ASTM F14-80(1995)e1
(Practice)Standard Practice for Making and Testing Reference Glass-Metal Bead-Seal
Standard Practice for Making and Testing Reference Glass-Metal Bead-Seal
SCOPE
1.1 This practice covers procedures for preparing and testing reference glass-to-metal bead-seals for determining the magnitude of thermal expansion (or contraction) mismatch between the glass and metal. Tests are in accordance with method F218 (2).
1.2 This practice applies to all glass-metal combinations, established or experimental, particularly those intended for electronic components.
1.3 The practical limit of the test in devising 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 and health practices and determine the applicability of regulatory limitations prior to use .
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e1
Designation: F 14 – 80 (Reapproved 1995)
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 and Testing Reference Glass-Metal Bead-Seal
This standard is issued under the fixed designation F 14; 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—Editorial changes were made throughout in November 1995.
1. Scope 3. Summary of Practice
1.1 This practice covers procedures for preparing and test- 3.1 Seals of a standard configuration are prepared from a
ing reference glass-to-metal bead-seals for determining the representative sample of each metal and glass to be tested.
magnitude of thermal expansion (or contraction) mismatch Each material is prepared by an approved method and sized as
between the glass and metal. Tests are in accordance with specified. The seal is formed, annealed, and measured for
method F218 (2). optical retardation from which the axial stress and expansion
1.2 This practice applies to all glass-metal combinations, mismatch are calculated. At least two specimens are required
established or experimental, particularly those intended for from which average values are obtained.
electronic components.
4. Significance and Use
1.3 The practical limit of the test in devising mismatch is
4.1 The term reference as employed in this practice implies
approximately 300 ppm, above which the glass is likely to
fracture. that both the glass and the metal of the reference glass-metal
seal will be a standard reference material such as those
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the supplied for other physical tests by the National Institute of
Standards and Technology, or a secondary reference material
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- whose sealing characteristics have been determined by seals to
a standard reference material (see NIST Special Publication
bility of regulatory limitations prior to use.
260). Until standard reference materials for seals are estab-
2. Referenced Documents
lished by the NIST, secondary reference materials may be
2.1 ASTM Standards: agreed upon between producer and user.
C 770 Test Method for Measurement of Glass Stress-
2 5. Apparatus
Optical Coefficient
F 15 Specification for Iron-Nickel-Cobalt Sealing Alloy 5.1 Polarimeter, as specified in Method F 218 for measur-
ing optical retardation and analyzing stress in glass.
F 30 Specification for Iron-Nickel Sealing Alloys
F 31 Specification for 42 % Nickel-6 % Chromium-Iron 5.2 Heat-Treating and Oxidizing Furnaces, with suitable
controls and with provisions for appropriate atmospheres
Sealing Alloy
F 79 Specification for Type 101 Sealing Glass (Annex A1) for preconditioning metal, if required.
F 105 Specifications for Type 58 Borosilicate Sealing 5.3 Glassworking Lamp or Sealing Furnace, radiant tube,
muffle, or r-f induction with suitable controls and provision for
Glass
F 218 Test Method for Analyzing Stress in Glass use with inert atmosphere.
5.4 Annealing Furnace, with capability of controlled cool-
F 256 Specification for Chromium-Iron Sealing Alloys with
18 or 28 % Chromium ing.
5.5 Ultrasonic Cleaner, optional.
F 257 Specifications for 28 % Chromium-Iron Alloy for
Sealing to Glass 5.6 Micrometer Caliper, with index permitting direct read-
ing of 0.02 cm.
6. Materials
This practice is under the jurisdiction of ASTM Committee C-14 on Glass and
6.1 Metal—Representative rod stock with out-of-round not
Glass Products and is the direct responsibility of Subcommittee C14.04 on Physical
exceeding 1 % shall be selected, preferably with a diameter in
and Mechanical Properties.
Current edition approved Nov. 10, 1995. Published January 1996. Originally
published as F14 – 61 T. Last previous edition F 14 – 80 (1991)e .
Available from NIST Standard Reference Materials, Gaithersburg, MD 20899.
Annual Book of ASTM Standards, Vol 15.02.
Gulati, S. T., and Hagy, H. E., “Expansion Measurement Using Short
Annual Book of ASTM Standards, Vol 10.04.
Cylindrical Seal: Theory and Measurement,” Thermal Expansion 6, edited by Ian D.
Discontinued, see 1973 Annual Book of ASTM Standards, Part 6.
Peggs, Plenum, New York, N. Y., 1978, pp. 113–130.
F14
the range 0.5 to 4 mm. Smaller diameters result in a loss of the glass in terms of degrees of rotation of the analyzer. Rotate
sensitivity and larger diameters tend to be cumbersome and in a direction that causes the black fringe seen within the glass
impractical. Surfaces shall be relatively free of scratches, to move toward the glass-metal interface. Stop rotation of the
machine marks, pits, or inclusions that would induce localized analyzer when the center of the black fringe is coincident with
stresses. Length requirements are discussed in 6.2. the glass-metal interface. This condition is termed the point of
6.2 Glass—Representative glass tubing of suitable optical extinction.
transmission with an inside diameter 0.15 to 0.25 mm larger
NOTE 1—Sealing combinations may exist in which the thermal expan-
than the metal rod diameter. The outside diameter of the tubing
sion coefficients of glass and metal at room temperature may differ
shall preferably be such that it produces a glass-to-metal
significantly. In these cases it may be important to record the temperature
diameter ratio between 1.5 and 2. The length of the tubing shall of the refraction liquid (or the seal) at the time the retardation is measured.
exceed four times the finished glass diameter. The length of the
9.1.3 Repeat the above for a total of four measurements per
metal rod must exceed the length of the tubing. Surface
seal equally spaced around the interface. Calculate average
contaminants shall be removed to reduce the risk of making
rotation, A.
bubbly seals. An ultrasonic water mark is recommended.
9.1.4 Record the optical retardations in degrees, the index of
refraction of the liquid, and the effective wavelength of the
7. Seal-Making Procedure
light used in the polarimeter.
7.1 The seal may be made either by flame-working tech-
niques or by heating the tubing-rod assembly in a furnace. In
10. Calculations
either c
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