1、Thermal spraying Determination of interfacial toughness of ceramic coatings by indentationBS ISO 20267:2017BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06 ISO 2017Thermal spraying Determination of interfacial toughness of ceramic coatings by indentationProjection th
2、ermique Dtermination de la tnacit interfaciale des revtements cramiques par indentationINTERNATIONAL STANDARDISO20267First edition2017-05Reference numberISO 20267:2017(E)National forewordThis British Standard is the UK implementation of ISO 20267:2017.The UK participation in its preparation was entr
3、usted to Technical Committee STI/40, Thermal spraying and thermally sprayed coatings.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 it
4、s correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017ISBN 978 0 580 89347 6ICS 25.220.99Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and
5、 Strategy Committee on 30 June 2017.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS ISO 20267:2017 ISO 2017Thermal spraying Determination of interfacial toughness of ceramic coatings by indentationProjection thermique Dtermination de la tnacit interfaciale des revt
6、ements cramiques par indentationINTERNATIONAL STANDARDISO20267First edition2017-05Reference numberISO 20267:2017(E)BS ISO 20267:2017ISO 20267:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part
7、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 requested from either ISO at the address below or ISOs member body
8、 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 20267:2017ISO 20267:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in
9、SwitzerlandAll 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 b
10、e requested 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.orgISO 20267:2017(E)Foreword ivIntroduction v1 Scope
11、 . 12 Normative references 13 Terms and definitions . 14 Symbols and units . 15 Principle 36 Test pieces and sample preparation 36.1 Thicknesses of coating and substrate . 46.2 Sample size . 46.3 Sample cutting . 46.4 Mounting 46.5 Surface polishing . 47 Apparatus . 58 Procedure and conditions of te
12、sting 58.1 Indentation . 58.2 Indentation and crack length measurement . 59 Evaluation of indentation interfacial toughness . 79.1 Analysis 79.2 Test validity 710 Test report . 810.1 Items to be reported . 810.2 Other items to be reported . 9Bibliography .10 ISO 2017 All rights reserved iiiContents
13、PageBS ISO 20267:2017ISO 20267:2017(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 member body
14、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 Electrotech
15、nical 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 types of ISO
16、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 held r
17、esponsible 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 informatio
18、n given for the convenience of users and does not constitute an endorsement. For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO)
19、principles in the Technical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .html. This document was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings.iv ISO 2017 All rights reservedBS ISO 20267:2017ISO 20267:2017(E)ForewordISO (the Interna
20、tional 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 member body interested in a subject for which a technical committee has be
21、en 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 Electrotechnical Commission (IEC) on all matters of electrotechnical stan
22、dardization. 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 types of ISO documents should be noted. This document was drafted in accord
23、ance 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 held responsible for identifying any or all such patent rights. Deta
24、ils 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 information given for the convenience of users and does not constitute a
25、n endorsement. For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the fo
26、llowing URL: www .iso .org/ iso/ foreword .html. This document was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings.iv ISO 2017 All rights reserved ISO 20267:2017(E)IntroductionThe interfacial toughness of thermal spray ceramic coatings is required for two reasons:a)
27、 to understand quantitatively degradation of adhesion in service;b) for life assessment of the coated components.Adhesion strength of thermal spray coatings is usually measured in accordance with the tensile method specified by ISO 14916. However, there is a technical limitation in the application o
28、f ISO 14916. It requires preparation of a tensile adhesion test specimen using glue and, as such, coatings with higher adhesion strength than glue cannot be quantitatively evaluated. By virtue of its simplicity and practicality, an indentation method is a promising method to evaluate the adhesion of
29、 such coatings. In this method, a Vickers hardness tester is used. An interfacial toughness value is evaluated by measuring a length of the crack formed after pushing the indenter on the coating interface. The application of the method specified in this document can reduce uncertainty over the adhes
30、ion strength evaluation of coatings and makes it possible to evaluate the adhesion strength in a simpler way.The results can be expressed either as a stress intensity factor, in MNm-3/2, or as a fracture surface energy, in Jm-2.“Interfacial toughness” can have several meanings.a) Interfacial fractur
31、e toughness, KIc, in MNm-3/2, is a material constant that shows how easily the coating may be peeled away from a substrate.b) Energy release rate (or work done to fracture), G, is an alternative expression for interfacial fracture toughness, often obtained by converting K to G i.e. G = K2(1 - 2)/E,
32、where E is Youngs modulus and is Poissons ratio. G has units of Jm-2.For the purposes of developing the test method, the term indentation interfacial toughness, KIFC, is defined separately from interfacial fracture toughness, KIc. The indentation interfacial toughness is a value obtained by using Vi
33、ckers hardness tester, and is calculated from the total length of cracks induced along the interface by the indentation. Shorter crack lengths indicate that the coating has higher interfacial toughness or adhesion strength than other samples with longer cracks. There is no standard method to determi
34、ne such interfacial toughness for thermal spray ceramic coatings, and different organizations or groups currently use their own evaluation procedures.When measurements are carefully performed following the methods defined in this document, the evaluation of crack length, and thus interfacial toughne
35、ss, will not require much effort and can describe the adhesion characteristics of the system (substrate chemistry, pre-preparation/roughness of substrate surface, coating chemistry and properties). This document recommends good practice to minimize uncertainty in the measurement procedures. ISO 2017
36、 All rights reserved vBS ISO 20267:2017BS ISO 20267:2017Thermal spraying Determination of interfacial toughness of ceramic coatings by indentation1 ScopeThis document specifies a method for measuring the interfacial toughness of thermal spray ceramic coatings at room temperature based on an indentat
37、ion method. The interfacial toughness is calculated from the mean length of cracks emanating from the corners of the impression induced by a Vickers hardness tester, and it is intended for use with ceramic coatings with a single layer or multilayers. The test procedures proposed in this document are
38、 intended for use in an ambient environment.This document is recommended for thermal spray ceramic coatings such as thermal barrier coatings, wear resistant coatings and electrical insulating coatings.2 Normative referencesThe following documents are referred to in the text in such a way that some o
39、r all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 6507-1, Metallic materials Vickers hardness test Part 1: Test methodISO
40、 6507-2, Metallic materials Vickers hardness test Part 2: Verification and calibration of testing machines3 Terms and definitionsNo terms and definitions are listed in this document.ISO and IEC maintain terminological databases for use in standardization at the following addresses: ISO Online browsi
41、ng platform: available at h t t p :/ www .iso .org/ obp IEC Electropedia: available at h t t p :/ www .electropedia .org/ 4 Symbols and unitsFor the purposes of this document, the symbols and units given in Table 1 apply (see also Figures 1 and 2).Table 1 Symbols and designationsSymbol Designation U
42、nita diagonal half-length of impression parallel to interface mc mean value of half crack length: (c1+ c2)/2 mc1, c2individual crack lengths at corner of impression (lengths from crack tip to centre of impression, parallel with the macroscopic interface)mE1Youngs modulus of ceramic coating GNm2E2You
43、ngs modulus of substrate (or bond coat) GNm2F test force (indentation load) NH mean value of distance from centre of impression to the interface: (H1+ H2)/2 mmH1, H2individual distance from centre of impression to interface mmINTERNATIONAL STANDARD ISO 20267:2017(E) ISO 2017 All rights reserved 1BS
44、ISO 20267:2017ISO 20267:2017(E)Symbol Designation UnitKIFCindentation interfacial toughness MNm-3/2l sample length mmT mean value of distance between crack tip and interface: (T1+ T2)/2 mmT1, T2individual distance between crack tip and interface mmt ceramic coating thickness mmtssubstrate (including
45、 bond coat) thickness mmw sample width mm bimaterial constant - constant value: 0,081 -1Poissons ratio of ceramic coating -2Poissons ratio of substrate (or bond coat) -Key1 ceramic coating 5 visible crack2 substrate (or bond coat) 6 crack root3 interface 7 crack tip4 impressionFigure 1 Schematic dia
46、gram of indentation characteristicsTable 1 (continued)2 ISO 2017 All rights reservedBS ISO 20267:2017ISO 20267:2017(E)Symbol Designation UnitKIFCindentation interfacial toughness MNm-3/2l sample length mmT mean value of distance between crack tip and interface: (T1+ T2)/2 mmT1, T2individual distance
47、 between crack tip and interface mmt ceramic coating thickness mmtssubstrate (including bond coat) thickness mmw sample width mm bimaterial constant - constant value: 0,081 -1Poissons ratio of ceramic coating -2Poissons ratio of substrate (or bond coat) -Key1 ceramic coating 5 visible crack2 substra
48、te (or bond coat) 6 crack root3 interface 7 crack tip4 impressionFigure 1 Schematic diagram of indentation characteristicsTable 1 (continued)2 ISO 2017 All rights reserved ISO 20267:2017(E)21lwttsKey1 ceramic coating2 substrate (with bond coat)Figure 2 Sample geometry5 PrincipleWhen a pyramidal Vick
49、ers diamond indenter is indented at the interface of the thermal spray coatings (see Figure 3), an interfacial crack is generated from a corner of the impression. The interfacial toughness is proportional to the indentation load divided by the square root of half the crack length.F3412Key1 ceramic coating2 substrate (with bond coat)3 visible crack4 Vickers diamond indenterFigure 3 Interfacial indentation test6 Test pieces and sample preparationThe substrate surface shoul
