1、BS EN1071-9:2009ICS 81.060.30NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDAdvanced technicalceramics Methodsof test for ceramiccoatingsPart 9: Determination of fracturestrainLicensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 01/12/2009 05:51, Uncontrolled
2、 Copy, (c) BSIThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 31 August2009 BSI 2009ISBN 978 0 580 63848 0Amendments/corrigenda issued since publicationDate CommentsBS EN 1071-9:2009National forewordThis British Standard is the UK implementation
3、of EN 1071-9:2009.The UK participation in its preparation was entrusted to TechnicalCommittee RPI/13, Advanced technical ceramics.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions
4、of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 01/12/2009 05:51, Uncontrolled Copy, (c) BSIBS EN 1071-9:2009EUROPEAN STANDARDNORME EUROPENNEEUROPIS
5、CHE NORMEN 1071-9July 2009ICS 81.060.30 Supersedes CEN/TS 1071-9:2004 English VersionAdvanced technical ceramics - Methods of test for ceramiccoatings - Part 9: Determination of fracture strainCramiques techniques avances - Mthodes dessai pourrevtements cramiques - Partie 9 : Dtermination de ladform
6、ation la ruptureHochleistungskeramik - Verfahren zur Prfung keramischerSchichten - Teil 9: Bestimmung der BruchdehnungThis European Standard was approved by CEN on 19 June 2009.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this Eu
7、ropeanStandard 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 CEN Management Centre or to any CEN member.This European Standard exists in three official versions (Englis
8、h, 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 CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyp
9、rus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT
10、 EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 1071-9:2009: ELicensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 01/
11、12/2009 05:51, Uncontrolled Copy, (c) BSIBS EN 1071-9:2009EN 1071-9:2009 (E) 2 Contents Page Foreword . 3 Introduction 5 1 Scope 6 2 Normative references . 6 3 Terms and definitions . 6 4 Significance and use 8 5 Principle . 8 6 Apparatus and materials 8 6.1 Instrumentation . 8 6.2 Specimen preparat
12、ion 9 7 Test procedure 11 7.1 Calibration . 11 7.2 Sample loading 11 7.3 Strain determination . 11 7.4 Crack detection . 11 7.5 Test parameters 12 8 Report . 12 Bibliography . 15 Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 01/12/2009 05:51, Uncontrolled Copy, (c) BSIBS EN 1071-9:2009EN 10
13、71-9:2009 (E) 3 Foreword This document (EN 1071-9:2009) has been prepared by Technical Committee CEN/TC 184 “Advanced technical ceramics”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or b
14、y endorsement, at the latest by January 2010, and conflicting national standards shall be withdrawn at the latest by January 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible fo
15、r identifying any or all such patent rights. This document supersedes CEN/TS 1071-9:2004. EN 1071 Advanced technical ceramics Methods of test for ceramic coatings consists of the following parts: Part 1: Determination of coating thickness by contact probe profilometer Part 2: Determination of coatin
16、g thickness by the crater grinding method Part 3: Determination of adhesion and other mechanical failure modes by a scratch test Part 4: Determination of chemical composition by electron probe microanalysis (EPMA) Part 5: Determination of porosity withdrawn Part 6: Determination of the abrasion resi
17、stance of coatings by a micro-abrasion wear test Part 7: Determination of hardness and Youngs modulus by instrumented indentation testing withdrawn Part 8: Rockwell indentation test for evaluation of adhesion Part 9: Determination of fracture strain Part 10: Determination of coating thickness by cro
18、ss sectioning Part 11: Determination of internal stress by the Stoney formula Part 12: Reciprocating wear test 1) Part 13: Determination of wear rate by the pin-on-disk method 1)Parts 7, 8 and 11 are Technical Specifications. Part 7 was withdrawn shortly after publication of EN ISO 14577-4:2007. 1)I
19、n preparation at the time of publication of this European Standard. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 01/12/2009 05:51, Uncontrolled Copy, (c) BSIBS EN 1071-9:2009EN 1071-9:2009 (E) 4 According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
20、following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia,
21、 Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 01/12/2009 05:51, Uncontrolled Copy, (c) BSIBS EN 1071-9:2009EN 1071-9:2009 (E) 5 Introduction The fracture strain of a coating is a critical factor often determining the performance
22、of a coated product. Clearly if stressed either directly or due to thermal effects (thermal expansion coefficient mismatch between the coating and substrate) coating cracking can occur if the critical fracture stress/strain is exceeded, and in many cases the effectiveness of the coating will be redu
23、ced. For example, corrosion resistant coatings lose their protective character if cracking occurs, and optical coatings become ineffective when cracked. In many cases cracking is the first stage of a much more serious form of failure in which large areas of the coating can spall. The extent to which
24、 coated components can withstand external applied loads is an important property in the application of any coated system, and usually it is necessary to know the failure stress. For calculation of the stress both the fracture strain and Youngs modulus of the coating should be known. EN ISO 14577-4 1
25、, which replaced Technical Specification CEN/TS 1071-7, can be used to measure the Youngs modulus by depth sensing indentation, but there are other methods involving flexure and impact excitation that may also be applied 2, 3. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 01/12/2009 05:51,
26、Uncontrolled Copy, (c) BSIBS EN 1071-9:2009EN 1071-9:2009 (E) 6 1 Scope This part of EN 1071 describes a method of measuring the fracture strain of ceramic coatings by means of uniaxial tension or compression tests coupled with acoustic emission to monitor the onset of cracking of the coating. Tensi
27、le or compressive strains can also be applied by flexure using four-point bending. Measurements can be made in favourable cases at elevated temperatures as well as at room temperature. 2 Normative references The following referenced documents are indispensable for the application of this document. F
28、or dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 10002-1, Metallic materials Tensile testing Part 1: Method of test at ambient temperature EN 10002-5, Metallic materials Tensile testing P
29、art 5: Method of testing at elevated temperature EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) ISO 12106, Metallic materials Fatigue testing Axial-strain-controlled method 3 Terms and definitions For the purposes of this docume
30、nt, the following terms and definitions apply. 3.1 fracture strain strain required to create a detectable crack in the coating NOTE The presence of the crack can be detected using optical or scanning electron microscopy, or indirectly using acoustic emission signals. 3.2 acoustic emission AE generat
31、ion of acoustic signals that are recorded as hits, counts, energy or amplitude NOTE See Figure 1 for definition of AE signals. 3.3 AE hit single acoustic event above a set threshold 3.4 AE energy area of the waveform of an AE hit 3.5 AE amplitude peak of the waveform of an AE hit Licensed Copy: Wang
32、 Bin, ISO/EXCHANGE CHINA STANDARDS, 01/12/2009 05:51, Uncontrolled Copy, (c) BSIBS EN 1071-9:2009EN 1071-9:2009 (E) 7 3.6 AE counts number of times the AE waveform passes a set threshold within a single hit 3.7 AE threshold arbitrary AE amplitude at which AE hits are deemed to be significant and abo
33、ve the AE signals generated by the test equipment 3.8 waveguide metallic wire connecting (usually by spot welding) the sample to the AE transducer 12478910563Key 1 Volts 6 Time 2 Rise time 7 Threshold crossing 3 Amplitude 8 Counts 4 Energy 9 Time 5 Threshold 10 Duration Figure 1 - Schematic represen
34、tation of AE signals Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 01/12/2009 05:51, Uncontrolled Copy, (c) BSIBS EN 1071-9:2009EN 1071-9:2009 (E) 8 4 Significance and use This test procedure covers the measurement of fracture strain in tension or compression in coatings subject to mechanic
35、al stress at ambient or elevated temperature. The method is applicable to cases where the substrate is sufficiently ductile such that fracture of the coating occurs before the substrate. In addition, if during plastic deformation of the substrate acoustic signals are generated, this may interfere wi
36、th those caused by coating fracture. Where possible it is recommended that a test be carried out with the uncoated substrate to determine whether such extraneous AE signals occur. 5 Principle Specimens of appropriate geometry are submitted to a mechanical stress; the subsequent strain is measured an
37、d the onset of coating failure is detected. The test draws upon the expertise of standard tensile and compressive tests but requires additional care due to the precision required of the measurements. The applied stress may be tensile or compressive and may be applied directly or in flexure. The test
38、 shall be carried out to satisfy the requirements of accepted standards for mechanical testing of materials under the selected method of loading. NOTE 1 Detection of the fracture of coatings can be carried in a number of ways. The most convenient is to use acoustic emission (AE), which allows contin
39、uous monitoring of the specimen. Acoustic signals are produced when a crack forms. These signals are captured using suitable detectors and the signals generated are then analysed. In many cases a waveguide is used to carry the signal from the specimen to the detector; this waveguide is normally a me
40、tallic material. Use of two AE detectors can help to eliminate extraneous signals coming from the loading mechanism. Commercially available AE systems can be used for this work. NOTE 2 Where AE cannot be used, crack detection is possible by high resolution video systems, which may allow continuous m
41、onitoring. Alternatively, optical or scanning electron microscopy can be used to examine the samples. Normally this is done post-test, but in situ examination is also possible. 6 Apparatus and materials 6.1 Instrumentation 6.1.1 In simplest terms the equipment required is a mechanism to apply load t
42、o the specimen; extensometry to measure the strain; and apparatus to detect/monitor fracture of the surface layer. Load is normally applied continuously through servo-electric testing machines; the load capacity of the frame should be sufficient to allow straining of the specimen to beyond the yield
43、 point of the substrate material. Continuation of the test to complete separation of the specimen is not normally required. 6.1.2 For flexural testing a suitable test jig is required four-point bending is recommended as this applies more uniform bending moment over the gauge length. A suitable jig i
44、s shown in Figure 2. 6.1.3 Extensometry should be sufficiently precise to measure strain at a resolution of 0,01%. 6.1.4 For tests at high temperatures using the uniaxial test configuration a furnace is required which allows access for attachment of load frame, extensometry, thermocouples and wavegu
45、ides to transmit the AE signals to the AE detector(s). For the four-point bend configuration, an oxidation resistant jig shall be used. NOTE Deformation of oxide layers formed on a metallic jig will probably contribute to AE signals during the test. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDA
46、RDS, 01/12/2009 05:51, Uncontrolled Copy, (c) BSIBS EN 1071-9:2009EN 1071-9:2009 (E) 9 6.1.5 Crack detection in the coating may be performed visually or by monitoring AE. Visual inspection requires suitable long focal length video facilities with a field of view containing the gauge length. At high
47、temperatures the availability of a cool path to the video camera is also required to avoid shimmer of the image. 1324Key 1 Load 2 Waveguides 3 Coating 4 AE detectors Figure 2 - Schematic diagram of a flexural jig with acoustic emission sensors 6.2 Specimen preparation 6.2.1 Standard specimens shall
48、be used as appropriate for the uniaxial or flexure test configurations; for uniaxial tensile tests the specimen shapes are defined in EN 10002-1, for compression tests in ISO 12106 and for flexure simple bar shaped samples of appropriate thickness can be used. The coating may be deposited on to the
49、sample after machining to the required shape, or in the case of flat specimens the test piece can be machined from the coated material. In the latter case, care shall be taken to avoid damage to the test region that may cause premature fracture. Generally the surface of the coating should not be ground or polished except where there is a requirement so to do. 6.2.2 The strain that is measured using this technique represents a summation of the inherent fracture strain of the surface layer and the residual strai
