ASTM D1082-17(2024)

Standard Test Method for Dissipation Factor and Permittivity (Dielectric Constant) of Mica

SIGNIFICANCE AND USE
4.1 The dissipation factor of natural muscovite mica, as determined by this test method, is of practical importance as a measure of the electrical energy lost as heat in the mica serving as the dielectric substance of capacitors, or in other applications in which the electric field is applied perpendicular to the plane of cleavage. The dissipation factor is particularly important in applications using mica at radio frequencies and in some less extensive audio frequency applications. This test method is suitable for specification acceptance and dielectric-loss control tests (see the Significance and Use of Test Methods D150).  
4.2 Relative Permittivity (Dielectric Constant)—The permittivity of natural muscovite mica is a measure of its relative ability to store electrostatic energy. Since the relative permittivity perpendicular to the cleavage plane is fairly uniform, regardless of origin, its practical significance is mainly for identification purposes, special uses, research, and design. If a loss index is desired, the value of the permittivity must be known (see the Significance and Use of Test Methods D150).
SCOPE
1.1 This test method covers the determination of the dissipation factor and the relative permittivity of natural block mica having thicknesses between 0.007 and 0.030 in. (0.18 and 0.77 mm) and mica films or capacitor splits between 0.0008 and 0.004 in. (0.02 and 0.10 mm) in thickness.  
1.2 The values stated in inch-pound units are to be regarded as the standard. The values in parentheses are for information purposes only.  
1.3 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. A specific warning statement is given in Section 7 and 6.1.1.  
Note 1: Procedures for the measurement of dissipation factor and permittivity are given in IEC Publication 60371-2, but the details of the procedure are somewhat different from those specified in this test method.  
1.4 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: 29-Feb-2024
• ICS: 73.080 - Non-metalliferous minerals
• Technical Committee: D09 - Electrical and Electronic Insulating Materials
• Drafting Committee: D09.01 - Electrical Insulating Products

Relations

• Replaces: ASTM D1082-17 - Standard Test Method for Dissipation Factor and Permittivity (Dielectric Constant) of Mica
• Effective Date: 01-Mar-2024
• Referred By: ASTM D748-18 - Standard Specification for Natural Block Mica and Mica Films Suitable for Use in Fixed Mica-Dielectric Capacitors
• Effective Date: 01-Mar-2024

Overview

ASTM D1082-17(2024) is the internationally recognized standard test method for measuring the dissipation factor (also known as dielectric loss) and permittivity (dielectric constant) of natural muscovite mica. Developed by ASTM International, this standard provides precise procedures crucial for evaluating mica used in electrical insulation, especially in applications such as capacitors, where mica’s dielectric properties are essential for performance and reliability.

Understanding the dissipation factor helps quantify electrical energy lost as heat in mica under an electric field, particularly when the field is perpendicular to the plane of cleavage. The relative permittivity provides insights into how well mica stores electrostatic energy, a property highly valued for both material identification and specialized engineering use.

Key Topics

• Dissipation Factor: Measures electrical energy loss as heat, a critical parameter for ensuring low loss in mica-based electrical components.
• Permittivity (Dielectric Constant): Indicates mica’s ability to store electrostatic energy, important for material specification and design.
• Specimen Types and Thicknesses: Covers natural block mica (0.007 to 0.030 in. thickness) and mica films (0.0008 to 0.004 in. thickness), providing flexibility for different industry requirements.
• Test Apparatus: Specifies options such as steel, mercury, and lead-foil electrodes, as well as relevant procedures for cleaning and conditioning specimens.
• Test Conditions: Details variables including temperature, pressure, humidity, and frequency for accurate measurement and repeatable results.
• Data Reporting: Guides users in documenting all relevant aspects of the test for proper evaluation and quality control.

Applications

The test method is particularly valuable for:

• Mica-based Capacitors: Ensures that mica insulation minimizes electrical energy loss, especially at radio frequencies and select audio frequencies.
• Dielectric Material Selection: Assists manufacturers and researchers in verifying mica’s suitability for various insulating applications in electronics.
• Material Identification: Permittivity values support accurate identification and classification of mica types.
• Specification Acceptance: Serves as a reliable reference for procurement and quality assurance of mica materials.
• Design and Research: Facilitates research and engineering by providing dependable dielectric property data, ensuring materials meet demanding electronic application requirements.

Industries benefiting from this standard include capacitor manufacturing, electrical insulation product development, and research institutions focused on dielectric materials.

Related Standards

For broader context and extended methodology, ASTM D1082-17(2024) references and aligns with several related standards:

• ASTM D150: Standard Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulation - foundational for understanding dielectric properties of a wide range of materials.
• ASTM D374: Test Methods for Thickness of Solid Electrical Insulation (Metric) - relevant for preparing and verifying specimen dimensions.
• ASTM D748: Specification for Natural Block Mica and Mica Films Suitable for Use in Fixed Mica-Dielectric Capacitors - offers related qualification details for mica materials.
• IEC 60371-2: Specification for insulating materials based on mica - Part 2: Methods of test - provides international perspectives on test procedures for mica-based materials.

By following ASTM D1082-17(2024), laboratories, manufacturers, and quality teams ensure consistent, accurate assessment of mica’s electrical properties, supporting high-performance electrical insulation and long-term reliability in critical electronic components.

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: D1082 − 17 (Reapproved 2024)
Standard Test Method for
Dissipation Factor and Permittivity (Dielectric Constant) of
Mica
This standard is issued under the fixed designation D1082; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope D748 Specification for Natural Block Mica and Mica Films
Suitable for Use in Fixed Mica-Dielectric Capacitors
1.1 This test method covers the determination of the dissi-
2.2 IEC Publication:
pation factor and the relative permittivity of natural block mica
Publication 60371-2 Specification for insulating materials
having thicknesses between 0.007 and 0.030 in. (0.18 and
based on mica—Part 2: Methods of test
0.77 mm) and mica films or capacitor splits between 0.0008
and 0.004 in. (0.02 and 0.10 mm) in thickness.
3. Summary of Test Method
1.2 The values stated in inch-pound units are to be regarded
3.1 Any of the techniques and apparatus set forth in Test
as the standard. The values in parentheses are for information
Methods D150 are suitable for measuring dissipation factor
purposes only.
and relative permittivity of block mica or film. Select an
1.3 This standard does not purport to address all of the
appropriate electrode system from those given in Section 5.
safety concerns, if any, associated with its use. It is the
3.2 If a relative order of magnitude of dissipation factor is
responsibility of the user of this standard to establish appro-
desired, the use of Method A in the Appendix of Specification
priate safety, health, and environmental practices and deter-
D748 is satisfactory.
mine the applicability of regulatory limitations prior to use. A
specific warning statement is given in Section 7 and 6.1.1.
4. Significance and Use
NOTE 1—Procedures for the measurement of dissipation factor and
4.1 The dissipation factor of natural muscovite mica, as
permittivity are given in IEC Publication 60371-2, but the details of the
determined by this test method, is of practical importance as a
procedure are somewhat different from those specified in this test method.
measure of the electrical energy lost as heat in the mica serving
1.4 This international standard was developed in accor-
as the dielectric substance of capacitors, or in other applica-
dance with internationally recognized principles on standard-
tions in which the electric field is applied perpendicular to the
ization established in the Decision on Principles for the
plane of cleavage. The dissipation factor is particularly impor-
Development of International Standards, Guides and Recom-
tant in applications using mica at radio frequencies and in some
mendations issued by the World Trade Organization Technical
less extensive audio frequency applications. This test method is
Barriers to Trade (TBT) Committee.
suitable for specification acceptance and dielectric-loss control
tests (see the Significance and Use of Test Methods D150).
2. Referenced Documents
4.2 Relative Permittivity (Dielectric Constant)—The per-
2.1 ASTM Standards:
mittivity of natural muscovite mica is a measure of its relative
D150 Test Methods for AC Loss Characteristics and Permit-
ability to store electrostatic energy. Since the relative permit-
tivity (Dielectric Constant) of Solid Electrical Insulation
tivity perpendicular to the cleavage plane is fairly uniform,
D374 Test Methods for Thickness of Solid Electrical Insu-
regardless of origin, its practical significance is mainly for
lation (Metric) D0374_D0374M
identification purposes, special uses, research, and design. If a
loss index is desired, the value of the permittivity must be
known (see the Significance and Use of Test Methods D150).
This test method is under the jurisdiction of ASTM Committee D09 on
5. Apparatus
Electrical and Electronic Insulating Materialsand is the direct responsibility of
Subcommittee D09.01 on Electrical Insulating Products.
5.1 For a general description of apparatus suitable for
Current edition approved March 1, 2024. Published March 2024. Originally
measuring dissipation factor and relative permittivity, refer to
approved in 1949. Last previous edition approved in 2017 as D1082 – 17. DOI:
10.1520/D1082-17R24.
Test Methods D150.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1082 − 17 (2024)
5.2 Select a suitable electrode arrangement from the follow- 5.2.2.1 The two outer electrodes shall be provided with a
ing: rubber tube attached to ⁄8-in. (3.2 mm) steel tubes located at
5.2.1 Steel Electrodes—Three electrodes made of stainless the bottom of each electrode. Small vent holes shall be
steel or nickel-plated tool steel will be required. The electrodes provided in the top of the outer electrodes to permit the escape
shall be cylindrical in shape and of a diameter sufficient to of entrapped air as the mercury rises. The center electrode shall
1 1
provide the minimum specified capacitance (Note 2). The be filled through a ⁄8-in. steel tube projecting approximately ⁄8
upper and lower electrodes shall have a minimum axial length in. above the top of the electrode and extending three fourths of
of ⁄2 in. (12.7 mm) and the center electrode shall have a the way down inside the steel ring. Vent holes shall be provided
maximum length of ⁄4 in. (6.35 mm). A low-resistance contact on either side of the projecting steel tube to permit entrapped
and conductor to the electrode is essential for dissipation factor air to escape as the mercury rises. With the test specimens
measurements in the order of 0.0001. The upper and lower clamped in position, the electrodes shall be in good alignment.
electrodes shall be electrically connected together, thus form- As in the case of the flat, steel electrodes, a two-terminal
ing a two-terminal capacitor, with the center electrode serving capacitor is formed with the center electrode serving as the
as the active or measuring terminal. The surfaces of the active or measuring terminal with the outer electrodes that are
electrodes adjacent to the specimen shall be ground and connected together by the steel yoke at the ground.
polished optically flat, and shall be parallel to each other. The
NOTE 3—Mercury electrodes having diameters of 1 ⁄4 in. (44.5 mm)
upper electrode shall be provided with a recess for a steel ball,
have been found satisfactory for mica specimens 2 by 2 in. by 0.001 to
so that the applied pressure will be uniformly distributed. The
0.030 in. (51 by 51 mm by 0.025 to 0.76 mm).
electrodes shall be carefully and accurately aligned without NOTE 4—Conducting paint electrodes can be substituted for mercury
electrodes.
scratching the surface of the mica specimen. It is recommended
that a slotted V-shaped jig be provided to aid with the aligning
5.2.3 Lead-Foil Electrodes—The use of lead-foil electrodes
of the electrodes.
0.0005 in. (0.013 mm) in thickness and 2.0 in. (51 mm) in
diameter is satisfactory for block mica 0.015 to 0.030 in. (0.38
3 1 1
NOTE 2—Steel electrodes having diameters of ⁄4 , 1, 1 ⁄4, and 1 ⁄2 in.
to 0.76 mm) in thickness. (See also metal-foil electrodes
(19, 25, 32, and 38 mm) have been found satisfactory for practical
thicknesses of mica specimens. described in the Section of Test Methods D150 under Electrode
Systems).
5.2.2 Mercury Electrodes—Three hollow, stainless steel or
nickel-plated cold-rolled steel electrodes mounted with the axis
5.3 The apparatus for the rapid, direct-reading method is set
horizontal so that the test specimens are in a vertical plane, will
forth in Append
...