ASTM F144-80(2005)

Standard Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric Methods

SIGNIFICANCE AND USE
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 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 problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Aug-2005
• ICS: 21.140 - Seals, glands
• Technical Committee: C14 - Glass and Glass Products
• Drafting Committee: C14.04 - Physical and Mechanical Properties

Relations

• Replaces: ASTM F144-80(2000) - Standard Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric Methods
• Effective Date: 01-Sep-2005
• Replaced By: ASTM F144-80(2010) - Standard Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric Methods
• Effective Date: 01-Apr-2010
• Referred By: ASTM F79-69(2019) - Standard Specification for Type 101 Sealing Glass
• Effective Date: 01-Sep-2005
• Referred By: ASTM F31-21 - Standard Specification for Nickel-Chromium-Iron Sealing Alloys
• Effective Date: 01-Sep-2005
• Referred By: ASTM F105-72(2019) - Standard Specification for Type 58 Borosilicate Sealing Glass
• Effective Date: 01-Sep-2005
• Referred By: ASTM F256-05(2020) - Standard Specification for Chromium-Iron Sealing Alloys with 18 or 28 Percent Chromium (Withdrawn 2023)
• Effective Date: 01-Sep-2005
• Referred By: ASTM F30-96(2017) - Standard Specification for Iron-Nickel Sealing Alloys
• Effective Date: 01-Sep-2005
• Referred By: ASTM F15-04(2022) - Standard Specification for Iron-Nickel-Cobalt Sealing Alloy
• Effective Date: 01-Sep-2005

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: F144 – 80 (Reapproved 2005)
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 3. Summary of Practice
1.1 This practice covers the preparation and testing of a 3.1 Seals of a standard configuration are prepared from
reference glass-metal sandwich seal for determining stress in representative specimens of the glass and metal to be tested.
the glass or for determining the degree of thermal expansion The glass and metal are cleaned, treated, and sized to specified
(or contraction) mismatch between the glass and metal. Tests proportions. Plane-interfaced seals are formed, annealed, and
are in accordance with Test Method F218 (Section 2). measured for residual optical retardation. The stress parallel to
1.2 This practice applies to all glass and metal (or alloy) the interface in each seal is calculated from the optical
combinations normally sealed together in the production of retardation, and the average stress and thermal expansion
electronic components. mismatch are computed for the sample.
1.3 The practical limit of the test in deriving mismatch is
4. Significance and Use
approximately 300 ppm, above which the glass is likely to
fracture. 4.1 The term “reference” as employed in this practice
implies that either the glass or the metal of the reference
1.4 This standard does not purport to address all of the
safety problems, if any, associated with its use. It is the glass-metal seal will be a “standard reference material” such as
those supplied for other physical tests by the National Institute
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- ofStandardsandTechnology,orasecondaryreferencematerial
whose sealing characteristics have been determined by seals to
bility of regulatory limitations prior to use.
a standard reference material (see NBS Special Publication
2. Referenced Documents
260). Until standard reference materials for seals are estab-
2.1 ASTM Standards: lished by the NIST, secondary reference materials may be
F15 Specification for Iron-Nickel-Cobalt Sealing Alloy agreed upon between manufacturer and purchaser.
F30 Specification for Iron-Nickel Sealing Alloys
5. Apparatus
F31 Specification for 42 % Nickel-6 % Chromium-Iron
Sealing Alloy 5.1 Polarimeter, as specified in Test Method F218 for
measuring optical retardation and analyzing stress in glass.
F47 Test Method for Crystallographic Perfection of Silicon
by Preferential Etch Techniques 5.2 Cut-Off Saw, with diamond-impregnated wheel and No.
180 grit abrasive blade under flowing coolant for cutting and
F79 Specification for Type 101 Sealing Glass
F105 Specification for Type 58 Borosilicate Sealing Glass fine-grinding glass rod.
5.3 Glass Polisher, buffing wheel with cerium oxide polish-
F218 Test Method for Measuring Optical Retardation and
Analyzing Stress in Glass ing powder or laboratory-type equipment with fine-grinding
and polishing laps.
F256 Specification for Chromium-Iron Sealing Alloys with
18 or 28 Percent Chromium 5.4 Heat-Treating and Oxidizing Furnaces, with suitable
controls and with provisions for appropriate atmospheres
(Annex A1) for preconditioning metal, if required.
This practice is under the jurisdiction of ASTM Committee C14 on Glass and
5.5 Sealing Furnace, radiant tube, muffle or r-f induction
Glass Products and is the direct responsibility of Subcommittee C14.04 on Physical
with suitable controls and provision for use with inert atmo-
and Mechanical Properties.
Current edition approved Sept. 1, 2005. Published October 2005. Originally
sphere.
approved in 1971T. Last previous edition approved in 2000 as F144 – 80(2000).
5.6 Annealing Furnace, with capability of controlled cool-
DOI: 10.1520/F0144-80R05.
2 ing.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.7 Ultrasonic Cleaner, optional.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Withdrawn.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F144 – 80 (2005)
5.8 Fixture for Furnace Sealing, design as suggested in
Annex A2.
5.9 Micrometer Caliper, with index permitting direct read-
FIG. 2 General Seal Configuration.
ing of 0.02 cm.
5.10 Immersion Mercury Thermometer.
preoxidize parts as described in Annex A1. Preoxidation
promotes a better glass-to-metal bond and relieves cold work-
6. Materials
ing stresses.
6.1 Metal—Five representative specimen pairs of the metal
8.2 Glass—Using optical glass techniques grind and polish
from either rod or plate stock with dimensions satisfying the
the sealing surfaces of the glass specimens with either wet
requirements of 7.1. The surfaces to be sealed should be
abrasive wheels or water slurries of abrasive on a lap. The
relatively free of scratches, machine marks, pits, or inclusions
polished surfaces should satisfy the dimensional criteria of 6.2
that would induce localized stresses. The sealing surfaces
and 7.2, and be without chips, nicks, or scratches. Remove any
should terminate in sharp edges at the peripheral corners to act
surface contaminants which could produce bubbly seals. An
as a glass stop. Edges that are rounded, such as appear on
ultrasonic wash may be used. See Annex A1.
tumbled parts, will have the tendency to permit glass overflow.
The opposite faces of each plate should be parallel within 0.5°.
9. Procedure for Making the Sandwich Seal
6.2 Glass—Five representative specimens of rod or plate
9.1 Record dimensions of metal plates and glass parts.
glass, cut with either diamond-impregnated or other abrasive
9.2 Make the seal in a furnace or by induction heating of the
cutting wheels under flowing water. Dimensions (volume)
metal utilizing suitable specimen holders or supports under
must satisfy the requirements of 7.2, and the faces should be
controlled conditions of temperature and time. See Annex A2.
flat and parallel within 0.5° for uniform flow during sealing.
10. Annealing
7. Test Specimens
10.1 Once a symmetrical, bubble-free seal has been made,
7.1 The metal specimens may take the form of circular,
proper annealing of the seal becomes the most critical part of
square,orrectangularplates.Ineachcasethedimensiond,Fig.
the procedure. It is by this operation that all stresses are
1, designates the path along which the optical retardation in the
relieved except those due to the difference in thermal contrac-
finished seal is measured. Two identical metal plates of any of
tion of the two materials from annealing temperature levels.
the indicated shapes are required for a seal. The thickness, t ,
m
This process involves heating the seal to a temperature
of each plate should be at least 0.7 mm and d/t should be at
m
somewhat higher than the annealing point of the glass and
least 6.
maintaining this temperature for a time sufficient to relieve the
7.2 Glass with suitable optical transmission of any shape
existing strain. The test specimen is then cooled slowly at a
maybeused,provideditflowsessentiallybubble-freetofillthe
constant rate.As an alternative, annealing can proceed directly
entire volume between the metal plates as in Fig. 2. Experience
on cooling during the making of a seal.
indicates, however, that best results are obtained with flat glass
10.2 Seal stress and associated expansion mismatch can be
conforming closely to the outline of the metal plates. The
varied markedly by annealing schedule modification. For this
thickness of the glass before sealing shall be such that it equals
reason, when the test is used as an acceptance specification, it
t after sealing within 15 %. Thus, the volume of glass
m
is strongly recommended that producer and user mutually
necessary to fill the void between the metal plates to a
definetheannealingscheduleandestablishrigidcontrolsforits
thickness equal to that of a single plate becomes the determin-
maintenance.
ing dimensional criterion for the glass.
7.3 When used as an acceptance test by producer and user,
11. Procedure for Measuring Optical Retardation
thenumberoftestsealsrepresentingonedeterminationshallbe
11.1 For each specimen measure the retardation in the
established by mutual agreement. However two seals are a
annealed seal due to the stress parallel to the interface
minimum requirement for one determination.
according to Test Method F218.
11.1.1 Positiontheplaneoftheseal(inanimmersionliquid,
8. Preparation of Specimens
if needed) in a direction 45° from the direction of vibration of
8.1 Metal—Chemically clean the specimens to remove
the polarizer and analyzer, so that the line of sight, or light
surface contaminants, especially lubricants and fingerprints
path, is through the maximum glass dimension in the direction
from fabrication and handling. Usually it is advisable to
d shown in Fig. 1. In a circular seal, for example, this would be
the diameter.
11.1.2 Determine the retardation along the light path
through the glass in terms of degrees of rotation of analyzer.
Rotate in a direction that causes the curved black fringes seen
within the glass to appear to merge in the center of cross
section of the glass and away from the glass–metal interfaces.
Rotate the analyzer so that any light or “gray” area which may
exist between the fringes disappears and a dark spot, or area, is
FIG. 1 Permissible Metal Shapes. formed. This condition is termed the point of extinction.
F144 – 80 (2005)
FIG. 3 Shape Factor
NOTE 1—Sealing combinations may exist in which the thermal expan- NOTE 3—In determining the light pat
...