ASTM F79-69(2019)

Standard Specification for Type 101 Sealing Glass

ABSTRACT
This specification covers Type 101 sealing glass for use in electronic applications. The glass shall have a finish that ensures smooth, even surfaces and freedom from cracks, checks, bubbles, and other laws of a character detrimental to the strength or life of the component or device for which its use is intended. Different test methods shall be performed in order to determine the following properties of the sealing glass: softening point, annealing point, thermal expansion coefficient, contraction coefficient, and bead seal.
SCOPE
1.1 This specification covers Type 101 sealing glass for use in electronic applications.  
Note 1: This specification is primarily intended to consider glass as most generally used, this is, glass in its transparent form as normally encountered in fabricating electronic devices. X1.3 lists sealing metals and alloys that are compatible with this glass. Type 101 glass in other forms such as powdered, crushed, sintered, fibrous, etc. are excluded. The requirements of this specification, as applied to these forms, must be established in the raw glass prior to its conversion.  
1.2 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

• Status: Published
• Publication Date: 31-Oct-2019
• ICS: 21.140 - Seals, glands
• Technical Committee: C14 - Glass and Glass Products
• Drafting Committee: C14.04 - Physical and Mechanical Properties

Relations

• Replaces: ASTM F79-69(2015) - Standard Specification for Type 101 Sealing Glass
• Effective Date: 01-Nov-2019
• Refers: ASTM C336-71(2020) - Standard Test Method for Annealing Point and Strain Point of Glass by Fiber Elongation
• Effective Date: 01-Aug-2020
• Refers: ASTM F14-80(2019) - Standard Practice for Making and Testing Reference Glass-Metal Bead-Seal
• Effective Date: 01-Nov-2019
• Refers: ASTM C598-93(2019) - Standard Test Method for Annealing Point and Strain Point of Glass by Beam Bending
• Effective Date: 01-Aug-2019
• Refers: ASTM C338-93(2019) - Standard Test Method for Softening Point of Glass
• Effective Date: 01-Aug-2019
• Refers: ASTM E228-11(2016) - Standard Test Method for Linear Thermal Expansion of Solid Materials With a Push-Rod Dilatometer
• Effective Date: 01-Sep-2016
• Refers: ASTM F144-80(2015) - Standard Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric Methods
• Effective Date: 01-May-2015
• Refers: ASTM C336-71(2015) - Standard Test Method for Annealing Point and Strain Point of Glass by Fiber Elongation
• Effective Date: 01-May-2015
• Refers: ASTM F14-80(2015) - Standard Practice for Making and Testing Reference Glass-Metal Bead-Seal
• Effective Date: 01-May-2015
• Refers: ASTM C598-93(2013) - Standard Test Method for Annealing Point and Strain Point of Glass by Beam Bending
• Effective Date: 01-Oct-2013
• Refers: ASTM C338-93(2013) - Standard Test Method for Softening Point of Glass
• Effective Date: 01-Oct-2013
• Refers: ASTM F14-80(2010) - Standard Practice for Making and Testing Reference Glass-Metal Bead-Seal
• Effective Date: 01-Apr-2010
• Refers: 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
• Refers: ASTM C336-71(2010) - Standard Test Method for Annealing Point and Strain Point of Glass by Fiber Elongation
• Effective Date: 01-Apr-2010
• Refers: ASTM E29-08 - Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Effective Date: 01-Oct-2008

Overview

ASTM F79-69(2019): Standard Specification for Type 101 Sealing Glass establishes internationally recognized requirements for Type 101 transparent sealing glass, primarily used in electronic applications. Developed under ASTM Committee C14, this specification defines the standards for quality, physical, and electrical properties necessary to ensure the glass performs reliably when used in fabricating electronic components and assemblies. The standard outlines necessary test methods, compatible materials, and criteria for work quality and appearance, helping manufacturers, purchasers, and engineers ensure consistency, durability, and compatibility in glass-to-metal seals for electronics.

Key Topics

• Scope and Applicability: Focuses exclusively on Type 101 sealing glass in transparent form for standard electronic uses, excluding other forms such as powdered or sintered glass.
• Workmanship and Appearance: Specifies that the glass must have smooth, even surfaces and be free of cracks, checks, bubbles, or any defects that could impair strength or longevity.
• Physical Properties: Requires conformance to key properties such as:
  • Softening point
  • Annealing point
  • Thermal expansion coefficient
  • Contraction coefficient
  • Electrical resistivity and dielectric properties
• Test Methods: Details standard ASTM test methods for verifying compliance, including:
  • C338 for softening point
  • C336 and C598 for annealing point
  • E228 for thermal expansion and contraction
  • D257 and D150 for electrical properties
• Compatible Metals and Alloys: Provides guidance on suitable sealing metals and alloys, such as Dumet, 52 Alloy, and platinum, ensuring proper glass-to-metal seals.
• Packaging and Identification: Outlines marking, packaging, and certification requirements to maintain traceability and product integrity.

Applications

Type 101 sealing glass is widely used in the electronics industry where glass-to-metal hermetic seals are critical. Typical applications include:

• Electronic Tubes and Components: Used to create airtight seals in electronic tubes, vacuum devices, and sensors.
• Hermetic Packages: Employed in the fabrication of hermetically sealed packages for semiconductors and electronic assemblies, ensuring reliability in harsh environments.
• Connector Technology: Applied in feedthroughs, relays, and connectors where insulation and sealing are necessary for safety and performance.
• Custom Electronic Assemblies: Utilized by manufacturers who require reliable glass-to-metal seals for specialty items such as aerospace and medical instrumentation.

Using ASTM F79-69(2019) ensures that the sealing glass has the proper mechanical and electrical properties for these demanding applications, reduces field failure rates, and ensures compatibility with recognized sealing alloys.

Related Standards

For fully compliant and optimized glass-to-metal sealing, the following related ASTM standards are commonly referenced alongside ASTM F79-69(2019):

• ASTM C336: Test Method for Annealing Point and Strain Point of Glass by Fiber Elongation
• ASTM C338: Test Method for Softening Point of Glass
• ASTM C598: Test Method for Annealing Point and Strain Point by Beam Bending
• ASTM E228: Test Method for Linear Thermal Expansion of Solid Materials
• ASTM D257: Test Methods for DC Resistance or Conductance of Insulating Materials
• ASTM D150: Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant)
• ASTM F14, F140, F144: Practices for Making and Testing Reference Glass-Metal Seals

ASTM F79-69(2019) supports best practices and global trade by aligning with WTO principles, thus facilitating the manufacturing and sourcing of high-quality sealing glass for electronic applications worldwide.

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:F79 −69 (Reapproved 2019)
Standard Specification for
Type 101 Sealing Glass
This standard is issued under the fixed designation F79; 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.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope F140 Practice for Making Reference Glass-Metal Butt Seals
and Testing for Expansion Characteristics by Polarimetric
1.1 This specification covers Type 101 sealing glass for use
Methods
in electronic applications.
F144 Practice for Making Reference Glass-Metal Sandwich
NOTE 1—This specification is primarily intended to consider glass as
Seal and Testing for Expansion Characteristics by Polari-
most generally used, this is, glass in its transparent form as normally
metric Methods
encounteredinfabricatingelectronicdevices.X1.3listssealingmetalsand
alloys that are compatible with this glass. Type 101 glass in other forms
3. Ordering Information
such as powdered, crushed, sintered, fibrous, etc. are excluded. The
requirements of this specification, as applied to these forms, must be
3.1 Orders for material under this specification shall include
established in the raw glass prior to its conversion.
the following information:
1.2 This international standard was developed in accor-
3.1.1 Form,
dance with internationally recognized principles on standard-
3.1.2 Type of glass,
ization established in the Decision on Principles for the
3.1.3 Dimensions,
Development of International Standards, Guides and Recom-
3.1.4 Marking and packaging, and
mendations issued by the World Trade Organization Technical
3.1.5 Certification (if required).
Barriers to Trade (TBT) Committee.
4. Chemical Composition
2. Referenced Documents
4.1 The typical chemical composition of this glass is as
2.1 ASTM Standards:
follows (Note 2):
C336 Test Method for Annealing Point and Strain Point of
Major Constituents Weight %
Glass by Fiber Elongation
C338 Test Method for Softening Point of Glass
Silica (SiO ) 56.0
Alumina (Al O)1.5
2 3
C598 Test Method for Annealing Point and Strain Point of
Soda (Na O) 4.0
Glass by Beam Bending
Potash (K O) 8.5
D150 Test Methods forAC Loss Characteristics and Permit-
Lead oxide (PbO) 29.0
tivity (Dielectric Constant) of Solid Electrical Insulation
Antimony trioxide (Sb O ) 1.0, max
2 3
D257 Test Methods for DC Resistance or Conductance of
Arsenic trioxide (As O ) 1.0, max
2 3
Insulating Materials
Halogens 0.2, max
E29 Practice for Using Significant Digits in Test Data to
Determine Conformance with Specifications
NOTE 2—Major constituents may be adjusted to give the desired
electricalandphysicalpropertiestotheglass.However,nochangeshallbe
E228 Test Method for Linear Thermal Expansion of Solid
made that alters any of these properties without due notification of, and
Materials With a Push-Rod Dilatometer
approval by, the user.
F14 Practice for Making and Testing Reference Glass-Metal
Bead-Seal
5. Physical Properties
5.1 The material shall conform to the physical properties
prescribed in Table 1. For electrical properties see Table 2 and
This specification is under the jurisdiction of ASTM Committee C14 on Glass
and Glass Products and is the direct responsibility of Subcommittee C14.04 on its Footnote A.
Physical and Mechanical Properties.
Current edition approved Nov. 1, 2019. Published November 2019. Originally
6. Workmanship, Finish, and Appearance
approved in 1967. Last previous edition approved in 2015 as F79 – 69 (2015). DOI:
10.1520/F0079-69R19.
6.1 The glass shall have a finish that ensures smooth, even
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
surfaces and freedom from cracks, checks, bubbles, and other
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
flaws of a character detrimental to the strength or life of the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. component or device for which its use is intended.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F79−69 (2019)
TABLE 1 Physical Requirements
A A
Property ASTM Test Method Condition Value
Softening point C338 sec 7.1 630 ± 10 °C
Annealing point C336 or C598 sec 7.2 435 ±10°C
Thermal expansion coefficient E228 sec 7.3 8.95 ± 0.20 ppm/°C
0to300 °C
Contraction coefficient E228 sec 7.4 10.10 ± 0.20 ppm/°C
(annealing point minus
15 to 30 °C)
A
Test methods and conditions are detailed in the appropriately referenced section of this specification.
A
TABLE 2 Electrical Properties
mal contraction curve and calculate the mean coefficient of
ASTM Test
linear thermal contraction between a point 15 °C below the
Property Condition Value (Typical)
Method
annealing point and 30 °C in accordance with Procedure B of
B
Volume resistivity (dc) D257 25 °C log R (Ω·cm) 17.0
Test Method E228.
250 °C log R (Ω·cm) 9.9
350 °C log R (Ω·cm) 7.8
7.5 Bead Seal Test—Thethermalcontractionmatchbetween
the glass and a sealing alloy may be determined by preparing
B
Dielectric constant (1 MHz) D150 20 °C 6.7
Dissipation factor (1 MHz) D150 20 °C 0.0014 and testing an assembly in accordance
...