1、Designation: D1082 00 (Reapproved 2011)D1082 17Standard Test Method forDissipation Factor and Permittivity (Dielectric Constant) ofMica1This standard is issued under the fixed designation D1082; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 This test method covers the determination of the dissipation factor and the relative pe
3、rmittivity of natural block mica havingthicknesses between 0.007 and 0.030 in. (0.18 and 0.77 mm) 0.77 mm) and mica films or capacitor splits between 0.0008 and 0.004in. (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 parent
4、heses are for informationpurposes only.1.3 This standard does not purport to address all of the safety problems,concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices anddetermi
5、ne the applicability of regulatory limitations prior to use. A specific warning statement is given in Section 7 and 6.1.1.NOTE 1Procedures for the measurement of dissipation factor and permittivity are given in IEC Publication 60371-2, but the details of the procedureare somewhat different from thos
6、e specified in this test method.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organ
7、ization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D150 Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical InsulationD374 Test Methods for Thickness of Solid Electrical Insulation (Metric) D0374_D0374MD748 S
8、pecification for Natural Block Mica and Mica Films Suitable for Use in Fixed Mica-Dielectric Capacitors2.2 IEC Publication:Publication 60371-2 Specification for insulating materials based on micaPart 2: Methods of test33. Summary of Test Method3.1 Any of the techniques and apparatus set forth in Tes
9、t Methods D150 may be used are suitable for measuring dissipationfactor and relative permittivity of block mica or film. Select an appropriate electrode system from those given in Section 5.3.2 If a relative order of magnitude of dissipation factor is desired, the use of Method A in the Appendix of
10、Specification D748is satisfactory.4. Significance and Use4.1 The dissipation factor of natural muscovite mica, as determined by this test method, is of practical importance as a measureof the electrical energy lost as heat in the mica serving as the dielectric substance of capacitors, or in other ap
11、plications in whichthe electric field is applied perpendicular to the plane of cleavage. The dissipation factor is particularly important in applicationsusing mica at radio frequencies and in some less extensive audio frequency applications. This test method is suitable forspecification acceptance a
12、nd dielectric-loss control tests (see the Significance and Use of Test Methods D150).1 This test method is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materialsand is the direct responsibility of SubcommitteeD09.01 on Electrical Insulating Products.Current ed
13、ition approved April 1, 2011Nov. 1, 2017. Published April 2011December 2017. Originally approved in 1949. Last previous edition approved in 20052011 asD1082 00 (2005).(2011). DOI: 10.1520/D1082-00R11.10.1520/D1082-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM
14、 Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.This document is not an ASTM standa
15、rd and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases
16、only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Relative Permi
17、ttivity (Dielectric Constant)The permittivity of natural muscovite mica is a measure of its relative abilityto store electrostatic energy. Since the relative permittivity perpendicular to the cleavage plane is fairly uniform, regardless oforigin, its practical significance is mainly for identificati
18、on 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).5. Apparatus5.1 For a general description of apparatus suitable for measuring dissipation factor and relative permittivity, refe
19、r to TestMethods D150.5.2 Select a suitable electrode arrangement from the following:5.2.1 Steel ElectrodesThree electrodes made of stainless steel or nickel-plated tool steel will be required. The electrodes shallbe cylindrical in shape and of a diameter sufficient to provide the minimum specified
20、capacitance (Note 2). The upper and lowerelectrodes shall have a minimum axial length of 12 in. (12.7 mm) and the center electrode shall have a maximum length of 14 in.(6.35 mm). A low-resistance contact and conductor to the electrode is essential for dissipation factor measurements in the orderof 0
21、.0001. The upper and lower electrodes shall be electrically connected together, thus forming a two-terminal capacitor, with thecenter electrode serving as the active or measuring terminal.The surfaces of the electrodes adjacent to the specimen shall be groundand polished optically flat, and shall be
22、 parallel to each other. The upper electrode shall be provided with a recess for a steel ball,so that the applied pressure will be uniformly distributed. The electrodes shall be carefully and accurately aligned withoutscratching the surface of the mica specimen. It is recommended that a slotted V-sh
23、aped jig be provided to aid with the aligningof the electrodes.NOTE 2Steel electrodes having diameters of 34 , 1, 114, and 112 in. (19, 25, 32, and 38 mm) have been found satisfactory for practical thicknessesof mica specimens.5.2.2 Mercury ElectrodesThree hollow, stainless steel or nickel-plated co
24、ld-rolled steel electrodes mounted with the axishorizontal so that the test specimens are in a vertical plane, will be required as shown in Fig. 1. The electrode assembly shall becylindrical in shape and of the same outside diameter, which shall be large enough to provide the minimum specified capac
25、itance(Note 3). Two adjustable electrodes having axial lengths of approximately 34 in. (19 mm), provided with suitable cavities, shallbe mounted on screws in a solid stainless steel or nickel-plated cold-rolled steel rectangular yoke. A center, or fixed, electrodeconsisting of a hollow ring approxim
26、ately 38 in. (9.5 mm) in length shall be mounted at the center of the steel yoke on a supportof insulating material such as polystyrene, hard rubber, low-loss ceramic, or quartz. All electrodes shall taper from the inside torather sharp edges approximately 164 in. (0.4 mm) in width.5.2.2.1 The two o
27、uter electrodes shall be provided with a rubber tube attached to 18-in. (3.2-mm) steel tubes located at thebottom of each electrode. Small vent holes shall be provided in the top of the outer electrodes to permit the escape of entrappedair as the mercury rises. The center electrode shall be filled t
28、hrough a 18-in. steel tube projecting approximately 18 in. above thetop of the electrode and extending three fourths of the way down inside the steel ring. Vent holes shall be provided on either sideof the projecting steel tube to permit entrapped air to escape as the mercury rises. With the test sp
29、ecimens clamped in position,the electrodes shall be in good alignment. As in the case of the flat, steel electrodes, a two-terminal capacitor is formed with thecenter electrode serving as the active or measuring terminal with the outer electrodes that are connected together by the steel yokeat the g
30、round.NOTE 3Mercury electrodes having diameters of 134 in. (44.5 mm) have been found satisfactory for mica specimens 2 by 2 in. by 0.001 to 0.030 in.(51 by 51 mm by 0.025 to 0.76 mm).NOTE 4Conducting paint electrodes can be substituted for mercury electrodes.FIG. 1 Mercury Electrode Test AssemblyD10
31、82 1725.2.3 Lead-Foil ElectrodesThe use of lead-foil electrodes 0.0005 in. (0.013 mm) in thickness and 2.0 in. (51 mm) in diameteris satisfactory for block mica 0.015 to 0.030 in. (0.38 to 0.76 mm) in thickness. (See also metal-foil electrodes described in theSection of Test Methods D150 under Elect
32、rode Systems).5.3 The apparatus for the rapid, direct-reading method is set forth in Appendix of Specification D748. This technique is for useonly where classification of relative magnitude of dissipation factor (or its reciprocal Q value) of block mica or films is desired.5.4 Thickness-measuring ap
33、paratus shall conform to the requirements set forth in Test Method A of Test Methods D374 whichdescribes a machinists micrometer caliper with a ratchet or friction thimble.6. Specimen Preparation and Conditioning6.1 The dielectric properties of mica are affected by temperature, humidity, pressure, e
34、tc. Therefore, preparation andconditioning of the specimen shall be made in the following manner:6.1.1 With the exception of the specimens used in 5.4, thoroughly and carefully clean the surfaces of the specimen with acamels-hair brush dipped in petroleum ether or vapor degrease using trichloroethyl
35、ene. Subsequent to the cleaning, exercise carenot to contaminate the surfaces in handling. (WarningPetroleum ether and trichlorethylene may be are hazardous. Useadequately ventilated work areas and observe all procedures for the safe handling of these liquids. Keep away from open flames.)6.1.2 After
36、 cleaning, place each specimen in an air oven maintained at 105 to 110C, for a period of 1 h. Upon removal fromthe oven, immediately store the specimen in a desiccator until ready for the test.6.2 Prepare two similar test specimens of approximately equal and uniform thickness for each measurement wh
37、en using steelor mercury electrodes (see Section 5).6.3 Only one test specimen is needed for testing with lead-foil electrodes.6.4 Obtain specimens from the same block or splitting when two specimens are used. Each specimen shall have a sufficient areaand thickness to give a total capacitance of not
38、 less than 200 pF. Test a sufficient number of specimens to obtain representativedata.7. Procedure7.1 When steel, mercury, or lead-foil electrodes are used, determine the dissipation factor and relative permittivity of the micain accordance with Test Methods D150 except for size and type of electrod
39、e.7.2 WarningMercury metal vapor poisoning has long been recognized as a hazard in industry. The exposure limits are setby governmental agencies and are usually based upon recommendations made by the American Conference of GovernmentalIndustrial Hygienists.4 The concentration of mercury vapor over s
40、pills from broken thermometers, barometers, and otherinstruments using mercury can easily exceed these exposure limits. Mercury, being a liquid with high surface tension and quiteheavy, will disperse into small droplets and seep into cracks and crevices in the floor. This increased area of exposure
41、addssignificantly to the mercury vapor concentration in air. The use of a commercially available emergency spill kit is recommendedwhenever a spill occurs. Mercury vapor concentration is easily monitored using commercially available sniffers. Make spot checksperiodically around operations where merc
42、ury is exposed to the atmosphere. Make thorough checks after spills.7.3 Certain types of micas are affected by pressure; therefore, when flat, steel electrodes are used, apply a sufficient range ofpressures (Note 5) so that plotting curves of pressure in pounds-force per square inch versus dissipati
43、on factor and relativepermittivity may be plotted.is possible.NOTE 5Pressures in the order of 100 to 10 000 psi may be are readily obtained by the use of an automobile-type hydraulic jack equipped with apressure gauge.7.4 Mercury and lead-foil electrodes give capacitance values comparable with those
44、 obtained at the highest pressures whenusing flat, steel electrodes (Note 6). Use clean mercury that has a bright surface that is free of scum. Observe health hazardprecautions when using mercury, particularly at elevated temperatures.NOTE 6In order to satisfactorily compare the dissipation factor a
45、nd relative permittivity of various specimens of mica, it may be necessary is advisableto investigate such properties over a wide frequency range. However, it is recommended that at least one measurement be made at 1000 kHz and atemperature of 25 6 5C, at a pressure of 1000 psi if flat steel electro
46、des are used.8. Calculation8.1 Since two specimens are used in each measurement when using steel or mercury electrodes, use the equivalent “parallelthickness” in calculating the relative permittivity as follows:Te51/1/t1!11/t2!# (1)4 The American Conference of Governmental Industrial Hygienists, Inc
47、. (ACGIH), 1330 Kemper Meadow Dr., Suite 600, Cincinnati, OH 45240.D1082 173where:Te = equivalent parallel thickness,t1 = thickness of the upper specimen, andt2 = thickness of the lower specimen.9. Report9.1 Report the following information:9.1.1 Identification of the mica tested,9.1.2 The date of t
48、esting,9.1.3 The test conditions, including frequency of the applied voltage, specimen temperature during testing, voltage stress on thespecimen, relative humidity during testing, type, and size of electrodes used.9.1.4 The applied pressure if flat steel electrodes are used,9.1.5 Capacitance of each
49、 specimen,9.1.6 The “parallel thickness” of each specimen,9.1.7 A plot of dissipation factor versus pressure if flat, steel electrodes are used,9.1.8 A plot of permittivity versus pressure if flat, steel electrodes are used,9.1.9 The value of the dissipation factor and the relative permittivity for each specimen,9.1.10 The method of measurement from Test Methods D150, if applicable, and9.1.11 The method used if techniques from Specification D748 were used.10. Precision and Bias10.1 This test method has been in use for many years, but no informatio
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