1、BRITISH STANDARD BS EN 13925-2:2003 Non-destructive testing X-ray diffraction from polycrystalline and amorphous materials Part 2: Procedures The European Standard EN 13925-2:2003 has the status of a British Standard ICS 19.100 BS EN 13925-2:2003 This British Standard was published under the authori
2、ty of the Standards Policy and Strategy Committee on 20 March 2003 BSI 20 March 2003 ISBN 0 580 41462 0 National foreword This British Standard is the official English language version of EN 13925-2:2003. The UK participation in its preparation was entrusted to Technical Committee WEE/46, Non-destru
3、ctive testing, 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 publications referred to in this document may be found in the BSI Catalo
4、gue 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 the necessary provisions of a contract. Users are responsible for its corr
5、ect 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 the interpretation, or proposals for change, and keep the UK interests inf
6、ormed; 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 23 and a back cover. The BSI copyright date displayed in this document indicates when the documen
7、t was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN139252 March2003 ICS19.100 Englishversion NondestructivetestingXraydiffractionfrompolycrystalline andamorphousmaterialsPart2:Procedures EssaisnondestructifsDiffractiondesrayo
8、nsXapplique auxmatriauxpolycristallinsetamorphesPartie2: Procdures ZerstrungsfreiePrfungRntgendiffraktometrievon polykristallinenundamorphenMaterialienTeil2: Verfahrensablufe ThisEuropeanStandardwasapprovedbyCENon29November2002. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichsti
9、pulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,Fren
10、ch,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheManagementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Hungary,I
11、celand,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Slovakia,Spain,Sweden,SwitzerlandandUn ited Kingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2003CEN Allrightsofexploitationinanyforman
12、dbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN139252:2003EEN139252:2003(E) 2 Contents page Foreword3 Introduction .4 1 Scope 4 2 Normativereferences 5 3 Termsanddefinitions. .5 4 Specimenpreparation .5 4.1 Generalpreparation. 5 4.2 Blockspecimens. .8 4.3 Powderspecimens 9 4.4 Analysis
13、ofsmallquantitiesofsample 11 4.5 Reactivesamplesandnonambientconditions . 11 5 Datacollection. .12 5.1 Generalconsiderations .12 5.2 Angularrangeandmodeofdatacollection. .12 5.3 Parametersrelevanttothequalityofcollecteddata 12 6 Dataprocessingandanalysis 13 6.1 Background 13 6.2 Peaksearching .13 6.
14、3 Patterndecompositionintoindividuallineprofilesincludingbackgroundsubtraction14 6.4 Phaseidentification .15 6.5 Indexing 15 6.6 Latticeparameterrefinement 15 6.7 Othertypesofanalysis . 16 AnnexA (informative) RelationshipbetweentheXRPDstandards .17 AnnexB (informative)ExampleofReportForm .18 AnnexC
15、 (informative)SchemeofatypicalprocedureforXRPDmeasurements .19 AnnexD (informative) Someanalyticalfunctionsusedforprofilefitting .20 AnnexE (informative) SomemethodsfortestingtheinternalconsistencyofXRPDdata21 E.1 General21 E.2 FiguresofMeritforFWHMsandintensities 21 E.3 FiguresofMeritforlinepositio
16、nsandlatticeparameters 22 Bibliography 23EN139252:2003(E) 3 Foreword Thisdocument(EN139252:2003)hasbeenpreparedbyTechnicalCommitteeCEN/TC138“Nondestructive testing“,thesecretariatofwhichisheldbyAFNOR. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,eitherbypublicationofanidenticaltextor
17、 byendorsement,atthelatestbySeptember2003,andconflictingnationalstandardsshallbewithdrawnatthe latestbySeptember2003. ThisEuropeanStandardabout“NondestructivetestingXraydiffractionfrompolycrystallineandamorphous material” iscomposedof: EN139251 Generalprinciples; EN 139252 Procedures; prEN139253 Ins
18、truments; prEN139254 Referencematerials. Inordertoexplaintherelationshipsbetweenthetopicsdescribedinthedifferentstandards,adiagramillustrating typicaloperationsinvolvedinXRPDanalysisisgiveninannexA. AnnexesAtoEareinformative. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizat
19、ionsofthefollowing countriesareboundtoimplementthisEuropeanStandard:Austria,Belgium,CzechRepublic,Denmark,Finland, France,Germany,Greece,Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal, Slovakia,Spain,Sweden,SwitzerlandandtheUnitedKingdom.EN139252:2003(E) 4 Introduction Xr
20、aypowderdiffraction(XRPD)isapowerfulNonDestructiveTesting(NDT)methodfordeterminingarangeof physicalandchemicalcharacteristicsofmaterials.Theseincludethetypeandquantitiesofphasespresent,the crystallographicunitcellandstructure,crystallographictexture,macrostress,crystallitesizeandmicrostrain,and thee
21、lectronradialdistributionfunction. ThisstandardaimstodescribethegeneralaspectsoftheXRPDtechniqueanditsapplicationsbutnottodefinea specificordetailedstandardforeachfieldofapplicationortypeofanalysis. Themainpurposesofthestandardaretherefore: toprovidepracticalguidance,unifiedconceptsandterminologyfor
22、useoftheXRPDtechniqueintheareaof NonDestructiveTestingwithgeneralinformationaboutitscapabilitiesandlimitationsofrelevanceto laboratoriesworkingatdifferentlevelsofsophistication,fromroutinetestingtoresearch; toprovideabasisforQualityAssuranceinXRPDlaboratoriesallowingperformancetestingandmonitoringof
23、 instrumentsaswellasthecomparisonofresultsfromdifferentinstruments; toprovideageneralbasis(withoutimposingspecifications)forfurtherspecificNDTproductstandardsand relatedQualityAssuranceapplications,withaspectscommontomostfieldsofapplication. Inordertomakethestandardimmediatelyusableinawiderangeoflab
24、oratoriesandapplications,diffractometers withBraggBrentanogeometryareconsideredinmoredetailsthanthediffractometersusingothergeometries. RadiationProtection. ExposureofanypartofthehumanbodytoXrayscanbeinjurioustohealth.Itistherefore essentialthatwheneverXrayequipmentisused,adequateprecautionsshouldbe
25、takentoprotecttheoperator andanyotherpersoninthevicinity.Recommendedpracticeforradiationprotectionaswellaslimitsforthelevels ofXradiationexposurearethoseestablishedbynationallegislationineachcountry.Iftherearenoofficial regulationsorrecommendationsinacountry,thelatestrecommendationsoftheInternationa
26、lCommissionon RadiologicalProtectionshouldbeapplied. 1 Scope ThisEuropeanStandardspecifiesthebasicproceduresappliedintheXrayPowderDiffraction(XRPD)method. Manyoftheseproceduresarecommontomosttypesofdiffractometerusedandtypesofanalysismentionedin EN 139251.Intheinterestsofclarityandimmediateusability
27、moredetailsaregivenforproceduresusing instrumentswithBraggBrentanogeometryandapplicationtophaseidentification.Aspectsofspecimen preparationanddataqualityassessment areincluded,butthestandardremainsnonexhaustive.Itisanticipated thatparticularstandardswilladdressspecificfieldsofapplicationinmoredetail
28、s.EN139252:2003(E) 5 2 Normativereferences ThisEuropeanStandardincorporatesbydatedorundatedreference,provisionsfromotherpublications.These normativereferencesarecitedattheappropriateplacesinthetext,andthepublicationsarelistedhereafter.For datedreferences,subsequentamendmentstoorrevisionsofanyofthese
29、publicationsapplytothisEuropean Standardonlywhenincorporatedinitbyamendmentorrevision.Forundatedreferencesthelatesteditionofthe publicationreferredtoapplies(includingamendments). EN139251:2003,NondestructivetestingXraydiffractionfrompolycrystallineandamorphousmaterials Part1:Generalprinciples. prEN1
30、39253, NondestructivetestingXraydiffractionfrompolycrystallineandamorphousmaterials Part3: Instruments. 3 Termsanddefinitions ForthepurposesofthisEuropeanStandard,thegeneraltermsanddefinitionsconcerningXraypowder diffraction 1) apply. 4 Specimenpreparation Thesampletreatmentandspecimenpreparationsha
31、llbeadaptedtothenatureofthesampleandthetypeof analysisinordertooptimisethequalityofthe datatobecollected 1,2.Asexplainedinclause5of EN139251:2003,thetermpowderwhenusedincrystallography,doesnotstrictlycorrespondtothecommon usage. 4.1 Generalpreparation 4.1.1 Lateralspecimensize Whenthetacompensatingv
32、ariableaperturesareused,thesurfaceareaofthespecimenirradiatedbythebeam canbekeptconstant(butnotthevolumefromwhichdiffractionismeasured).Thespecimenshallalwaysintercept thewholeincidentbeamtoavoidalossofdiffractedintensity.Thiscanbechecked,forexample,byinitially investigatingtherangeofanglestobemeasu
33、red,afterreplacementofthespecimenwithafluorescentscreenof thesamedimensions.Alternatively,thelengthofthespecimensurfaceirradiatedbytheXraybeamcanbe calculatedusingtheequation: Irradiatedlength(mm)= R a /sin q (1) where R istheradiusofthegoniometer,inmillimetres; a isthedivergenceangleofthebeam,inrad
34、ians; q ishalfthediffractionangle2 q ,indegreesorradians. Inpractice,withfixedapertureslits,theincidentbeamatlow2q anglesoftenspreadsbeyondthespecimen surface.Thecorrespondingdiffractedintensitiescanbeapproximatelycorrectedbycomparingthemwithdata recordedinthesameangulardomainbutusingafixedslitofsma
35、lleraperture. 1 ) aEuropeandraftstandard(WI00138078“NondestructivetestingXraypowderdiffractionTerminology“)isin preparationEN139252:2003(E) 6 Whenasmallamountofapowderistobeexamined,thediffractedintensitycanbemaximisedbypreparingitto formathinlayerwithalargeareainterceptingtheincidentXraybeam. Whens
36、pecimenswithlowattenuationareinvestigatedondiffractometersworkinginareflectiongeometry,itshould alsobetakenintoaccountthat,atlowdiffractionangles,theincidentanddiffractedXraysmaypropagatea considerabledistanceinadirectionnearlyparalleltothespecimensurface.Thustheoptimumlateralsamplesize mightbeconsi
37、derablylargerthantheareaofintersectionoftheincidentXraybeamwiththespecimensurface. 4.1.2 Effectofspecimendisplacement AspecimensurfacethatisoffsetwithreferencetotheBraggBrentanogoniometer2 q rotationaxis,resultsinaline shiftbyanangle,inradiansof 2 ) () R h / cosq D q q q D 2 2 2 2 theo obs - = - = (
38、2) where D (2q ) istheshift(inradians)inthetheoreticallinepositiontoalignitwiththeobservedposition.Itispositive whenthespecimensurfaceisdisplacedtowardsthesourceanddetector; 2q obs and2 q theo aretheobserveddiffractionangleandthediffractionanglecalculatedfromtheBragglaw; D h isthespecimensurfacedisp
39、lacement(inmillimetres) measuredalongthebisectoroftheanglebetween theincidentbeamandthediffractedbeam.ItispositiveifthespecimensurfacemovesawayfromtheXray sourceandthedetector. R istheradiusofthegoniometer(inmillimetres). ThisisillustratedschematicallyinFigure1. 2 )Thisequationissimilartothatgivenby
40、Wilson3.EN139252:2003(E) 7 Key 1 Source 2B i s e c t o r 3 Detector Thesymbolsaredefinedinequation(2) Figure1Relationshipsbetweenthespecimendisplacementandthediffractionlineposition Specimendisplacementssmallerthan20 m maredifficulttoavoid.Forexample,withagoniometerof200mm radius,thisoffsetwouldresu
41、ltinamaximumangularerrorof0,01(2 q ). Useofanappropriateinternalstandardallowsthedetectionandcorrectionofthiseffectsimultaneouslywiththat arisingfromspecimentransparency. 4.1.3 Effectsofspecimenthicknessandtransparency WhentheXRPDmethodisappliedinareflectiongeometryitisoftenpreferabletoworkwithspeci
42、mensofinfinite thickness.Thismeansthat,foragivenmassattenuationandapparentdensityofthespecimenandagivenrange ofdiffractionangles,thediffractedintensityfromthebackofthespecimenisnegligible. Toensurethatthediffractedintensityisatleast99,9%ofthemaximumattainablebyincreasingthespecimen thickness,thethic
43、knessshallbeatleast4: () / sin 45 . 3 r m q = t (3) where t isthethickness,expressedincentimetres; r isthespecimendensity,themassofthespecimendividedbyitsvolumeincludingvoidsexpressedin gramspercubiccentimetre; m istheweightedsumofthemassattenuationcoefficients(oftenreferredtoasthemassabsorption coefficient)expressedinsquarecentimetrespergram5.Itisadditiveforthemassattenuationcoefficients oftheconstituentelementsofthematerialwhe
