EN ISO 16773-4-2009 en Paints and varnishes - Electrochemical impedance spectroscopy (EIS) on high-impedance coated specimens - Part 4 Examples of spectra of polymer-coated specime.pdf

1、BS EN ISO16773-4:2009ICS 87.040NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPaints and varnishes Electrochemicalimpedancespectroscopy (EIS) onhigh-impedance coatedspecimensPart 4: Examples of spectra of polymer-coated specimens (ISO 16773-4:2009)This British

2、Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2009. BSI 2009ISBN 978 0 580 63955 5Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 16773-4:2009National forewordThis British Standard is the UK implementation of EN ISO16773

3、-4:2009. The UK participation in its preparation was entrusted to TechnicalCommittee STI/10, Test methods for paints.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 provisionsof a contract

4、. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 16773-4May 2009ICS 87.040English VersionPaints and varnishes - Electrochemical impedance spectroscopy(EIS) on hig

5、h-impedance coated specimens - Part 4: Examplesof spectra of polymer-coated specimens (ISO 16773-4:2009)Peintures et vernis - Spectroscopie dimpdancelectrochimique (SIE) sur des prouvettes revtues dehaute impdance - Partie 4: Exemples de spectresdprouvettes revtues de polymres (ISO 16773-4:2009)Besc

6、hichtungsstoffe - ElektrochemischeImpedanzspektroskopie (EIS) von beschichteten Probenmit hoher Impedanz - Teil 4: Beispiele fr Spektren vonpolymerbeschichteten Proben (ISO 16773-4:2009)This European Standard was approved by CEN on 30 April 2009.CEN members are bound to comply with the CEN/CENELEC I

7、nternal Regulations which stipulate the conditions for giving this EuropeanStandard 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 me

8、mber.This European Standard exists in three official versions (English, 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

9、 are the national standards bodies of 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, Slovenia, Spain, Sweden, Switz

10、erland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT 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 ISO

11、 16773-4:2009: EBS EN ISO 16773-4:2009EN ISO 16773-4:2009 (E) 3 Foreword This document (EN ISO 16773-4:2009) 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.

12、This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2009, and conflicting national standards shall be withdrawn at the latest by November 2009. Attention is drawn to the possibility that some

13、 of the elements 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. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to imple

14、ment 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, Slovenia, Spain, Sweden, Switzerland

15、and the United Kingdom. Endorsement notice The text of ISO 16773-4:2009 has been approved by CEN as a EN ISO 16773-4:2009 without any modification. BS EN ISO 16773-4:2009ISO 16773-4:2009(E) ISO 2009 All rights reserved iiiContents Page Foreword iv 1 Scope 1 2 Theoretical background 1 Annex A (inform

16、ative) Examples .5 Annex B (informative) Composition of concentrated artificial rain water.17 Bibliography 18 BS EN ISO 16773-4:2009ISO 16773-4:2009(E) iv ISO 2009 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bod

17、ies (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 been established has the right to be represented on that committee. International organization

18、s, 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 standardization. International Standards are drafted in accordance with the rules given in the I

19、SO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the

20、 member bodies casting a vote. 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. ISO 16773-4 was prepared by Technical Committee ISO/TC 35, Paints and

21、varnishes, Subcommittee SC 9, General test methods for paints and varnishes. ISO 16773 consists of the following parts, under the general title Paints and varnishes Electrochemical impedance spectroscopy (EIS) on high-impedance coated specimens: Part 1: Terms and definitions Part 2: Collection of da

22、ta Part 3: Processing and analysis of data from dummy cells Part 4: Examples of spectra of polymer-coated specimens BS EN ISO 16773-4:2009INTERNATIONAL STANDARD ISO 16773-4:2009(E) ISO 2009 All rights reserved 1Paints and varnishes Electrochemical impedance spectroscopy (EIS) on high-impedance coate

23、d specimens Part 4: Examples of spectra of polymer-coated specimens 1 Scope This part of ISO 16773 gives some typical examples of impedance spectra of high-impedance coated metal samples. Some guidance on interpretation of such spectra is also given. 2 Theoretical background 2.1 Basic considerations

24、 A basic introduction to electrochemical impedance spectroscopy, especially in connection with corrosion, is given in ASTM G 106. 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

25、other experimental and theoretical considerations to be taken into account. 2.2 Examples of models 2.2.1 Purely capacitive coating A 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 circ

26、uit for a purely capacitive coating The model includes a resistor representing the resistance R of the solution and, connected in series with it, a capacitor representing the capacitance C of the coating. In practice, the resistance of a perfect coating can often not be seen in the given frequency r

27、ange. 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 Annex A of ISO 16773-2:2007). BS EN ISO 16773-4:2009ISO 16773-4:2009(E) 2 ISO 2009 All rights reservedKey X1frequency f, in Hz Y1impedance Z, in X2

28、frequency f, in Hz Y2phase angle , in degrees Figure 2 Bode plot for a perfect coating 2.2.2 Randles equivalent circuit The 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

29、 3 Randles equivalent circuit BS EN ISO 16773-4:2009ISO 16773-4:2009(E) ISO 2009 All rights reserved 3The Bode plot for a Randles equivalent circuit is shown in Figure 4. Key X logf (f in Hz) Y1log|Z| (Z in ) Y2| (degrees) 1 phase angle 2 impedance Z Figure 4 Bode plot for a Randles equivalent circu

30、it 2.2.3 Extended Randles equivalent circuit Quite often, fitting experimental data 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. Figure 5 Extended Randles equivalent cir

31、cuit NOTE This model is not necessarily the most appropriate and other models are not excluded. In the case of high-impedance coatings, the charge-transfer resistance Rctand double-layer capacitance Cdlin the extended Randles circuit correspond to properties of the coating rather than to corrosion p

32、rocesses 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 solution resistance is

33、 a property of the test solution and the test cell geometry, not a property of the coating. BS EN ISO 16773-4:2009ISO 16773-4:2009(E) 4 ISO 2009 All rights reservedKey X logf (f in Hz) Y1log|Z| (Z in ) Y2| (degrees) 1 phase angle 2 impedance Z Figure 6 Bode plot for an extended Randles equivalent ci

34、rcuit BS EN ISO 16773-4:2009ISO 16773-4:2009(E) ISO 2009 All rights reserved 5Annex A (informative) Examples A.1 General This 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

35、 different equipment and materials. This collection of spectra 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 mat

36、erials. BS EN ISO 16773-4:2009ISO 16773-4:2009(E) 6 ISO 2009 All rights reservedA.2 Example 1 This example shows how a smaller than usual thickness of a high-build coating material can be used to investigate the influence of immersion time on EIS measurements. Details: Two-component epoxy coating, t

37、ypically used for (maritime) steel constructions, above and below the water level. Airless spray application. DFT (dry film thickness) 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 arti

38、ficial rainwater (see Annex B). A vertical three-electrode set-up, with a saturated Ag/AgCl reference electrode, was used. Spectra were recorded after defined periods of immersion. Key X frequency f, in Hz Y1modulus of the impedance |Z|, in cm2Y2phase angle , in degrees t = 0 h t = 2 h t = 24 h t =

39、168 h t = 503 h Figure A.1 Bode plot for a high-build coating material under immersion conditions BS EN ISO 16773-4:2009ISO 16773-4:2009(E) ISO 2009 All rights reserved 7A.3 Example 2 This example concerns a surface-tolerant coating material which does not require the same amount of surface pretreat

40、ment as that in Example 1. Usually, derusting with mechanical tools is used rather than grit blasting. 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) p

41、aint 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). A vertical three-

42、electrode set-up, with a saturated Ag/AgCl reference electrode, was used. Spectra were recorded after defined periods of immersion. Key X frequency f, in Hz Y1modulus of the impedance |Z|, in cm2Y2phase angle , in degrees t = 0 h t = 2 h t = 24 h t = 168 h t = 502 h Figure A.2 Bode plot for a surfac

43、e-tolerant coating material under immersion conditions BS EN ISO 16773-4:2009ISO 16773-4:2009(E) 8 ISO 2009 All rights reservedA.4 Example 3 This example represents a high-build, solvent-free coating material with high abrasion resistance, applied as a single coat. Details: Solvent-free two-componen

44、t epoxy coating for grit-blasted metals, concrete and fibreglass in aggressive environments. High abrasion resistance and corrosion protection. Application by airless spray or brush. DFT recommended by the manufacturer: 500 m to 1 000 m as one coat. Measurements were performed on one coat on steel,

45、DFT 230 m, on an area of 10 cm2at 21 C using concentrated artificial rainwater (see Annex B). A vertical three-electrode set-up, with a saturated Ag/AgCl reference electrode, was used. Spectra were recorded after defined periods of immersion. Key X frequency f, in Hz Y1modulus of the impedance |Z|,

46、in cm2Y2phase angle , in degrees t = 0 h t = 2 h t = 24 h t = 168 h t = 505 h Figure A.3 Bode plot for a solvent-free coating material under immersion conditions BS EN ISO 16773-4:2009ISO 16773-4:2009(E) ISO 2009 All rights reserved 9A.5 Example 4 This example concerns a representative powder coatin

47、g applied by spray on aluminium. The quite large measurement area of 16,5 cm2allowed a three-electrode set-up to be used, but the open-circuit potential was not delivered with the spectra. The discontinuities in the phase-angle plot are due to potentiostat current range changes combined with the low

48、 capacitance of the system being examined, indicating incorrect setting of the measurement device. Details: Polyester powder coating material sprayed on chromatized aluminium frames as a single coat with a DFT of (93 3) m. No ageing. Measurements were performed at 25 C in 3 g/l Na2SO4solution on an

49、area of 16,5 cm2. A three-electrode set-up, with an Ag/AgCl reference electrode, in a vertical plastic tube was used. Key X frequency f, in Hz Y1modulus of the impedance |Z|, in cm2Y2phase angle , in degrees Figure A.4 Bode plot for a powder coating before ageing BS EN ISO 16773-4:2009ISO 16773-4:2009(E) 10 ISO 2009 All rights reservedThe spectra shown in Figure A.5 were obtained after ageing through eight thermal cycles, the coating remaining continuo