1、BSI Standards PublicationBS ISO 18550:2016Fine ceramics (advancedceramics, advanced technicalceramics) Testing methodfor macro-heterogeneity inmicrostructureBS ISO 18550:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18550:2016. The UK participation in it
2、s preparation was entrusted to TechnicalCommittee RPI/13, Advanced technical ceramics.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for i
3、ts correct application. The British Standards Institution 2016. Published by BSI Standards Limited 2016ISBN 978 0 580 81869 1 ICS 81.060.30 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy
4、 and Strategy Committee on 31 March 2016.Amendments issued since publicationDate T e x t a f f e c t e d ISO 2016Fine ceramics (advanced ceramics, advanced technical ceramics) Testing method for macro-heterogeneity in microstructureCramiques techniques Mthode dessai relative aux macro-htrognits dans
5、 la microstructureINTERNATIONAL STANDARDISO 18550First edition 2016-03-01Reference number ISO 18550:2016(E)BS ISO 18550:2016ISO 18550:2016(E)ii ISO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this
6、publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the
7、country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 18550:2016ISO 18550:2016(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 App
8、aratus . 16 Test specimen 27 Procedure. 27.1 Measurement of specimen thickness 27.2 Observation 27.3 Magnification 28 Measurement of macro-heterogeneities . 38.1 Determination of specimen volume under examination 38.2 Measurement of the size of macro-heterogeneities 39 Analysis 39.1 Maximum and mini
9、mum size . 39.2 Size interval . 39.3 Size and population of defect . 39.4 Graph . 410 Test report . 4Annex A (informative) Refractive indices of solid and liquids . 5Annex B (informative) Examples of macro-heterogeneities observed in transmission mode . 6Bibliography 9 ISO 2016 All rights reserved i
10、iiContents PageBS ISO 18550:2016ISO 18550:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each m
11、ember body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
12、Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different typ
13、es of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be
14、held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is informat
15、ion given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the f
16、ollowing URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 206, Fine ceramics.iv ISO 2016 All rights reservedBS ISO 18550:2016INTERNATIONAL STANDARD ISO 18550:2016(E)Fine ceramics (advanced ceramics, advanced technical ceramics) Testing method for macro-h
17、eterogeneity in microstructure1 ScopeThis International Standard specifies a test method for determining macro-heterogeneities within the microstructure of fine ceramics that are above a certain size within the volume of the material and affect materials mechanical strength properties. This method i
18、s limited to fine ceramics with a porosity of less than 10 vol% and that are transparent for visible light in the form of a thin specimen.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dat
19、ed references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories3 Terms and definitionsFor the purposes of this docume
20、nt, the following terms and definitions apply.3.1coarse macro-heterogeneitymacro-heterogeneity, e.g. agglomerates, pores, inclusion, grains, with a size above 10 m significantly affecting the mechanical strength3.2coarse macro-heterogeneity distributionsize distribution of coarse macro-heterogeneiti
21、es3.3equivalent circle diameterdiameter of a circle having the same area as the coarse macro-heterogeneity4 PrincipleA variety of ceramics are composed of transparent materials and their macro-heterogeneity is observed in the transmission mode on a thin specimen.5 Apparatus5.1 Microscope, enabling t
22、he observation in the transmission mode. The microscope shall have a maximum magnification of the objective lens of 10 and an illumination system with an adjustable aperture. A certified graticule shall be used for the calibration of the magnification.5.2 Cutting machine, suitable machine capable of
23、 cutting the ceramics.5.3 Grinding machine, suitable machine capable of grinding the ceramics. ISO 2016 All rights reserved 1BS ISO 18550:2016ISO 18550:2016(E)5.4 Polishing machine, suitable machine capable of polishing the ceramics.5.5 Micrometer, capable of measuring the thickness of the polished
24、ceramic section with an accuracy of 2 m.5.6 Microscope slide, suitable transparent microscope slide for mounting the test-piece in the microscope.5.7 Transparent film with circles of various diameter, to determine the equivalent circle diameter of defects.6 Test specimenThe specimen shall be thin en
25、ough for observation in the transmission mode of the microscope. The typical thickness depends on the material and its porosity, and is between 30 m and 200 m.The specimen shall be prepared as follows.a) Cut a thin slab from the ceramic using a cutting machine. A thickness of the slab of more than 1
26、 mm plus the final thickness is recommended. For a ceramic with thickness of less than 2 mm, this process can be omitted.b) One face of the slab shall be ground using a grinding machine and polished with a polishing machine by using polishing grains of a sequence of decreasing sizes with the finishi
27、ng grit size of less than 1 m.c) The other face of the slab shall be ground to adjust the thickness of the slab appropriately. Finally, the ground face shall be polished with the polishing machine by using polishing grains of a sequence of decreasing sizes as mentioned above to prepare a thin specim
28、en for observation.d) Finally, mount the thin specimen on the microscope slide for observation. Transparent thermoplastic resin is recommended for mounting.e) The thickness of the specimen must be adjusted for adequate transparency before examination. With a specimen of adequate transparency, defect
29、s located at any depth in the specimen can be well focused. Scratches on both front and back surfaces are conveniently used to examine the applicability of this International Standard. If they are clearly seen from the opposite side, this International Standard can be applied.7 Procedure7.1 Measurem
30、ent of specimen thicknessThe thickness of the specimen shall be measured at the centre of the specimen with a micrometer to the nearest 0,002 mm.7.2 ObservationAdjust the microscope as follows; set the numerical aperture of the condenser lens in the illumination system 0,1 or less. The objective len
31、s used for observation should have the magnification under 10.7.3 MagnificationThe minimum sizes of defects subjected for examination is 10 m equivalent circle diameter. With the numerical aperture of the lens of 0,1, the maximum thicknesses of specimens which can be examined in one micrograph will
32、be 48 m and 28 m multiplied by the refractive index of the specimen, for the objective lenses of magnifications 4 and 10, respectively.2 ISO 2016 All rights reservedBS ISO 18550:2016ISO 18550:2016(E)The position of focus should be at half of the specimen thickness from the top surface. The refractiv
33、e index of major phase shall be used for a specimen with multiple phases.If the specimen is highly transparent, a thicker specimen can be used. A series of micrographs shall be taken by changing the position of focus through the depth direction of specimen. The interval in the position of focus shal
34、l be less than 48 m and 28 m multiplied by the refractive index of the specimen, for the objective lenses of magnifications 4 and 10, respectively.The photographed areas shall not overlap and micrographs should cover at least 100 macro-heterogeneities which shall be analysed.8 Measurement of macro-h
35、eterogeneities8.1 Determination of specimen volume under examinationThe volume, V, under examination is given by the image area, Ai, the thickness, t, of the slab, and the number, nL, of locations under examination.V = Ai t nL(1)8.2 Measurement of the size of macro-heterogeneitiesThe net magnificati
36、on shall be adjusted to make the defect of the minimum size appear to be over 5 mm equivalent circle diameter on the micrograph. A transparent film with circles of various diameters shall be used to determine the equivalent circle diameter. Determine the size for at least 100 macro-heterogeneities.9
37、 Analysis9.1 Maximum and minimum sizeDetermine the largest and smallest macro-heterogeneity.9.2 Size intervalAt least five size intervals shall be taken between the size of the largest and smallest defects in the analysis. The intervals may not be equal, but at least five macro-heterogeneities shoul
38、d be present in each interval, except in the interval containing the largest macro-heterogeneity.9.3 Size and population of defectThe size and the population of macro-heterogeneities for each size interval are given by Formulae (2) and (3).di,m= (di,l+ di,u)/2 (2)wheredi,mis the mean size of interva
39、l i;di,lis the lower limit of the interval i;di,uis the upper limit of the interval i. ISO 2016 All rights reserved 3BS ISO 18550:2016ISO 18550:2016(E)pi= ni/(di,u di,l) V (3)wherepiis the population on interval i;niis the number of defects belonging to interval i.The unit to express population is t
40、he number of macro-heterogeneities/mm3/m.9.4 GraphPlot the logarithm of the population as a function of the size of macro-heterogeneities.10 Test reportThe test report shall be in accordance with the provisions of ISO/IEC 17025 and shall include at least the following information:a) a reference to t
41、his International Standard, i.e. ISO 18550;b) the name of the specimen;c) the preparation method of specimen:1) machining method;2) thickness of specimen;d) the observation method:1) name of microscope;2) objective lens (type, magnification, optical system);3) numerical aperture in observation;e) th
42、e micrographs micrographs of specimen and microscale taken at the magnification of observation and the results (e), if required;f) the measured results for size distribution of coarse non-uniform structure:1) size distribution of non-uniform structure (equivalent circle diameter);2) volume for obser
43、vation.4 ISO 2016 All rights reservedBS ISO 18550:2016ISO 18550:2016(E)Annex A (informative) Refractive indices of solid and liquidsRefractive index (R.I.) varies with the wave length. It decreases with increasing wave length. Materials of crystallographically cubic symmetry have a single value at e
44、ach wave length. Those of non-cubic crystal structures have multiple values. Average values are given for them in Table A.1. Values at the wave length of 632,8 nm are listed in Table A.1.Table A.1 Refractive indices (R.I.) of various materials at the wave length 632,8 nmMaterials R.I.Al2O31,770AlN 2
45、,165MgO 1,735SiC 2,635SiO21,457Si3N42,023BaTiO32,411TiO22,874ZrO22,208Source: http:/ ISO 2016 All rights reserved 5BS ISO 18550:2016ISO 18550:2016(E)Annex B (informative) Examples of macro-heterogeneities observed in transmission modeMacro-heterogeneities, e.g. agglomerates, pores, inclusion, grains
46、, are found in essentially any ceramic. Figure B.1 shows the structure of alumina ceramics observed with a transmission optical microscope. Dark features of various shapes correspond to heterogeneities in the structure. Figure B.2 shows the population of macro-heterogeneities determined through the
47、analysis of micrographs taken at various locations of the ceramics. A linear relationship is noted in this log-log plot. This relationship was noted in all other systems examined so far.Key1 flaw2 equivalent circle, flaw size = equivalent circle diameterFigure B.1 Optical micrograph of a ceramic and
48、 the determination of equivalent circle diameter of a flaw6 ISO 2016 All rights reservedBS ISO 18550:2016ISO 18550:2016(E)10010-110-210-310-310 100 1000YXy = ax-ba = 6.355 X 1012b = 7.959ba = 6,355 1012b = 7,9591010Y23KeyX flaw equivalent circle diameter/mY population of flaw/mm3m1Figure B.2 Size di
49、stribution of macro-heterogeneities in an alumina ceramicExamples of other macro-heterogeneities are shown in Figures B.3 and B.4 for a silicon nitride ceramic and a zirconia ceramic, respectively.Figure B.3 Macro-heterogeneities in a silicon nitride ceramic (100 m thick) ISO 2016 All rights reserved 7BS ISO 18550:2016ISO 18550:2016(E)Figure B.4 Macro-heterogeneities in a zirconia ceramic (100 m thick)8 ISO 2016 All rights reservedBS ISO 18550
