ASTM F144-80(1995)e1

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

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-Dec-1999
• Technical Committee: C14 - Glass and Glass Products
• Drafting Committee: C14.04 - Physical and Mechanical Properties

Relations

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By: ASTM F256-05(2020) - Standard Specification for Chromium-Iron Sealing Alloys with 18 or 28 Percent Chromium (Withdrawn 2023)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

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
e1
Designation: F 144 – 80 (Reapproved 1995) An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Practice for
Making Reference Glass-Metal Sandwich Seal and Testing
for Expansion Characteristics by Polarimetric Methods
This standard is issued under the fixed designation F 144; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Section 14 was added editorially in September 1995.
1. Scope The glass and metal are cleaned, treated, and sized to specified
proportions. Plane-interfaced seals are formed, annealed, and
1.1 This practice covers the preparation and testing of a
measured for residual optical retardation. The stress parallel to
reference glass-metal sandwich seal for determining stress in
the interface in each seal is calculated from the optical
the glass or for determining the degree of thermal expansion
retardation, and the average stress and thermal expansion
(or contraction) mismatch between the glass and metal. Tests
mismatch are computed for the sample.
are in accordance with Method F 218 (Section 2).
1.2 This practice applies to all glass and metal (or alloy)
4. Significance and Use
combinations normally sealed together in the production of
4.1 The term “reference” as employed in this practice
electronic components.
implies that either the glass or the metal of the reference
1.3 The practical limit of the test in deriving mismatch is
glass-metal seal will be a “standard reference material” such as
approximately 300 ppm, above which the glass is likely to
those supplied for other physical tests by the National Institute
fracture.
of Standards and Technology, or a secondary reference material
1.4 This standard does not purport to address all of the
whose sealing characteristics have been determined by seals to
safety problems, if any, associated with its use. It is the
a standard reference material (see NBS Special Publication
responsibility of the user of this standard to establish appro-
260). Until standard reference materials for seals are estab-
priate safety and health practices and determine the applica-
lished by the NIST, secondary reference materials may be
bility of regulatory limitations prior to use.
agreed upon between manufacturer and purchaser.
2. Referenced Documents
5. Apparatus
2.1 ASTM Standards:
5.1 Polarimeter, as specified in Method F 218 for measur-
F 15 Specification for Iron-Nickel-Cobalt Sealing Alloy
2 ing optical retardation and analyzing stress in glass.
F 30 Specification for Iron-Nickel Sealing Alloys
5.2 Cut-Off Saw, with diamond-impregnated wheel and No.
F 31 Specification for 42 Percent Nickel-6 Percent
2 180 grit abrasive blade under flowing coolant for cutting and
Chromium-Iron Sealing Alloy
fine-grinding glass rod.
F 47 Test Method for Crystallographic Perfection of Silicon
3 5.3 Glass Polisher, buffing wheel with cerium oxide polish-
by Preferential Etch Techniques
4 ing powder or laboratory-type equipment with fine-grinding
F 79 Specification for Type 101 Sealing Glass
4 and polishing laps.
F 105 Specification for Type 58 Borosilicate Sealing Glass
2 5.4 Heat-Treating and Oxidizing Furnaces, with suitable
F 218 Test Method for Analyzing Stress in Glass
controls and with provisions for appropriate atmospheres
F 256 Specification for Chromium-Iron Sealing Alloys with
2 (Annex A1) for preconditioning metal, if required.
18 or 28 % Chromium
5.5 Sealing Furnace, radiant tube, muffle or r-f induction
3. Summary of Practice with suitable controls and provision for use with inert atmo-
sphere.
3.1 Seals of a standard configuration are prepared from
5.6 Annealing Furnace, with capability of controlled cool-
representative specimens of the glass and metal to be tested.
ing.
5.7 Ultrasonic Cleaner, optional.
This specification is under the jurisdiction of ASTM Committee C-14 on Glass
5.8 Fixture for Furnace Sealing, design as suggested in
and Glass Products and is the direct responsibility of Subcommittee C14.04 on
Physical and Mechanical Properties. Annex A2.
Current edition approved July 3, 1980. Published September 1980. Originally
5.9 Micrometer Caliper, with index permitting direct read-
published as F 144 – 71 T. Last previous edition F 144 – 73.
2 ing of 0.02 cm.
Annual Book of ASTM Standards, Vol 10.04.
Annual Book of ASTM Standards, Vol 10.05. 5.10 Immersion Mercury Thermometer.
Annual Book of ASTM Standards, Vol 15.02.
F 144
6. Materials
6.1 Metal—Five representative specimen pairs of the metal
from either rod or plate stock with dimensions satisfying the FIG. 2 General Seal Configuration.
requirements of 7.1. The surfaces to be sealed should be
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, or rectangular plates. In each case the dimension d, 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
may be used, provided it flows essentially bubble-free to fill the
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
define the annealing schedule and establish rigid controls for its
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
the number of test seals representing one determination shall be
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 Method F 218.
11.1.1 Position the plane of the seal (in an immersion liquid,
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
preoxidize parts as described in Annex A1. Preoxidation
the diameter.
promotes a better glass-to-metal bond and relieves cold work-
11.1.2 Determine the retardation along the light path
ing stresses.
through the glass in terms of degrees of rotation of analyzer.
8.2 Glass—Using optical glass techniques grind and polish
Rotate in a direction that causes the curved black fringes seen
the sealing surfaces of the glass specimens with either wet
within the glass to appear to merge in the center of cross
abrasive wheels or water slurries of abrasive on a lap. The
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
formed. This condition is termed the point of extinction.
NOTE 1—Sealin
...