ASTM_D_3386_-_00.pdf

Designation:D 3386 00An American National StandardStandard Test Method forCoefficient of Linear Thermal Expansion of ElectricalInsulating Materials1This standard is issued under the fixed designation D 3386;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This test method covers determination of the coefficientof linear thermal expansion of electrical insulating materials byuse of a thermomechanical analyzer.1.2 This test method is applicable to materials that are solidover the entire range of temperature used,and that retainsufficient hardness and rigidity over the temperature range sothat irreversible indentation of the specimen by the sensingprobe does not occur.1.3 Transition temperatures also may be obtained by thistest method.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.5 The values stated in SI units are the standard.NOTE1There is no similar or equivalent ISO/IEC standard.2.Referenced Documents2.1 ASTM Standards:D 374M Test Methods for Thickness of Solid ElectricalInsulation(Metric)2D 696 Test Method for Coefficient of Linear Thermal Ex-pansion of Plastics Between 30C and 30C3D 1711 Terminology Relating to Electrical Insulation2D 6054 Practice for Coordinating Electrical Insulating Ma-terials for Testing43.Terminology3.1 See Terminology D 1711 for definitions of other termsrelating to electrical insulation.4.Summary of Test Method4.1 This test method uses a thermomechanical analyzer todetermine the change of dimension as a function of tempera-ture of a small specimen of a solid electrical insulatingmaterial.Coefficients of linear thermal expansion are calcu-lated from the values.Other thermal observations may also bemade.5.Significance and Use5.1 Measurements of coefficient of linear thermal expansionare useful in evaluating the suitability of solid insulatingmaterials for use in combination with other materials wheremechanical stresses may develop as a result of differences incoefficients.5.2 This test method may be compared with Test MethodD 696,but tests made with this test method use much smallerspecimens.This eliminates the need for large liquid baths andgreatly reduces the time required to reach temperature equilib-rium.As a result,the time required for making a test is less thanfor Test Method D 696,and the test method can convenientlybe used over a wider temperature range than for Test MethodD 696.6.Apparatus6.1 The thermomechanical analyzer shall include:6.1.1 Aspecimen holder and probe,into which the specimencan be placed.Changes in height of the specimen are sensed bymovement of the probe.Use a probe of a shape and size suchthat,for the material being tested,the load applied to thespecimen by the probe shall not cause indentation of thespecimen within the range of test temperatures of interest.6.1.2 Means for sensing movement of the probe resultingfrom changes in height of the specimen and for translatingthese movements into a signal suitable for input to the recorder.The sensing element should be capable of sensing a change inheight of 0.1 m of the test specimen,with provisions for lesssensitive ranges when needed.6.1.3 Means for uniformly heating the specimen holder at apredetermined rate over the range of temperatures of interest.This will consist of a furnace and temperature controller with1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.01 on Electrical Insulating Varnishes,Powders,and Encapsu-lating Compounds.Current edition approved Dec.10,2000.Published January 2001.Originallypublished as D 3386 84.Last previous edition D 3386 94.2Annual Book of ASTM Standards,Vol 10.01.3Annual Book of ASTM Standards,Vol 08.01.4Annual Book of ASTM Standards,Vol 10.02.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.provisions for precooling the furnace and specimen holderwhen measurements of subambient temperatures are to bemade.6.1.4 Means for measuring temperature in immediate prox-imity to the test specimen.6.1.5 Equipment for recording changes in specimen heightas a function of specimen temperature.6.1.6 Micrometer,meeting the requirements of Test Meth-ods D 374M.NOTE2Instruments from TA Instruments and Perkin-Elmer havebeen found suitable.7.Test Specimens7.1 Specimens shall be between 2.5 and 7.5 mm in heightand shall have flat and parallel upper and lo