ASTM F144-80(2019)
(Practice)Standard Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric Methods
Standard Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric Methods
SIGNIFICANCE AND USE
4.1 The term “reference” as employed in this practice implies that either the glass or the metal of the reference glass-metal seal will be a “standard reference material” such as those supplied for other physical tests by the National Institute of Standards and Technology, or a secondary reference material whose sealing characteristics have been determined by seals to a standard reference material (see NBS Special Publication 260). Until standard reference materials for seals are established by the NIST, secondary reference materials may be agreed upon between manufacturer and purchaser.
SCOPE
1.1 This practice covers the preparation and testing of a reference glass-metal sandwich seal for determining stress in the glass or for determining the degree of thermal expansion (or contraction) mismatch between the glass and metal. Tests are in accordance with Test Method F218 (Section 2).
1.2 This practice applies to all glass and metal (or alloy) combinations normally sealed together in the production of electronic components.
1.3 The practical limit of the test in deriving mismatch is approximately 300 ppm, above which the glass is likely to fracture.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F144 −80 (Reapproved 2019)
Standard Practice for
Making Reference Glass-Metal Sandwich Seal and Testing
for Expansion Characteristics by Polarimetric Methods
ThisstandardisissuedunderthefixeddesignationF144;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope by Preferential Etch Techniques (Withdrawn 1998)
F79 Specification for Type 101 Sealing Glass
1.1 This practice covers the preparation and testing of a
F105 Specification for Type 58 Borosilicate Sealing Glass
reference glass-metal sandwich seal for determining stress in
F218 Test Method for Measuring Optical Retardation and
the glass or for determining the degree of thermal expansion
Analyzing Stress in Glass
(or contraction) mismatch between the glass and metal. Tests
F256 Specification for Chromium-Iron Sealing Alloys with
are in accordance with Test Method F218 (Section 2).
18 or 28 Percent Chromium
1.2 This practice applies to all glass and metal (or alloy)
3. Summary of Practice
combinations normally sealed together in the production of
electronic components.
3.1 Seals of a standard configuration are prepared from
representative specimens of the glass and metal to be tested.
1.3 The practical limit of the test in deriving mismatch is
The glass and metal are cleaned, treated, and sized to specified
approximately 300 ppm, above which the glass is likely to
proportions. Plane-interfaced seals are formed, annealed, and
fracture.
measured for residual optical retardation. The stress parallel to
1.4 This standard does not purport to address all of the
the interface in each seal is calculated from the optical
safety concerns, if any, associated with its use. It is the
retardation, and the average stress and thermal expansion
responsibility of the user of this standard to establish appro-
mismatch are computed for the sample.
priate safety, health, and environmental practices and deter-
4. Significance and Use
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
4.1 The term “reference” as employed in this practice
dance with internationally recognized principles on standard-
implies that either the glass or the metal of the reference
ization established in the Decision on Principles for the
glass-metal seal will be a “standard reference material” such as
Development of International Standards, Guides and Recom-
those supplied for other physical tests by the National Institute
mendations issued by the World Trade Organization Technical
ofStandardsandTechnology,orasecondaryreferencematerial
Barriers to Trade (TBT) Committee.
whose sealing characteristics have been determined by seals to
a standard reference material (see NBS Special Publication
2. Referenced Documents
260). Until standard reference materials for seals are estab-
2 lished by the NIST, secondary reference materials may be
2.1 ASTM Standards:
agreed upon between manufacturer and purchaser.
F15 Specification for Iron-Nickel-Cobalt Sealing Alloy
F30 Specification for Iron-Nickel Sealing Alloys
5. Apparatus
F31 Specification for Nickel-Chromium-Iron SealingAlloys
5.1 Polarimeter, as specified in Test Method F218 for
F47 Test Method for Crystallographic Perfection of Silicon
measuring optical retardation and analyzing stress in glass.
5.2 Cut-Off Saw, with diamond-impregnated wheel and No.
180 grit abrasive blade under flowing coolant for cutting and
This practice is under the jurisdiction of ASTM Committee C14 on Glass and
fine-grinding glass rod.
Glass Products and is the direct responsibility of Subcommittee C14.04 on Physical
and Mechanical Properties.
5.3 Glass Polisher, buffing wheel with cerium oxide polish-
Current edition approved Nov. 1, 2019. Published November 2019. Originally
ing powder or laboratory-type equipment with fine-grinding
approved in 1971. Last previous edition approved in 2015 as F144 – 80 (2015).
DOI: 10.1520/F0144-80R19.
and polishing laps.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F144 − 80 (2019)
5.4 Heat-Treating and Oxidizing Furnaces, with suitable
controls and with provisions for appropriate atmospheres
(Annex A1) for preconditioning metal, if required.
FIG. 2 General Seal Configuration.
5.5 Sealing Furnace, radiant tube, muffle or r-f induction
with suitable controls and provision for use with inert atmo-
sphere.
necessary to fill the void between the metal plates to a
5.6 Annealing Furnace, with capability of controlled cool- thickness equal to that of a single plate becomes the determin-
ing dimensional criterion for the glass.
ing.
7.3 When used as an acceptance test by producer and user,
5.7 Ultrasonic Cleaner, optional.
thenumberoftestsealsrepresentingonedeterminationshallbe
5.8 Fixture for Furnace Sealing, design as suggested in
established by mutual agreement. However two seals are a
Annex A2.
minimum requirement for one determination.
5.9 Micrometer Caliper, with index permitting direct read-
ing of 0.02 cm.
8. Preparation of Specimens
5.10 Immersion Mercury Thermometer.
8.1 Metal—Chemically clean the specimens to remove sur-
face contaminants, especially lubricants and fingerprints from
6. Materials
fabrication and handling. Usually it is advisable to preoxidize
6.1 Metal—Five representative specimen pairs of the metal parts as described in AnnexA1. Preoxidation promotes a better
glass-to-metal bond and relieves cold working stresses.
from either rod or plate stock with dimensions satisfying the
requirements of 7.1. The surfaces to be sealed should be
8.2 Glass—Using optical glass techniques grind and polish
relatively free of scratches, machine marks, pits, or inclusions
the sealing surfaces of the glass specimens with either wet
that would induce localized stresses. The sealing surfaces
abrasive wheels or water slurries of abrasive on a lap. The
should terminate in sharp edges at the peripheral corners to act
polished surfaces should satisfy the dimensional criteria of 6.2
as a glass stop. Edges that are rounded, such as appear on
and 7.2, and be without chips, nicks, or scratches. Remove any
tumbled parts, will have the tendency to permit glass overflow.
surface contaminants which could produce bubbly seals. An
The opposite faces of each plate should be parallel within 0.5°.
ultrasonic wash may be used. See Annex A1.
6.2 Glass—Five representative specimens of rod or plate
9. Procedure for Making the Sandwich Seal
glass, cut with either diamond-impregnated or other abrasive
cutting wheels under flowing water. Dimensions (volume)
9.1 Record dimensions of metal plates and glass parts.
must satisfy the requirements of 7.2, and the faces should be
9.2 Make the seal in a furnace or by induction heating of the
flat and parallel within 0.5° for uniform flow during sealing.
metal utilizing suitable specimen holders or supports under
controlled conditions of temperature and time. See Annex A2.
7. Test Specimens
7.1 The metal specimens may take the form of circular,
10. Annealing
square,orrectangularplates.Ineachcasethedimensiond,Fig.
10.1 Once a symmetrical, bubble-free seal has been made,
1, designates the path along which the optical retardation in the
proper annealing of the seal becomes the most critical part of
finished seal is measured. Two identical metal plates of any of
the procedure. It is by this operation that all stresses are
the indicated shapes are required for a seal. The thickness, t ,
m
relieved except those due to the difference in thermal contrac-
of each plate should be at least 0.7 mm and d/t should be at
m
tion of the two materials from annealing temperature levels.
least 6.
This process involves heating the seal to a temperature
7.2 Glass with suitable optical transmission of any shape
somewhat higher than the annealing point of the glass and
maybeused,provideditflowsessentiallybubble-freetofillthe
maintaining this temperature for a time sufficient to relieve the
entire volume between the metal plates as in Fig. 2. Experience
existing strain. The test specimen is then cooled slowly at a
indicates, however, that best results are obtained with flat glass
constant rate.As an alternative, annealing can proceed directly
conforming closely to the outline of the metal plates. The
on cooling during the making of a seal.
thickness of the glass before sealing shall be such that it equals
10.2 Seal stress and associated expansion mismatch can be
t after sealing within 15 %. Thus, the volume of glass
m
varied markedly by annealing schedule modification. For this
reason, when the test is used as an acceptance specification, it
is strongly recommended that producer and user mutually
definetheannealingscheduleandestablishrigidcontrolsforits
maintenance.
11. Procedure for Measuring Optical Retardation
11.1 For each specimen measure the retardation in the
annealed seal due to the stress parallel to the interface
FIG. 1 Permissible Metal Shapes. according to Test Method F218.
F144 − 80 (2019)
11.1.1 Positiontheplaneoftheseal(inanimmersionliquid, where:
if needed) in a direction 45° from the direction of vibration of
S = stress parallel to interface, Pa,
the polarizer and analyzer, so that the line of sight, or light ¯
R = averageretardationperunitlengthofthetestspecimens,
path, is through the maximum glass dimension in the direction
nm/cm, and
d shown in Fig. 1. In a circular seal, for example, this would be
K = stress-optical coefficient of the glass, nm/cm·Pa.
NOTE 4—The stress-optical coefficient K of any reference glass shall be
the diameter.
supplied by the producer. Values for typical sealing glasses are found in
11.1.2 Determine the retardation along the light path
Table A1 of Specifications
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