1、Electrochemical impedance spectroscopy (EIS) on coated and uncoated metallic specimensPart 4: Examples of spectra of polymer-coated and uncoated specimensBS EN ISO 16773-4:2017BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06National forewordThis British Standard is t
2、he UK implementation of EN ISO 16773-4:2017. It is identical to ISO 16773-4:2017. It supersedes BS EN ISO 16773-4:2009, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee STI/10, Test methods for paints.A list of organizations represented on this committe
3、e 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 its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017ISBN 978 0 580 79675 3ICS 87.040Comp
4、liance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2017.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN ISO 16773-4:2017EU
5、ROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 167734April 2017ICS 87.040 Supersedes EN ISO 16773-4:2009EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGCENCENELEC Management Centre: Avenue Marnix 17, B1000 Brussels 2017 CEN Ref. No. EN ISO 16773
6、-4:2017: EAll rights of exploitation in any form and by any means reserved worldwide for CEN national MembersElectrochemical impedance spectroscopy (EIS) on coated and uncoated metallic specimens - Part 4: Examples of spectra of polymer-coated and uncoated specimens (ISO 16773-4:2017)Spectroscopie d
7、impdance lectrochimique (SIE) sur des prouvettes mtalliques revtues et non revtues - Partie 4: Exemples de spectres dprouvettes revtues de polymres et non revtues (ISO 16773-4:2017)Elektrochemische Impedanzspektroskopie (EIS) an beschichteten und unbeschichteten metallischen Proben - Teil 4: Beispie
8、le fr Spektren von polymerbeschichteten und unbeschichteten Proben (ISO 16773-4:2017)This European Standard was approved by CEN on 20 February 2017.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of
9、 a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German).
10、 A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyp
11、rus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and U
12、nited Kingdom.English VersionEN ISO 167734:2017 (E)European forewordThis document (EN ISO 16773-4:2017) has been prepared by Technical Committee ISO/TC 35 “Paints and varnishes” in collaboration with Technical Committee CEN/TC 139 “Paints and varnishes” the secretariat of which is held by DIN.This E
13、uropean Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2017, and conflicting national standards shall be withdrawn at the latest by October 2017.Attention is drawn to the possibility that some of the e
14、lements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights.This document supersedes EN ISO 16773-4:2009.According to the CEN-CENELEC Internal Regulations, the national standards organizations of the fol
15、lowing countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,
16、 Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.Endorsement noticeThe text of ISO 16773-4:2017 has been approved by CEN as EN ISO 16773-4:2017 without any modification.iiBS EN ISO 16773-4:2017ISO 167734:2017(E)Foreword iv1 Sco
17、pe . 12 Normative references 13 Terms and definitions . 14 Theoretical background . 14.1 Basic considerations 14.2 Examples of models 24.2.1 Purely capacitive coating 24.2.2 Randles equivalent circuit . 34.2.3 Extended Randles equivalent circuit 3Annex A (informative) Examples 5Annex B (informative)
18、 Composition of concentrated artificial rain water 35Bibliography .36 ISO 2017 All rights reserved iiiContents PageBS EN ISO 16773-4:2017ISO 167734:2017(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The
19、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 been established has the right to be represented on that committee. International organizations, governmental and non-gover
20、nmental, in liaison with ISO, also take part in the work. ISO collaborates closely 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
21、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 accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the pos
22、sibility 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. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list
23、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 an endorsement.For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related t
24、o 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 following URL: www.iso.org/iso/foreword.html.This document was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subco
25、mmittee SC 9, General test methods for paints and varnishes in collaboration with ISO/TC 156, Corrosion of metals and alloys.This second edition cancels and replaces the first edition (ISO 16773-4:2009), which has been technically revised with the following changes.a) The introductory element of the
26、 title, Paints and varnishes, has been omitted, because the scope has been broadened to include metals and alloys. The main element of the title has been changed to Electrochemical impedance spectroscopy (EIS) on coated and uncoated metallic specimens.b) A reference to ISO/TR 16208 and ASTM G106 for
27、 examples of spectra for low-impedance systems (range from, e.g. 10 to 1 000 ) has been added.c) Examples for uncoated specimens have been added.A list of all parts in the ISO 16773 series can be found on the ISO website.iv ISO 2017 All rights reservedBS EN ISO 16773-4:2017Electrochemical impedance
28、spectroscopy (EIS) on coated and uncoated metallic specimens Part : Examples of spectra of polymercoated and uncoated specimens1 ScopeThis document gives some typical examples of impedance spectra of polymer-coated and uncoated specimens (see Annex A). Some guidance on interpretation of such spectra
29、 is also given. Further examples of spectra of low-impedance systems (range from, e.g. 10 to 1 000 ) are given in ISO/TR 16208 and in ASTM G106. ISO 16773-2 gives guidelines for optimizing the collection of EIS data with focus on high-impedance systems.2 Normative referencesThe following documents a
30、re referred to in the text in such a way that some or 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 16773-1, Electroche
31、mical impedance spectroscopy (EIS) on coated and uncoated metallic specimens Part 1: Terms and definitions3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 16773-1 apply.ISO and IEC maintain terminological databases for use in standardization at the fol
32、lowing addresses: IEC Electropedia: available at http:/www.electropedia.org/ ISO Online browsing platform: available at http:/www.iso.org/obp/4 Theoretical background4.1 Basic considerationsA basic introduction to electrochemical impedance spectroscopy, especially in connection with corrosion, is gi
33、ven in ASTM G106.It is not intended to limit the interpretation of EIS measurements to the models given below. Other interpretations may be valid. The choice of the proper model requires other experimental and theoretical considerations to be taken into account.INTERNATIONAL STANDARD ISO 167734:2017
34、(E) ISO 2017 All rights reserved 1BS EN ISO 16773-4:2017ISO 167734:2017(E)4.2 Examples of models4.2.1 Purely capacitive coatingA metal covered with an undamaged coating generally has a very high impedance. The equivalent circuit for such a situation is shown in Figure 1.Figure 1 Equivalent circuit f
35、or a purely capacitive coatingThe model includes a resistor representing the resistance Rs, of the solution and, connected in series with it, a capacitor representing the capacitance Cc, of the coating.In practice, the resistance of a perfect coating can often not be seen in the given frequency rang
36、e. Any deviation from the graph given in the Bode plot in Figure 2 indicates either a modified model or the input limits of the impedance device (see ISO 16773-2:2016, Annex A).KeyX1 frequency, f, in Hz X2 frequency, f, in HzY1 impedance, Z, in Y2 phase angle, , in degreesFigure 2 Bode plot for a pe
37、rfect coating2 ISO 2017 All rights reservedBS EN ISO 16773-4:2017ISO 167734:2017(E)4.2.2 Randles equivalent circuitThe Randles equivalent circuit includes the resistance of the solution Rs, the capacitance of the coating Ccand the ohmic resistance of the coating Rc, as shown in Figure 3.Figure 3 Ran
38、dles equivalent circuitThe Bode plot for a Randles equivalent circuit is shown in Figure 4.KeyX logf (f in Hz)Y1 log|Z| (Z in )Y2 | (degrees)1 impedance, Z2 phase angle, Figure 4 Bode plot for a Randles equivalent circuit4.2.3 Extended Randles equivalent circuitQuite often, fitting experimental data
39、 to the model shown in Figure 3 results in systematic errors. In such cases, the literature shows that it is possible to use the model shown in Figure 5 to obtain a better fit. ISO 2017 All rights reserved 3BS EN ISO 16773-4:2017ISO 167734:2017(E)Figure 5 Extended Randles equivalent circuitNOTE This
40、 model is not necessarily the most appropriate and other models are not excluded.In most cases of high-impedance coatings, RBand CBare the charge-transfer resistance Rctand double-layer capacitance Cdl, respectively, in the extended Randles circuit corresponding to properties of the coating rather t
41、han to corrosion processes in the underlying metal.The Bode plot shown in Figure 6 clearly shows the additional contribution of these two added elements. Again, the Bode plot does not go high enough in frequency to measure the solution resistance. In practice, this is not a problem because the solut
42、ion resistance is a property of the test solution and the test cell geometry and not a property of the coating.KeyX logf (f in Hz)Y1 log|Z| (Z in )Y2 | (degrees)1 impedance, Z2 phase angle, Figure 6 Bode plot for an extended Randles equivalent circuit4 ISO 2017 All rights reservedBS EN ISO 16773-4:2
43、017ISO 167734:2017(E)Annex A (informative) ExamplesA.1 GeneralThis annex contains a collection of spectra obtained from materials described briefly in the relevant clause. The examples were obtained from various laboratories using a range of different equipment and materials.This collection of spect
44、ra is not intended to imply that all the materials mentioned necessarily give spectra similar to those shown or that the spectra given here are free of experimental errors. The collection does not represent the complete range of coating materials.A.2 Example 1This example shows how a smaller than us
45、ual thickness of a high-build coating material can be used to investigate the influence of immersion time on EIS measurements (see Figure A.1).Details: Two-component epoxy coating, typically used for (maritime) steel constructions, above and below the water level. Airless spray application. Dry film
46、 thickness (DFT) recommended by the manufacturer: 1 000 m to 3 000 m.Measurements were performed on one coat on steel, DFT 200 m, on an area of 10 cm2at 21 C using concentrated artificial rainwater (see Annex B). A vertical three-electrode setup, with a saturated Ag/AgCl reference electrode, was use
47、d. Spectra were recorded after defined periods of immersion. ISO 2017 All rights reserved 5BS EN ISO 16773-4:2017ISO 167734:2017(E)KeyX frequency, f, in HzY1 modulus of the impedance, |Z|, in cm2Y2 modulus of the phase angle, |, in degreest = 0 ht = 2 ht = 24 ht = 168 ht = 504 hFigure A.1 Bode plot
48、for a highbuild coating material under immersion conditionsA.3 Example 2This example concerns a surface-tolerant coating material which does not require the same amount of surface pretreatment as that in Example 1 (see Figure A.2). Usually, de-rusting with mechanical tools is used rather than grit b
49、lasting.Details: Surface-tolerant two-component epoxy coating for (maritime) steel constructions, above and below the water level, can be applied on corroded steel, grit-blasted steel and old (undamaged) paint coatings. Application by airless spray, conventional spray, brushing or rolling. DFT recommended by the manufacturer: 100 m to 200 m.Measurements were performed on one coat on steel, DFT 250 m, on an area of 10 cm2at 21 C using concentrated artificial rainwater (see Annex B).
