07-05 1989-04-27 Getters Spa Dispositivo getter atto a ridurre il metano nei gas residui in un tubo a vuoto.
US4717500A (en) * 1985-11-27 1988-01-05 Union Carbide Corporation Getter device for frit sealed picture tubes

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Publication number Publication date
CN1036703C (zh) 1997-12-17
CN1083413A (zh) 1994-03-09
JPH05131134A (ja) 1993-05-28
ITMI911038A1 (it) 1992-10-16
EP0509971A1 (en) 1992-10-21
IT1246786B (it) 1994-11-26
DE69205050T2 (de) 1996-03-07
ITMI911038A0 (it) 1991-04-16
DE69205050D1 (de) 1995-11-02
JP2627703B2 (ja) 1997-07-09

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