SIST EN ISO 16866:2023
(Main)Metallic and other inorganic coatings - Simultaneous thickness and electrode potential determination of individual layers in multilayer nickel deposits (STEP test) (ISO 16866:2020)
Metallic and other inorganic coatings - Simultaneous thickness and electrode potential determination of individual layers in multilayer nickel deposits (STEP test) (ISO 16866:2020)
This document specifies a method for measuring the thickness of the individual nickel layers in electroplated multilayer nickel coatings and measuring the potential differences between the individual nickel layers in electroplated multilayer nickel coatings.
The measurement of coatings or layer systems other than electroplated multilayer nickel coatings is outside the scope of this document.
Metallische und andere anorganische Überzüge - Schichtpotentialmessung von galvanischen Mehrfach-Nickelschichtsystemen (STEP-Test) (ISO 16866:2020)
Revêtements métalliques et autres revêtements inorganiques - Détermination simultanée de l'épaisseur et du potentiel d'électrode de couches individuelles dans des dépôts de nickel multicouches (essai STEP) (ISO 16866:2020)
Le présent document spécifie une méthode de mesurage de l’épaisseur des couches de nickel individuelles dans des revêtements électrolytiques de nickel multicouches et des différences de potentiel entre ces couches.
Le mesurage des revêtements ou des systèmes de couches autres que les revêtements électrolytiques de nickel multicouches est hors du domaine d’application du présent document.
Kovinske in druge anorganske prevleke - Istočasno določevanje debeline in potenciala elektrode posameznih plasti v večplastnih nikljevih depozitih (preskus STEP) (ISO 16866:2020)
Ta dokument določa metodo za merjenje debeline posameznih plasti niklja v galvaniziranih večplastnih nikljevih prevlekah in merjenje potencialnih razlik med posameznimi plastmi niklja v galvaniziranih večplastnih nikljevih prevlekah.
Merjenje prevlek ali sistemov slojev, razen galvaniziranih večslojnih prevlek iz niklja, je zunaj področja uporabe tega dokumenta.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 16866:2023
01-januar-2023
Nadomešča:
SIST EN 16866:2018
Kovinske in druge anorganske prevleke - Istočasno določevanje debeline in
potenciala elektrode posameznih plasti v večplastnih nikljevih depozitih (preskus
STEP) (ISO 16866:2020)Metallic and other inorganic coatings - Simultaneous thickness and electrode potential
determination of individual layers in multilayer nickel deposits (STEP test) (ISO
16866:2020)Metallische und andere anorganische Überzüge - Schichtpotentialmessung von
galvanischen Mehrfach-Nickelschichtsystemen (STEP-Test) (ISO 16866:2020)
Revêtements métalliques et autres revêtements inorganiques - Détermination
simultanée de l'épaisseur et du potentiel d'électrode de couches individuelles dans des
dépôts de nickel multicouches (essai STEP) (ISO 16866:2020)Ta slovenski standard je istoveten z: EN ISO 16866:2022
ICS:
25.220.40 Kovinske prevleke Metallic coatings
SIST EN ISO 16866:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------SIST EN ISO 16866:2023
---------------------- Page: 2 ----------------------
SIST EN ISO 16866:2023
EN ISO 16866
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2022
EUROPÄISCHE NORM
ICS 25.220.40 Supersedes EN 16866:2017
English Version
Metallic and other inorganic coatings - Simultaneous
thickness and electrode potential determination of
individual layers in multilayer nickel deposits (STEP test)
(ISO 16866:2020)
Revêtements métalliques et autres revêtements Metallische und andere anorganische Überzüge -
inorganiques - Détermination simultanée de Schichtpotentialmessung von galvanischen Mehrfach-
l'épaisseur et du potentiel d'électrode de couches Nickelschichtsystemen (STEP-Test) (ISO 16866:2020)
individuelles dans des dépôts de nickel multicouches(essai STEP) (ISO 16866:2020)
This European Standard was approved by CEN on 30 October 2022.
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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16866:2022 E
worldwide for CEN national Members.---------------------- Page: 3 ----------------------
SIST EN ISO 16866:2023
EN ISO 16866:2022 (E)
Contents Page
European foreword ....................................................................................................................................................... 3
---------------------- Page: 4 ----------------------SIST EN ISO 16866:2023
EN ISO 16866:2022 (E)
European foreword
The text of ISO 16866:2020 has been prepared by Technical Committee ISO/TC 107 "Metallic and other
inorganic coatings” of the International Organization for Standardization (ISO) and has been taken over
as EN ISO 16866:2022 by Technical Committee CEN/TC 262 “Metallic and other inorganic coatings,
including for corrosion protection and corrosion testing of metals and alloys” 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 May 2023, and conflicting national standards shall be
withdrawn at the latest by May 2023.Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 16866:2017.Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.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,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.Endorsement notice
The text of ISO 16866:2020 has been approved by CEN as EN ISO 16866:2022 without any modification.
---------------------- Page: 5 ----------------------SIST EN ISO 16866:2023
---------------------- Page: 6 ----------------------
SIST EN ISO 16866:2023
INTERNATIONAL ISO
STANDARD 16866
First edition
2020-10
Metallic and other inorganic
coatings — Simultaneous thickness
and electrode potential determination
of individual layers in multilayer
nickel deposits (STEP test)
Revêtements métalliques et autres revêtements inorganiques —
Détermination simultanée de l'épaisseur et du potentiel d'électrode
de couches individuelles dans des dépôts de nickel multicouches
(essai STEP)
Reference number
ISO 16866:2020(E)
ISO 2020
---------------------- Page: 7 ----------------------
SIST EN ISO 16866:2023
ISO 16866:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 be requested from either ISO at the address
below or ISO’s member body in the country of the requester.ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 16866:2023
ISO 16866:2020(E)
Contents Page
Foreword ........................................................................................................................................................................................................................................iv
Introduction ..................................................................................................................................................................................................................................v
1 Scope ................................................................................................................................................................................................................................. 1
2 Normative references ...................................................................................................................................................................................... 1
3 Terms and definitions ..................................................................................................................................................................................... 1
4 Test equipment....................................................................................................................................................................................................... 1
4.1 Construction of the measuring cell........................................................................................................................................ 1
4.2 Composition of the test solution .............................................................................................................................................. 2
5 Requirements .......................................................................................................................................................................................................... 3
6 Sampling ........................................................................................................................................................................................................................ 3
7 Factors influencing measurement accuracy ............................................................................................................................ 3
7.1 Electrolyte ................................................................................................................................................................................................... 3
7.2 Conditioning .............................................................................................................................................................................................. 3
7.3 Ni deposits .................................................................................................................................................................................................. 3
7.4 Surface cleanliness .............................................................................................................................................................................. 3
7.5 Measurement area and contact pressure ......................................................................................................................... 3
7.6 Electrical contact ................................................................................................................................................................................... 4
7.7 Complete dissolution ......................................................................................................................................................................... 4
8 Procedure..................................................................................................................................................................................................................... 4
8.1 General ........................................................................................................................................................................................................... 4
8.2 Measurement ............................................................................................................................................................................................ 4
8.3 Evaluation .................................................................................................................................................................................................... 5
9 Measurement uncertainty .......................................................................................................................................................................... 8
10 Test report ................................................................................................................................................................................................................... 9
Annex A (informative) Precision data obtained by a round robin test ..........................................................................10
Bibliography .............................................................................................................................................................................................................................11
© ISO 2020 – All rights reserved iii---------------------- Page: 9 ----------------------
SIST EN ISO 16866:2023
ISO 16866:2020(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.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 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 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 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 of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.This document was prepared by the European Committee for Standardization (CEN) (as EN 16866:2017)
and was adopted, without modification, by Technical Committee ISO/TC 107, Metallic and other inorganic
coatings.Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.iv © ISO 2020 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 16866:2023
ISO 16866:2020(E)
Introduction
The abbreviated term “STEP” represents “Simultaneous Thickness and Electrode Potential
determination”.The STEP test can be used to measure, in one single operating step, the parameters (thickness of the
individual nickel layers and the potential differences among them) relevant for the course of corrosion
in a multilayer nickel system. Provided suitable instruments are applied, it can also be used to
document them.The test is a modification of the well-known coulometric method for the measurement of the coating
thickness. This method takes advantage of the fact that, following the anodic dissolution of a nickel
coating, a potential jump takes place of which the magnitude can be measured against a reference
electrode.Although, nowadays, the STEP test has been incorporated into a number of company standards,
particularly in the automobile industry, there are currently no uniform and generally acknowledged
potential difference values available. At present, values between 80 mV and 150 mV are assumed for
double nickel layers, with the semi-bright nickel layer always being nobler than the bright one.
Likewise, no obligatory numerical values are available, currently, regarding the potential difference
between bright nickel layers and existing special nickel layers (e.g. in the case of micro-porous
chromium plating). According to the current practical experience, the potential difference is larger
than approximately 20 mV, with the bright nickel layer always having to be less noble than the special
nickel layer.© ISO 2020 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 16866:2023
---------------------- Page: 12 ----------------------
SIST EN ISO 16866:2023
INTERNATIONAL STANDARD ISO 16866:2020(E)
Metallic and other inorganic coatings — Simultaneous
thickness and electrode potential determination of
individual layers in multilayer nickel deposits (STEP test)
1 Scope
This document specifies a method for measuring the thickness of the individual nickel layers in
electroplated multilayer nickel coatings and measuring the potential differences between the individual
nickel layers in electroplated multilayer nickel coatings.The measurement of coatings or layer systems other than electroplated multilayer nickel coatings is
outside the scope of this document.2 Normative references
The following documents are 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 2177, Metallic coatings — Measurement of coating thickness — Coulometric method by anodic
dissolutionISO 3696, Water for analytical laboratory use — Specification and test methods
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp— IEC Electropedia: available at http:// www .electropedia .org/
4 Test equipment
4.1 Construction of the measuring cell
Figure 1 shows two examples of the typical schematic construction of a measuring cell used for the
simultaneous determination of layer thicknesses and potential differences in multilayer nickel systems.
The cells differ with regard to the implementation of the reference electrode. In Figure 1 a), the
reference electrode is a silver wire coated with silver chloride and positioned at the edge of the cell; in
Figure 1 b), it is a silver ring coated with silver chloride and positioned at the bottom of the cell. With
regard to measurement uncertainty, both variants provide the same result for the measurement of the
potential difference and (following calibration) the measurement of the layer thickness, independent of
the concrete implementation of the reference electrode.NOTE 1 The silver ring used as the reference electrode in Figure 1 b) is of advantage insofar as the adjustment
of the silver wire, which would otherwise be required, becomes unnecessary, leading to results that are more
exact and more reproducible.NOTE 2 The circulated volume of electrolyte solution is typically around 0,1 ml per s.
© ISO 2020 – All rights reserved 1---------------------- Page: 13 ----------------------
SIST EN ISO 16866:2023
ISO 16866:2020(E)
a) Measuring cell with silver wire, coated b) Measuring cell with silver ring, coated
with AgCl, used as t...
SLOVENSKI STANDARD
oSIST prEN ISO 16866:2022
01-september-2022
Kovinske in druge anorganske prevleke - Istočasno določevanje debeline in
potenciala elektrode posameznih plasti v večplastnih nikljevih depozitih (preskus
STEP) (ISO 16866:2020)Metallic and other inorganic coatings - Simultaneous thickness and electrode potential
determination of individual layers in multilayer nickel deposits (STEP test) (ISO
16866:2020)Metallische und andere anorganische Überzüge - Schichtpotentialmessung von
galvanischen Mehrfach-Nickelschichtsystemen (STEP-Test) (ISO 16866:2020)
Revêtements métalliques et autres revêtements inorganiques - Détermination
simultanée de l'épaisseur et du potentiel d'électrode de couches individuelles dans des
dépôts de nickel multicouches (essai STEP) (ISO 16866:2020)Ta slovenski standard je istoveten z: prEN ISO 16866
ICS:
25.220.40 Kovinske prevleke Metallic coatings
oSIST prEN ISO 16866:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------oSIST prEN ISO 16866:2022
---------------------- Page: 2 ----------------------
oSIST prEN ISO 16866:2022
INTERNATIONAL ISO
STANDARD 16866
First edition
2020-10
Metallic and other inorganic
coatings — Simultaneous thickness
and electrode potential determination
of individual layers in multilayer
nickel deposits (STEP test)
Revêtements métalliques et autres revêtements inorganiques —
Détermination simultanée de l'épaisseur et du potentiel d'électrode
de couches individuelles dans des dépôts de nickel multicouches
(essai STEP)
Reference number
ISO 16866:2020(E)
ISO 2020
---------------------- Page: 3 ----------------------
oSIST prEN ISO 16866:2022
ISO 16866:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 be requested from either ISO at the address
below or ISO’s member body in the country of the requester.ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 16866:2022
ISO 16866:2020(E)
Contents Page
Foreword ........................................................................................................................................................................................................................................iv
Introduction ..................................................................................................................................................................................................................................v
1 Scope ................................................................................................................................................................................................................................. 1
2 Normative references ...................................................................................................................................................................................... 1
3 Terms and definitions ..................................................................................................................................................................................... 1
4 Test equipment....................................................................................................................................................................................................... 1
4.1 Construction of the measuring cell........................................................................................................................................ 1
4.2 Composition of the test solution .............................................................................................................................................. 2
5 Requirements .......................................................................................................................................................................................................... 3
6 Sampling ........................................................................................................................................................................................................................ 3
7 Factors influencing measurement accuracy ............................................................................................................................ 3
7.1 Electrolyte ................................................................................................................................................................................................... 3
7.2 Conditioning .............................................................................................................................................................................................. 3
7.3 Ni deposits .................................................................................................................................................................................................. 3
7.4 Surface cleanliness .............................................................................................................................................................................. 3
7.5 Measurement area and contact pressure ......................................................................................................................... 3
7.6 Electrical contact ................................................................................................................................................................................... 4
7.7 Complete dissolution ......................................................................................................................................................................... 4
8 Procedure..................................................................................................................................................................................................................... 4
8.1 General ........................................................................................................................................................................................................... 4
8.2 Measurement ............................................................................................................................................................................................ 4
8.3 Evaluation .................................................................................................................................................................................................... 5
9 Measurement uncertainty .......................................................................................................................................................................... 8
10 Test report ................................................................................................................................................................................................................... 9
Annex A (informative) Precision data obtained by a round robin test ..........................................................................10
Bibliography .............................................................................................................................................................................................................................11
© ISO 2020 – All rights reserved iii---------------------- Page: 5 ----------------------
oSIST prEN ISO 16866:2022
ISO 16866:2020(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.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 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 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 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 of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.This document was prepared by the European Committee for Standardization (CEN) (as EN 16866:2017)
and was adopted, without modification, by Technical Committee ISO/TC 107, Metallic and other inorganic
coatings.Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.iv © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 16866:2022
ISO 16866:2020(E)
Introduction
The abbreviated term “STEP” represents “Simultaneous Thickness and Electrode Potential
determination”.The STEP test can be used to measure, in one single operating step, the parameters (thickness of the
individual nickel layers and the potential differences among them) relevant for the course of corrosion
in a multilayer nickel system. Provided suitable instruments are applied, it can also be used to
document them.The test is a modification of the well-known coulometric method for the measurement of the coating
thickness. This method takes advantage of the fact that, following the anodic dissolution of a nickel
coating, a potential jump takes place of which the magnitude can be measured against a reference
electrode.Although, nowadays, the STEP test has been incorporated into a number of company standards,
particularly in the automobile industry, there are currently no uniform and generally acknowledged
potential difference values available. At present, values between 80 mV and 150 mV are assumed for
double nickel layers, with the semi-bright nickel layer always being nobler than the bright one.
Likewise, no obligatory numerical values are available, currently, regarding the potential difference
between bright nickel layers and existing special nickel layers (e.g. in the case of micro-porous
chromium plating). According to the current practical experience, the potential difference is larger
than approximately 20 mV, with the bright nickel layer always having to be less noble than the special
nickel layer.© ISO 2020 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST prEN ISO 16866:2022
---------------------- Page: 8 ----------------------
oSIST prEN ISO 16866:2022
INTERNATIONAL STANDARD ISO 16866:2020(E)
Metallic and other inorganic coatings — Simultaneous
thickness and electrode potential determination of
individual layers in multilayer nickel deposits (STEP test)
1 Scope
This document specifies a method for measuring the thickness of the individual nickel layers in
electroplated multilayer nickel coatings and measuring the potential differences between the individual
nickel layers in electroplated multilayer nickel coatings.The measurement of coatings or layer systems other than electroplated multilayer nickel coatings is
outside the scope of this document.2 Normative references
The following documents are 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 2177, Metallic coatings — Measurement of coating thickness — Coulometric method by anodic
dissolutionISO 3696, Water for analytical laboratory use — Specification and test methods
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp— IEC Electropedia: available at http:// www .electropedia .org/
4 Test equipment
4.1 Construction of the measuring cell
Figure 1 shows two examples of the typical schematic construction of a measuring cell used for the
simultaneous determination of layer thicknesses and potential differences in multilayer nickel systems.
The cells differ with regard to the implementation of the reference electrode. In Figure 1 a), the
reference electrode is a silver wire coated with silver chloride and positioned at the edge of the cell; in
Figure 1 b), it is a silver ring coated with silver chloride and positioned at the bottom of the cell. With
regard to measurement uncertainty, both variants provide the same result for the measurement of the
potential difference and (following calibration) the measurement of the layer thickness, independent of
the concrete implementation of the reference electrode.NOTE 1 The silver ring used as the reference electrode in Figure 1 b) is of advantage insofar as the adjustment
of the silver wire, which would otherwise be required, becomes unnecessary, leading to results that are more
exact and more reproducible.NOTE 2 The circulated volume of electrolyte solution is typically around 0,1 ml per s.
© ISO 2020 – All rights reserved 1---------------------- Page: 9 ----------------------
oSIST prEN ISO 16866:2022
ISO 16866:2020(E)
a) Measuring cell with silver wire, coated b) Measuring cell with silver ring, coated
with AgCl, used as the reference electrode with AgCl in the electrolyte-wetted area,
used as the reference electrodeKey
1 pump
2 measuring instrument (with constant-current source and voltmeter)
3 reference electrode
4 electrode surface wetted with electrolyte
5 dissolving electrolyte
6 counter electrode (cathode)
7 gasket
8 working electrode (anode, measurement object with nickel layer system)
Figure 1 — Typical schematic constructions of the measuring cell
4.2 Composition of the test solution
Nickel(II)-chloride hexahydrate (NiCl ⋅ 6 H O) 300 g/l
2 2
Sodium chloride (NaCl) 50 g/l
Boric acid (H BO ) 25 g/l
3 3
pH value 3,0
Water of grade 3 in accordance with ISO 3696.
2 © ISO 2020 – All rights reserved
---------------------- Page: 10 ----------------------
oSIST prEN ISO 16866:2022
ISO 16866:2020(E)
The pH value should be complied with as closely as possible. If required, it is adjusted by means of
diluted hydrochloric acid or sodium hydroxide solution.5 Requirements
The geometry of the parts to be tested shall be such that the measuring cell can be attached to the
surface in a liquid-tight way, at the respective points to be measured.Prior to this, the surface to be measured shall be appropriately de-chromed and activated (e.g. in a
1:1 dilution of chemically pure, concentrated hydrochloric acid). When selecting the de-chroming
and activating procedures, it shall be ensured that the nickel coating is not visibly damaged by these
procedures.6 Sampling
Sampling from the ongoing production of parts should be performed in accordance with ISO 2859-1 and
ISO 2859-2. The tolerable margin of error is specified by the client.7 Factors influencing measurement accuracy
7.1 Electrolyte
Each measurement shall be carried out using a fresh electrolyte. Used electrolytes can result in falsified
measurement results.7.2 Conditioning
New reference electrodes or ones which have not been in use for an extended period of time shall be
conditioned (creation of a silver chloride layer at the electrode surface) prior to use. The lack of or
inadequate conditioning results in falsified or atypical courses of measurement that cannot be correctly
interpreted. Any conditioning and potentially required cleaning are carried out in accordance with the
...
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