ASTM D1082-00(2011)
(Test Method)Standard Test Method for Dissipation Factor and Permittivity (Dielectric Constant) of Mica
Standard Test Method for Dissipation Factor and Permittivity (Dielectric Constant) of Mica
SIGNIFICANCE AND USE
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).
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 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. 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.
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Standards Content (Sample)
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Designation: D1082 − 00 (Reapproved 2011)
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 3. Summary of Test Method
1.1 This test method covers the determination of the dissi- 3.1 Any of the techniques and apparatus set forth in Test
pation factor and the relative permittivity of natural block mica Methods D150 may be used for measuring dissipation factor
having thicknesses between 0.007 and 0.030 in. (0.18 and 0.77 and relative permittivity of block mica or film. Select an
mm) and mica films or capacitor splits between 0.0008 and appropriate electrode system from those given in Section 5.
0.004 in. (0.02 and 0.10 mm) in thickness.
3.2 If a relative order of magnitude of dissipation factor is
1.2 The values stated in inch-pound units are to be regarded desired, the use of Method A in the Appendix of Specification
as the standard. The values in parentheses are for information D748 is satisfactory.
purposes only.
4. Significance and Use
1.3 This standard does not purport to address all of the
safety problems, if any, associated with its use. It is the 4.1 The dissipation factor of natural muscovite mica, as
responsibility of the user of this standard to establish appro- determined by this test method, is of practical importance as a
priate safety and health practices and determine the applica- measureoftheelectricalenergylostasheatinthemicaserving
bility of regulatory limitations prior to use. Aspecific warning as the dielectric substance of capacitors, or in other applica-
statement is given in Section 7 and 6.1.1. tions in which the electric field is applied perpendicular to the
plane of cleavage. The dissipation factor is particularly impor-
NOTE 1—Procedures for the measurement of dissipation factor and
tantinapplicationsusingmicaatradiofrequenciesandinsome
permittivity are given in IEC Publication 60371-2, but the details of the
lessextensiveaudiofrequencyapplications.Thistestmethodis
procedure are somewhat different from those specified in this test method.
suitable for specification acceptance and dielectric-loss control
2. Referenced Documents
tests (see the Significance and Use of Test Methods D150).
2.1 ASTM Standards:
4.2 Relative Permittivity (Dielectric Constant)—The per-
D150 Test Methods forAC Loss Characteristics and Permit-
mittivity of natural muscovite mica is a measure of its relative
tivity (Dielectric Constant) of Solid Electrical Insulation
ability to store electrostatic energy. Since the relative permit-
D374 Test Methods for Thickness of Solid Electrical Insu-
tivity perpendicular to the cleavage plane is fairly uniform,
lation (Metric) D0374_D0374M
regardless of origin, its practical significance is mainly for
D748 Specification for Natural Block Mica and Mica Films
identification purposes, special uses, research, and design. If a
Suitable for Use in Fixed Mica-Dielectric Capacitors
loss index is desired, the value of the permittivity must be
known (see the Significance and Use of Test Methods D150).
2.2 IEC Publication:
Publication 60371-2 Specification for insulating materials
5. Apparatus
based on mica—Part 2: Methods of test
5.1 For a general description of apparatus suitable for
measuring dissipation factor and relative permittivity, refer to
This test method is under the jurisdiction of ASTM Committee D09 on
Test Methods D150.
Electrical and Electronic Insulating Materialsand is the direct responsibility of
Subcommittee D09.01 on Electrical Insulating Products.
5.2 Select a suitable electrode arrangement from the follow-
Current edition approved April 1, 2011. Published April 2011. Originally
ing:
approved in 1949. Last previous edition approved in 2005 as D1082 – 00 (2005).
5.2.1 Steel Electrodes—Three electrodes made of stainless
DOI: 10.1520/D1082-00R11.
steel or nickel-plated tool steel will be required.The electrodes
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
shall be cylindrical in shape and of a diameter sufficient to
Standards volume information, refer to the standard’s Document Summary page on
provide the minimum specified capacitance (Note 2). The
the ASTM website.
upper and lower electrodes shall have a minimum axial length
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. of ⁄2 in. (12.7 mm) and the center electrode shall have a
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1082 − 00 (2011)
maximum length of ⁄4 in. (6.35 mm).Alow-resistance contact air to escape as the mercury rises. With the test specimens
and conductor to the electrode is essential for dissipation factor clamped in position, the electrodes shall be in good alignment.
measurements in the order of 0.0001. The upper and lower As in the case of the flat, steel electrodes, a two-terminal
electrodes shall be electrically connected together, thus form- capacitor is formed with the center electrode serving as the
ing a two-terminal capacitor, with the center electrode serving active or measuring terminal with the outer electrodes that are
as the active or measuring terminal. The surfaces of the connected together by the steel yoke at the ground.
electrodes adjacent to the specimen shall be ground and
NOTE 3—Mercury electrodes having diameters of 1 ⁄4 in. (44.5 mm)
polished optically flat, and shall be parallel to each other. The
have been found satisfactory for mica specimens 2 by 2 in. by 0.001 to
upper electrode shall be provided with a recess for a steel ball,
0.030 in. (51 by 51 mm by 0.025 to 0.76 mm).
so that the applied pressure will be uniformly distributed. The
NOTE 4—Conducting paint electrodes can be substituted for mercury
electrodes shall be carefully and accurately aligned without
electrodes.
scratchingthesurfaceofthemicaspecimen.Itisrecommended
5.2.3 Lead-Foil Electrodes—The use of lead-foil electrodes
that a slotted V-shaped jig be provided to aid with the aligning
0.0005 in. (0.013 mm) in thickness and 2.0 in. (51 mm) in
of the electrodes.
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
describedintheSectionofTestMethodsD150underElectrode
thicknesses of mica specimens.
Systems).
5.2.2 Mercury Electrodes—Three hollow, stainless steel or
5.3 The apparatus for the rapid, direct-reading method is set
nickel-platedcold-rolledsteelelectrodesmountedwiththeaxis
forth inAppendix of Specification D748. This technique is for
horizontalsothatthetestspecimensareinaverticalplane,will
use only where classification of relative magnitude of dissipa-
berequiredasshowninFig.1.Theelectrodeassemblyshallbe
tion factor (or its reciprocal Q value) of block mica or films is
cylindrical in shape and of the same outside diameter, which
desired.
shall be large enough to provide the minimum specified
capacitance (Note 3). Two adjustable electrodes having axial
5.4 Thickness-measuring apparatus shall conform to the
lengths of approximately ⁄4 in. (19 mm), provided with
requirements set forth in Test MethodAof Test Methods D374
suitable cavities, shall be mounted on screws in a solid
which describes a machinist’s micrometer caliper with a
stainless steel or nickel-plated cold-rolled steel rectang
...
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