1、Designation: D2149 13Standard Test Method forPermittivity (Dielectric Constant) And Dissipation Factor OfSolid Dielectrics At Frequencies To 10 MHz AndTemperatures To 500C1This standard is issued under the fixed designation D2149; the number immediately following the designation indicates the year o
2、foriginal adoption or, in the case of 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. Scope1.1 This test method covers the determination of the relativep
3、ermittivity (dielectric constant) and dissipation factor of soliddielectrics from 50 Hz to 10 MHz over a range of temperaturesfrom 80 to 500C.2,3Two procedures are included as follows:1.1.1 Procedure AUsing Micrometer Electrode.1.1.2 Procedure BUsing Precision Capacitor.NOTE 1In common usage the wor
4、d “relative” is frequently dropped.1.2 This standard does not purport to address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prio
5、r to use.2. Referenced Documents2.1 ASTM Standards:4D150 Test Methods for AC Loss Characteristics and Permit-tivity (Dielectric Constant) of Solid Electrical InsulationD1711 Terminology Relating to Electrical InsulationE197 Specification for Enclosures and Servicing Units forTests Above and Below Ro
6、om Temperature (Withdrawn1981)53. Terminology3.1 Definitions:3.1.1 Permittivity and dissipation factor are fully defined inTerminology D1711. Briefly, the permittivity of an insulatingmaterial is the ratio of the capacitance between two conductorswhen embedded in the material to the capacitance betw
7、een thesame configuration of conductors in a vacuum (or air). Thedissipation factor is the ratio of the resistive to capacitivecurrents in the dielectric. The product of the permittivity anddissipation factor is the loss index.4. Significance and Use4.1 Permittivity and dissipation factor are sensit
8、ive tochanges in chemical composition, impurities, and homogene-ity. Measurement of these properties is, therefore, useful forquality control and for determining the effect of environmentssuch as moisture, heat, or radiation.5. Apparatus5.1 Measuring CircuitsSuitable measuring circuits aredescribed
9、in Test Methods D150. For measurements from 50Hz to 100 kHz a substitution method using a low-voltagecapacitance bridge is recommended. For measurements at 1MHz and above, a resonant-circuit susceptance variationmethod is recommended. The Q of the circuit has to be at least200 except for very low lo
10、ss materials, for which a Q of 500 orhigher is desirable.5.2 Test EnclosureUnless testing only at roomtemperature, it is necessary to adapt a Hartshorn-Ward typespecimen holder to a temperature-controlled test enclosure.Where applicable, use the requirements for a gradeAenclosureas in Specification
11、E197. A suggested arrangement is shown inFig. 1. This arrangement provides terminal connections awayfrom the temperature zone.5.3 Specimen HolderThe suggested arrangement shownin Fig. 1 incorporates the following requirements:5.3.1 The selection of the metals is of utmost importance.The metal has to
12、 be of good thermal and electrical conductivityand yet be oxidation resistant and have sufficient strength tomaintain its mechanical dimensions after repeated heating.1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct
13、responsibility ofSubcommittee D09.12 on Electrical Tests.Current edition approved May 1, 2013. Published June 2013. Originallyapproved in 1963. Last previous edition approved in 2004 as D2149 97 (2004),which was withdrawn in January 2013 and reinstated in May 2013. DOI:10.1520/D2149-13.2R. Bartnikas
14、, Chapter 2, “Alternating-Current Loss and PermittivityMeasurements,” Engineering Dielectrics, Vol IIB, Electrical Properties of SolidInsulating Materials, Measurement Techniques, R. Bartnikas, Editor, ASTM STP926, ASTM, Philadelphia, 1987.3R. Bartnikas, Chapter 1, “Dielectric Loss in Solids,” Engin
15、eering Dielectrics,Vol IIA, Electrical Properties of Solid Insulating Materials: Molecular Structure andElectrical Behavior, R. Bartnikas and R. M. Eichorn, Editors, ASTM STP 783,ASTM Philadelphia, 1983.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Ser
16、vice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.5The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Con
17、shohocken, PA 19428-2959. United States1AISI Stainless No. 316 fulfills these requirements except forthe thermal conductivity. The time required for a specimen toreach equilibrium in a holder made from this material is quitelong. Precious metal alloys such as type B silver-magnesium-nickel have bett
18、er overall properties but require special heattreating.5.3.2 The preferable insulator materials are aluminumoxide, beryllium oxide, or polytetrafluoroethylene.5.3.3 Use electrodes 50 mm in diameter and at least 5 mmthick, with sharp corners. Maintain electrode parallellism towithin 0.01 mm.5.3.4 Sel
19、ect a length and cross-section for the lower tube sothat the temperature of each insulator does not exceed 100Cwhen the oven is at 500C. Select a length and cross-section forthe upper tube so that the drive nut can be touched with theoperators fingers (keep the drive nut less than 60C) when theoven
20、is at 500C.5.3.5 Use a micrometer or dial gage with a precision of0.005 mm to determine electrode separation and to monitorspecimen expansion.6. Electrodes6.1 Prior to measurement, apply conducting film or foilelectrodes to both flat surfaces of the specimen. (The specimenthickness is to be determin
21、ed before applying electrodes.)Silver paint, tin or tin-lead foil, or evaporated metal electrodeshave ranges of usefulness. Evaporated metal electrodes are themost suitable. When the specimen is porous sprayed-on metalelectrodes are useful. Additional information on the suitabilityof various electro
22、de systems is contained in Test MethodsD150.7. Sampling7.1 See ASTM standards for specific materials.8. Test Specimen8.1 Use a disk test specimen with a diameter of 40.00 60.01 mm and a thickness of 2 to 3 mm. Finish the surfaces to1.8 m or better and maintain parallel surfaces to within 0.01mm. The
23、 samples have to be free of bubbles and other defects.9. Standard Test Frequencies9.1 Unless otherwise specified, make measurements at oneor more of the following frequencies:60 Hz 100 000 Hz100 Hz 1 MHz400 Hz 10 MHz1000 HzFIG. 1 Suggested Specimen HolderD2149 132Common test frequencies are 60 Hz, 1
24、000 Hz, and 1 MHz.10. Temperature Control10.1 Take measurements at frequent temperature intervals(not to exceed 20C), until the required temperature range hasbeen traversed. Reduce the temperature to the lowest requiredtest temperature and leave until equilibrium has been achieved.Determine equilibr
25、ium by clamping a specimen between theholder electrodes and balancing or peaking the measuringcircuit until no change takes place between balances made 2min apart. After the required measurements have been made atthe lowest test temperature increase the temperature at the rateof 2 6 0.5C/min to the
26、next test temperature. Follow thisprocedure for achieving the test temperature until the requiredtemperature range has been traversed. Take measurements atapproximately the same test temperatures as the temperature isincreasing and as the temperature is decreasing. Measurementsas temperature is bein
27、g increased and decreased are necessaryto guard against possible hysteresis in electrical properties dueto such factors as moisture and chemical change.11. Conditioning11.1 Prior to applying electrodes condition the specimens at23 6 1C and 50 6 2 % relative humidity for a minimum of 40h. Carry out r
28、oom-temperature tests in the Standard LaboratoryAtmosphere of 23 6 1C and 50 6 2 % relative humidity.12. Procedure A (Using Micrometer Electrode)12.1 Refer to Test Methods D150. Center the specimenbetween the electrodes and rotate the drive nut until the frictionis felt to suddenly decrease. Read th
29、is micrometer setting andcheck it against the setting at which the friction first increaseson increasing the electrode spacing. Balance or peak themeasuring circuit. Open the electrodes and remove the speci-men. Then restore the balance of the measuring apparatuswithout changing its capacitance sett
30、ing by reducing thespacing between the electrodes and adjusting the measuringcircuit to balance the loss component. Note the new dissipationfactor and micrometer setting, and so forth.12.2 At each test temperature and each required frequencydetermine the capacitance and dissipation factor of eachspe
31、cimen.13. Procedure B (Using Precision Capacitor)13.1 Procedure B can be used when the frequency can bekept constant or when the measuring circuit, as is the case withthe bridges, is stable with frequency changes. In this proceduredetermine the C at room temperature for each frequencyrequired as in
32、Procedure A. Then center and clamp thespecimen between the electrodes and change the temperature tothe first temperature, taking measurements at each requiredfrequency to determine the change in capacitance of thespecimen.13.2 Procedure B requires a variable-precision capacitorwith a precision of 0.
33、01 pf in parallel with the specimen holderto determine the change in specimen capacitance with tempera-ture and frequency.14. Calculation14.1 Procedure ACalculate the capacitance, Cs, and dis-sipation factor, Ds, of the specimen as follows:Cs5 Co2 Ct1Cv(1)Cs5 C1Cv(2)Ds5 Ct/CsDi2 Dv! (3)where:Co= cap
34、acitance of the specimen holder with the specimenout,Ci= capacitance of the electrodes set at the average mea-sured thickness of the specimen (Note 2),Cv= equivalent geometric vacuum capacitance of thespecimen,Ct= total capacitance at the unknown terminals of themeasuring circuit,Di= dissipation fac
35、tor of the measuring circuit as indicatedby the measuring circuit when the specimen is betweenthe electrodes, andDo= dissipation factor of the measuring circuit as indicatedby the measuring circuit when the circuit has beenrebalanced with the specimen removed from theelectrodes.NOTE 2If the secondar
36、y electrodes are quite thin and the maximumthickness of the specimen is close to the average thickness, this setting canbe considered the same as the micrometer reading when the specimen isclamped between the electrodes.14.2 Procedure BCalculate the capacitance of the speci-men as follows:Cs5 C1CRT2
37、 CT1Cv(4)where:CRT= capacitance of the precision capacitor at room tem-perature when the measuring circuit is balanced, andCT= capacitance of the precision capacitor at a temperaturetest point when the measuring circuit is balanced.14.3 Calculate the dissipation factor as in Procedure A (Eq3).15. Le
38、ad Length Correction15.1 In both Procedures A and B, keep the length of theleads to a minimum between the measuring circuit and thespecimen holder. The C from Procedure A will be correct, butthe dissipation factors as seen by the measuring instrument andthe change from C as in Procedure B will be in
39、 error if theleads are long. The amount of error will depend on thefrequency, lead length, and the capacitance of the specimen. Tocorrect for the lead error it is necessary to calibrate themeasuring circuit by calibrating the specimen holder at lowfrequency and using its capacitance (CH) to calibrat
40、e themeasuring circuit at higher frequencies. A typical curve isshown in Fig. 2. This type of curve at the measuring frequencycan be used to correct for lead errors. The change in capaci-tance in Procedure B can be directly corrected by the curve Cmversus CH. The dissipation factors from both Proced
41、ures A andB can be corrected by the following expression if the dissipa-tion factor of the specimen is less than 0.10:D2149 133Ds5 Ct/Cs!Dt2 Do!CH/Cm!2(5)where:CH= capacitance of the specimen holder, andCm= capacitance indicated by the measuring circuit.If CH/Cmis not less than 0.99, no correction f
42、or lead lengthis required.16. Report16.1 Report the following:16.1.1 Description of the specimen, including name, grade,color, and manufacturer,16.1.2 Dimensions of test specimen,16.1.3 Conditioning of test specimen and type of secondaryelectrodes,16.1.4 Measuring circuit and procedure,16.1.5 Test v
43、oltage, and16.1.6 Permittivity and dissipation factor at each tempera-ture and frequency reported.17. Precision and Bias17.1 PrecisionThe precision of this test method has notbeen determined.17.2 BiasThe bias of this test method has not beendetermined.18. Keywords18.1 dielectric constants; dissipati
44、on factors; micrometerelectrodes; permittivities; precision capacitors; relative permit-tivitiesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determin
45、ation of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or wit
46、hdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that yo
47、ur comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (sin
48、gle or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 2 Typical Calibration of Measuring CircuitD2149 134
