ASTM_D_6744_-_06_2011e1.pdf

Designation:D674406(Reapproved 2011)1Standard Test Method forDetermination of the Thermal Conductivity of AnodeCarbons by the Guarded Heat Flow Meter Technique1This standard is issued under the fixed designation D6744;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()indicates an editorial change since the last revision or reapproval.1NOTEUpdate wording in Notes 14,6.3.2,12.1.8,and updated notation in Section 13 editorially in August 2011.1.Scope1.1 This test method covers a steady-state technique for thedetermination of the thermal conductivity of carbon materialsin thicknesses of less than 25 mm.The test method is useful forhomogeneous materials having a thermal conductivity in theapproximate range 1 30 W/(mK),(thermal resistance inthe range from 10 to 400 104m2K/W)over the approxi-mate temperature range from 150 to 600 K.It can be usedoutside these ranges with reduced accuracy for thicker speci-mens and for thermal conductivity values up to 60 W/(mK).NOTE1It is not recommended to test graphite cathode materials usingthis test method.Graphites usually have a very low thermal resistance,andthe interfaces between the specimen to be tested and the instrumentbecome more significant than the specimen itself.1.2 This test method is similar in concept to Test MethodsE1530 and C518.Significant attention has been paid to ensurethat the thermal resistance of contacting surfaces is minimizedand reproducible.1.3 The values stated in SI units are regarded as standard.The values given in parentheses are for information only.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.2.Referenced Documents2.1 ASTM Standards:2C518 Test Method for Steady-State Thermal TransmissionProperties by Means of the Heat Flow Meter ApparatusE1530 Test Method for Evaluating the Resistance to Ther-mal Transmission of Materials by the Guarded Heat FlowMeter Technique3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 average temperature,nthe average temperature of asurface is the area-weighted mean temperature of that surface.3.1.2 heat flux transducer,HFT,na device that producesan electrical output that is a function of the heat flux,in apredefined and reproducible manner.3.1.3 thermal conductance,C,nthe time rate of heat fluxthrough a unit area of a body induced by unit temperaturedifference between the body surfaces.3.1.4 thermal conductivity,of a solid material,nthetime rate of heat flow,under steady conditions,through unitarea,per unit temperature gradient in the direction perpendicu-lar to the area.3.1.5 thermal resistance,R,nthe reciprocal of thermalconductance.3.2 Symbols:=thermal conductivity,W/(mK),Btuin/(hft2F)C=thermal conductance,W/(m2K),Btu/(hft2F)R=thermal resistance,m2K/W,hft2F/Btux=specimen thickness,mm,inA=specimen cross sectional area,m2,ft2Q=heat flow,W,Btu/h=heat flux transducer output,mVN=heat flux transducer calibration constant,W/(m2mV),Btu/(hft2mV)N=heat flux,W/m2,Btu/(hft2)T=temperature difference,C,FTg=temperature of guard heater,C,FTu=temperature of upper heater,C,FTl=temperature of lower heater,C,FT1=temperature of one surface of the specimen,C,FT2=temperature of the other surface of the specimen,C,FTm=mean temperature of the specimen,C,F1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.05 on Properties of Fuels,Petroleum Coke and Carbon Material.Current edition approved May 1,2011.Published August 2011.Originallyapproved in 2001.Last previous edition in 2006 as D674406.DOI:10.1520/D6744-06R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 s=unknown specimenr=known calibration or reference specimeno=contacts4.Summary of Test Method4.1 A specimen and a heat flux transducer(HFT)aresandwiched between two flat plates controlled at differenttemperatures,to produce a heat flow through the test stack.Areproducible load is applied to the test stack by pneumatic orhydraulic means,to ensure that there is a reproducible contactresistance between the specimen and plate surfaces.A cylin-drical guard surrounds the test stack and is maintained at auniform mean temperature of the two plates,in order tominimize lateral heat flow to and from the stack.At steady-state,the difference in temperature between the su