EN 623-3:2001

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Advanced technical ceramics - Monolithic ceramics - General and textural properties - Part 3: Determination of grain size and size distribution (characterized by the Linear Intercept Method)Hochleistungskeramik - Monolithische Keramik - Allgemeine undstrukturelle Eigenschaften - Teil 3: Bestimmung der Korngrößeund der Korngrößenverteilung (Linienschnittverfahren)Céramiques techniques avancées - Céramiques monolithiques - Propriétés générales et texturales - Partie 3: Détermination de la taille des grains et de la distribution granulométrique (selon la méthode de l'intersection linéaire)Advanced technical ceramics - Monolithic ceramics - General and textural properties - Part 3: Determination of grain size and size distribution (characterized by the Linear Intercept Method)81.060.30Sodobna keramikaAdvanced ceramicsICS:Ta slovenski standard je istoveten z:EN 623-3:2001SIST EN 623-3:2002en01-januar-2002SIST EN 623-3:2002SLOVENSKI
STANDARDSIST ENV 623-3:20001DGRPHãþD

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 623-3May 2001ICS 81.060.30Supersedes ENV 623-3:1993English versionAdvanced technical ceramics - Monolithic ceramics - Generaland textural properties - Part 3: Determination of grain size andsize distribution (characterized by the Linear Intercept Method)Céramiques techniques avancées - Méthodes d'essai pourcéramiques monolithiques - Propriétés générales ettexturales - Partie 3: Détermination de la taille des grainsHochleistungskeramik - Monolithische Keramik -Allgemeine und strukturelle Eigenschaften - Teil 3:Bestimmung der KorngrößeThis European Standard was approved by CEN on 19 April 2001.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2001 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 623-3:2001 ESIST EN 623-3:2002

Page 2EN 623-3:2001ContentsPage1 Scope.32 Normative references.33 Terms and definitions.44 Significance and use.45 Apparatus.56 Test piece preparation.67 Photomicrography.78 Measurement of micrographs.89 Calculation of results.1010 Interferences and uncertainties.1011
Test Report.11Annex A (informative) Bibliography on stereology and grain size measurement.13Annex B (informative)
Grinding and polishing procedures.14Annex C (informative) Etching procedures.16Annex D (informative) Setting Köhler illumination in an optical microscope.18Annex E (informative) Round-robin verification of the procedure in this standard.19Annex F (informative) Grain size distribution measurement.20Annex G (informative)
Results sheet - Grain size in accordance with EN 623-3.21SIST EN 623-3:2002

Page 3EN 623-3:2001ForewordThis European Standard has been prepared by Technical Committee CEN/TC 184 "Advancedtechnical ceramics ", the secretariat of which is held by BSI.This European Standard shall be given the status of a national standard, either by publicationof an identical text or by endorsement, at the latest by November 2001, and conflictingnational standards shall be withdrawn at the latest by November 2001.This European Standard supersedes ENV 623-3:1993.Annexes A, B, C, D, E, F and G are informative.According to the CEN/CENELEC Internal Regulations, the national standards organizationsof the following countries are bound to implement this European Standard: Austria, Belgium,Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the UnitedKingdom.1ScopeThis Part of EN 623 describes manual methods of making measurements for the determinationof mean linear intercept grain size of advanced technical ceramics using photomicrographs ofpolished and etched test pieces. This is not the true mean grain diameter, but a somewhatsmaller parameter representing the average path length of a line drawn across a two-dimensionalsection. The relationship to true grain dimensions depends on grain shape and degree ofmicrostructural anisotropy. This standard contains two methods, A and B.Method A applies to single-phase ceramics, and to ceramics with a principal crystalline phaseand a glassy grain-boundary phase of less than about 5% by volume for which interceptcounting suffices. Method B applies to ceramics with more than about 5% by volume of poresor secondary phases, or ceramics with more than one major crystalline phase where individualintercept lengths are measured, which can optionally be used to create a size distribution. Thislatter method allows the pores or phases to be distinguished and the mean linear intercept sizefor each to be calculated separately.NOTE A method of determining volume fraction(s) of secondary phase(s) is under development as ENV 623-5; thiswill provide a means of determining whether Method A or Method B should be applied in borderline cases.Some users of this standard may wish to apply automatic or semiautomatic image analysis tomicrographs or directly captured microstructural images This is permitted by this standardprovided that the technique employed simulates the manual method (see clause 4 and 8.4).2Normative referencesThis European Standard incorporates, by dated or undated reference, provisions from otherpublications. These normative references are cited at the appropriate places in the text and thepublications are listed hereafter. For dated references, subsequent amendments to or revisions ofany of these publications apply to this European Standard only when incorporated in it bySIST EN 623-3:2002

Page 4EN 623-3:2001amendment or revision. For undated references the latest edition of the publication referred toapplies (including amendments).ENV 1006Advanced technical ceramics - Methods of testing monolithic ceramics -Guidance on the sampling and selection of test piecesEN ISO/IEC 17025General requirements for the competence of testing and calibrationlaboratories (ISO/IEC 17025:1999)3Terms and definitionsFor the purposes of this European standard, the following terms and definitions apply.3.1grain sizesize of the distinct crystals in a material, and for the purposes of this method of test, that of theprimary or major phase.3.2mean linear intercept grain sizethe average value of the distance between grain boundaries as shown by randomly positionedlines drawn across a micrograph or other image of the microstructure.4Significance and useThe mean grain size and the distribution of grain sizes of a ceramic material play an importantrole in determining many properties, and thus grain size characterization is an important tool forensuring consistency of manufacture. There are many measures of grain size and/or shape, butthe linear intercept method provides the simplest possible method from a two dimensionalsection through the material. However, it must be recognised that the numerical value obtainedfor the mean linear intercept size is somewhat smaller than most other measures of grain sizebecause intercepts can cross grains at any position, and not necessarily along the largest axis.The relationship between mean linear intercept size and a true three-dimensional grain size isnot simple, and depends on the grain shape and the average number of facets. NOTE Annex A contains a bibliography of sources dealing with stereology and methods of sizing three-dimensionalobjects.This Standard provides a simple method of measuring intercept distances in single-phasematerials based on counting the number of intersections along given lengths of randomlyorientated and positioned lines or randomly positioned circles drawn onto a micrograph of asuitably sectioned, polished and etched test-piece. The length of lines crossing large poresresiding at grain boundaries can be ignored, thus eliminating any bias that porosity mayintroduce, but small pores within grains should be ignored. In materials which contain morethan one phase, the phases may be continuous or as isolated grains. It may be necessary tocharacterize the different phases separately. The principal purpose of this standard is to permitcharacterization of the major phases. The same intercept principle as for single-phase materialsSIST EN 623-3:2002

Page 5EN 623-3:2001can be used, but the individual intercept lengths across each phase must be measured, ratherthan just counted. The characterization of minor phases may require different treatment, whichis outside the scope of this Standard.If the material possesses a microstructure which has a preferred orientation of the primary orsecondary phases, the results of this measurement may not be representative of the truecharacter of the material. Rather than using randomly orientated lines, it may be necessary tomake measurements restricted to specific orientations. If undertaken, this must be reported inthe report.This Standard does not cover methods of measuring mean grain size by counting usingcalibrated microscope stage movement or projection onto screens, accompanied by visualobservation. While this latter method may produce an equivalent result to the analysis ofmicrographs, it does not provide a means of verification of the results of the measurement, sinceno permanent record is obtained.If automatic or semiautomatic image analysis (AIA) is to be used it must be recognised thatdifferent AIA systems approach the measurement in different ways, and may use differentparameters to linear intercept distance, such as those based on grain area by pixel counting. Inorder to obtain results equivalent to those of the manual method described in this standard, theAIA system needs to be programmed to operate in a similar way to the manual method. Byagreement between parties, such a near-equivalent AIA method may be used as an alternative tothe manual method, and if undertaken must be reported in the report.5Apparatus5.1Sectioning equipmentA suitable diamond-bladed cut-off saw to prepare the initial section for investigation. The sawshall be metal bonded with a diamond grit size of 125 mm to 150 mm and shall be cooled.NOTE The grit size is designated D151 in
ISO 6106, see annex A.5.2Mounting equipmentSuitable metallurgical mounting equipment and media for providing firm gripping of the testpieces for polishing.5.3Grinding and polishing equipmentSuitable grinding and polishing equipment, employing diamond abrasive media.NOTE Annex
B recommends techniques and abrasives.5.4MicroscopeAn optical or scanning electron microscope with photomicrographic facilities.
A referencegraticule is required for determination of magnification in an optical microscope, and areference square grid or latex spheres are required for calibration of magnification in a scanningelectron microscope. In all cases, the calibration of dimensions of the references shall beSIST EN 623-3:2002

Page 6EN 623-3:2001traceable to national or international standards of length measurement.An optical microscope is additionally required for assessing quality of polishing (see 6.4).5.5Calibrated rule or scaleA calibrated rule or scale reading to better than 0.5 mm and accurate to better than 0,5%.6Test piece preparation6.1 SamplingThe test pieces shall be sampled in accordance with the guidelines given in ENV 1006, andsubject to agreement between parties.NOTE Depending on the objectives of the measurement, it is desirable to maintain full knowledge of the positionswithin components or test pieces from which sections are prepared.6.2CuttingThe required section of the test piece shall be cut using the diamond saw (see 5.1).NOTE For routine inspection of materials, a small area of not more than 10 mm side is normally adequate as thesection to be polished.6.3MountingMount the test piece using an appropriate mounting medium. If the ceramic is suspected to havesignificant open porosity in some regions (see clause 1) it is advisable to vacuum impregnate thetest piece with liquid mounting resin before encapsulating as this will provide some supportduring polishing.NOTE It is not essential to encapsulate the test piece. For example, it could be affixed to a metal holder. However,encapsulation in a polymer-based medium allows easy gripping and handling, especially of small irregularly shapedtest pieces and of weak, friable materials. The method of mounting selected should take into account the etchingprocedure to be used; see annex C.6.4Grinding and polishingGrind and polish the surface of the test piece. Care should be taken to ensure that grindingproduces a plana
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