1、BRITISH STANDARD BS EN 1159-2:2003 Advanced technical ceramics Ceramic composites Thermophysical properties Part 2: Determination of thermal diffusivity The European Standard EN 1159-2:2003 has the status of a British Standard ICS 81.060.30 BS EN 1159-2:2003 This British Standard, was published unde
2、r the authority of the Standards Policy and Strategy Committee on 5 November 2003 BSI 5 November 2003 ISBN 0 580 42891 5 National foreword This British Standard is the official English language version of EN 1159-2:2003. It supersedes DD ENV 1159-2:1994 which is withdrawn. The UK participation in it
3、s preparation was entrusted to Technical Committee RPI/13, Advanced technical ceramics, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European
4、 publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all t
5、he necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on t
6、he interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 13 and a back cover. The
7、 BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN11592 September2003 ICS81.060.30 SupersedesENV11592:1993 Englishversion AdvancedtechnicalceramicsCe
8、ramiccomposites ThermophysicalpropertiesPart2:Determinationofthermal diffusivity CramiquestechniquesavancesCramiques compositesPropritsthermophysiquesPartie2: Dterminationdeladiffusivitthermique HochleistungskeramikKeramischeVerbundwerkstoffe ThermophysikalischeEigenschaftenTeil2:Bestimmung derTempe
9、raturleitfhigkeit ThisEuropeanStandardwasapprovedbyCENon1August2003. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnatio
10、nal standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheManagementCentrehasthesamestatusasth
11、e official versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Slovakia,Spain,Sweden,SwitzerlandandUn ited Kingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMIT
12、EUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2003CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN11592:2003EEN11592:2003(E) 2 Contents Page Foreword. 3 1 Scope . 4 2 Normativereferences . 4 3 Term
13、sanddefinitions. 4 4 Principle. 4 5 Apparatus 5 5.1 Heatpulsesource . 5 5.2 Testchamber . 5 5.3 Detectors 5 5.3.1 Measurementofabsolutetemperature. 5 5.3.2 Transientdetectors. 5 5.4 Dataacquisition 6 6 Testspecimens . 6 7 Testspecimenpreparation . . 7 7.1 Machiningandpreparation. . 7 7.2 Numberoftes
14、tspecimens . 7 8 Procedure 7 8.1 Calibrationofapparatus . 7 8.2 Procedure 7 9 Results . 8 10 Testreport . 8 AnnexA (informative) Unidimensionalthermalmodel 11 Bibliography . 13EN11592:2003(E) 3 Foreword Thisdocument(EN11592:2003)hasbeenpreparedbyTechnicalCommitteeCEN/TC 184“Advanced technicalceramic
15、s”,thesecretariatofwhichisheldbyBSI. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,eitherbypublicationofanidentical textorbyendorsement,atthelatestbyMarch2004,andconflictingnationalstandardsshallbewithdrawnat thelatestbyMarch2004. EN1159consistsoffourparts: Part1:Determinationoftherma
16、lexpansion Part2:Determinationofthermaldiffusivity Part3:Determinationofspecificheatcapacity Part4:Determinationofthermalconductivity AnnexAisinformative. ThedocumentsupersedesENV11592:1993. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizationsofthefollowing countriesareboun
17、dtoimplementthisEuropeanStandard:Austria,Belgium,CzechRepublic,Denmark, Finland,France,Germany,Greece,Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands, Norway,Portugal,Slovakia,Spain,Sweden,SwitzerlandandtheUnitedKingdom.EN11592:2003(E) 4 1Scope ThispartofEN1159describesthelaserflashmethod
18、forthedeterminationofthermaldiffusivityofceramic matrixcompositeswithcontinuousfibrereinforcement. Theexperimentalconditionsaresuchthatthematerialbehavesinanhomogeneousmannerforeachofits axesofanisotropyandthattheheattransferoccursonlybythermalconduction. Themethodisapplicabletomaterialswhicharephys
19、icallyandchemicallystableduringthemeasurement, andcoverstherangeoftemperaturebetween100Kand2800K.Itissuitableforthemeasurementof thermaldiffusivityvaluesintherangebetween10 4 m 2 s 1 and10 7 m 2 s 1 . 2 Normativereferences ThisEuropeanStandardincorporatesbydatedorundatedreference,provisionsfromother
20、publications. Thesenormativereferencesarecitedattheappropriateplacesinthetextandthepublicationsarelisted hereafter.Fordatedreferences,subsequentamendmentstoorrevisionsofanyofthesepublicationsapplyto thisEuropeanStandardonlywhenincorporatedinitbyamendmentorrevision.Forundatedreferencesthe latestediti
21、onofthepublicationreferredtoapplies(includingamendments). ENV8435, AdvancedtechnicalceramicsMonolithicceramicsMechanicaltestsatroomtemperature Part5:Statisticalanalysis. ENV13233, AdvancedtechnicalceramicsCeramiccompositesNotationsandsymbols. EN605841, ThermocouplesPart1:Referencetables(IEC605841:19
22、95). ISO3611, Micrometercallipersforexternalmeasurement. 3 Termsanddefinitions ForthepurposesofthisEuropeanStandard,thetermsanddefinitionsgiveninENV13233andthefollowing apply. 3.1 thermaldiffusivity, a ratioofthethermalconductivitytotheproductofthebulkdensityandthespecificheatcapacity 3.2 transienth
23、alftime, t 1/2 timefromtheinitiationofthepulseuntiltheincreaseofthetemperatureonthebackfaceofthetestspecimen reachesonehalfofthemaximumtemperatureincrease 3.3 thickness, h dimensionofthetestspecimeninthedirectionofheattransfermeasurement 4Principle Onesideofaplaneandparalleltestpieceisexposedtoaunif
24、ormlydistributedenergypulsethatisofvery shortdurationcomparedtothetransienthalftime.EN11592:2003(E) 5 Thetransienttemperaturerise( D T)ontheoppositeface(backface)oraquantitydirectlyproportionalto D Tis recordedasafunctionoftime( t)(seeFigure1). Thethermaldiffusivityisobtainedbycomparingtheexperiment
25、althermogramwithatheoreticalmodel,which isaunidimensionalanalyticalthermalmodel,withtwoparameters,asdescribedinannexA.Ifothermodels areused,theyaretobespecifiedinthetestreport. 5Apparatus 5.1Heatpulsesource Theheatpulsesourcemaybeaflashtubeorapulselaser. Thepulseenergyshallbeasuniformaspossibleovert
26、hefrontfaceofthetestpiece. 5.2Testchamber Thetestchambershallbeeitherafurnaceoracryostat,capableofoperationwithinthetemperaturerange required,oradraughtproofenclosureforambienttemperaturemeasurement. Thedesignofthefurnaceshallmeetthefollowingrequirements: a) itshallcontainaworkingareainwhichthespati
27、altemperaturegradientissufficientlylow( 5K)toresult inahomogeneoustemperatureonthetestpiece; b) insteadystateconditions,thedriftintemperatureshallbelessthan0,01K/s; c) theheatpulsesourcemaybeplacedeitherinsidethefurnaceoroutsidethefurnace;inthatcase,the furnaceshallbefittedwithawindow,transparenttot
28、hepulseradiation; d) thefurnaceshallprovidesuitableaccessformeasurementof D Toraquantitydirectlyproportionalto D T onthebackfaceofthetestpiece. NOTE1 Measurementundervacuumwillreduceconvectionlosses. NOTE2 Whenthetestisperformedundergas,thetestpieceshouldbeinahorizontalpositioninordertoreduce convec
29、tioneffectsofthegasonthespecimen. 5.3Detectors 5.3.1 Measurementofabsolutetemperature Thetemperatureofthetestpieceshallbemeasuredeitherwithathermocouple(inaccordancewithEN 605841)orwithanopticalpyrometer. 5.3.2Transient detectors Thedetectorshallbeeitheraninfrareddetector,athermocoupleoranyothermean
30、sthatdoesnotdisturbthe measurementofthetransientresponseofthespecimen.Itshallbecapableofdetectingchangesof0,05Kin thetemperatureofthetestpiece,withalinearresponseovertherangeoftemperaturechangelessthanor equalto5K.EN11592:2003(E) 6 Itshallhavearesponsetime: t d 0,002 h 2 / a where t d istheresponset
31、ime,insecond,(s) h isthethickness,inmetre,(m) a isthethermaldiffusivity,insquaremetrespersecond(m 2 .s 1 ) Thisconditionshallbeverifiedafterwardsandifitisnotmetthesizeofthespecimenshallbeincreased. Theinfrareddetector,whenused,shallbeofatypeappropriatetotheminimumtestpiecetemperature,for example: a)
32、 Hg/Cd/Tecell,liquidnitrogencooled,fortestspecimentemperatureswithintherange300Kto800K; b) PbScellfortestspecimentemperaturesabove500K. Careshallbetakenthatthesignalcomesonlyfromthecentralareaofthebackface,thatiswithatolerance of5%ofthediameterofthetestspecimen. Thermocouples,whenused,shallbeofthese
33、paratedjunctiontype,thehotjunctionbeingthebackfaceofthe testpiece.TheyshallbeinaccordancewithEN605841.Electricallynonconductivematerialshallbecoated onthefrontfaceandontherearface,withathincoatingofhighthermalconductivitymaterialinorderto ensureaccuratemeasurementofsurfacetemperatures. NOTE1 Inorder
34、tominimizeheatlosses,theuseofthethermocoupleswithwiresofthesmallestpossiblediameteris recommended. NOTE2 Thethermocoupletypemostoftenusedischromelalumelformeasurementsfromroomtemperatureupto1 100K.Semiconductingcouplesmayalsobeused:Bi 2 Te 3 from90Kto400KandFeSi 2 fortemperaturesupto1100K. Fortemper
35、aturesover1100K,anoncontactmeasurementtechniqueisrecommended. 5.4Dataacquisition Thedataacquisitionsystemusedmaybeanalogueordigital.Itshallbeequippedwithmeansofrecordingthe temperaturechangeversustime(before,duringandafterthepulse)andthetimeorigin.Thesemeansshall beaccuratetowithin0,02ms. 6 Testspec
36、imens Thesizeofthetestspecimensshallbefixedtomeettherequirementsforapplicationofthechosenthermal model(forexampleliketheonedescribedinannexA).Generallyadiscofadiameterbetween8mmand25 mmisused. Thethicknessofthespecimenshallbesufficientinordertoavoidinfluenceofmaterialhomogeneity.This shallbeensuredb
37、yperformingtestsontwoseriesoftestspecimenswithathicknessratioofabout2. Recommendedstartingthicknessesarebetween1mmand10mm.Homogeneousmaterialbehaviourcanbe assumedwhenthemeanvaluesofthethermaldiffusivitydeterminedfromeachseriesdonotdifferbymore than10%.EN11592:2003(E) 7 7 Testspecimenpreparation 7.1
38、Machiningandpreparation Testspecimensshallbecutwiththeirlongitudinalaxiscoincidingwithoneoftheprincipaldirectionsofthe reinforcement.Thefacesshallbeflatandparallel.Theplanparallelismofthetwofacesshallbebetterthan 0,05mm. Ifthetestspecimenistransparenttotheinfraredradiationattheconsideredwavelengthof
39、thelaser,acoating isnecessary.Thiscoatingshallbeopaque,absorbent,adherentandcompatiblewiththetestspecimen. Ifthetestspecimenisnonconductive,andifathermocoupleisusedtomeasurethetemperatureontheback face,anadequateconductivecoatingshallbeused. 7.2Numberoftestspecimens Aminimumofthreetestspecimensshall
40、betested. Ifastatisticalevaluationisrequired,thenumberoftestspecimensshallbeinaccordancewithENV8435. 8Procedure 8.1Calibrationofapparatus Asthemeasurementofthermaldiffusivityisanabsolutemethod,referencetypematerialswithknown diffusivitiescanbeusedtocheckthesystem.Thehomogeneityofthelaserbeamcanbever
41、ifiedby photographicpaper(Polaroidtype). NOTE Thereisnorecognisedstandardreferencematerialforthermaldiffusivitymeasurements,althoughseveral materialsareused(forexamplePOCOgraphite,ARMCOiron). 8.2Procedure Thepulsedurationshallbelessthanorequalto0,003 a h 2 toallowfordirectapplicationofthetheoretical
42、 model.Ingeneralthiscorrespondstoaperiodlessthan1/50oftransienthalftime( t 1/2 ). NOTE Whenthisconditionisnotobeyed,acorrectionofthethermogramispossiblebyplacingthetimeoriginatthe energeticbarycentre t b ofpulse(seeFigure1). Measurethethicknessofthetestspecimenwithin0,01mm,usingmicrometercallipersin
43、accordancewith ISO3611.Inacasewhereacoatingisused,makethemeasurementbeforecoating.Whenthechangein thicknessduetothermalexpansionislargerthan1%,applyacorrectiontothemeasuredthicknessvalue. Fixthetestspecimensuchasthefrontfaceshallbeperpendiculartotheheatsourcebeam.Thermallosses fromthespecimentothesurroundingenvironmentshallbekepttoaminimumandthecontactareaoftest piecewiththesampleholdershallbeassmallaspossible.
