1、BSI Standards PublicationBS ISO 27307:2015Thermal spraying Evaluationof adhesion/cohesion ofthermal sprayed ceramiccoatings by transverse scratchtestingBS ISO 27307:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 27307:2015.The UK participation in its prep
2、aration was entrusted to TechnicalCommittee STI/40, Thermal spraying and thermally sprayed coatings.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are respo
3、nsible for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 66562 2ICS 25.220.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards
4、Policy and Strategy Committee on 30 June 2015.Amendments issued since publicationDate Text affectedBS ISO 27307:2015 ISO 2015Thermal spraying Evaluation of adhesion/cohesion of thermal sprayed ceramic coatings by transverse scratch testingProjection thermique valuation des proprits dadhrence/cohsion
5、 des revtements cramiques appliqus par projection thermique, par essai de rayure transversaleINTERNATIONAL STANDARDISO27307First edition2015-06-15Reference numberISO 27307:2015(E)BS ISO 27307:2015ISO 27307:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in Swit
6、zerlandAll rights reserved. Unless otherwise specified, no part of this 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 re
7、quested from either ISO at the address below or ISOs member body in the 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 27307:2015ISO 27307:2015(E)Foreword ivIntroduc
8、tion v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Equipment and materials 26 Procedures of transverse scratch testing 26.1 General requirements for the testing specimen . 26.2 Environmental conditions . 26.3 Scratch testing on cross-section . 26.4 Evaluation of failu
9、re mode 37 Scratch testing report 4Annex A (informative) Typical coating failure modes after scratch testing 5Annex B (normative) Transverse scratch testing record. 6Annex C (informative) Round robin test results of transverse scratch testing for plasma sprayed ceramic coatings 7Bibliography .26 ISO
10、 2015 All rights reserved iiiContents PageBS ISO 27307:2015ISO 27307:2015(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 t
11、echnical committees. Each member 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 clos
12、ely with the International 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 n
13、eeded for the different types 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 paten
14、t rights. ISO shall not be 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 i
15、n this document is information 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 Barrie
16、rs to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 107, Metallic and other inorganic coatings.iv ISO 2015 All rights reservedBS ISO 27307:2015ISO 27307:2015(E)IntroductionThermal sprayed ceramic coatings have been widely
17、 applied in modifying surface properties of metal components. It is useful to prevent various types of wear, corrosion, and thermal damage, thereby extending components service life and reducing the need for expensive and repetitive maintenance. Droplet morphology, size and density of pores, inter/i
18、ntra-lamellar thermal cracks, and trapped inclusions are used to characterize the microstructure of thermal sprayed ceramic coatings. Although cracks are purposely introduced to the coating structures, for example, in thermal barrier coating for improvement of its thermal performance, the poor bondi
19、ng between splats and the imperfections in the form of pores or thermal cracks cause the mechanical properties of thermal sprayed ceramic coatings to be considerably less than those of the corresponding monolithic materials. Evidently, the durability and functionality of coatings is critically depen
20、dent on the adhesion between the coating and the underlying substrate as well as the cohesion among splats. So, the adhesion/cohesion strength is one of the most important properties for thermal sprayed coatings and needs to be evaluated systematically.To assist and promote the development of therma
21、l sprayed ceramic coatings, it is important that good test methods are available for evaluation of their adhesive and cohesive strength. This International Standard gives guidance conducting of transverse scratch testing which can provide this information. ISO 2015 All rights reserved vBS ISO 27307:
22、2015BS ISO 27307:2015Thermal spraying Evaluation of adhesion/cohesion of thermal sprayed ceramic coatings by transverse scratch testing1 ScopeThis International Standard specifies a method for adhesion and cohesion evaluation of thermal sprayed ceramic coating-substrate systems by means of a transve
23、rse scratch test. This International Standard is suitable for thermal sprayed ceramic coatings with thickness from 50 m to over 1 000 m. It is also suitable for testing ceramic coatings deposited by other spray coating processes, such as cold spray, as well as aerosol deposition.2 Normative referenc
24、esThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 20
25、502, Fine ceramics (advanced ceramics, advanced technical ceramics) Determination of adhesion of ceramic coatings by scratch testing3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1adhesionstate in which coatings and the underlying substrate are
26、held together by interfacial forces which may consist of valence forces or interlocking forces or both3.2cohesionstrength of bonding between structural elements in coatings4 PrincipleScratch testing involves drawing an indenter of known geometry across a coating-substrate system. In this test, the i
27、ndenter is of a known material, size, and geometry such as a Rockwell conical diamond indenter. Testing is performed over a given length under a constant load. If the coating is removed from the substrate, then the adhesion of the coating-substrate system can be evaluated and the adhesion level may
28、be ranked against similar coating-substrate system combinations. If the failure occurs only in the thermal sprayed ceramic coating, it reveals the cohesion of coatings itself. In the case of no observed failure, the test load may be increased until the coating failure occurs. The various coating fai
29、lure modes during scratch testing are shown in Annex A.During scratch testing, cracks can form as a result of the tensile stress induced behind indenter and these stresses could balance the compressive frictional stresses ahead. Crack formation can be detected by means of an acoustic emission (AE) s
30、ensor attached to the indenter holder of scratch testing machine. In addition, the tangential force between the indenter and test surface can be monitored to provide more information on the failure conditions. This tangential force, often incorrectly referred to as a frictional force, is the result
31、of both friction between the indenter and the test specimen and the ploughing force required to deform the coating-substrate system.INTERNATIONAL STANDARD ISO 27307:2015(E) ISO 2015 All rights reserved 1BS ISO 27307:2015ISO 27307:2015(E)5 Equipment and materialsA scratch testing machine is an instru
32、ment used to rigidly hold the indenter and to apply both the normal load and the driving force to produce scratches. In general, the displacement of a spring is used to achieve the chosen loading program. Magnetically driven assemblies are equally appropriate.The scratch testing machine consists of
33、a rigidly mounted diamond indenter, normally having Rockwell conical diamond geometry. In the present case, a diamond indenter with a 20 m tip radius is recommended. The scratch tester used shall have been calibrated in accordance with the procedures given in ISO 20502.6 Procedures of transverse scr
34、atch testing6.1 General requirements for the testing specimenThe specimen size for scratch testing varies as the sample holders of scratch testing machines differ. Generally, a specimen size of 20 20 mm2is recommended.After spraying, the coatings are sectioned perpendicular to the coating surface an
35、d embedded in a suitable material and then polished.Using standard metallographic procedures, the cross-section of the coatings shall be polished to Ra 100:1, ensuring that the substrate, coating and mounting medium are all in the field of view.Figure 1 Schematic of scratch testing on cross-section
36、of thermal sprayed ceramic coating/substrate system6.4 Evaluation of failure modeUsing the images taken after scratch testing, determine the percentage of each failure mode present. Typical failure modes of no crack, cohesive crack, and adhesive crack are illustrated in Annex A.Adhesive failure is i
37、ndicated by the presence of cracks generated at an interface between the coating and another part of the coating-substrate system (bond coat/substrate or top coat/bond coat), whereas cracks generated within the coating are indicative of cohesive failure. In the case of both types of failure being pr
38、esent in a sample group, a failure mode is regarded as valid if it constitutes more than 30 % of the observed failures.Example of failure mode analysis. ISO 2015 All rights reserved 3BS ISO 27307:2015ISO 27307:2015(E)Table 1 Example of evaluation of the failure modeCoatingaLoadNumber of scratchesNo
39、crack Cohesive crack Adhesive crackA 3 12 80 20 0A 5 12 75 25 0A 10 12 60 35 5A 13 12 45 40 15A 15 12 0 65 35A 20 12 0 20 80B 3 12 80 20 0B 5 12 55 33 12B 10 12 20 45 35B 13 12 10 40 50B 15 12 0 20 80B 20 12 0 0 100aFor coating A: coating strength = 10 N, adhesive strength = 15 N. For coating B: coa
40、ting strength = 5 N, adhesive strength = 10 N.7 Scratch testing reportThe scratch testing report shall include the following information:a) environmental conditions (temperature and relative humidity);b) coating and substrate thickness and materials;c) coating process used;d) indenter tip radius;e)
41、indenter traverses speed;f) test load;g) percentage of each failure mode.NOTE A model form for scratch testing record is presented in Annex B.4 ISO 2015 All rights reservedBS ISO 27307:2015ISO 27307:2015(E)Annex A (informative) Typical coating failure modes after scratch testinga) No crackb) Cohesiv
42、e crackc) Adhesive crackFigure A.1 Typical coating failure modes after scratch testing ISO 2015 All rights reserved 5BS ISO 27307:2015ISO 27307:2015(E)Annex B (normative) Transverse scratch testing recordDocument No.Temperature C Relative humidity %Substrate material Coating materialTest condition I
43、ndenter traverse speed mm/minScratch length mmTest resultsTest load No. Results Test load No. ResultsN 1 No crack/Cohesive/Adhesive N No crack/Cohesive/AdhesiveN 2 NN 3 NN 4 NN 5 NN NN NN NPercentage of each failure modeLoad (N)No crack (%)Cohesive crack (%)Adhesive crack (%)Load (N)No crack (%)Cohe
44、sive crack (%)Adhesive crack (%)DateInstituteOperator6 ISO 2015 All rights reservedBS ISO 27307:2015ISO 27307:2015(E)Annex C (informative) Round robin test results of transverse scratch testing for plasma sprayed ceramic coatingsThe round robin test has been done for a reference guide to evaluate ad
45、hesion/cohesion strength of plasma sprayed ceramic coatings among Korea, Japan, and Finland on the basis of ISO/TC 107 N 939 Resolution 17.Commercially available TiO2and yttria-stabilized zirconia (YSZ) powders were used to prepare thermal sprayed coatings. TiO2and YSZ coatings with 50 m of NiCr bon
46、d coat and 150 m of ceramic top coating were deposited on stainless steel substrates by commercial plasma spray system. Argon was used as a primary plasma gas and hydrogen was used as an auxiliary one.After spraying, test samples were prepared in a standard way of grinding and polishing, where the c
47、oatings were sectioned perpendicular to the coated surface. The scratch test was conducted on the cross-section of the spray coatings using different scratch test machine in three countries, Korea, Japan, and Finland, separately. The test conditions are listed in Table C.1.Table C.1 Test condition u
48、sed in the round robin testKorea Japan FinlandIndenter Conical diamond with 120 angle and 20 m 2,0 m tip radiusConical diamond with 120 angle and 20 m tip radiusConical diamond with 120 angle and 20 m 1,0 m tip radiusScratch mode Constant load Constant load Constant loadLoad tested3 N, 5 N, 10 N, 13
49、 N, 15 N, and 20 N3 N, 5 N, 10 N, 13 N, 15 N, and 20 N3 N, 5 N, 10 N, 13 N, 15 N, and 20 NScratch length 2 mm 2 mm 2 mmScratch speed 0,1 mm/s 0,1 mm/s 6,6 mm/sNo. of measurement 4 4 4 per specimenNo. of specimen 3 3 3 per applied loadRelative humidity 50 %Temperature 22 CFigures C.1 and C.2 show optical micrographs on the cross-section of plasma sprayed TiO2coatings scratched at a constant load of 3 N and 20 N, which was tested in Finland. From the results, 4 of no cracks and 6 of cohesive cracks wer
