ASTM F111-96(2002)

Standard Practice for Determining Barium Yield, Getter Gas Content, and Getter Sorption Capacity for Barium Flash Getters (Withdrawn 2008)

SCOPE
1.1 This practice describes techniques for the determination of evaporated barium yield, getter gas content, and getter carbon monoxide sorption capacity for barium flash getters used in electron devices. Test conditions are chosen to approximate use conditions.
1.2 Auxiliary procedures for cleaning, for determining vacuum system leak-up rates, for flashing getters, and for determining barium content in both getter fill and films are also given.
1.3 The various tests described are destructive in nature. In general the tests are semiquantitative but they can be expected to yield comparative information on a single-laboratory basis to the precision indicated. No information relative to multilaboratory reproducibility is available.
1.4 List of Methods DescribedMethodSectionBarium Content, Determination of,9Acid-Base Titration Method9.6Complexation (Titration) Method9.7Gravimetric Method9.4Photometric Method9.5Weight Difference Method9.8Barium Yield, Determination of,10Carbon Monoxide Sorption Characteristics, Determination of12Cleaning Procedures6Getter Mount6.3Getter Test Bulb6.4Flashing Procedures8Gas Content, Determination of for Doped Getters:11Hydrogen11.7Nitrogen for Undoped Getters:11.8Preflash Gas Content11.5Total Gas Content11.4Leak-Up Rates, Determination of7
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 4.
WITHDRAWN RATIONALE
Formerly under the jurisdiction of Committee F01 on Electronics, this practice was withdrawn in June 2008 in accordance with section 10.5.3.1 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.

General Information

• Status: Withdrawn
• Publication Date: 09-Jun-1996
• Withdrawal Date: 30-Jul-2008
• ICS: 31.100 - Electronic tubes
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.03 - Metallic Materials, Wire Bonding, and Flip Chip

Relations

• Replaces: ASTM F111-96 - Standard Practice for Determining Barium Yield, Getter Gas Content, and Getter Sorption Capacity for Barium Flash Getters
• Effective Date: 10-Jun-1996

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:F 111–96 (Reapproved 2002)
Standard Practice for
Determining Barium Yield, Getter Gas Content, and Getter
Sorption Capacity for Barium Flash Getters
This standard is issued under the fixed designation F 111; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This practice describes techniques for the determination 2.1 ASTM Standards:
of evaporated barium yield, getter gas content, and getter D 1193 Specification for Reagent Water
carbon monoxide sorption capacity for barium flash getters
3. Terminology
usedinelectrondevices.Testconditionsarechosentoapproxi-
mate use conditions. 3.1 Definitions of Terms Specific to this Standard:
3.1.1 barium flash getters—used to remove residual gases
1.2 Auxiliary procedures for cleaning, for determining
vacuum system leak-up rates, for flashing getters, and for present after exhaust or generated during device operation by
sorption with a barium film produced by heating the getter.
determiningbariumcontentinbothgetterfillandfilmsarealso
given. 3.1.2 barium yield, M—the weight of barium in milligrams
evaporated when a getter is flashed. Flash conditions are
1.3 The various tests described are destructive in nature. In
general the tests are semiquantitative but they can be expected specified in terms of start time and total time.
3.1.2.1 start time, t —the interval in seconds between the
to yield comparative information on a single-laboratory basis
s
to the precision indicated. No information relative to multi- application of heating power and the onset of barium evapo-
ration. This value depends on the power applied.
laboratory reproducibility is available.
1.4 List of Methods Described: 3.1.2.2 total time, t—the full interval in seconds during
t
which heating power is applied to the getter.
Method Section
Barium Content, Determination of, 9
3.1.3 carbon monoxide sorption capacity, C—the quantity
Acid-Base Titration Method 9.6
of CO sorbed at room temperature (25°C) measured in
Complexation (Titration) Method 9.7
millitorr-litres until the terminal gettering rate is reached.
Gravimetric Method 9.4
Photometric Method 9.5
3.1.4 conductance, F—of a system for a given gas or vapor
Weight Difference Method 9.8
is the ratio of throughput of gas, Q, to the partial pressure
Barium Yield, Determination of, 10
difference across the system, P −P , in the steady state. It is
Carbon Monoxide Sorption Characteristics, Determination of 12
2 1
Cleaning Procedures 6
measured in liters per second, and given by F=Q/(P −P )
2 1
Getter Mount 6.3
where P is the upstream pressure, and P is the downstream
2 1
Getter Test Bulb 6.4
pressure.
Flashing Procedures 8
Gas Content, Determination of for Doped Getters: 11
3.1.5 flashing—theevaporationofbarium,containedwithin
Hydrogen 11.7
a getter, as a consequence of induction or resistance heating of
Nitrogen for Undoped Getters: 11.8
the getter.
Preflash Gas Content 11.5
Total Gas Content 11.4
3.1.6 Gas Content:
Leak-Up Rates, Determination of 7
3.1.6.1 preflash gas content, PGC—the quantity of gas in
1.5 This standard does not purport to address all of the
millitorr-litresreportedasnitrogenequivalentevolvedatflash-
safety concerns, if any, associated with its use. It is the
ingafterithasbeendegassedat350°Cfor15minunderkinetic
responsibility of whoever uses this standard to consult and
vacuum conditions.
establish appropriate safety and health practices and deter-
3.1.6.2 totalgascontent,TGC—ofagetteristhequantityof
mine the applicability of regulatory limitations prior to use.
gasinmillitorr-litresreportedasnitrogenequivalentevolvedat
Specific hazard statements are given in Section 4.
flashing when a getter is heated from room temperature.
This practice is under the jurisdiction ofASTM Committee F01 on Electronics
and is the direct responsibility of Subcommittee F01.03 on Metallic Materials.
Current edition approved June 10, 1996. Published August 1996. Originally
published as F111–69T. Last previous edition F111–72 (1991). Annual Book of ASTM Standards, Vol 11.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F 111–96 (2002)
TABLE 2 Bulbs and Coils for Determination of CO Sorption
3.1.7 getter mount—a mechanical device used to secure the
Characteristics
getter and its integral support leg (if any) at the specified
position in the getter test bulb.
Getter Type Test Bulb Test Bulb Dimensions Coil
3.1.8 gettering rate, G—defined as the volume of gas
sorbed in 1 s and is measured in litres per second. 3
Receiving tube spherical bulb 100-cm spherical flask F
(all) (OD60mm)
3.1.8.1 terminal getter rate—reached when the gettering
OD 12–13 mm standard TV bulb 12-in., 110° neck, OD 20 E
rate decreases to 1 L/s for large (TV) getters or 0.1 L/s for
TV mm
small (receiving tube) getters. It is used to define the end point OD 18–19 mm standard TV bulb 19-in., 114° neck, OD 28.5 F
TV mm
of the CO sorption capacity test.
OD 25–26 mm standard TV bulb 23-in., 92° neck, OD 36.5 F
A
3.1.9 getter test bulb—that portion of the apparatus in TV mm H
A
which the getter is flashed (see Table 1 and Table 2).
Used for antenna-mounted getters.
3.1.10 mass throughput, Q—the quantity of gas flowing
through a given plane in unit time and is measured in
millitorr-litres per second.
4. Safety Hazards
3.1.11 molecular flow region—that pressure region where
4.1 Eye protection is mandatory in the presence of large
gases or vapors flow under conditions such that the largest
evacuated glass vessels or picture-tube bulbs, which should
internal dimension of a transverse section of the vessel is
also be surrounded by suitable mechanical protection against
smaller than the mean free path. Under these conditions the
implosion.
rate of flow is limited not by collisions between molecules but
by collisions of molecules with the walls.
5. Test Specimens
3.1.12 sorption by a getter—the process of removing gases
5.1 The test specimens are commercial barium flass getters
and vapors by adsorption and absorption phenomena.
usedinelectrondevices.Themajorcomponentsofagetterare:
3.1.12.1 Absorption, deals with gas interactions in the bulk
the fill, the container, and the support.
ofthegetterfilmandisdependentondiffusionrates,solubility,
5.1.1 The Getter Fill is based on barium alloy, BaAl,to
and chemical reactions.
minimize the reactions of barium with the atmosphere.
5.1.1.1 AnendothermicgetterfillusestheBaAl alloyalone
3.1.12.2 adsorption—describes gas interactions at the sur-
and requires continued heating above 1050°C to liberate and
face of the getter film.
evaporate the barium.
3.1.12.3 Quantities of sorbed gas are measured in millitorr-
5.1.1.2 An exothermic getter fill is produced by intimately
litres.
mixingaboutfourmolesofnickelwithonemoleofthebarium
alloy. On heating to about 800°C, the nickel reacts exother-
mally with the alloy, liberating and evaporating 10 to 30% of
TABLE 1 Suggested Bulb and Coil Dimensions
the barium. Continued heating is required to evaporate most of
NOTE 1—The getters are centered in both coaxial and tangential coils.
the remaining barium.
5.1.1.3 The getter may be gas doped. Hydrogen may be
Bulb
added to the fill for reported beneficial effects on electron
Outside
Getter Type A
emission. Nitrogen may be added to influence the distribution
Length, Height,
Number Diameter,
mm mm
andtoproduceamoreporousfilmandtherebyincreasethegas
mm
sorption capacity as measured below.
Coaxial Flashing: 5.1.2 The Getter Container form depends on the method of
Receiving tube A 20 100 35
supplying heating power for flashing.
TV black and white B 35 250 150
5.1.2.1 If resistance heating is to be used it should have an
TV color C 60 320 140
Tangential Flashing (optional):
open geometry, more or less rectilinear.
B C
TV color D 80 320 90
5.1.2.2 If induction heating is to be used it should have the
form of a closed loop. The present trend is to employ a
Coil
ring-shaped channel. In such cases the getter-channel cross
Inside
Getter Type
section may be varied to influence, to a certain extent, the
Height,
Number Diameter, Tuns
mm
getter film-deposition pattern.
mm
5.1.3 A Getter Support is used for mounting and position-
Coaxial Flashing: ing the getter in electron devices. It may or may not be an
Receiving tube E 23 16 3.5
integral part of the getter.
TV black and white F 51 22 5.5
5.2 Nominal getter sizes which are currently available are
TV color G 70 22 5.5
Tangential Flashing (optional): listed in Appendix X1.
D
TV color H 51 15 6.0
5.3 Getter Description—The getter manufacturer shall fur-
A
Measured from bottom of getter to dome of bulb.
nish on request the following data:
B
Bulb axis inclined 30° from the vertical.
5.3.1 Type of fill (endothermic or exothermic).
C
Measured from center of getter to dome of bulb.
D
A two-layer coil with three turns per layer. 5.3.2 Recommended yield, start, and total times.
F 111–96 (2002)
5.3.3 Ifgasdopedornot.Ifdoped,thenwithwhichgas;and 6.5.1 Wash twice with HCl (1+17) to dissolve barium.
themaximumtemperaturetimeconditionwhichcausesnoloss 6.5.2 Rinse with tap water.
of doping. 6.5.3 Rinse with acetone to eliminate oils and greases.
5.3.4 Container size (outside diameter in millimetres for
NOTE 1—The acetone may be replaced by the more active cleaning
ring getters; length times width, each in millimetres, for loop
solution of 6.3.4. Use solution at room temperature.
getters; and length, in millimetres for resistance-heated get-
6.5.4 Rinse twice with DIW.
ters).
6.5.5 Drain.
5.3.5 Container (channel) shape (ring with high inside wall,
6.5.6 Dry using a clean oil-free air blast, or better: vacuum
ringwithhighoutsidewall,ringwithequalheightwalls,getter
dry, with or without bake, using a trapped mechanical pump to
tubing, and so forth).
minimize hydrocarbon contamination.
5.3.6 If magnetic or antimagnetic.
5.3.7 Shape of support (ribbon, wire, tab).
7. Leak-Up Rates
5.3.8 Special features such as ceramic spacers, etc., if any.
7.1 Significance—The leak-up rate gives a measure of the
5.4 Getter Lot Number—To any getter production batch a
cleanliness and freedom from leaks of vacuum system.
lot number is assigned and the production date is given. From
7.2 Summary—The vacuum test chamber which contains a
the lot number, date, and the internal manufacturer’s control
pressure gage is isolated from the vacuum pumps by a suitable
chartsitshallbepossibletotracebackalltheproductioncycles
valve and the changes in pressure with time are recorded to
up to the incoming raw materials.
obtain the data needed to calculate leak-up rates. A gas burst
5.5 Specimen Handling:
may be observed initially on closing the valve due to the
5.5.1 Handle getters only with clean tools, lint free gloves,
liberation of sorbed gases in the valve, but the pressure will
or finger cots, never with bare hands.
reachasteady-statevaluewithinseveralseconds.Thepressure
5.5.2 For long term storage, store the getters in a phospho-
may then continue to rise in a manner controlled by any real
ruspentoxideairdesiccatororequivalent.Assoonasthegetter
leaks and relatively high vapor pressure contaminants within
canisopened,placegetterstobetestedinaconventionalsilica
the vacuum chamber. The pressure may decrease with time
gel desiccator. Initiate all measurement between 24 and 48 h
indicating a clean leak-free system and pressure-gage pump-
after placing the getters in the conventional silica gel desicca-
ing.
tor.
7.3 Procedure:
6. Cleaning Procedures
7.3.1 Measure the leak-up rate during the determinations of
6.1 Scope—The following cleaning procedures shall be
gas content (11.4.4) and sorption capacity (12.4.7). The appa-
usedforgettermountsandgettertestbulbsusedinSections10, ratus used is described in these sections. At the appropriate
11, and 12.
stage of these determinations, indicated in the relevant text,
6.2 Significance—Cleaning procedures are necessary not valve off the test chamber from the vacuum pumps and record
only to ready the mount and bulb for the tests but also to
the initial pressure P.After a time, t, record the final pressure
i
minimize possible errors.Aresidue of barium can cause errors P.
f
in the barium yield determination when chemical methods are
7.3.2 The value of P and P should be such that there is a
f i
used. Oils and greases can adversely effect the vacuum. reasonabledifferencebetweenthem.Allowachangeofatleast
6.3 Materials and Reagents: a factor of 2 in pressure unless the leak-up rate is extremely
6.3.1 Hydrochloric Acid (1+17)—add 1 part of concen- low.
trated HCl (sp gr 1.19) to 17 parts of deionized water. 7.4 Calculations—Calculate the system leak-up rate, Q ,in
L
6.3.2 Deionized Water (DIW)—At least 2-MV resistivity. millitorr-litres per second using the following equation:
6.3.3 Acetone, cp.
Q 5V~P 2P !/t
L f i
6.3.4 Cleaning Solution—Add 2 volumes of concentrated
HF (sp gr 1.15), 33 volumes of concentrated HNO (sp gr where:
V = system volume, litres,
1.42),and2volumesofsurfaceactiveagentto100volumesof
P = final pressure, mtorr, in the valved-off test chamber,
DIW. f
P = initial pressure, mtorr, in the valved-off chamber, and
6.3.5 Alkylaryl polyether alcohol (OPE—7 to 8) is a liquid, i
t = time of pressure rise, s.
nonionic surface active (wetting) agent. It is listed as an
7.5 Sensitivity—Using commercial Bayert-Alpert design
industrial detergent and emulsifier, effective in aqueous min-
−9
ionization gages and controls (10.10 torr most sensitive
eral acids with good hard (glass) surface detergency and low
−8
full-scale range) and a 1-L volume leak-up rates of 1.10
foam. Any such agent, without filler, ionic or nonionic that
mtorr·litres/s are readily measurable.
meets the properties listed above is acceptable.
6.4 Mount Cleaning:
8. Getter Flashing
6.4.1 Wash with HCl (1+17).
6.4.2 Rinse with DIW. 8.1 Summary of Procedure—Getters are flashed by induc-
6.4.3 Dry with acetone. tion or resistance heating using the required power to achieve
6.4.4 Handleonlywithcleantools,lintfreegloves,orfinger the specified start time. This power is applied for the specified
cots. total time. The quantity of barium evaporated can then be
6.5 Getter Test Bulb Cleaning: determined using the analytic methods given in Section 9.
F 111–96 (2002)
8.2 Significance—Thebariumyieldofagetterwhenflashed to determine the power supplied. Connect a voltmeter in
at the manufacturer’s recommended start and total times is one parallel with the cu
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