SIST EN ISO 17475:2008
(Main)Corrosion of metals and alloys - Electrochemical test methods - Guidelines for conducting potentiostatic and potentiodynamic polarization measurements (ISO 17475:2005)
Corrosion of metals and alloys - Electrochemical test methods - Guidelines for conducting potentiostatic and potentiodynamic polarization measurements (ISO 17475:2005)
This International Standard applies to corrosion of metals and alloys, and describes the procedure for conducting potentiostatic and potentiodynamic polarization measurements.
The test method can be used to characterise the electrochemical kinetics of anodic and cathodic reactions, he onset of localised corrosion and the repassivation behaviour of a metal.
Korrosion von Metallen und Legierungen - Elektrochemische Prüfverfahren - Leitfaden für die Durchführung potentiostatischer und potentiodynamischer Polarisationsmessungen (ISO 17475:2005/Cor 1:2006)
Diese Internationale Norm gilt für die Korrosion von Metallen und Legierungen, und sie beschreibt Verfahren
zu potentiostatischen und potentiodynamischen Polarisationsmessungen.
Die Verfahren können angewendet werden, um die elektrochemische Kinetik bei anodischen und
kathodischen Reaktionen, den Beginn örtlicher Korrosion und das Repassivierungsverhalten eines Metalls zu
beschreiben.
Corrosion des métaux et alliages - Méthodes d'essais électrochimiques - Lignes directrices pour la réalisation de mesures de polarisations potentiostatique et potentiodynamique (ISO 17475:2005)
L'ISO 17475:2005 s'applique à la corrosion des métaux et des alliages, et décrit le mode opératoire qui permet de réaliser des mesures de polarisations potentiostatique et potentiodynamique.
Cette méthode d'essai peut être utilisée pour caractériser la cinétique électrochimique des réactions anodiques et cathodiques, l'amorçage d'une corrosion localisée et le comportement du métal à la repassivation.
Korozija kovin in zlitin - Elektrokemijske preskusne metode - Smernice za izvajanje potenciostatičnih in potenciodinamičnih meritev polarizacije (ISO 17475:2005)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 17475:2008
01-julij-2008
.RUR]LMDNRYLQLQ]OLWLQ(OHNWURNHPLMVNHSUHVNXVQHPHWRGH6PHUQLFH]D
L]YDMDQMHSRWHQFLRVWDWLþQLKLQSRWHQFLRGLQDPLþQLKPHULWHYSRODUL]DFLMH ,62
Corrosion of metals and alloys - Electrochemical test methods - Guidelines for
conducting potentiostatic and potentiodynamic polarization measurements (ISO
17475:2005)
Corrosion des métaux et alliages - Méthodes d'essais électrochimiques - Lignes
directrices pour la réalisation de mesures de polarisations potentiostatique et
potentiodynamique (ISO 17475:2005)
Ta slovenski standard je istoveten z: EN ISO 17475:2008
ICS:
77.060 Korozija kovin Corrosion of metals
SIST EN ISO 17475:2008 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
EUROPEAN STANDARD
EN ISO 17475
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2008
ICS 77.060
English Version
Corrosion of metals and alloys - Electrochemical test methods -
Guidelines for conducting potentiostatic and potentiodynamic
polarization measurements (ISO 17475:2005/Cor 1:2006)
Corrosion des métaux et alliages - Méthodes d'essais Korrosion von Metallen und Legierungen -
électrochimiques - Lignes directrices pour la réalisation de Elektrochemische Prüfverfahren - Leitfaden für die
mesures de polarisations potentiostatique et Durchführung potentiostatischer und potentiodynamischer
potentiodynamique (ISO 17475:2005/Cor 1:2006) Polarisationsmessungen (ISO 17475:2005/Cor 1:2006)
This European Standard was approved by CEN on 21 March 2008.
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 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 Management Centre has the same status as the
official versions.
CEN members 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, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17475:2008: E
worldwide for CEN national Members.
---------------------- Page: 2 ----------------------
EN ISO 17475:2008 (E)
Contents Page
Foreword.3
2
---------------------- Page: 3 ----------------------
EN ISO 17475:2008 (E)
Foreword
The text of ISO 17475:2005/Cor 1:2006 has been prepared by Technical Committee ISO/TC 156 “Corrosion
of metals and alloys” of the International Organization for Standardization (ISO) and has been taken over as
EN ISO 17475:2008 by Technical Committee CEN/TC 262 “Metallic and other inorganic coatings” the
secretariat of which is held by BSI.
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 October 2008, and conflicting national standards shall be withdrawn at
the latest by October 2008.
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 organizations of the following
countries are bound to implement 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 and the United Kingdom.
Endorsement notice
The text of ISO 17475:2005/Cor 1:2006 has been approved by CEN as a EN ISO 17475:2008 without any
modification.
3
---------------------- Page: 4 ----------------------
INTERNATIONAL ISO
STANDARD 17475
First edition
2005-10-01
Corrosion of metals and alloys —
Electrochemical test methods —
Guidelines for conducting potentiostatic
and potentiodynamic polarization
measurements
Corrosion des métaux et alliages — Méthodes d'essais
électrochimiques — Lignes directrices pour la réalisation de mesures de
polarisations potentiostatique et potentiodynamique
Reference number
ISO 17475:2005(E)
©
ISO 2005
---------------------- Page: 5 ----------------------
ISO 17475:2005(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2005
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
Web www.iso.org
Published in Switzerland
ii © ISO 2005 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 17475:2005(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Principle. 1
4 Apparatus . 4
5 Procedure . 7
6 Test report . 9
Annex A (informative) Method of preventing a crevice attack for certain applications. 10
Annex B (informative) Potential of selected reference electrodes at 25 °C with respect to the
standard hydrogen electrode (SHE) . 12
Bibliography . 13
© ISO 2005 – All rights reserved iii
---------------------- Page: 7 ----------------------
ISO 17475:2005(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 17475 was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys, in
collaboration with the Korea Research Institute of Standards and Science.
iv © ISO 2005 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 17475:2005(E)
Introduction
Corrosion of metals and alloys in aqueous solutions is generally caused by an electrochemical mechanism.
Therefore, one can measure or analyse corrosion phenomena, utilizing a variety of electrochemical
[1] [2]
techniques. This International Standard, based on ASTM G5 and ASTM G150 , defines basic guidelines
for potentiostatic potentiodynamic polarization measurements to characterize an electrochemical kinetics of
anodic and cathodic reactions.
© ISO 2005 – All rights reserved v
---------------------- Page: 9 ----------------------
INTERNATIONAL STANDARD ISO 17475:2005(E)
Corrosion of metals and alloys — Electrochemical test
methods — Guidelines for conducting potentiostatic
and potentiodynamic polarization measurements
1 Scope
This International Standard applies to corrosion of metals and alloys, and describes the procedure for
conducting potentiostatic and potentiodynamic polarization measurements.
The test method can be used to characterise the electrochemical kinetics of anodic and cathodic reactions,
the onset of localised corrosion and the repassivation behaviour of a metal.
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 8044:1999, Corrosion of metals and alloys — Basic terms and definitions
ISO 8407:1991, Corrosion of metals and alloys — Removal of corrosion products from corrosion test
specimens
ISO 9400:1990, Nickel-based alloys — Determination of resistance to intergranular corrosion
ISO 11463:1995, Corrosion of metals and alloys — Evaluation of pitting corrosion
ISO 11846:1995, Corrosion of metals and alloys — Determination of resistance to intergranular corrosion of
solution heat-treatable aluminium alloys
3 Principle
3.1 When a metal is immersed in a solution, the rate of the anodic reaction and that of the cathodic reaction
will be in balance at the open-circuit potential (free corrosion potential, E ). If the electrode potential is
cor
displaced from the open-circuit value, the applied current measured will represent the difference between the
anodic-reaction current and the cathodic-reaction current. If the displacement of potential is sufficiently large,
the net current will be essentially equal to the anodic or cathodic-reaction kinetics, depending on whether the
potential is made respectively more positive or more negative with respect to the open-circuit value as shown
for a metal in the active state in acid solutions [Figure 1 a)] and in neutral aerated solutions [Figure 1 b)].
3.2 In certain metal-environment combinations, the metal may be in the passive state (Figure 2). If an
aggressive anion is present and the potential is increased (made more positive) with respect to the open-
circuit potential, localised breakdown of passivity (e.g. pitting, crevice corrosion, intergranular attack) can
result with an attendant increase in the applied current (Figure 2). The potential corresponding to the increase
in current can be used as a measure of the resistance of a metal to localised corrosion.
© ISO 2005 – All rights reserved 1
---------------------- Page: 10 ----------------------
ISO 17475:2005(E)
a) Corrosion rate is under diffusion control
b) Example by diffusion of oxygen in water
Key
X potential
Y log current density
1 cathodic
2 anodic
E corrosion potential
cor
i corrosion current density
cor
E reversible electrode potential
r
i exchange current density
o
i limiting diffusion current density, which corresponds to the maximum diffusion rate of oxygen in the solution
d
Figure 1 — Schematic anodic and cathodic polarization curves for metals corroding
in a system where the cathodic reaction is reduction of protons
2 © ISO 2005 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 17475:2005(E)
a) Metals with active-passive transition
b) Metals without active-passive transition
Key
X potential
Y log current density
E corrosion potential
cor
i corrosion current density
cor
E passivation potential
pp
i critical current density for passivation
crit
i passive current density
p
E flade potential
f
E breakdown potential
b
E secondary passivation potential
sp
a
Active.
b
Passive.
c
Transpassive.
Figure 2 — Schematic anodic polarization curves
© ISO 2005 – All rights reserved 3
---------------------- Page: 12 ----------------------
ISO 17475:2005(E)
3.3 If the potential is subsequently decreased after the onset of localised corrosion, the potential at which
repassivation occurs (when the applied current returns to approximately the same value as the passive
current) can be considered to be indicative of the resistance of the metal to propagation of localised corrosion;
the more noble the potential, the greater the resistance.
3.4 The displacement in potential can be stepwise, with the magnitude of the potential step and the time at
a specific potential selected according to the application and purpose of the experiment. This type of testing is
known as potentiostatic.
3.5 When the potential is displaced in a continuous mode at a controlled scan (displacement) rate, the test
is described as potentiodynamic.
3.6 The kinetics of the electrochemical processes occurring on the surface can be time dependent, for
example due to film formation, and hence the time that the potential is held at a specific potential in
potentiostatic testing or the potential scan rate in potentiodynamic testing can be critical. For example, too
high a rate of change may lead to overestimation of the breakdown potential for localised attack. For this
reason, the interpretation of polarization data shall be considered carefully, particularly when applied to
service conditions.
3.7 The measurement of the electrode potential can be influenced by ohmic drop in the solution. For
solutions of low conductivity, a correction shall be made.
4 Apparatus
4.1 Potentiostat
The potentiostat should be capable of controlling the electrode potential to within ± 1 mV of a preset value. A
scanning potentiostat is used for potentiodynamic measurements. For such measurements, the potentiostat
shall be capable of automatically scanning the potential at a constant rate between preset potentials.
4.2 Electrode potential-measuring instruments
11 14
The instrument should have a h
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.