EN ISO 13129:2012

SLOVENSKI STANDARD
01-april-2014
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Paints and varnishes - Electrochemical measurement of the protection provided to steel
by paint coatings - Current interrupter (CI) technique, relaxation voltammetry (RV)
technique and DC transient (DCT) measurements (ISO 13129:2012)
Beschichtungsstoffe - Elektrochemische Messung der Schutzwirkung von
Beschichtungen auf Stahl - Stromunterbrechungsverfahren (CI), Relaxationsvoltametrie
(RV) und Gleichstromtransientenmessung (DCT) (ISO 13129:2012)
Peintures et vernis - Mesurage électrochimique de la protection apportée à l'acier par
des revêtements de peinture - Technique du courant interrompu (CI), voltamétrie de
relaxation (VR) et mesurages de courants continus transitoires (CCT) (ISO 13129:2012)
Ta slovenski standard je istoveten z: EN ISO 13129:2012
ICS:
87.040 Barve in laki Paints and varnishes
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 13129
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2012
ICS 87.040
English Version
Paints and varnishes - Electrochemical measurement of the
protection provided to steel by paint coatings - Current
interrupter (CI) technique, relaxation voltammetry (RV)
technique and DC transient (DCT) measurements (ISO
13129:2012)
Peintures et vernis - Mesurage électrochimique de la Beschichtungsstoffe - Elektrochemische Messung der
protection apportée à l'acier par des revêtements de Schutzwirkung von Beschichtungen auf Stahl -
peinture - Technique du courant interrompu (CI), Stromunterbrechnugsverfahren (CI), Relaxationsvoltametrie
voltamétrie de relaxation (VR) ou mesurages de courants (RV) oder Gleichstromtransientenmessung (DCT) (ISO
continus transitoires (CCT) (ISO 13129:2012) 13129:2012)
This European Standard was approved by CEN on 1 September 2012.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of 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). 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, Cyprus, 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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13129:2012: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 13129:2012) 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 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 June 2013, and conflicting national standards shall be withdrawn at
the latest by June 2013.
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 for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following
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, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 13129:2012 has been approved by CEN as a EN ISO 13129:2012 without any modification.
INTERNATIONAL ISO
STANDARD 13129
First edition
2012-10-01
Paints and varnishes — Electrochemical
measurement of the protection provided
to steel by paint coatings — Current
interrupter (CI) technique, relaxation
voltammetry (RV) technique and DC
transient (DCT) measurements
Peintures et vernis — Mesurage électrochimique de la protection
apportée à l’acier par des revêtements de peinture — Technique du
courant interrompu (CI), voltamétrie de relaxation (VR) et mesurages de
courants continus transitoires (CCT)
Reference number
ISO 13129:2012(E)
©
ISO 2012
ISO 13129:2012(E)
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
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Published in Switzerland
ii © ISO 2012 – All rights reserved

ISO 13129:2012(E)
Contents Page
Foreword .iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Apparatus . 2
4.1 Faraday cage . 2
4.2 Cell for sample, including electrode holder . 2
4.3 Galvanostat . 3
4.4 Potentiostat . 3
4.5 Electrodes . 3
4.6 Electrolyte . 4
5 Specimens . 4
5.1 Preconditioning of specimens . 4
5.2 Environmental control . 4
5.3 Evaluation of specimens exposed to weathering in the laboratory and in the field . 4
5.4 Number of specimens and repeatability of results . 5
6 Experimental procedure . 5
6.1 General . 5
6.2 Current interrupter technique . 5
6.3 Relaxation voltammetry . 6
6.4 DC transient measurements . 7
7 Expression of results . 8
8 Precision . 8
9 Test report . 8
Annex A (normative) Description of the dummy cell .10
Annex B (informative) Further considerations concerning measurements on coatings .12
Annex C (informative) Examples of results .14
Bibliography .15
ISO 13129:2012(E)
Foreword
ISO (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 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
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/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 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 13129 was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 9,
General test methods for paints and varnishes.
iv © ISO 2012 – All rights reserved

ISO 13129:2012(E)
Introduction
Quantitative assessment of protection performance of organic coatings has been required in industry, for
example for evaluating the durability of organic coatings or judging the life of protective coatings. Electrochemical
methods can be used for these purposes. The current interrupter (CI) technique, relaxation voltammetry (RV)
and DC transient (DCT) measurements are simple techniques giving effective data which are comparable with
electrochemical impedance spectroscopy (EIS) in principle.
An advantage is that the principle is simple and time for one measurement is short.
INTERNATIONAL STANDARD ISO 13129:2012(E)
Paints and varnishes — Electrochemical measurement of
the protection provided to steel by paint coatings — Current
interrupter (CI) technique, relaxation voltammetry (RV)
technique and DC transient (DCT) measurements
1 Scope
This International Standard specifies the procedure for evaluation of the experimental set-up of electrochemical
measurements on high-impedance coated samples using methods that are based on the current interrupter
(CI) technique, relaxation voltammetry (RV) or DC transient (DCT) measurements.
It provides specific definitions and guidance on optimizing the collection of CI, RV and DCT data from high-
impedance systems. High impedance in the context of intact coatings refers to systems with an impedance
9 2
greater than 10 Ω/cm . This does not preclude measurements on systems with lower impedance. This
International Standard deals in particular with:
— instrumental set-up: requirements and shortcomings;
— data validation: checking the measurement range and the accuracy of the data;
— performing CI, RV, DCT measurements: specimen considerations and instrumental parameters;
— the experimental results: different methods of presenting CI, RV and DCT data.
Following the recommendations should ensure the acquisition of CI, RV and DCT data that can be used to study the
performance of the specimen. This International Standard does not give guidelines for the interpretation of the data.
2 Normative references
The following referenced documents are indispensable for the application 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, Paints and varnishes ― Electrochemical impedance spectroscopy (EIS) on high-impedance
coated specimens ― Part 1: Terms and definitions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16773-1 and the following apply.
3.1
excitation
application of a voltage, U , or current, I , to force the system into a new state
exc exc
3.2
current interrupter method
CI method
electrochemical technique which allows the relaxation potential of an electrochemical system to be recorded as a
function of time just after the excitation current is interrupted and the potential decay curve obtained to be analysed
ISO 13129:2012(E)
3.3
relaxation voltammetry
RV
electrochemical technique in which a potential is applied for a given excitation time and then the current is
interrupted and just the potential is monitored as a function of time
3.4
DC transient measurement
DCT measurement
electrochemical technique in which a coated sample is charged such that the potential is shifted and then the
sample is isolated and the potential is monitored against time while the potential returns to the open-circuit potential
3.5
potential/time decay curve
curve of potential, U(t), plotted over time, while potential is changing after a defined excitation is removed
3.6
sampling rate
number of data points per time interval
3.7
time constant
product of resistor and capacitor values used in equivalent circuits, which has the dimensions of time
4 Apparatus
4.1 Faraday cage
The Faraday cage shall be constructed of metal sheet which reduces electromagnetic interference to the
electrochemical cell (or circuit), and shall be connected to the instrument earth.
4.2 Cell for sample, including electrode holder
NOTE 1 Various types of measurement cell exist which are suitable for use with this International Standard. Most
commonly used are two-electrode and three-electrode arrangements for measurements in an aqueous electrolyte.
The cell should be constructed of materials that will not corrode, otherwise deteriorate or contaminate the
solution (e.g. PMMA, PTFE or glass). A material compatibility test should be carried out.
The cell shall be leak-proof to ensure that the geometrical surface of the specimen does not change with time.
The cell should preferably be designed to allow the following items to be inserted into the electrolyte chamber:
the working electrode, the reference electrode, the counter-electrode.
Sometimes a thermometer (for temperature control) and gas inlet/outlet tubes to modify the oxygen content of
the electrolyte are used. When using an inert gas, a gas scrubber should be used.
An example of an electrochemical cell is shown in Figure 1.
2 © ISO 2012 – All rights reserved

ISO 13129:2012(E)
Key
1 reference electrode
2 counter-electrode
3 electrolyte
4 O-ring
5 coating
6 working electrode
Figure 1 — Example of an electrochemical cell
The components shown in Figure 1 are described in ISO 16773-2.
NOTE 2 This drawing does not imply that other designs are unsuitable.
4.3 Galvanostat
Use a galvanostat which applies a current with a rectangular pulse waveform and has a fall time no less than
10 times faster than that of the time constant of the sample.
4.4 Potentiostat
The potentiostat controls the potential of the working electrode with respect to the reference electrode. The
potentiostat input impedance shall be high and the response time shall be fast.
4.5 Electrodes
4.5.1 Working electrode
Use as the working electrode a conductive substrate covered by the coating to be investigated. The exposed
area should be accurately known, constant with time, and adequate for the investigation. A large area makes
the measurement more sensitive for single defects (pores) and gives better signal-to-noise ratio.
4.5.2 Reference electrode
A low-impedance and low-noise reference electrode is recommended (a Luggin probe is not required). The
potential of the reference electrode should be checked periodically to verify the accuracy of the electrode and
its stability with time.
ISO 13129:2012(E)
4.5.3 Counter-electrode
Use an inert conductor such as platinum with preferably a large surface area oriented parallel to the working
electrode in order to ensure a homogeneous current distribution.
4.6 Electrolyte
The resistance of the solution should be low in comparison to the impedance of the system being investigated.
Different types of electrolyte may be used. Non-aggressive electrolytes can be employed to characterize the
properties of the system without introducing corrosion. An aggressive solution may be selected to characterize
the corrosion resistance of the system. The electrolyte should be chosen with the end use of the coating in mind.
5 Specimens
5.1 Preconditioning of specimens
Proper preparation and preconditioning of coated specimens is critical for successful and reliable experimental data.
5.2 Environmental control
The coating should be applied and cured in accordance with the manufacturer’s recommendations unless
otherwise agreed upon between the interested parties. The film thickness should be as uniform as possible.
The exact film thickness should be measured and reported (e.g. in accordance with ISO 2808). Temperature
and humidity control during the application, curing, conditioning and measurement of organic coatings is crucial
for a proper determination of the coating resistance.
The temperature of the specimens during measurements should be held constant to within ±2 °C, preferably
within ±1 °C, at 23 °C, if not otherwise specified. Relative values for comparison between specimens outside
these guidelines are acceptable if all the specimens are run under the same conditions. When the coating
capacitance is the main parameter of interest, control of relative humidity during specimen conditioning is very
important. To ensure reproducible conditioning, the humidity should be (50 ± 5) %, unless agreed otherwise.
For reliable measurements, temperature control should be equal to or better than ±1 °C. For conditioning
prior to measurement, an accuracy of ±2 °C is sufficient for most cases. Each specimen should be kept under
controlled conditions in order to prevent post-curing, degradation or any unintended irreversible modification
of the coating.
5.3 Evaluation of specimens exposed to weathering in the laboratory and in the field
Measurements may be used to further characterize coating degradation during a weathering test. Specimens
are measured after different elapsed times during the test and on completion of the test. Such weathering tests
can be salt spray exposure in accordance with ISO 9227, exposure in a humidity chamber in accordance with
ISO 6270-1, or cyclic tests. Other test methods are also used.
It might be advisable to use separate specimens at different elapsed times because a discontinuity in weathering
could influence the results. When the coated specimens are removed from the test chamber for measurement,
they typically go through a change in temperature and humidity. Some drying-out can occur if they are removed
for more than a few minutes. Further, the coating is exposed to an electrolyte in the electrochemical cell, which
can be different from the fluid in the test chamber. Therefore, special attention should be given to the precise
procedure and timing when changing, removing and replacing specimens for measurement. The procedural
details should be reported with the results.
If the measurement is done in an aggressive electrolyte (e.g. one containing an organic solvent), the exposure
of the coating to the electrolyte may be considered as an additional component of the weathering test. In the
case of cyclic weathering tests, measurements will depend upon the specific cycle the specimens are in. To
allow comparison of measurements to reveal trends and changes, sequential measurements should be taken
at the same time and in the same part of the cycle.
4 © ISO 2012 – All rights r
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