SIST EN ISO 21968:2005
(Main)Non-magnetic metallic coatings on metallic and non-metallic basis materials - Measurement of coating thickness - Phase-sensitive eddy-current method (ISO 21968:2005)
Non-magnetic metallic coatings on metallic and non-metallic basis materials - Measurement of coating thickness - Phase-sensitive eddy-current method (ISO 21968:2005)
ISO 21968:2005 describes a method of using phase-sensitive eddy-current instruments for non-destructive measurements of the thickness of non-magnetic metallic coatings on metallic and non-metallic basis materials such as zinc, cadmium, copper, tin or chromium on steel, as well as copper or silver on composite materials.
The phase-sensitive method can be applied without thickness errors to smaller surface areas and to stronger surface curvatures than the amplitude-sensitive eddy-current method described in ISO 2360, and is less affected by the magnetic properties of the basis material. However, the phase-sensitive method is more affected by the electrical properties of the coating materials.
Nichtmagnetische metallische Überzüge auf metallischen und nichtmetallischen Grundwerkstoffen - Messung der Schichtdicke - Phasensensitives Wirbelstromverfahren (ISO 21968:2005)
Revetements métalliques non magnétiques sur des matériaux de base métalliques et non métalliques - Mesurage de l'épaisseur de revetement - Méthode par courants de Foucault sensible aux variations de phase (ISO 21968:2005)
L'ISO 21968:2005 décrit une méthode utilisant des instruments fonctionnant par courants de Foucault sensible aux variations de phase pour le mesurage non destructif de l'épaisseur des revêtements métalliques non magnétiques sur des matériaux de base métalliques et non métalliques, tels que le zinc, le cadmium, le cuivre, l'étain ou le chrome sur de l'acier, ainsi que le cuivre ou l'argent sur des matériaux composites.
La méthode sensible aux variations de phase peut être appliquée sans erreur d'épaisseur à des surfaces planes plus petites et à des surfaces courbes plus accentuées que la méthode par courants de Foucault sensible aux variations d'amplitude, décrite dans l'ISO 2360, et est moins affectée par les propriétés magnétiques du matériau de base. Toutefois, la méthode sensible aux variations de phase est davantage affectée par les propriétés électriques des matériaux de revêtement.
Nemagnetne kovinske prevleke na kovinskih in nekovinskih osnovnih materialih – Merjenje debeline nanosa prevleke – Metoda vrtinčnih tokov (ISO 21968:2005)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 21968:2005
01-oktober-2005
1HPDJQHWQHNRYLQVNHSUHYOHNHQDNRYLQVNLKLQQHNRYLQVNLKRVQRYQLKPDWHULDOLK±
0HUMHQMHGHEHOLQHQDQRVDSUHYOHNH±0HWRGDYUWLQþQLKWRNRY ,62
Non-magnetic metallic coatings on metallic and non-metallic basis materials -
Measurement of coating thickness - Phase-sensitive eddy-current method (ISO
21968:2005)
Nichtmagnetische metallische Überzüge auf metallischen und nichtmetallischen
Grundwerkstoffen - Messung der Schichtdicke - Phasensensitives Wirbelstromverfahren
(ISO 21968:2005)
Revetements métalliques non magnétiques sur des matériaux de base métalliques et
non métalliques - Mesurage de l'épaisseur de revetement - Méthode par courants de
Foucault sensible aux variations de phase (ISO 21968:2005)
Ta slovenski standard je istoveten z: EN ISO 21968:2005
ICS:
25.220.40 Kovinske prevleke Metallic coatings
SIST EN ISO 21968:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 21968:2005
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SIST EN ISO 21968:2005
EUROPEAN STANDARD
EN ISO 21968
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2005
ICS 25.220.40
English Version
Non-magnetic metallic coatings on metallic and non-metallic
basis materials - Measurement of coating thickness - Phase-
sensitive eddy-current method (ISO 21968:2005)
Revêtements métalliques non magnétiques sur des Nichtmagnetische metallische Überzüge auf metallischen
matériaux de base métalliques et non métalliques - und nichtmetallischen Grundwerkstoffen - Messung der
Mesurage de l'épaisseur de revêtement - Méthode par Schichtdicke - Phasensensitives Wirbelstromverfahren
courants de Foucault sensible aux variations de phase (ISO (ISO 21968:2005)
21968:2005)
This European Standard was approved by CEN on 22 June 2005.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
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Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21968:2005: E
worldwide for CEN national Members.
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SIST EN ISO 21968:2005
EN ISO 21968:2005 (E)
Foreword
This document (EN ISO 21968:2005) has been prepared by Technical Committee ISO/TC 107
"Metallic and other inorganic coatings" in collaboration with 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 January 2006, and conflicting national
standards shall be withdrawn at the latest by January 2006.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 21968:2005 has been approved by CEN as EN ISO 21968:2005 without any
modifications.
2
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SIST EN ISO 21968:2005
INTERNATIONAL ISO
STANDARD 21968
First edition
2005-07-15
Non-magnetic metallic coatings on
metallic and non-metallic basis
materials — Measurement of coating
thickness — Phase-sensitive eddy-
current method
Revêtements métalliques non magnétiques sur des matériaux de base
métalliques et non métalliques — Mesurage de l'épaisseur de
revêtement — Méthode par courants de Foucault sensible aux
variations de phase
Reference number
ISO 21968:2005(E)
©
ISO 2005
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SIST EN ISO 21968:2005
ISO 21968:2005(E)
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ii © ISO 2005 – All rights reserved
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SIST EN ISO 21968:2005
ISO 21968:2005(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Principle. 1
3 Equipment . 2
4 Sampling. 2
5 Factors affecting measurement accuracy.2
5.1 Coating thickness. 2
5.2 Electrical properties of the basis materials . 2
5.3 Electrical properties of the coating materials. 2
5.4 Basis-metal thickness . 2
5.5 Edge effects. 3
5.6 Surface curvature . 3
5.7 Surface roughness . 3
5.8 Lift-off effect. 3
5.9 Probe pressure. 4
5.10 Probe tilt . 4
5.11 Temperature effects. 4
5.12 Intermediate coatings. 4
6 Procedure . 4
6.1 Calibration of instruments . 4
6.2 Determination. 5
7 Expression of results . 6
8 Measurement uncertainty . 6
9 Test report . 6
Annex A (informative) Eddy-current generation in a metallic conductor. 8
Annex B (normative) Test for edge effect. 10
Bibliography . 12
© ISO 2005 – All rights reserved iii
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SIST EN ISO 21968:2005
ISO 21968:2005(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 21968 was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings,
Subcommittee SC 2, Test methods.
iv © ISO 2005 – All rights reserved
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SIST EN ISO 21968:2005
INTERNATIONAL STANDARD ISO 21968:2005(E)
Non-magnetic metallic coatings on metallic and non-metallic
basis materials — Measurement of coating thickness —
Phase-sensitive eddy-current method
1 Scope
This International Standard describes a method of using phase-sensitive eddy-current instruments for non-
destructive measurements of the thickness of non-magnetic metallic coatings on metallic and non-metallic
basis materials, such as:
a) zinc, cadmium, copper, tin or chromium on steel;
b) copper or silver on composite materials.
The phase-sensitive method can be applied without thickness errors to smaller surface areas and to stronger
[1]
surface curvatures than the amplitude-sensitive eddy-current method described in ISO 2360 , and is less
affected by the magnetic properties of the basis material. However, the phase-sensitive method is more
affected by the electrical properties of the coating materials.
When measuring metallic coatings on metallic basis materials, the product of conductivity and permeability
(σ, µ) of one of the materials should be at least a factor of 1,5 times the product of conductivity and
permeability for the other material. Non-ferromagnetic materials have a relative permeability of 1.
2 Principle
An eddy-current probe (or integrated probe/instrument) is placed on (or near) the surface of the coating(s) to
be measured, and the thickness is read from the instrument's readout.
For each instrument, there is a maximum measurable thickness of the coating.
Since this thickness range depends on both the applied frequency of the probe system and the electrical
properties of the coating, the maximum thickness should be determined experimentally, unless otherwise
specified by the manufacturer.
An explanation of eddy-current generation and the calculation of the maximum measurable coating thickness,
d , is given in Annex A.
max
However, in the absence of any other information, the maximum measurable coating thickness, d , can be
max
estimated using Equation (1):
(1)
d = 0,8δ
max 0
where δ is the standard penetration depth of the coating material [see Equation (A.1)].
0
© ISO 2005 – All rights reserved 1
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SIST EN ISO 21968:2005
ISO 21968:2005(E)
3 Equipment
3.1 Probe, containing an eddy-current generator, and a detector linked to a system capable of measuring
and displaying changes in amplitude and phase, normally as a direct readout of coating thickness.
NOTE 1 The probe and measuring system/display may be integrated into a single instrument.
NOTE 2 Factors affecting measurement accuracy are discussed in Clause 5.
4 Sampling
Sampling depends on the specific application and coating to be tested; the area, location and number of test
specimens shall be agreed between interested parties and shall be included in the test report (see Clause 9).
5 Factors affecting measurement accuracy
5.1 Coating thickness
A measurement uncertainty is inherent in the method. For thin coatings, this measurement uncertainty (in
absolute terms) is constant, independent of the coating thickness. The absolute value of the uncertainty
depends on the applied frequency of the probe system, and also on the conductivity and permeability of the
used sample materials. With increasing thickness within the measurement range of the probe system, this
uncertainty becomes a function of the thickness and is approximately a constant fraction of that thickness.
The mean of several measurements should be used as the thickness value to reduce the uncertainty,
especially in the lower part of the measurement range of the used probe system.
5.2 Electrical properties of the basis materials
Both conductivity and permeability have some effect on the measurement, but these effects are small when
[1]
compared to those with the amplitude method described in ISO 2360 .
5.3 Electrical properties of the coating materials
Coating thickness measurements are affected by the electrical conductivity of the coating material, which in
turn can be dependent upon composition, the coating process (additives, contaminants, etc.) and any
post-coating treatments, such as heating or mechanical working.
5.4 Basis-metal thickness
For each instrument, there is a critical minimum basis-metal thickness above which measurements will not be
affected by an increase in thickness.
This thickness depends on both the applied frequency of the probe system and the electrical and magnetic
properties of the basis material. Its value should be determined experimentally, unless otherwise specified by
the manufacturer.
An explanation of eddy-current generation and the calculation of the minimum basis-material thickness, d ,
min
is given in Annex A.
However, in the absence of any other information, the required minimum thickness of basis material, d , can
min
be calculated from Equation (2):
d = 2,5δ (2)
min 0
where δ is the standard penetration depth of the metallic basis material [see Equation (A.1)].
0
2 © ISO 2005 – All rights reserved
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SIST EN ISO 21968:2005
ISO 21968:2005(E)
5.5 Edge effects
Eddy-current instruments can be sensitive to abrupt changes in surface contour of the test specimen.
...
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